1
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Zhang M, Xu S, Sano Y. Deep carbon recycling viewed from global plate tectonics. Natl Sci Rev 2024; 11:nwae089. [PMID: 38933601 PMCID: PMC11203916 DOI: 10.1093/nsr/nwae089] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Revised: 03/01/2024] [Accepted: 03/05/2024] [Indexed: 06/28/2024] Open
Abstract
Plate tectonics plays an essential role in the redistribution of life-essential volatile elements between Earth's interior and surface, whereby our planet has been well tuned to maintain enduring habitability over much of its history. Here we present an overview of deep carbon recycling in the regime of modern plate tectonics, with a special focus on convergent plate margins for assessing global carbon mass balance. The up-to-date flux compilation implies an approximate balance between deep carbon outflux and subduction carbon influx within uncertainty but remarkably limited return of carbon to convecting mantle. If correct, carbon would gradually accumulate in the lithosphere over time by (i) massive subsurface carbon storage occurring primarily in continental lithosphere from convergent margins to continental interior and (ii) persistent surface carbon sinks to seafloors sustained by high-flux deep CO2 emissions to the atmosphere. Further assessment of global carbon mass balance requires updates on fluxes of subduction-driven carbon recycling paths and reduction in uncertainty of deep carbon outflux. From a global plate tectonics point of view, we particularly emphasize that continental reworking is an important mechanism for remobilizing geologically sequestered carbon in continental crust and sub-continental lithospheric mantle. In light of recent advances, future research is suggested to focus on a better understanding of the reservoirs, fluxes, mechanisms, and climatic effects of deep carbon recycling following an integrated methodology of observation, experiment, and numerical modeling, with the aim of decoding the self-regulating Earth system and its habitability from the deep carbon recycling perspective.
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Affiliation(s)
- Maoliang Zhang
- School of Earth System Science, Tianjin University, Tianjin 300072, China
| | - Sheng Xu
- School of Earth System Science, Tianjin University, Tianjin 300072, China
| | - Yuji Sano
- Marine Core Research Institute, Kochi University, Kochi 783-8502, Japan
- Atmosphere and Ocean Research Institute, The University of Tokyo, Chiba 277-8564, Japan
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2
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Wei GY, Li G. Atmospheric oxygenation as a potential trigger for climate cooling. Sci Bull (Beijing) 2024:S2095-9273(24)00340-2. [PMID: 38902175 DOI: 10.1016/j.scib.2024.05.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2024] [Revised: 04/26/2024] [Accepted: 04/28/2024] [Indexed: 06/22/2024]
Abstract
Secular changes in atmospheric CO2 and consequent global climate variations, are commonly attributed to global outgassing and the efficiency of silicate weathering, which may have been linked to mountain formation, land/arc distribution, and plant colonization through geological time. Although oxidative weathering has been shown to exert a significant role in the propagation of weathering fronts through the oxidation of Fe-bearing minerals, the influence of atmospheric O2 concentration (pO2) on silicate weathering, CO2 consumption, and global climate has not been thoroughly evaluated. This study presents a numerical model aimed at estimating the effects of pO2 on the climate, considering the influence of pO2 on the regolith thickness and thus weathering duration of granitic domains. Our model simulations reveal that an increase in weathering efficiency, through deeper penetration of the oxidative weathering front in the granitic regolith, would independently introduce a steady-state climate cooling of up to ∼8 °C, in step with one-order of magnitude rise in pO2. This temperature change may have repeatedly initiated the runaway ice-albedo feedback, leading to global glacial events (e.g., Neoproterozoic Snowball Earth). Increasing granitic weathering efficiency caused by a substantial pO2 increase may also have contributed to the development of icehouse climate during the Phanerozoic.
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Affiliation(s)
- Guang-Yi Wei
- School of Earth Sciences and Engineering, and Frontiers Science Center for Critical Earth Material Cycling, Nanjing University, Nanjing 210023, China
| | - Gaojun Li
- School of Earth Sciences and Engineering, and Frontiers Science Center for Critical Earth Material Cycling, Nanjing University, Nanjing 210023, China.
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3
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Wei GY, Zhao M, Sperling EA, Gaines RR, Kalderon-Asael B, Shen J, Li C, Zhang F, Li G, Zhou C, Cai C, Chen D, Xiao KQ, Jiang L, Ling HF, Planavsky NJ, Tarhan LG. Lithium isotopic constraints on the evolution of continental clay mineral factory and marine oxygenation in the earliest Paleozoic Era. SCIENCE ADVANCES 2024; 10:eadk2152. [PMID: 38552018 PMCID: PMC10980266 DOI: 10.1126/sciadv.adk2152] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/08/2023] [Accepted: 02/26/2024] [Indexed: 04/01/2024]
Abstract
The evolution of oxygen cycles on Earth's surface has been regulated by the balance between molecular oxygen production and consumption. The Neoproterozoic-Paleozoic transition likely marks the second rise in atmospheric and oceanic oxygen levels, widely attributed to enhanced burial of organic carbon. However, it remains disputed how marine organic carbon production and burial respond to global environmental changes and whether these feedbacks trigger global oxygenation during this interval. Here, we report a large lithium isotopic and elemental dataset from marine mudstones spanning the upper Neoproterozoic to middle Cambrian [~660 million years ago (Ma) to 500 Ma]. These data indicate a dramatic increase in continental clay formation after ~525 Ma, likely linked to secular changes in global climate and compositions of the continental crust. Using a global biogeochemical model, we suggest that intensified continental weathering and clay delivery to the oceans could have notably increased the burial efficiency of organic carbon and facilitated greater oxygen accumulation in the earliest Paleozoic oceans.
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Affiliation(s)
- Guang-Yi Wei
- School of Earth Sciences and Engineering, and Frontiers Science Center for Critical Earth Material Cycling, Nanjing University, Nanjing 210023, China
- Department of Earth and Planetary Sciences, Yale University, New Haven, CT 06520-8109, USA
| | - Mingyu Zhao
- Department of Earth and Planetary Sciences, Yale University, New Haven, CT 06520-8109, USA
- Key Laboratory of Cenozoic Geology and Environment, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, China
| | - Erik A. Sperling
- Department of Earth and Planetary Sciences, Stanford University, Stanford, CA 94305, USA
| | | | - Boriana Kalderon-Asael
- Department of Earth and Planetary Sciences, Yale University, New Haven, CT 06520-8109, USA
| | - Jun Shen
- State Key Laboratory of Geological Processes and Mineral Resources, China University of Geosciences, Wuhan 430074, China
| | - Chao Li
- State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation and Institute of Sedimentary Geology, Chengdu University of Technology, Chengdu 610059, China
- Key Laboratory of Deep-time Geography and Environment Reconstruction and Applications of Ministry of Natural Resources, Chengdu University of Technology, Chengdu 610059, China
- International Center for Sedimentary Geochemistry and Biogeochemistry Research, Chengdu University of Technology, Chengdu 610059, China
| | - Feifei Zhang
- School of Earth Sciences and Engineering, and Frontiers Science Center for Critical Earth Material Cycling, Nanjing University, Nanjing 210023, China
| | - Gaojun Li
- School of Earth Sciences and Engineering, and Frontiers Science Center for Critical Earth Material Cycling, Nanjing University, Nanjing 210023, China
| | - Chuanming Zhou
- State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology, and Center for Excellence in Life and Palaeoenvironment, Chinese Academy of Sciences, Nanjing 210008, China
| | - Chunfang Cai
- Key Laboratory of Cenozoic Geology and Environment, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, China
| | - Daizhao Chen
- Key Laboratory of Cenozoic Geology and Environment, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, China
| | - Ke-Qing Xiao
- State Key Lab of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Shuangqing Rd. 18, 10085, Beijing, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Lei Jiang
- Key Laboratory of Cenozoic Geology and Environment, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, China
| | - Hong-Fei Ling
- School of Earth Sciences and Engineering, and Frontiers Science Center for Critical Earth Material Cycling, Nanjing University, Nanjing 210023, China
| | - Noah J. Planavsky
- Department of Earth and Planetary Sciences, Yale University, New Haven, CT 06520-8109, USA
| | - Lidya G. Tarhan
- Department of Earth and Planetary Sciences, Yale University, New Haven, CT 06520-8109, USA
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4
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Fu M, Abbot DS, Koeberl C, Fedorov A. Impact-induced initiation of Snowball Earth: A model study. SCIENCE ADVANCES 2024; 10:eadk5489. [PMID: 38335287 PMCID: PMC10857373 DOI: 10.1126/sciadv.adk5489] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/28/2023] [Accepted: 01/10/2024] [Indexed: 02/12/2024]
Abstract
During the Neoproterozoic and Paleoproterozoic eras, geological evidence points to several "Snowball Earth" episodes when most of Earth's surface was covered in ice. These global-scale glaciations represent the most marked climate changes in Earth's history. We show that the impact winter following an asteroid impact comparable in size to the Chicxulub impact could have led to a runaway ice-albedo feedback and global glaciation. Using a state-of-the-art atmosphere-ocean climate model, we simulate the climate response following an impact for preindustrial, Last Glacial Maximum (LGM), Cretaceous-like, and Neoproterozoic climates. While warm ocean temperatures in the preindustrial and Cretaceous-like climates prevent Snowball initiation, the colder oceans of the LGM and cold Neoproterozoic climate scenarios rapidly form sea ice and demonstrate high sensitivity to the initial condition of the ocean. Given suggestions of a cold pre-Snowball climate, we argue the initiation of Snowball Earth by a large impact is a robust possible mechanism, as previously suggested by others, and conclude by discussing geologic tests.
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Affiliation(s)
- Minmin Fu
- Department of Earth and Planetary Sciences, Yale University, 210 Whitney Ave., New Haven, CT 06511, USA
| | - Dorian S. Abbot
- Department of Geophysical Sciences, University of Chicago, 5734 S Ellis Ave., Chicago, IL 60637, USA
| | - Christian Koeberl
- Department of Lithospheric Research, University of Vienna, Althanstrasse 14, 1090 Vienna, Austria
| | - Alexey Fedorov
- Department of Earth and Planetary Sciences, Yale University, 210 Whitney Ave., New Haven, CT 06511, USA
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5
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Boulila S, Peters SE, Müller RD, Haq BU, Hara N. Earth's interior dynamics drive marine fossil diversity cycles of tens of millions of years. Proc Natl Acad Sci U S A 2023; 120:e2221149120. [PMID: 37428908 PMCID: PMC10629558 DOI: 10.1073/pnas.2221149120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Accepted: 05/24/2023] [Indexed: 07/12/2023] Open
Abstract
The fossil record reveals that biotic diversity has fluctuated quasi-cyclically through geological time. However, the causal mechanisms of biotic diversity cycles remain unexplained. Here, we highlight a common, correlatable 36 ± 1 Myr (million years) cycle in the diversity of marine genera as well as in tectonic, sea-level, and macrostratigraphic data over the past 250 Myr of Earth history. The prominence of the 36 ± 1 Myr cycle in tectonic data favors a common-cause mechanism, wherein geological forcing mechanisms drive patterns in both biological diversity and the preserved rock record. In particular, our results suggest that a 36 ± 1 Myr tectono-eustatically driven sea-level cycle may originate from the interaction between the convecting mantle and subducting slabs, thereby pacing mantle-lithospheric deep-water recycling. The 36 ± 1 Myr tectono-eustatic driver of biodiversity is likely related to cyclic continental inundations, with expanding and contracting ecological niches on shelves and in epeiric seas.
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Affiliation(s)
- Slah Boulila
- Sorbonne Université, CNRS, Institut des Sciences de la Terre Paris, ParisF-75005, France
- Astronomie et Systèmes Dynamiques/Institut de Mécanique Céleste et de Calcul des Ephémérides, CNRS-UMR8028, Observatoire de Paris, Paris Sciences & Lettres University, Sorbonne Université, Paris75014, France
| | - Shanan E. Peters
- Department of Geoscience, University of Madison, Madison, WI53706
| | - R. Dietmar Müller
- EarthByte Group, School of Geosciences, University of Sydney, Sydney, NSW2006, Australia
| | - Bilal U. Haq
- Sorbonne Université, CNRS, Institut des Sciences de la Terre Paris, ParisF-75005, France
- Smithsonian Institution, Washington,DC20024
| | - Nathan Hara
- Département d’astronomie, Université de Genève, Genève1290, Switzerland
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6
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Shetye S, Pratihary A, Shenoy D, Kurian S, Gauns M, Uskaikar H, Naik B, Nandakumar K, Borker S. Rice husk as a potential source of silicate to oceanic phytoplankton. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 879:162941. [PMID: 36934917 DOI: 10.1016/j.scitotenv.2023.162941] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2022] [Revised: 03/10/2023] [Accepted: 03/14/2023] [Indexed: 05/17/2023]
Abstract
Global oceans are witnessing changes in the phytoplankton community composition due to various environmental stressors such as rising temperature, stratification, nutrient limitation, and ocean acidification. The Arabian Sea is undergoing changes in its phytoplankton community composition, especially during winter, with the diatoms being replaced by harmful algal blooms (HABs) of dinoflagellates. Recent studies have already highlighted dissolved silicate (DSi) limitation and change in Silicon (Si)/Nitrogen (N) ratios as the factors responsible for the observed changes in the phytoplankton community in the Arabian Sea. Our investigation also revealed Si/N < 1 in the northern Arabian Sea, indicating DSi limitation, especially during winter. Here, we demonstrate that rice husk with its phytoliths is an important source of bioavailable DSi for oceanic phytoplankton. Our experiment showed that a rice husk can release ∼12 μM of DSi in 15 days and can release DSi for ∼20 days. The DSi availability increased diatom abundance up to ∼9 times. The major benefitted diatom species from DSi enrichment were Nitzshia spp., Striatella spp., Navicula spp., Dactiliosolen spp., and Leptocylindrus spp. The increase in diatom abundance was accompanied by an increase in fucoxanthin and dimethyl sulphide (DMS), an anti-greenhouse gas. Thus, the rice husk with its buoyancy and slow DSi release has the potential to reduce HABs, and increase diatoms and fishery resources in addition to carbon dioxide (CO2) sequestration in DSi-limited oceanic regions such as the Arabian Sea. Rice husk if released at the formation site of the Subantarctic mode water in the Southern Ocean could supply DSi to the thermocline in the global oceans thereby increasing diatom blooms and consequently the biotic carbon sequestration potential of the entire ocean.
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Affiliation(s)
- Suhas Shetye
- CSIR-National Institute of Oceanography, Dona Paula 403 004, Goa, India.
| | - Anil Pratihary
- CSIR-National Institute of Oceanography, Dona Paula 403 004, Goa, India
| | - Damodar Shenoy
- CSIR-National Institute of Oceanography, Dona Paula 403 004, Goa, India
| | - Siby Kurian
- CSIR-National Institute of Oceanography, Dona Paula 403 004, Goa, India
| | - Mangesh Gauns
- CSIR-National Institute of Oceanography, Dona Paula 403 004, Goa, India
| | - Hema Uskaikar
- CSIR-National Institute of Oceanography, Dona Paula 403 004, Goa, India
| | - Bhagyashri Naik
- CSIR-National Institute of Oceanography, Dona Paula 403 004, Goa, India
| | - K Nandakumar
- CSIR-National Institute of Oceanography, Dona Paula 403 004, Goa, India
| | - Sidhesh Borker
- CSIR-National Institute of Oceanography, Dona Paula 403 004, Goa, India
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7
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Bayon G, Patriat M, Godderis Y, Trinquier A, De Deckker P, Kulhanek DK, Holbourn A, Rosenthal Y. Accelerated mafic weathering in Southeast Asia linked to late Neogene cooling. SCIENCE ADVANCES 2023; 9:eadf3141. [PMID: 36989371 PMCID: PMC10058235 DOI: 10.1126/sciadv.adf3141] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/13/2022] [Accepted: 03/01/2023] [Indexed: 06/19/2023]
Abstract
Arc-continent collision in Southeast Asia during the Neogene may have driven global cooling through chemical weathering of freshly exposed ophiolites resulting in atmospheric CO2 removal. Yet, little is known about the cause-and-effect relationships between erosion and the long-term evolution of tectonics and climate in this region. Here, we present an 8-million-year record of seawater chemistry and sediment provenance from the eastern Indian Ocean, near the outflow of Indonesian Throughflow waters. Using geochemical analyses of foraminiferal shells and grain size-specific detrital fractions, we show that erosion and chemical weathering of ophiolitic rocks markedly increased after 4 million years (Ma), coincident with widespread island emergence and gradual strengthening of Pacific zonal sea-surface temperature gradients. Together with supportive evidence for enhanced mafic weathering at that time from re-analysis of the seawater 87Sr/86Sr curve, this finding suggests that island uplift and hydroclimate change in the western Pacific contributed to maintaining high atmospheric CO2 consumption throughout the late Neogene.
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Affiliation(s)
- Germain Bayon
- Univ Brest, CNRS, Ifremer, Geo-Ocean, F-29280 Plouzané, France
| | - Martin Patriat
- Univ Brest, CNRS, Ifremer, Geo-Ocean, F-29280 Plouzané, France
| | - Yves Godderis
- Géosciences-Environnement Toulouse, CNRS-Université Paul Sabatier, F-31400 Toulouse, France
| | - Anne Trinquier
- Univ Brest, CNRS, Ifremer, Geo-Ocean, F-29280 Plouzané, France
| | - Patrick De Deckker
- The Australian National University, Research School of Earth Sciences, Canberra, ACT 2601, Australia
| | - Denise K. Kulhanek
- Institute of Geosciences, Christian-Albrechts-University of Kiel, 24118 Kiel, Germany
| | - Ann Holbourn
- Institute of Geosciences, Christian-Albrechts-University of Kiel, 24118 Kiel, Germany
| | - Yair Rosenthal
- Department of Marine and Coastal Sciences and Department of Earth and Planetary Sciences, Rutgers, State University of New Jersey, New Brunswick, NJ 08901, USA
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8
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Shen H, Zhao L, Guo Z, Yuan H, Yang J, Wang X, Guo Z, Deng C, Wu F. Dynamic link between Neo-Tethyan subduction and atmospheric CO 2 changes: insights from seismic tomography reconstruction. Sci Bull (Beijing) 2023; 68:637-644. [PMID: 36907675 DOI: 10.1016/j.scib.2023.03.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Revised: 02/20/2023] [Accepted: 02/21/2023] [Indexed: 03/09/2023]
Abstract
Volcanic arc degassing contributes significantly to atmospheric CO2 levels and therefore has a pivotal impact on paleoclimate changes. The Neo-Tethyan decarbonation subduction is thought to have played a major role in Cenozoic climate changes, although there are still no quantifiable restrictions. Here we build past subduction scenarios using an improved seismic tomography reconstruction method and calculate the subducted slab flux in the India-Eurasia collision region. We find remarkable synchronicity between calculated slab flux and paleoclimate parameters in the Cenozoic, indicating a causal link between these processes. The closure of the Neo-Tethyan intra-oceanic subduction resulted in more carbon-rich sediments subducting along the Eurasia margin, as well as continental arc volcanoes, which further triggered global warming up to the Early Eocene Climatic Optimum. The abrupt termination of the Neo-Tethyan subduction due to the India-Eurasia collision could be the primary tectonic cause of the ∼50-40 Ma CO2 drop. The gradual decrease in atmospheric CO2 concentration after 40 Ma may be attributed to enhance continental weathering due to the growth of the Tibetan Plateau. Our results contribute to a better understanding of the dynamic implications of Neo-Tethyan Ocean evolution and may provide new constraints for future carbon cycle models.
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Affiliation(s)
- Hao Shen
- State Key Laboratory of Lithospheric Evolution, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China; College of Earth and Planetary Science, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Liang Zhao
- State Key Laboratory of Lithospheric Evolution, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China; College of Earth and Planetary Science, University of Chinese Academy of Sciences, Beijing 100049, China.
| | - Zhengtang Guo
- Key Laboratory of Cenozoic Geology and Environment, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China; College of Earth and Planetary Science, University of Chinese Academy of Sciences, Beijing 100049, China.
| | - Huaiyu Yuan
- Australian Research Council Centre of Excellence for Core to Crust Fluid Systems, Department of Earth and Environmental Sciences, Macquarie University, New South Wales 2109, Australia
| | - Jianfeng Yang
- State Key Laboratory of Lithospheric Evolution, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China
| | - Xinxin Wang
- State Key Laboratory of Lithospheric Evolution, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China
| | - Zhengfu Guo
- Key Laboratory of Cenozoic Geology and Environment, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China
| | - Chenglong Deng
- State Key Laboratory of Lithospheric Evolution, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China
| | - Fuyuan Wu
- State Key Laboratory of Lithospheric Evolution, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China
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9
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Boyce CK, Ibarra DE, Nelsen MP, D'Antonio MP. Nitrogen-based symbioses, phosphorus availability, and accounting for a modern world more productive than the Paleozoic. GEOBIOLOGY 2023; 21:86-101. [PMID: 35949039 DOI: 10.1111/gbi.12519] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Revised: 07/07/2022] [Accepted: 07/22/2022] [Indexed: 06/15/2023]
Abstract
Evolution of high-productivity angiosperms has been regarded as a driver of Mesozoic ecosystem restructuring. However, terrestrial productivity is limited by availability of rock-derived nutrients such as phosphorus for which permanent increases in weathering would violate mass balance requirements of the long-term carbon cycle. The potential reality of productivity increases sustained since the Mesozoic is supported here with documentation of a dramatic increase in the evolution of nitrogen-fixing or nitrogen-scavenging symbioses, including more than 100 lineages of ectomycorrhizal and lichen-forming fungi and plants with specialized microbial associations. Given this evidence of broadly increased nitrogen availability, we explore via carbon cycle modeling how enhanced phosphorus availability might be sustained without violating mass balance requirements. Volcanism is the dominant carbon input, dictating peaks in weathering outputs up to twice modern values. However, times of weathering rate suppression may be more important for setting system behavior, and the late Paleozoic was the only extended period over which rates are expected to have remained lower than modern. Modeling results are consistent with terrestrial organic matter deposition that accompanied Paleozoic vascular plant evolution having suppressed weathering fluxes by providing an alternative sink of atmospheric CO2 . Suppression would have then been progressively lifted as the crustal reservoir's holding capacity for terrestrial organic matter saturated back toward steady state with deposition of new organic matter balanced by erosion of older organic deposits. Although not an absolute increase, weathering fluxes returning to early Paleozoic conditions would represent a novel regime for the complex land biota that evolved in the interim. Volcanism-based peaks in Mesozoic weathering far surpass the modern rates that sustain a complex diversity of nitrogen-based symbioses; only in the late Paleozoic might these ecologies have been suppressed by significantly lower rates. Thus, angiosperms are posited to be another effect rather than proximal cause of Mesozoic upheaval.
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Affiliation(s)
- C Kevin Boyce
- Department of Geological Sciences, Stanford University, Stanford, California, USA
| | - Daniel E Ibarra
- Department of Geological Sciences, Stanford University, Stanford, California, USA
- Department of Earth and Planetary Science, University of California, Berkeley, California, USA
- Institute at Brown for Environment and Society and the Department of Earth, Environmental and Planetary Science, Brown University, Providence, Rhode Island, USA
| | - Matthew P Nelsen
- Negaunee Integrative Research Center, The Field Museum, Chicago, Illinois, USA
| | - Michael P D'Antonio
- Department of Geological Sciences, Stanford University, Stanford, California, USA
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10
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Low atmospheric CO 2 levels before the rise of forested ecosystems. Nat Commun 2022; 13:7616. [PMID: 36539413 PMCID: PMC9768202 DOI: 10.1038/s41467-022-35085-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Accepted: 11/18/2022] [Indexed: 12/24/2022] Open
Abstract
The emergence of forests on Earth (~385 million years ago, Ma)1 has been linked to an order-of-magnitude decline in atmospheric CO2 levels and global climatic cooling by altering continental weathering processes, but observational constraints on atmospheric CO2 before the rise of forests carry large, often unbound, uncertainties. Here, we calibrate a mechanistic model for gas exchange in modern lycophytes and constrain atmospheric CO2 levels 410-380 Ma from related fossilized plants with bound uncertainties of approximately ±100 ppm (1 sd). We find that the atmosphere contained ~525-715 ppm CO2 before continents were afforested, and that Earth was partially glaciated according to a palaeoclimate model. A process-driven biogeochemical model (COPSE) shows the appearance of trees with deep roots did not dramatically enhance atmospheric CO2 removal. Rather, shallow-rooted vascular ecosystems could have simultaneously caused abrupt atmospheric oxygenation and climatic cooling long before the rise of forests, although earlier CO2 levels are still unknown.
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11
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Pu JP, Macdonald FA, Schmitz MD, Rainbird RH, Bleeker W, Peak BA, Flowers RM, Hoffman PF, Rioux M, Hamilton MA. Emplacement of the Franklin large igneous province and initiation of the Sturtian Snowball Earth. SCIENCE ADVANCES 2022; 8:eadc9430. [PMID: 36417531 PMCID: PMC9683727 DOI: 10.1126/sciadv.adc9430] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Accepted: 10/25/2022] [Indexed: 06/16/2023]
Abstract
During the Cryogenian (720 to 635 Ma ago) Snowball Earth glaciations, ice extended to sea level near the equator. The cause of this catastrophic failure of Earth's thermostat has been unclear, but previous geochronology has suggested a rough coincidence of glacial onset with one of the largest magmatic episodes in the geological record, the Franklin large igneous province. U-Pb geochronology on zircon and baddeleyite from sills associated with the paleo-equatorial Franklin large igneous province in Arctic Canada record rapid emplacement between 719.86 ± 0.21 and 718.61 ± 0.30 Ma ago, 0.9 to 1.6 Ma before the onset of widespread glaciation. Geologic observations and (U-Th)/He dates on Franklin sills are compatible with major post-Franklin exhumation, possibly due to development of mafic volcanic highlands on windward equatorial Laurentia and increased global weatherability. After a transient magmatic CO2 flux, long-term carbon sequestration associated with increased weatherability could have nudged Earth over the threshold for runaway ice-albedo feedback.
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Affiliation(s)
- Judy P. Pu
- Department of Earth and Planetary Sciences, Harvard University, Cambridge, MA, USA
- Department of Earth Science, University of California, Santa Barbara, Santa Barbara, CA, USA
| | - Francis A. Macdonald
- Department of Earth and Planetary Sciences, Harvard University, Cambridge, MA, USA
- Department of Earth Science, University of California, Santa Barbara, Santa Barbara, CA, USA
| | - Mark D. Schmitz
- Department of Geosciences, Boise State University, Boise, ID, USA
| | | | | | - Barra A. Peak
- Department of Geological Sciences, University of Colorado, Boulder, CO, USA
| | - Rebecca M. Flowers
- Department of Geological Sciences, University of Colorado, Boulder, CO, USA
| | - Paul F. Hoffman
- Department of Earth and Planetary Sciences, Harvard University, Cambridge, MA, USA
- School of Earth and Ocean Sciences, University of Victoria, Victoria, British Columbia, Canada
| | - Matthew Rioux
- Department of Earth Science, University of California, Santa Barbara, Santa Barbara, CA, USA
| | - Michael A. Hamilton
- Department of Earth Sciences, University of Toronto, Toronto, Ontario, Canada
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12
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Herbert TD, Dalton CA, Liu Z, Salazar A, Si W, Wilson DS. Tectonic degassing drove global temperature trends since 20 Ma. Science 2022; 377:116-119. [PMID: 35771904 DOI: 10.1126/science.abl4353] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
The Miocene Climatic Optimum (MCO) from ~17 to 14 million years ago (Ma) represents an enigmatic reversal in Cenozoic cooling. A synthesis of marine paleotemperature records shows that the MCO was a local maximum in global sea surface temperature superimposed on a period from at least 19 Ma to 10 Ma, during which global temperatures were on the order of 10°C warmer than at present. Our high-resolution global reconstruction of ocean crustal production, a proxy for tectonic degassing of carbon, suggests that crustal production rates were ~35% higher than modern rates until ~14 Ma, when production began to decline steeply along with global temperatures. The magnitude and timing of the inferred changes in tectonic degassing can account for the majority of long-term ice sheet and global temperature evolution since 20 Ma.
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Affiliation(s)
| | | | - Zhonghui Liu
- Department of Earth Sciences, University of Hong Kong, Hong Kong, China
| | - Andrea Salazar
- Department of Earth and Planetary Science, Harvard University, Cambridge, MA, USA
| | - Weimin Si
- DEEPS, Brown University, Providence, RI 02912, USA
| | - Douglas S Wilson
- Department of Earth Science, University of California, Santa Barbara, CA, USA
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13
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Müller RD, Mather B, Dutkiewicz A, Keller T, Merdith A, Gonzalez CM, Gorczyk W, Zahirovic S. Evolution of Earth's tectonic carbon conveyor belt. Nature 2022; 605:629-639. [PMID: 35614243 DOI: 10.1038/s41586-022-04420-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Accepted: 01/13/2022] [Indexed: 11/09/2022]
Abstract
Concealed deep beneath the oceans is a carbon conveyor belt, propelled by plate tectonics. Our understanding of its modern functioning is underpinned by direct observations, but its variability through time has been poorly quantified. Here we reconstruct oceanic plate carbon reservoirs and track the fate of subducted carbon using thermodynamic modelling. In the Mesozoic era, 250 to 66 million years ago, plate tectonic processes had a pivotal role in driving climate change. Triassic-Jurassic period cooling correlates with a reduction in solid Earth outgassing, whereas Cretaceous period greenhouse conditions can be linked to a doubling in outgassing, driven by high-speed plate tectonics. The associated 'carbon subduction superflux' into the subcontinental mantle may have sparked North American diamond formation. In the Cenozoic era, continental collisions slowed seafloor spreading, reducing tectonically driven outgassing, while deep-sea carbonate sediments emerged as the Earth's largest carbon sink. Subduction and devolatilization of this reservoir beneath volcanic arcs led to a Cenozoic increase in carbon outgassing, surpassing mid-ocean ridges as the dominant source of carbon emissions 20 million years ago. An increase in solid Earth carbon emissions during Cenozoic cooling requires an increase in continental silicate weathering flux to draw down atmospheric carbon dioxide, challenging previous views and providing boundary conditions for future carbon cycle models.
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Affiliation(s)
- R Dietmar Müller
- EarthByte Group, School of Geosciences, The University of Sydney, Sydney, New South Wales, Australia.
| | - Ben Mather
- EarthByte Group, School of Geosciences, The University of Sydney, Sydney, New South Wales, Australia
| | - Adriana Dutkiewicz
- EarthByte Group, School of Geosciences, The University of Sydney, Sydney, New South Wales, Australia
| | - Tobias Keller
- School of Geographical and Earth Sciences, University of Glasgow, Glasgow, Scotland
| | - Andrew Merdith
- School of Earth and Environment, University of Leeds, Leeds, UK
| | - Christopher M Gonzalez
- Centre for Exploration Targeting, School of Earth Science, University of Western Australia, Crawley, Western Australia, Australia
| | - Weronika Gorczyk
- Centre for Exploration Targeting, School of Earth Science, University of Western Australia, Crawley, Western Australia, Australia
| | - Sabin Zahirovic
- EarthByte Group, School of Geosciences, The University of Sydney, Sydney, New South Wales, Australia
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14
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Spahr D, König J, Bayarjargal L, Milman V, Perlov A, Liermann HP, Winkler B. Sr[C 2O 5] is an Inorganic Pyrocarbonate Salt with [C 2O 5] 2- Complex Anions. J Am Chem Soc 2022; 144:2899-2904. [PMID: 35134291 DOI: 10.1021/jacs.2c00351] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
The synthesis of a novel type of carbonate, namely of the inorganic pyrocarbonate salt Sr[C2O5], which contains isolated [C2O5]2--groups, significantly extends the crystal chemistry of inorganic carbonates beyond the established sp2- and sp3-carbonates. We synthesized Sr[C2O5] in a laser-heated diamond anvil cell by reacting Sr[CO3] with CO2. By single crystal synchrotron diffraction, Raman spectroscopy, and density functional theory (DFT) calculations, we show that it is a pyrocarbonate salt. Sr[C2O5] is the first member of a novel family of inorganic carbonates. We predict, based on DFT calculations, that further inorganic pyrocarbonates can be obtained and that these will be relevant to geoscience and may provide a better understanding of reactions converting CO2 into useful inorganic compounds.
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Affiliation(s)
- Dominik Spahr
- Institute of Geosciences, Goethe University Frankfurt, Altenhöferallee 1, 60438 Frankfurt, Germany
| | - Jannes König
- Institute of Geosciences, Goethe University Frankfurt, Altenhöferallee 1, 60438 Frankfurt, Germany
| | - Lkhamsuren Bayarjargal
- Institute of Geosciences, Goethe University Frankfurt, Altenhöferallee 1, 60438 Frankfurt, Germany
| | - Victor Milman
- Dassault Systèmes BIOVIA, 334 Cambridge Science Park, Cambridge CB4 0WN, United Kingdom
| | - Alexander Perlov
- Dassault Systèmes BIOVIA, 334 Cambridge Science Park, Cambridge CB4 0WN, United Kingdom
| | | | - Björn Winkler
- Institute of Geosciences, Goethe University Frankfurt, Altenhöferallee 1, 60438 Frankfurt, Germany
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15
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Wang ZX, Liu SA, Li S, Liu D, Liu J. Linking deep CO2 outgassing to cratonic destruction. Natl Sci Rev 2022; 9:nwac001. [PMID: 35673528 PMCID: PMC9166544 DOI: 10.1093/nsr/nwac001] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2021] [Revised: 12/23/2021] [Accepted: 12/29/2021] [Indexed: 11/16/2022] Open
Abstract
Outgassing of carbon dioxide from the Earth's interior regulates the surface climate through deep time. Here we examine the role of cratonic destruction in mantle CO2 outgassing via collating and presenting new data for Paleozoic kimberlites, Mesozoic basaltic rocks and their mantle xenoliths from the eastern North China Craton (NCC), which underwent extensive destruction in the early Cretaceous. High Ca/Al and low Ti/Eu and δ26Mg are widely observed in lamprophyres and mantle xenoliths, which demonstrates that the cratonic lithospheric mantle (CLM) was pervasively metasomatized by recycled carbonates. Raman analysis of bubble-bearing melt inclusions shows that redox melting of the C-rich CLM produced carbonated silicate melts with high CO2 content. The enormous quantities of CO2 in these magmas, together with substantial CO2 degassing from the carbonated melt–CLM reaction and crustal heating, indicate that destruction of the eastern NCC resulted in rapid and extensive mantle CO2 emission, which partly contributed to the early Cretaceous greenhouse climate episode.
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Affiliation(s)
- Zhao-Xue Wang
- State Key Laboratory of Geological Processes and Mineral Resources, China University of Geosciences, Beijing100083, China
| | - Sheng-Ao Liu
- State Key Laboratory of Geological Processes and Mineral Resources, China University of Geosciences, Beijing100083, China
| | - Shuguang Li
- State Key Laboratory of Geological Processes and Mineral Resources, China University of Geosciences, Beijing100083, China
| | - Di Liu
- State Key Laboratory of Geological Processes and Mineral Resources, China University of Geosciences, Beijing100083, China
| | - Jingao Liu
- State Key Laboratory of Geological Processes and Mineral Resources, China University of Geosciences, Beijing100083, China
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16
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Petrizzo MR, MacLeod KG, Watkins DK, Wolfgring E, Huber BT. Late Cretaceous Paleoceanographic Evolution and the Onset of Cooling in the Santonian at Southern High Latitudes (IODP Site U1513, SE Indian Ocean). PALEOCEANOGRAPHY AND PALEOCLIMATOLOGY 2022; 37:e2021PA004353. [PMID: 35910494 PMCID: PMC9303530 DOI: 10.1029/2021pa004353] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Revised: 12/06/2021] [Accepted: 12/09/2021] [Indexed: 06/15/2023]
Abstract
The latest Cenomanian to Santonian sedimentary record recovered at IODP Expedition 369 Site U1513 in the Mentelle Basin (SE Indian Ocean, paleolatitude 60°S at 85 Ma) is studied to interpret the paleoceanographic evolution in the Southern Hemisphere. The planktonic foraminiferal assemblage changes, the depth ecology preferences of different species, and the surface and seafloor temperature inferred from the stable isotopic values measured on foraminiferal tests provide meaningful information to the understanding of the Late Cretaceous climate. The hothouse climate during the Turonian-Santonian, characterized by weak latitudinal temperature gradients and high atmospheric CO2 concentrations, is followed by a progressive cooling during the Campanian. At Site U1513 the beginning of this climatic transition is nicely recorded within the Santonian, as indicated by an ∼1‰ increase in δ18O values of planktonic foraminifera suggesting a decline in surface water paleotemperatures of 4°C. The onset of cooling is mirrored by changes in the planktonic foraminiferal assemblages including extinctions among surface and deep dwellers, appearances and diversification of newly evolving taxa, and changes from predominantly epifaunal oxic to infaunal dysoxic/suboxic taxa among co-occurring benthic foraminifera. Overall, the data presented here document an interval in the Santonian during which the rate of southern high latitude cooling increased. Both surface and bottom waters were affected, although the cooling signal is more evident in the data for surface waters. This pattern of cooling ascribes the deterioration of the Late Cretaceous climate to decreased CO2 in the atmosphere and changes in the oceanic circulation correlated with enhanced meridional circulation.
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Affiliation(s)
| | - Kenneth G. MacLeod
- Department of Geological SciencesUniversity of Missouri‐ColumbiaColumbiaMOUSA
| | - David K. Watkins
- Department of Earth and Atmospheric SciencesUniversity of NebraskaLincolnNEUSA
| | - Erik Wolfgring
- Department of Earth Sciences "Ardito Desio"University of MilanMilanItaly
- Department of GeologyUniversity of ViennaViennaAustria
| | - Brian T. Huber
- National Museum of Natural HistorySmithsonian InstitutionWashingtonDCUSA
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17
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Liu Y, Chen W, Foley SF, Shen Y, Chen C, Li J, Ou X, He D, Feng Q, Lin J. The largest negative carbon isotope excursions in Neoproterozoic carbonates caused by recycled carbonatite volcanic ash. Sci Bull (Beijing) 2021; 66:1925-1931. [PMID: 36654402 DOI: 10.1016/j.scib.2021.04.021] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2021] [Revised: 03/23/2021] [Accepted: 03/25/2021] [Indexed: 02/03/2023]
Abstract
The late Ediacaran Shuram Excursion (SE) records the most prominent negative δ13C excursions (δ13C = -12‰) during Earth's history. It has been hypothesized to have resulted from oxidation of dissolved organic matter, diagenetic or authigenic precipitates. However, the origin of the SE remains enigmatic; current models face challenges regarding the significant amount of atmospheric oxygen needed to balance such extensive oxidation and sustained inputs of light carbon with extremely negative C isotope compositions. Here, we show that the Doushantuo Formation at the Jiulongwan section in South China, a key stratum recording the SE event, contains mineralogical and geochemical signatures related to igneous processes. Both the occurrence of ankerite, feldspar, moissanite and euhedral quartz in the SE samples and the relatively consistent Ce anomalies of carbonate and O isotopes of quartz indicate a contribution from an igneous source. In particular, the SE samples have trace element and C isotope compositions similar to those of recycled carbonatites formed by decarbonation and melting of sedimentary carbonate rocks. These observations suggest that the deep cycle of ancient carbonate rocks, which were subjected to decarbonation during subduction, melting and eruption related to the breakup of the Rodinia supercontinent, contributed to the SE. This igneous model for the SE may provide a connection between the deep and shallow carbon cycles of the Earth.
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Affiliation(s)
- Yongsheng Liu
- State Key Laboratory of Geological Processes and Mineral Resources, School of Earth Sciences, China University of Geosciences, Wuhan 430074, China.
| | - Wei Chen
- State Key Laboratory of Geological Processes and Mineral Resources, School of Earth Sciences, China University of Geosciences, Wuhan 430074, China
| | - Stephen F Foley
- Department of Earth and Environmental Sciences, Macquarie University, North Ryde, NSW 2109, Australia
| | - Yan'an Shen
- School of Earth and Space Sciences, University of Science and Technology of China, Hefei 230026, China
| | - Chunfei Chen
- Department of Earth and Environmental Sciences, Macquarie University, North Ryde, NSW 2109, Australia
| | - Junhua Li
- State Key Laboratory of Geological Processes and Mineral Resources, School of Earth Sciences, China University of Geosciences, Wuhan 430074, China
| | - Xiaobin Ou
- State Key Laboratory of Geological Processes and Mineral Resources, School of Earth Sciences, China University of Geosciences, Wuhan 430074, China
| | - Detao He
- State Key Laboratory of Geological Processes and Mineral Resources, School of Earth Sciences, China University of Geosciences, Wuhan 430074, China
| | - Qinglai Feng
- State Key Laboratory of Geological Processes and Mineral Resources, School of Earth Sciences, China University of Geosciences, Wuhan 430074, China
| | - Jie Lin
- State Key Laboratory of Geological Processes and Mineral Resources, School of Earth Sciences, China University of Geosciences, Wuhan 430074, China
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18
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Chen C, Förster MW, Foley SF, Liu Y. Massive carbon storage in convergent margins initiated by subduction of limestone. Nat Commun 2021; 12:4463. [PMID: 34294696 PMCID: PMC8298627 DOI: 10.1038/s41467-021-24750-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2021] [Accepted: 06/22/2021] [Indexed: 11/30/2022] Open
Abstract
Remobilization of sedimentary carbonate in subduction zones modulates arc volcanism emissions and thus Earth’s climate over geological timescales. Although limestones (or chalk) are thought to be the major carbon reservoir subducted to subarc depths, their fate is still unclear. Here we present high-pressure reaction experiments between impure limestone (7.4 wt.% clay) and dunite at 1.3–2.7 GPa to constrain the melting behaviour of subducted natural limestone in contact with peridotite. The results show that although clay impurities significantly depress the solidus of limestone, melting will not occur whilst limestones are still part of the subducting slab. Buoyancy calculations suggest that most of these limestones would form solid-state diapirs intruding into the mantle wedge, resulting in limited carbon flux to the deep mantle (< ~10 Mt C y−1). Less than 20% melting within the mantle wedge indicates that most limestones remain stable and are stored in subarc lithosphere, resulting in massive carbon storage in convergent margins considering their high carbon flux (~21.4 Mt C y−1). Assimilation and outgassing of these carbonates during arc magma ascent may dominate the carbon flux in volcanic arcs. Experiments and buoyancy calculations reveal that subduction of limestone results in massive carbon storage in arc lithosphere, forming an important carbon reservoir in convergent margins. Remobilization of this carbon reservoir during arc magma ascent may dominate carbon emissions at volcanic arcs.
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Affiliation(s)
- Chunfei Chen
- Department of Earth and Environmental Sciences and ARC Centre of Excellence for Core to Crust Fluid Systems, Macquarie University, North Ryde, NSW, Australia. .,State Key Laboratory of Geological Processes and Mineral Resources, School of Earth Sciences, China University of Geosciences, Wuhan, China.
| | - Michael W Förster
- Department of Earth and Environmental Sciences and ARC Centre of Excellence for Core to Crust Fluid Systems, Macquarie University, North Ryde, NSW, Australia.,Research School of Earth Sciences, Australia National University, Canberra, ACT, Australia
| | - Stephen F Foley
- Department of Earth and Environmental Sciences and ARC Centre of Excellence for Core to Crust Fluid Systems, Macquarie University, North Ryde, NSW, Australia.,Research School of Earth Sciences, Australia National University, Canberra, ACT, Australia
| | - Yongsheng Liu
- State Key Laboratory of Geological Processes and Mineral Resources, School of Earth Sciences, China University of Geosciences, Wuhan, China.
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19
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Geochemical Characteristics of Late Ordovician Shales in the Upper Yangtze Platform, South China: Implications for Redox Environmental Evolution. MINERALS 2021. [DOI: 10.3390/min11070710] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Changes to the redox environment of seawater in the Late Ordovician affect the process of organic matter enrichment and biological evolution. However, the evolution of redox and its underlying causes remain unclear. This paper analyzed the vertical variability of main, trace elements and δ34Spy from a drill core section (well ZY5) in the Upper Yangtze Platform, and described the redox conditions, paleoproductivity and paleoclimate variability recorded in shale deposits of the P. pacificus zone and M. extraordinarius zone that accumulated during Wufeng Formation. The results showed that shale from well ZY5 in Late Ordovician was deposited under oxidized water environment, and there are more strongly reducing bottom water conditions of the M. extraordinarius zone compared with the P. pacificus zone. Excess silica (SiO2(exc)) and substitution index of paleoproductivity (Y) indicated that the P. pacificus zone had higher paleoproductivity whereas the M. extraordinarius zone was lower. The high productivity level controlled O2 release in the shallow water area as well as the oxidation degree of the P. pacificus zone. The decrease of productivity and the relatively stagnant water mass of the inner Yangtze Sea controlled the formation of relatively reduced water conditions in the M. extraordinarius zone. The chemical index of alteration (CIA) results suggested that palaeoclimatic conditions changed from warm and humid to cold and dry climate from the P. pacificus to the M. extraordinarius zones in the study area. A comparative analysis of the published Fe-S-C data for the Xiushan Datianba section showed that in the P. pacificus zone of the inner Yangtze Sea, warm and humid climate conditions drove high productivity, sulphate flux and low reactive iron flux, which promoted the expansion of oxic ocean-surface waters and mid-depth euxinic waters. In the M. extraordinarius zone, the cold and dry climate with significant uplift of the Xiang’e Submarine High led to the relative sea level decline, resulting in low productivity, sulfate flux and high reactive iron flux, which promoted the expansion of the mid-depth ferruginous waters and the shrinkage of oxic ocean-surface waters. The results offered new insights into the co-evolution of continents and oceans, and explained the role of continental weathering and uplift of the Xiang’e Submarine High in the exchange of sulfate flux and nutrients in the redox environment change of inner Yangtze Sea during the Late Ordovician.
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20
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Guo Z, Wilson M, Dingwell DB, Liu J. India-Asia collision as a driver of atmospheric CO 2 in the Cenozoic. Nat Commun 2021; 12:3891. [PMID: 34162840 PMCID: PMC8222363 DOI: 10.1038/s41467-021-23772-y] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2019] [Accepted: 05/03/2021] [Indexed: 02/05/2023] Open
Abstract
Deep Earth degassing is a critical forcing factor for atmospheric CO2 variations and palaeoclimate changes in Earth's history. For the Cenozoic, the key driving mechanism of atmospheric CO2 variations remains controversial. Here we analyse three stages of collision-related magmatism in Tibet, which correspond temporally with the three major stages of atmospheric CO2 variations in the Cenozoic and explore the possibility of a causal link between these phenomena. To this end we present geochemical data for the three stages of magmatic rocks in Tibet, which we use to inform a model calculating the continental collision-induced CO2 emission flux associated with the evolving Neo-Tethyan to continental subduction over the Cenozoic. The correlation between our modelled CO2 emission rates and the global atmospheric CO2 curve is consistent with the hypothesis that the India-Asia collision was the primary driver of changes in atmospheric CO2 over the Cenozoic.
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Affiliation(s)
- Zhengfu Guo
- grid.9227.e0000000119573309Key Laboratory of Cenozoic Geology and Environment, Institute of Geology and Geophysics, Chinese Academy of Sciences (CAS), Beijing, China ,grid.9227.e0000000119573309CAS Center for Excellence in Life and Paleoenvironment, Beijing, China
| | - Marjorie Wilson
- grid.9909.90000 0004 1936 8403School of Earth and Environment, University of Leeds, Leeds, UK
| | - Donald B. Dingwell
- grid.5252.00000 0004 1936 973XDepartment of Earth and Environmental Sciences, Ludwig-Maximilians-Universität, Munich, Germany
| | - Jiaqi Liu
- grid.9227.e0000000119573309Key Laboratory of Cenozoic Geology and Environment, Institute of Geology and Geophysics, Chinese Academy of Sciences (CAS), Beijing, China
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21
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Quantitative comparison of geological data and model simulations constrains early Cambrian geography and climate. Nat Commun 2021; 12:3868. [PMID: 34162853 PMCID: PMC8222365 DOI: 10.1038/s41467-021-24141-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Accepted: 06/01/2021] [Indexed: 11/09/2022] Open
Abstract
Marine ecosystems with a diverse range of animal groups became established during the early Cambrian (~541 to ~509 Ma). However, Earth's environmental parameters and palaeogeography in this interval of major macro-evolutionary change remain poorly constrained. Here, we test contrasting hypotheses of continental configuration and climate that have profound implications for interpreting Cambrian environmental proxies. We integrate general circulation models and geological observations to test three variants of the 'Antarctocentric' paradigm, with a southern polar continent, and an 'equatorial' configuration that lacks polar continents. This quantitative framework can be applied to other deep-time intervals when environmental proxy data are scarce. Our results show that the Antarctocentric palaeogeographic paradigm can reconcile geological data and simulated Cambrian climate. Our analyses indicate a greenhouse climate during the Cambrian animal radiation, with mean annual sea-surface temperatures between ~9 °C to ~19 °C and ~30 °C to ~38 °C for polar and tropical palaeolatitudes, respectively.
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22
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Yang Y, Zhang C, Lenton TM, Yan X, Zhu M, Zhou M, Tao J, Phelps TJ, Cao Z. The evolution pathway of ammonia-oxidizing archaea shaped by major geological events. Mol Biol Evol 2021; 38:3637-3648. [PMID: 33993308 PMCID: PMC8382903 DOI: 10.1093/molbev/msab129] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Primordial nitrification processes have been studied extensively using geochemical approaches, but the biological origination of nitrification remains unclear. Ammonia-oxidizing archaea (AOA) are widely distributed nitrifiers and implement the rate-limiting step in nitrification. They are hypothesized to have been important players in the global nitrogen cycle in Earth’s early history. We performed systematic phylogenomic and marker gene analyses to elucidate the diversification timeline of AOA evolution. Our results suggested that the AOA ancestor experienced terrestrial geothermal environments at ∼1,165 Ma (1,928–880 Ma), and gradually evolved into mesophilic soil at ∼652 Ma (767–554 Ma) before diversifying into marine settings at ∼509 Ma (629–412 Ma) and later into shallow and deep oceans, respectively. Corroborated by geochemical evidence and modeling, the timing of key diversification nodes can be linked to the global magmatism and glaciation associated with the assembly and breakup of the supercontinent Rodinia, and the later oxygenation of the deep ocean. Results of this integrated study shed light on the geological forces that may have shaped the evolutionary pathways of the AOA, which played an important role in the ancient global nitrogen cycle.
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Affiliation(s)
- Yiyan Yang
- Department of Gastroenterology, Shanghai 10th People's Hospital, School of Life Sciences and Technology, Tongji University, Shanghai, 200092, China
| | - Chuanlun Zhang
- Shenzhen Key Laboratory of Marine Archaea Geo-Omics, Southern University of Science and Technology, Shenzhen, 518055, P.R. China.,Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou, 510000, China.,Shanghai Sheshan National Geophysical Observatory, Shanghai, 201602, China
| | - Timothy M Lenton
- Global Systems Institute, University of Exeter, Exeter, EX4 4QE, United Kingdom
| | - Xinmiao Yan
- Department of Gastroenterology, Shanghai 10th People's Hospital, School of Life Sciences and Technology, Tongji University, Shanghai, 200092, China
| | - Maoyan Zhu
- State Key Laboratory of Palaeobiology and Stratigraphy & Center for Excellence in Life and Paleoenvironment, Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, Nanjing, 210008, P.R. China.,College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing, 100049, P.R. China
| | - Mengdi Zhou
- Department of Gastroenterology, Shanghai 10th People's Hospital, School of Life Sciences and Technology, Tongji University, Shanghai, 200092, China
| | - Jianchang Tao
- Shenzhen Key Laboratory of Marine Archaea Geo-Omics, Southern University of Science and Technology, Shenzhen, 518055, P.R. China
| | - Tommy J Phelps
- Shenzhen Key Laboratory of Marine Archaea Geo-Omics, Southern University of Science and Technology, Shenzhen, 518055, P.R. China
| | - Zhiwei Cao
- Department of Gastroenterology, Shanghai 10th People's Hospital, School of Life Sciences and Technology, Tongji University, Shanghai, 200092, China
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23
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Abstract
The diversification of complex animal life during the Cambrian Period (541–485.4 Ma) is thought to have been contingent on an oxygenation event sometime during ~850 to 541 Ma in the Neoproterozoic Era. Whilst abundant geochemical evidence indicates repeated intervals of ocean oxygenation during this time, the timing and magnitude of any changes in atmospheric pO2 remain uncertain. Recent work indicates a large increase in the tectonic CO2 degassing rate between the Neoproterozoic and Paleozoic Eras. We use a biogeochemical model to show that this increase in the total carbon and sulphur throughput of the Earth system increased the rate of organic carbon and pyrite sulphur burial and hence atmospheric pO2. Modelled atmospheric pO2 increases by ~50% during the Ediacaran Period (635–541 Ma), reaching ~0.25 of the present atmospheric level (PAL), broadly consistent with the estimated pO2 > 0.1–0.25 PAL requirement of large, mobile and predatory animals during the Cambrian explosion. The evolution of complex animal life in the Cambrian period is thought to be related to oxygenation of the Earth System, however the timing, magnitude and mechanism of this oxygenation event remain uncertain. Here, the authors use a biogeochemical model which links tectonic CO2 degassing rates to carbon and sulphur burial, and suggest that atmospheric pO2 increased by ~50% during the Ediacaran Period.
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24
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Macdonald FA, Swanson-Hysell NL, Park Y, Lisiecki L, Jagoutz O. Arc-continent collisions in the tropics set Earth's climate state. Science 2019; 364:181-184. [PMID: 30872536 DOI: 10.1126/science.aav5300] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2018] [Accepted: 02/26/2019] [Indexed: 11/02/2022]
Abstract
On multimillion-year time scales, Earth has experienced warm ice-free and cold glacial climates, but it is unknown whether transitions between these background climate states were the result of changes in carbon dioxide sources or sinks. Low-latitude arc-continent collisions are hypothesized to drive cooling by exhuming and eroding mafic and ultramafic rocks in the warm, wet tropics, thereby increasing Earth's potential to sequester carbon through chemical weathering. To better constrain global weatherability through time, the paleogeographic position of all major Phanerozoic arc-continent collisions was reconstructed and compared to the latitudinal distribution of ice sheets. This analysis reveals a strong correlation between the extent of glaciation and arc-continent collisions in the tropics. Earth's climate state is set primarily by global weatherability, which changes with the latitudinal distribution of arc-continent collisions.
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Affiliation(s)
- Francis A Macdonald
- Department of Earth Science, University of California, Santa Barbara, CA 93106, USA.
| | | | - Yuem Park
- Department of Earth and Planetary Science, University of California, Berkeley, CA 94720, USA
| | - Lorraine Lisiecki
- Department of Earth Science, University of California, Santa Barbara, CA 93106, USA
| | - Oliver Jagoutz
- Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
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25
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Smolarek-Lach J, Marynowski L, Trela W, Wignall PB. Mercury Spikes Indicate a Volcanic Trigger for the Late Ordovician Mass Extinction Event: An Example from a Deep Shelf of the Peri-Baltic Region. Sci Rep 2019; 9:3139. [PMID: 30816186 PMCID: PMC6395715 DOI: 10.1038/s41598-019-39333-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2018] [Accepted: 01/17/2019] [Indexed: 11/17/2022] Open
Abstract
The Late Ordovician mass extinction (LOME) was the second largest Phanerozoic crisis, but its cause remains elusive. Several triggering mechanisms have been proposed over the years, including bioevolutionary events, oceanographic changes, and geotectonic processes. Here, we report the presence of Hg spikes in the Zbrza PIG-1 borehole from the Upper Ordovician deep shelf sections of the peri-Baltic region. A strong positive anomaly in the lower late Katian (Hg/TOC = 2537.3 ppb/wt%) was noted. No correlation between Hg and TOC (R2 = 0.07) was distinguished in the Hirnantian, although several positive anomalies were found. Because the Hg/Mo ratio showed trends very similar to those of Hg/TOC, it seems likely that TOC values reflect the redox conditions. In order to evaluate the role of anoxia in levels of Hg enrichment several redox indicators were measured. These showed that the elevated mercury values in the Hirnantian are not caused by anoxia/euxinia because euxinic biomarkers (maleimides and aryl isoprenoids) are present in very low abundance and pyrite framboids are absent. In total, positive Hg/TOC anomalies occur in the lower late Katian, at the Katian - Hirnantian boundary, and in the late Hirnantian. The lack of a strong Hg/TOC correlation, Ni enrichments, and the absence of ‘anoxic indicators’ (no biomarkers, no framboids, low Mo concentration) at these levels, supports the interpretation that Hg enrichment is due to enhanced environmental loading. We conclude that our Hg and Hg/TOC values were associated with volcanic pulses which triggered the massive environmental changes resulting in the Late Ordovician mass extinction.
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Affiliation(s)
| | - Leszek Marynowski
- Faculty of Earth Sciences, University of Silesia, Sosnowiec, 41-200, Poland
| | - Wiesław Trela
- Polish Geological Institute ‒ National Research Institute, Kielce, 25-953, Poland
| | - Paul B Wignall
- School of Earth and Environment, University of Leeds, Leeds, LS2 9JT, UK
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26
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Dating the late Proterozoic stratigraphic record. Emerg Top Life Sci 2018; 2:137-147. [PMID: 32412613 DOI: 10.1042/etls20170167] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2018] [Revised: 05/29/2018] [Accepted: 05/31/2018] [Indexed: 11/17/2022]
Abstract
The Tonian and Cryogenian periods (ca. 1000-635.5 Ma) witnessed important biological and climatic events, including diversification of eukaryotes, the rise of algae as primary producers, the origin of Metazoa, and a pair of Snowball Earth glaciations. The Tonian and Cryogenian will also be the next periods in the geological time scale to be formally defined. Time-calibrating this interval is essential for properly ordering and interpreting these events and establishing and testing hypotheses for paleoenvironmental change. Here, we briefly review the methods by which the Proterozoic time scale is dated and provide an up-to-date compilation of age constraints on key fossil first and last appearances, geological events, and horizons during the Tonian and Cryogenian periods. We also develop a new age model for a ca. 819-740 Ma composite section in Svalbard, which is unusually complete and contains a rich Tonian fossil archive. This model provides useful preliminary age estimates for the Tonian succession in Svalbard and distinct carbon isotope anomalies that can be globally correlated and used as an indirect dating tool.
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27
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Tang C. Did Earth drive itself to a snowball? Sci Bull (Beijing) 2018; 63:1032-1033. [PMID: 36755453 DOI: 10.1016/j.scib.2018.07.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Affiliation(s)
- Chunan Tang
- State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, Nanjing 210008, China; State Key Laboratory of Geological Processes and Mineral Resources, China University of Geosciences (Wuhan), Wuhan 430074, China.
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28
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Abstract
On greater than million year timescales, carbon in the ocean-atmosphere-biosphere system is controlled by geologic inputs of CO2 through volcanic and metamorphic degassing. High atmospheric CO2 and warm climates in the Cretaceous have been attributed to enhanced volcanic emissions of CO2 through more rapid spreading at mid-ocean ridges and, in particular, to a global flare-up in continental arc volcanism. Here, we show that global flare-ups in continental arc magmatism also enhance the global flux of nutrients into the ocean through production of windblown ash. We show that up to 75% of Si, Fe and P is leached from windblown ash during and shortly after deposition, with soluble Si, Fe and P inputs from ash alone in the Cretaceous being higher than the combined input of dust and rivers today. Ash-derived nutrient inputs may have increased the efficiency of biological productivity and organic carbon preservation in the Cretaceous, possibly explaining why the carbon isotopic signature of Cretaceous seawater was high. Variations in volcanic activity, particularly continental arcs, have the potential of profoundly altering carbon cycling at the Earth’s surface by increasing inputs of CO2 and ash-borne nutrients, which together enhance biological productivity and burial of organic carbon, generating an abundance of hydrocarbon source rocks.
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29
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Mills BJW, Batterman SA, Field KJ. Nutrient acquisition by symbiotic fungi governs Palaeozoic climate transition. Philos Trans R Soc Lond B Biol Sci 2018; 373:20160503. [PMID: 29254967 PMCID: PMC5745338 DOI: 10.1098/rstb.2016.0503] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/27/2017] [Indexed: 11/12/2022] Open
Abstract
Fossil evidence from the Rhynie chert indicates that early land plants, which evolved in a high-CO2 atmosphere during the Palaeozoic Era, hosted diverse fungal symbionts. It is hypothesized that the rise of early non-vascular land plants, and the later evolution of roots and vasculature, drove the long-term shift towards a high-oxygen, low CO2 climate that eventually permitted the evolution of mammals and, ultimately, humans. However, very little is known about the productivity of the early terrestrial biosphere, which depended on the acquisition of the limiting nutrient phosphorus via fungal symbiosis. Recent laboratory experiments have shown that plant-fungal symbiotic function is specific to fungal identity, with carbon-for-phosphorus exchange being either enhanced or suppressed under superambient CO2 By incorporating these experimental findings into a biogeochemical model, we show that the differences in these symbiotic nutrient acquisition strategies could greatly alter the plant-driven changes to climate, allowing drawdown of CO2 to glacial levels, and altering the nature of the rise of oxygen. We conclude that an accurate depiction of plant-fungal symbiotic systems, informed by high-CO2 experiments, is key to resolving the question of how the first terrestrial ecosystems altered our planet.This article is part of a discussion meeting issue 'The Rhynie cherts: our earliest terrestrial ecosystem revisited'.
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Affiliation(s)
| | - Sarah A Batterman
- School of Geography, University of Leeds, Leeds LS2 9JT, UK
- Priestley International Centre for Climate, University of Leeds, Leeds LS2 9JT, UK
- Smithsonian Tropical Research Institute, Ancon, Panama
| | - Katie J Field
- Centre for Plant Sciences, School of Biology, University of Leeds, Leeds LS2 9JT, UK
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30
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Mason E, Edmonds M, Turchyn AV. Remobilization of crustal carbon may dominate volcanic arc emissions. Science 2018; 357:290-294. [PMID: 28729507 DOI: 10.1126/science.aan5049] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2017] [Accepted: 06/16/2017] [Indexed: 11/02/2022]
Abstract
The flux of carbon into and out of Earth's surface environment has implications for Earth's climate and habitability. We compiled a global data set for carbon and helium isotopes from volcanic arcs and demonstrated that the carbon isotope composition of mean global volcanic gas is considerably heavier, at -3.8 to -4.6 per mil (‰), than the canonical mid-ocean ridge basalt value of -6.0‰. The largest volcanic emitters outgas carbon with higher δ13C and are located in mature continental arcs that have accreted carbonate platforms, indicating that reworking of crustal limestone is an important source of volcanic carbon. The fractional burial of organic carbon is lower than traditionally determined from a global carbon isotope mass balance and may have varied over geological time, modulated by supercontinent formation and breakup.
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Affiliation(s)
- Emily Mason
- Department of Earth Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EQ, UK
| | - Marie Edmonds
- Department of Earth Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EQ, UK.
| | - Alexandra V Turchyn
- Department of Earth Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EQ, UK
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31
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Mills BJW, Scotese CR, Walding NG, Shields GA, Lenton TM. Elevated CO 2 degassing rates prevented the return of Snowball Earth during the Phanerozoic. Nat Commun 2017; 8:1110. [PMID: 29062095 PMCID: PMC5736558 DOI: 10.1038/s41467-017-01456-w] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2017] [Accepted: 09/18/2017] [Indexed: 11/29/2022] Open
Abstract
The Cryogenian period (~720-635 Ma) is marked by extensive Snowball Earth glaciations. These have previously been linked to CO2 draw-down, but the severe cold climates of the Cryogenian have never been replicated during the Phanerozoic despite similar, and sometimes more dramatic changes to carbon sinks. Here we quantify the total CO2 input rate, both by measuring the global length of subduction zones in plate tectonic reconstructions, and by sea-level inversion. Our results indicate that degassing rates were anomalously low during the Late Neoproterozoic, roughly doubled by the Early Phanerozoic, and remained comparatively high until the Cenozoic. Our carbon cycle modelling identifies the Cryogenian as a unique period during which low surface temperature was more easily achieved, and shows that the shift towards greater CO2 input rates after the Cryogenian helped prevent severe glaciation during the Phanerozoic. Such a shift appears essential for the development of complex animal life.
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Affiliation(s)
- Benjamin J W Mills
- School of Earth and Environment, University of Leeds, Leeds, LS2 9JT, UK.
- Earth System Science, College of Life and Environmental Sciences, University of Exeter, Exeter, EX4 4QE, UK.
| | - Christopher R Scotese
- Department of Earth and Planetary Sciences, Northwestern University, Evanston, IL, 60201, USA
| | - Nicholas G Walding
- Earth System Science, College of Life and Environmental Sciences, University of Exeter, Exeter, EX4 4QE, UK
| | - Graham A Shields
- Department of Earth Sciences, University College London, Gower Street, London, WC1E 6BT, UK
| | - Timothy M Lenton
- Earth System Science, College of Life and Environmental Sciences, University of Exeter, Exeter, EX4 4QE, UK
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32
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Sternai P, Caricchi L, Garcia-Castellanos D, Jolivet L, Sheldrake TE, Castelltort S. Magmatic pulse driven by sea-level changes associated with the Messinian salinity crisis. NATURE GEOSCIENCE 2017; 10:783-787. [PMID: 29081834 PMCID: PMC5654511 DOI: 10.1038/ngeo3032] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Accepted: 08/23/2017] [Indexed: 06/07/2023]
Abstract
Between 5 and 6 million years ago, during the so-called Messinian salinity crisis, the Mediterranean basin became a giant salt repository. The possibility of abrupt and kilometre-scale sea-level changes during this extreme event is debated. Messinian evaporites could signify either deep- or shallow-marine deposits, and ubiquitous erosional surfaces could indicate either subaerial or submarine features. Significant and fast reductions in sea level unload the lithosphere, which can increase the production and eruption of magma. Here we calculate variations in surface load associated with the Messinian salinity crisis and compile the available time constraints for pan-Mediterranean magmatism. We show that scenarios involving a kilometre-scale drawdown of sea level imply a phase of net overall lithospheric unloading at a time that appears synchronous with a magmatic pulse from the pan-Mediterranean igneous provinces. We verify the viability of a mechanistic link between unloading and magmatism using numerical modelling of decompression partial mantle melting and dike formation in response to surface load variations. We conclude that the Mediterranean magmatic record provides an independent validation of the controversial kilometre-scale evaporative drawdown and sheds new light on the sensitivity of magmatic systems to the surface forcing.
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Affiliation(s)
- Pietro Sternai
- Department of Earth Sciences, University of Geneva, Geneva, Switzerland
| | - Luca Caricchi
- Department of Earth Sciences, University of Geneva, Geneva, Switzerland
| | | | - Laurent Jolivet
- Intitut des Sciences de la Terre d’Orléans, University
of Orléans, Orléans, France
| | - Tom E. Sheldrake
- Department of Earth Sciences, University of Geneva, Geneva, Switzerland
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33
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Eliason CM, Hudson L, Watts T, Garza H, Clarke JA. Exceptional preservation and the fossil record of tetrapod integument. Proc Biol Sci 2017; 284:rspb.2017.0556. [PMID: 28878057 DOI: 10.1098/rspb.2017.0556] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2017] [Accepted: 07/25/2017] [Indexed: 01/06/2023] Open
Abstract
The fossil record of exceptionally preserved soft tissues in Konservat-Lagerstätten provides rare yet significant insight into past behaviours and ecologies. Such deposits are known to occur in bursts rather than evenly through time, but reasons for this pattern and implications for the origins of novel structures remain unclear. Previous assessments of these records focused on marine environments preserving chemically heterogeneous tissues from across animals. Here, we investigate the preservation of skin and keratinous integumentary structures in land-dwelling vertebrates (tetrapods) through time, and in distinct terrestrial and marine depositional environments. We also evaluate previously proposed biotic and abiotic controls on the distribution of 143 tetrapod Konservat-Lagerstätten from the Permian to the Pleistocene in a multivariate framework. Gap analyses taking into account sampling intensity and distribution indicate that feathers probably evolved close to their first appearance in the fossil record. By contrast, hair and archosaur filaments are weakly sampled (five times less common than feathers), and their origins may significantly pre-date earliest known occurrences in the fossil record. This work suggests that among-integument variation in preservation can bias the reconstructed first origins of integumentary novelties and has implications for predicting where, and in what depositional environments, to expect further discoveries of exquisitely preserved tetrapod integument.
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Affiliation(s)
- Chad M Eliason
- Department of Geological Sciences, The University of Texas at Austin, Austin, TX 78713, USA .,Department of Integrative Biology, The University of Texas at Austin, Austin, TX 78713, USA.,Field Museum of Natural History, Chicago, IL 60605, USA
| | - Leah Hudson
- Department of Geological Sciences, The University of Texas at Austin, Austin, TX 78713, USA
| | - Taylor Watts
- Department of Geological Sciences, The University of Texas at Austin, Austin, TX 78713, USA
| | - Hector Garza
- Department of Geological Sciences, The University of Texas at Austin, Austin, TX 78713, USA
| | - Julia A Clarke
- Department of Geological Sciences, The University of Texas at Austin, Austin, TX 78713, USA .,Department of Integrative Biology, The University of Texas at Austin, Austin, TX 78713, USA
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34
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Future climate forcing potentially without precedent in the last 420 million years. Nat Commun 2017; 8:14845. [PMID: 28375201 PMCID: PMC5382278 DOI: 10.1038/ncomms14845] [Citation(s) in RCA: 129] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2015] [Accepted: 02/06/2017] [Indexed: 11/08/2022] Open
Abstract
The evolution of Earth's climate on geological timescales is largely driven by variations in the magnitude of total solar irradiance (TSI) and changes in the greenhouse gas content of the atmosphere. Here we show that the slow ∼50 Wm-2 increase in TSI over the last ∼420 million years (an increase of ∼9 Wm-2 of radiative forcing) was almost completely negated by a long-term decline in atmospheric CO2. This was likely due to the silicate weathering-negative feedback and the expansion of land plants that together ensured Earth's long-term habitability. Humanity's fossil-fuel use, if unabated, risks taking us, by the middle of the twenty-first century, to values of CO2 not seen since the early Eocene (50 million years ago). If CO2 continues to rise further into the twenty-third century, then the associated large increase in radiative forcing, and how the Earth system would respond, would likely be without geological precedent in the last half a billion years.
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35
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Bataille CP, Willis A, Yang X, Liu XM. Continental igneous rock composition: A major control of past global chemical weathering. SCIENCE ADVANCES 2017; 3:e1602183. [PMID: 28345044 PMCID: PMC5342656 DOI: 10.1126/sciadv.1602183] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/09/2016] [Accepted: 02/02/2017] [Indexed: 06/06/2023]
Abstract
The composition of igneous rocks in the continental crust has changed throughout Earth's history. However, the impact of these compositional variations on chemical weathering, and by extension on seawater and atmosphere evolution, is largely unknown. We use the strontium isotope ratio in seawater [(87Sr/86Sr)seawater] as a proxy for chemical weathering, and we test the sensitivity of (87Sr/86Sr)seawater variations to the strontium isotopic composition (87Sr/86Sr) in igneous rocks generated through time. We demonstrate that the 87Sr/86Sr ratio in igneous rocks is correlated to the epsilon hafnium (εHf) of their hosted zircon grains, and we use the detrital zircon record to reconstruct the evolution of the 87Sr/86Sr ratio in zircon-bearing igneous rocks. The reconstructed 87Sr/86Sr variations in igneous rocks are strongly correlated with the (87Sr/86Sr)seawater variations over the last 1000 million years, suggesting a direct control of the isotopic composition of silicic magmatism on (87Sr/86Sr)seawater variations. The correlation decreases during several time periods, likely reflecting changes in the chemical weathering rate associated with paleogeographic, climatic, or tectonic events. We argue that for most of the last 1000 million years, the (87Sr/86Sr)seawater variations are responding to changes in the isotopic composition of silicic magmatism rather than to changes in the global chemical weathering rate. We conclude that the (87Sr/86Sr)seawater variations are of limited utility to reconstruct changes in the global chemical weathering rate in deep times.
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Affiliation(s)
- Clément P. Bataille
- Department of Geological Sciences, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Amy Willis
- Department of Statistical Science, Cornell University, Ithaca, NY 14853, USA
| | - Xiao Yang
- Department of Geological Sciences, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Xiao-Ming Liu
- Department of Geological Sciences, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
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36
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Abstract
A study of zircon minerals from around the world shows that volcanism is a key driver of long-term climate change
[Also see Report by
McKenzie
et al.
]
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Affiliation(s)
- Lee Kump
- Department of Geosciences, Pennsylvania State University, University Park, PA 16802, USA
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