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Continental flood basalts drive Phanerozoic extinctions. Proc Natl Acad Sci U S A 2022; 119:e2120441119. [PMID: 36095185 PMCID: PMC9499591 DOI: 10.1073/pnas.2120441119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Refinements of the geological timescale driven by the increasing precision and accuracy of radiometric dating have revealed an apparent correlation between large igneous provinces (LIPs) and intervals of Phanerozoic faunal turnover that has been much discussed at a qualitative level. However, the extent to which such correlations are likely to occur by chance has yet to be quantitatively tested, and other kill mechanisms have been suggested for many mass extinctions. Here, we show that the degree of temporal correlation between continental LIPs and faunal turnover in the Phanerozoic is unlikely to occur by chance, suggesting a causal relationship linking extinctions and continental flood basalts. The relationship is stronger for LIPs with higher estimated eruptive rates and for stage boundaries with higher extinction magnitudes. This suggests LIP magma degassing as a primary kill mechanism for mass extinctions and other intervals of faunal turnover, which may be related to [Formula: see text], Cl, and F release. Our results suggest continental LIPs as a major, direct driver of extinctions throughout the Phanerozoic.
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Intraplate Strike-Slip Corridor within South America (NE Border of the Paraná Basin) Unveiled by Structural Analysis of Faults and Fracture Swarms. GEOSCIENCES 2022. [DOI: 10.3390/geosciences12020101] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
We present the effect of neotectonics in intracratonic settings as revealed by the surface, brittle deformation associated to a regionally-sized shear corridor, which affects Southeastern Brazil. The deformation zone is characterized by the presence of nearly orthogonal fracture sets, interpreted as systematic and non-systematic joints often cutting Quaternary deposits. An original methodology of fault and joint inversion by the Monte Carlo converging approach is used to infer multiple paleostress fields. The method provides the best orientation of the principal paleo-stresses responsible for the observed fracturing. At each step of the inversion process, structures are uniquely associated to the stress tensor that provides the lowest error. The results showed the poly-phased tectonic history of the shear corridor studied and paleostresses compatible with a regional strike-slip motion. Specifically, an E-W, left-lateral shear was followed by an E-W, right-lateral kinematics related to the post-Paleogene drifting of South American Plate and its clockwise rotation. The latter tectonic event is presently responsible for brittle deformation observed in Quaternary deposits. The proposed deformation corridor may represent the Cenozoic reactivation of an ancient weakness zone. We speculate that the described intraplate strike-slip deformation belt represents the continental prosecution of the Rio de Janeiro fracture zone.
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BENITES SUSANA, SOMMER CARLOSA, LIMA EVANDROFDE, SAVIAN JAIROF, HAAG MAURICIOB, MONCINHATTO THIAGOR, TRINDADE RICARDOIDA. Characterization of volcanic structures associated to the silicic magmatism of the Paraná-Etendeka Province, in the Aparados da Serra region, southern Brazil. AN ACAD BRAS CIENC 2020; 92:e20180981. [DOI: 10.1590/0001-3765202020180981] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2018] [Accepted: 12/18/2018] [Indexed: 11/21/2022] Open
Affiliation(s)
- SUSANA BENITES
- Universidade Federal do Rio Grande do Sul,Instituto de Geociencias, Brazil
| | | | | | | | - MAURICIO B. HAAG
- Universidade Federal do Rio Grande do Sul,Instituto de Geociencias, Brazil
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Ferreira GS, Bronzati M, Langer MC, Sterli J. Phylogeny, biogeography and diversification patterns of side-necked turtles (Testudines: Pleurodira). ROYAL SOCIETY OPEN SCIENCE 2018; 5:171773. [PMID: 29657780 PMCID: PMC5882704 DOI: 10.1098/rsos.171773] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Accepted: 02/26/2018] [Indexed: 05/13/2023]
Abstract
Pleurodires or side-necked turtles are today restricted to freshwater environments of South America, Africa-Madagascar and Australia, but in the past they were distributed much more broadly, being found also on Eurasia, India and North America, and marine environments. Two hypotheses were proposed to explain this distribution; in the first, vicariance would have shaped the current geographical distribution and, in the second, extinctions constrained a previously widespread distribution. Here, we aim to reconstruct pleurodiran biogeographic history and diversification patterns based on a new phylogenetic hypothesis recovered from the analysis of the largest morphological dataset yet compiled for the lineage, testing which biogeographical process prevailed during its evolutionary history. The resulting topology generally agrees with previous hypotheses of the group and shows that most diversification shifts were related to the exploration of new niches, e.g. littoral or marine radiations. In addition, as other turtles, pleurodires do not seem to have been much affected by either the Cretaceous-Palaeogene or the Eocene-Oligocene mass extinctions. The biogeographic analyses highlight the predominance of both anagenetic and cladogenetic dispersal events and support the importance of transoceanic dispersals as a more common driver of area changes than previously thought, agreeing with previous studies with other non-turtle lineages.
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Affiliation(s)
- Gabriel S. Ferreira
- Biology Department, FFCLRP, University of São Paulo, Ribeirão Preto, Brazil
- Senckenberg Center for Human Evolution and Palaeoenvironment (HEP) at Eberhard Karls Universität, Sigwartstraße 10, 72076 Tübingen, Germany
- Fachbereich Geowissenschaften der Eberhard Karls Universität Tübingen, Hölderlinstraße 12, 72074 Tübingen, Germany
| | - Mario Bronzati
- Bayerische Staatssammlung für Paläontologie und Geologie, Richard-Wagner-Strasse 10, 80333 Munich, Germany
- Department of Earth and Enviromental Sciences, Ludwig–Maximilians–Universität, Richard-Wagner-Strasse 10, 80333 Munich, Germany
| | - Max C. Langer
- Biology Department, FFCLRP, University of São Paulo, Ribeirão Preto, Brazil
| | - Juliana Sterli
- CONICET-Museo Paleontológico Egidio Feruglio, Fontana 140, 9100 Trelew, Chubut, Argentina
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Multilocus phylogeny and statistical biogeography clarify the evolutionary history of major lineages of turtles. Mol Phylogenet Evol 2017; 113:59-66. [DOI: 10.1016/j.ympev.2017.05.008] [Citation(s) in RCA: 97] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2016] [Revised: 04/13/2017] [Accepted: 05/09/2017] [Indexed: 11/19/2022]
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Tennant JP, Mannion PD, Upchurch P, Sutton MD, Price GD. Biotic and environmental dynamics through the Late Jurassic-Early Cretaceous transition: evidence for protracted faunal and ecological turnover. Biol Rev Camb Philos Soc 2017; 92:776-814. [PMID: 26888552 PMCID: PMC6849608 DOI: 10.1111/brv.12255] [Citation(s) in RCA: 63] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2015] [Revised: 01/18/2016] [Accepted: 01/20/2016] [Indexed: 11/29/2022]
Abstract
The Late Jurassic to Early Cretaceous interval represents a time of environmental upheaval and cataclysmic events, combined with disruptions to terrestrial and marine ecosystems. Historically, the Jurassic/Cretaceous (J/K) boundary was classified as one of eight mass extinctions. However, more recent research has largely overturned this view, revealing a much more complex pattern of biotic and abiotic dynamics than has previously been appreciated. Here, we present a synthesis of our current knowledge of Late Jurassic-Early Cretaceous events, focusing particularly on events closest to the J/K boundary. We find evidence for a combination of short-term catastrophic events, large-scale tectonic processes and environmental perturbations, and major clade interactions that led to a seemingly dramatic faunal and ecological turnover in both the marine and terrestrial realms. This is coupled with a great reduction in global biodiversity which might in part be explained by poor sampling. Very few groups appear to have been entirely resilient to this J/K boundary 'event', which hints at a 'cascade model' of ecosystem changes driving faunal dynamics. Within terrestrial ecosystems, larger, more-specialised organisms, such as saurischian dinosaurs, appear to have suffered the most. Medium-sized tetanuran theropods declined, and were replaced by larger-bodied groups, and basal eusauropods were replaced by neosauropod faunas. The ascent of paravian theropods is emphasised by escalated competition with contemporary pterosaur groups, culminating in the explosive radiation of birds, although the timing of this is obfuscated by biases in sampling. Smaller, more ecologically diverse terrestrial non-archosaurs, such as lissamphibians and mammaliaforms, were comparatively resilient to extinctions, instead documenting the origination of many extant groups around the J/K boundary. In the marine realm, extinctions were focused on low-latitude, shallow marine shelf-dwelling faunas, corresponding to a significant eustatic sea-level fall in the latest Jurassic. More mobile and ecologically plastic marine groups, such as ichthyosaurs, survived the boundary relatively unscathed. High rates of extinction and turnover in other macropredaceous marine groups, including plesiosaurs, are accompanied by the origin of most major lineages of extant sharks. Groups which occupied both marine and terrestrial ecosystems, including crocodylomorphs, document a selective extinction in shallow marine forms, whereas turtles appear to have diversified. These patterns suggest that different extinction selectivity and ecological processes were operating between marine and terrestrial ecosystems, which were ultimately important in determining the fates of many key groups, as well as the origins of many major extant lineages. We identify a series of potential abiotic candidates for driving these patterns, including multiple bolide impacts, several episodes of flood basalt eruptions, dramatic climate change, and major disruptions to oceanic systems. The J/K transition therefore, although not a mass extinction, represents an important transitional period in the co-evolutionary history of life on Earth.
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Affiliation(s)
- Jonathan P. Tennant
- Department of Earth Science and EngineeringImperial College LondonSouth KensingtonLondonSW7 2AZU.K.
| | - Philip D. Mannion
- Department of Earth Science and EngineeringImperial College LondonSouth KensingtonLondonSW7 2AZU.K.
| | - Paul Upchurch
- Department of Earth SciencesUniversity College LondonLondonWC1E 6BTU.K.
| | - Mark D. Sutton
- Department of Earth Science and EngineeringImperial College LondonSouth KensingtonLondonSW7 2AZU.K.
| | - Gregory D. Price
- School of Geography, Earth and Environmental SciencesPlymouth UniversityPlymouthPL4 8AAU.K.
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Bonotto DM. The dissolved uranium concentration and 234U/ 238U activity ratio in groundwaters from spas of southeastern Brazil. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2017; 166:142-151. [PMID: 27020173 DOI: 10.1016/j.jenvrad.2016.03.009] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2015] [Revised: 03/04/2016] [Accepted: 03/08/2016] [Indexed: 06/05/2023]
Abstract
This paper describes the natural radioactivity due to 238U and 234U in 75 water sources from spas located in 14 municipalities in São Paulo and Minas Gerais states, Brazil. These waters are extensively utilized for drinking in public places, bottling and bathing purposes, among other uses. The water samples were taken from springs and pumped tubular wells drilled into different aquifer systems in the Paraná and Southeastern Shield hydrogeological provinces. The measurements of alpha-emitting radionuclides were also accompanied by the monitoring of temperature, pH, Eh, electrical conductivity, dissolved gases (O2, CO2, H2S, radon, thoron) and major constituents. The dissolved U concentration data were lognormally distributed. The median and mean values corresponded to 0.02 and 0.09 μg/L, respectively. Significant relationships were found among the 234U/238U activity ratio (AR) of dissolved uranium, the total dissolved solids (TDS) and dissolved bicarbonate contents, and also between the AR and dissolution rate in the monitored sites. The logU versus AR diagram used for the hydrogeochemical prospecting of concealed U deposits indicated that the water sources were mainly from reduced environments. The possibility of using the reciprocal of the dissolved U concentration and AR data to determine mixing volumes of different groundwater masses was demonstrated. The highest dissolved U concentration (4.82 μg/L) was well below the maximum allowed by WHO.
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Affiliation(s)
- Daniel Marcos Bonotto
- Departamento de Petrologia e Metalogenia, IGCE-Instituto de Geociências e Ciências Exatas, UNESP-Universidade Estadual Paulista Júlio de Mesquita Filho, Av. 24-A, No. 1515, CP 178, CEP 13506-900, Rio Claro, SP, Brazil.
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Joyce WG, Rabi M, Clark JM, Xu X. A toothed turtle from the Late Jurassic of China and the global biogeographic history of turtles. BMC Evol Biol 2016; 16:236. [PMID: 27793089 PMCID: PMC5084352 DOI: 10.1186/s12862-016-0762-5] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2016] [Accepted: 09/06/2016] [Indexed: 11/11/2022] Open
Abstract
BACKGROUND Turtles (Testudinata) are a successful lineage of vertebrates with about 350 extant species that inhabit all major oceans and landmasses with tropical to temperate climates. The rich fossil record of turtles documents the adaptation of various sub-lineages to a broad range of habitat preferences, but a synthetic biogeographic model is still lacking for the group. RESULTS We herein describe a new species of fossil turtle from the Late Jurassic of Xinjiang, China, Sichuanchelys palatodentata sp. nov., that is highly unusual by plesiomorphically exhibiting palatal teeth. Phylogenetic analysis places the Late Jurassic Sichuanchelys palatodentata in a clade with the Late Cretaceous Mongolochelys efremovi outside crown group Testudines thereby establishing the prolonged presence of a previously unrecognized clade of turtles in Asia, herein named Sichuanchelyidae. In contrast to previous hypotheses, M. efremovi and Kallokibotion bajazidi are not found within Meiolaniformes, a clade that is here reinterpreted as being restricted to Gondwana. CONCLUSIONS A revision of the global distribution of fossil and recent turtle reveals that the three primary lineages of derived, aquatic turtles, including the crown, Paracryptodira, Pan-Pleurodira, and Pan-Cryptodira can be traced back to the Middle Jurassic of Euramerica, Gondwana, and Asia, respectively, which resulted from the primary break up of Pangaea at that time. The two primary lineages of Pleurodira, Pan-Pelomedusoides and Pan-Chelidae, can similarly be traced back to the Cretaceous of northern and southern Gondwana, respectively, which were separated from one another by a large desert zone during that time. The primary divergence of crown turtles was therefore driven by vicariance to the primary freshwater aquatic habitat of these lineages. The temporally persistent lineages of basal turtles, Helochelydridae, Meiolaniformes, Sichuanchelyidae, can similarly be traced back to the Late Mesozoic of Euramerica, southern Gondwana, and Asia. Given the ambiguous phylogenetic relationships of these three lineages, it is unclear if their diversification was driven by vicariance as well, or if they display a vicariance-like pattern. The clean, primary signal apparent among early turtles is secondarily obliterated throughout the Late Cretaceous to Recent by extensive dispersal of continental turtles and by multiple invasions of marine habitats.
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Affiliation(s)
- Walter G. Joyce
- Department of Geosciences, University of Fribourg, Chemin de Musée 6, 1700 Fribourg, Switzerland
| | - Márton Rabi
- Department of Geosciences, University of Tübingen, Hölderlinstrasse 12, 72074 Tübingen, Germany
- Department of Geosciences, University of Turin, Via Valperga Caluso 35, 10125 Torino, Italy
| | - James M. Clark
- Department of Biological Sciences, George Washington University, 800 22nd Street, NW, Suite 6000, Washington, DC 20052 USA
| | - Xing Xu
- Key Laboratory of Vertebrate Evolution and Human Origin of Chinese Academy of Sciences, Institute of Vertebrate Paleontology & Paleoanthropology, Chinese Academy of Sciences, 142 Xizhimenwai Street, Beijing, 100044 China
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Self S, Thordarson T, Keszthelyi L. Emplacement of Continental Flood Basalt Lava Flows. LARGE IGNEOUS PROVINCES: CONTINENTAL, OCEANIC, AND PLANETARY FLOOD VOLCANISM 2013. [DOI: 10.1029/gm100p0381] [Citation(s) in RCA: 99] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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Peate DW. The Paraná-Etendeka Province. LARGE IGNEOUS PROVINCES: CONTINENTAL, OCEANIC, AND PLANETARY FLOOD VOLCANISM 2013. [DOI: 10.1029/gm100p0217] [Citation(s) in RCA: 103] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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Jacques PD, Machado R, Nummer AR. A comparison for a multiscale study of structural lineaments in southern Brazil: LANDSAT-7 ETM+ and shaded relief images from SRTM3-DEM. AN ACAD BRAS CIENC 2012. [DOI: 10.1590/s0001-37652012000400008] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
This paper presents a comparison of descriptive statistics obtained for brittle structural lineaments extracted manually from LANDSAT images and shaded relief images from SRTM 3 DEM at 1:100, 000 and 1:500, 000 scales. The selected area is located in the southern of Brazil and comprises Precambrian rocks and stratigraphic units of the Paraná Basin. The application of this methodology shows that the visual interpretation depends on the kind of remote sensing image. The resulting descriptive statistics obtained for lineaments extracted from the images do not follow the same pattern according to the scale adopted. The main direction obtained for Proterozoic rocks using both image types at a 1:500, 000 scale are close to NS±10, whereas at a 1:100, 000 scale N45E was obtained for shaded relief images from SRTM 3 DEM and N10W for LANDSAT images. The Paleozoic sediments yielded the best results for the different images and scales (N50W). On the other hand, the Mesozoic igneous rocks showed greatest differences, the shaded relief images from SRTM 3 DEM images highlighting NE structures and the LANDSAT images highlighting NW structures. The accumulated frequency demonstrated high similarity between products for each image type no matter the scale, indicating that they can be used in multiscale studies. Conversely, major differences were found when comparing data obtained using shaded relief images from SRTM 3 DEM and Landsat images at a 1:100, 000 scale.
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Affiliation(s)
- Patricia D. Jacques
- CPRM, Serviço Geológico do Brasil, Brasil; Universidade de São Paulo, Brasil
| | - Romulo Machado
- Universidade de São Paulo, Brasil; Universidade de São Paulo, Brasil
| | - Alexis R. Nummer
- Universidade de São Paulo, Brasil; Universidade Federal Rural do Rio de Janeiro, Brasil
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Farnetani CG, Richards MA. Numerical investigations of the mantle plume initiation model for flood basalt events. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/94jb00649] [Citation(s) in RCA: 181] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Raposo MIB, Ernesto M. An Early Cretaceous paleomagnetic pole from Ponta Grossa dikes (Brazil): Implications for the South American Mesozoic apparent polar wander path. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/95jb01681] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Sallun AE, Suguio K. Quaternary colluvial episodes (Upper Paraná River Hydrographic Basin, Brazil). AN ACAD BRAS CIENC 2010. [DOI: 10.1590/s0001-37652010000300018] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Colluvial deposits occur extensively in the Upper Paraná River Hydrographic Basin (UPRHB) in Southeastern,Southern, and Western central Brazil. These deposits were recognized as an allostratigraphic unit and related to creeping during the Quaternary. Every studied colluvial profile is homogeneous, which indicates relatively long periods of landscape stability that is sufficient for the development of a thick soil cover. The deposits were dated by luminescence and indicate periods of more intense colluvial deposition between 6 and 220 ky B.P. These events correspond approximately to the transitions between the oxygen isotope stages 2-3-4 and 5-6, suggesting that this aggradation was influenced by climatic changes. However, the most important alluviation episode was tentatively correlated with the Middle to Upper Pleniglacial of the Wisconsin glaciation. The most intensive and frequent periods of precipitation that occurred during climate transitions are probably correlated with aggradation events. The regularity of the colluvial deposits suggests continuous uplift accompanied by sediment deposition throughout the UPRHB due to neotectonic activity during the last million years.
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Campbell IH, Czamanske GK, Fedorenko VA, Hill RI, Stepanov V. Synchronism of the siberian traps and the permian-triassic boundary. Science 2010; 258:1760-3. [PMID: 17831657 DOI: 10.1126/science.258.5089.1760] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Uranium-lead ages from an ion probe were taken for zircons from the ore-bearing Noril'sk I intrusion that is comagmatic with, and intrusive to, the Siberian Traps. These values match, within an experimental error of +/-4 million years, the dates for zircons extracted from a tuff at the Permian-Triassic (P-Tr) boundary. The results are consistent with the hypothesis that the P-Tr extinction was caused by the Siberian basaltic flood volcanism. It is likely that the eruption of these magmas was accompanied by the injection of large amounts of sulfur dioxide into the upper atmosphere, which may have led to global cooling and to expansion of the polar ice cap. The P-Tr extinction event may have been caused by a combination of acid rain and global cooling as well as rapid and extreme changes in sea level resulting from expansion of the polar ice cap.
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Bonotto D, Caprioglio L, Bueno T, Lazarindo J. Dissolved 210Po and 210Pb in Guarani aquifer groundwater, Brazil. RADIAT MEAS 2009. [DOI: 10.1016/j.radmeas.2009.03.022] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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17
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Chavagnac V, German CR, Taylor RN. Global environmental effects of large volcanic eruptions on ocean chemistry: Evidence from “hydrothermal” sediments (ODP Leg 185, Site 1149B). ACTA ACUST UNITED AC 2008. [DOI: 10.1029/2007jb005333] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Bonotto DM, Bueno TO. The natural radioactivity in Guarani aquifer groundwater, Brazil. Appl Radiat Isot 2008; 66:1507-22. [PMID: 18436448 DOI: 10.1016/j.apradiso.2008.03.008] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2008] [Revised: 03/16/2008] [Accepted: 03/17/2008] [Indexed: 11/18/2022]
Abstract
The measurements of gross alpha and gross beta radioactivity in groundwater samples from Guarani aquifer in Brazil are reported in this paper together with the activity concentration of the natural dissolved radionuclides (40)K, (238)U, (234)U, (226)Ra, (222)Rn, (210)Po, (210)Pb, (232)Th, (228Th), and (228)Ra. Most of the gross alpha radioactivity values were below the critical level of detection corresponding to 1 mBq/L, however, the whole data set for the gross beta radioactivity and radionuclides (40)K, (238)U, (234)U, (226)Ra, (222)Rn, (210)Po, (210)Pb, and (228)Ra was submitted to a statistical treatment, considering class intervals arranged in geometric progression, because of the great variability of the activity. The analysis indicated lognormal distribution of the data, as usually observed in samples taken from the natural context. An inverse relationship between the gross alpha and gross beta activity has been identified and is related to an increase in the K content in the water. The mobility coefficient has been estimated for (238)U, (226)Ra, (232)Th and (228)Ra in Guarani aquifer and the results indicated that the radioelement solubility in the studied system varies according to the following order: radium>uranium>thorium. The implications of the data obtained in terms of standards established for defining the drinking water quality have also been discussed.
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Affiliation(s)
- D M Bonotto
- Departamento de Petrologia e Metalogenia, Universidade Estadual Paulista, Av. 24-A No. 1515, C.P. 178, CEP 13506-900, Rio Claro, São Paulo, Brazil.
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Cresswell RG, Bonotto DM. Some possible evolutionary scenarios suggested by 36Cl measurements in Guarani aquifer groundwaters. Appl Radiat Isot 2008; 66:1160-74. [PMID: 18308575 DOI: 10.1016/j.apradiso.2008.01.011] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2007] [Revised: 12/22/2007] [Accepted: 01/09/2008] [Indexed: 11/29/2022]
Abstract
The Guarani aquifer underlies 1.2 M km2 in the Paraná sedimentary basin of South America and is an important source of water for industry, agriculture, and domestic supplies. To determine the sustainability of this aquifer we need to understand the dynamics of the groundwater system. This paper describes the first 36Cl measurements on aquifer groundwaters and some measurements on South American rainwaters, thought to be indicative of the recharge water. The results are compared to previous work in the region, including other radioisotope analyses. A simple model is developed, incorporating radioactive decay, allowing scenarios to be developed for mixing different waters at different mixing rates. Thus, mixing scenarios consistent with other hydrogeological and hydrogeochemical data could be assessed. A model that mixes fresh recharging waters with formational waters, that contain elevated chloride levels, but low (in situ) 36Cl levels, can explain most of the results presented here. The expectation that rainwater samples would provide a good end-member for modelling recharge proved problematic, however. As a consequence, it is suggested that either: the recharge waters are not sourced from the same locations as the rains; that the current rainfall and fallout conditions were significantly different in the past; or that the low levels of chloride in rainfall may have allowed some contamination of the samples by old (36Cl-free) chloride during the recharge process.
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Affiliation(s)
- R G Cresswell
- CSIRO Land and Water, 120 Meiers Road, Indooroopilly, Queensland 4068, Australia.
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20
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Eastern Paraguay: an overview of the post-Paleozoic magmatism and geodynamic implications. RENDICONTI LINCEI 2007. [DOI: 10.1007/bf02974464] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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21
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Barabino G, Gomes CB, Traversa G. The Lages diatremes: mineral composition and petrological implications. AN ACAD BRAS CIENC 2007. [DOI: 10.1590/s0001-37652007000300010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Chemical data of heavy minerals from Lages diatremes in southern Brazil have been studied with the aim of characterizing the sample source(s). Three groups of minerals are recognized: I) aluminian-chromian pyroxene, pyrope garnet and chromian spinel, which represent disaggregated fragments of spinel, spinel+garnet and garnet facies peridotite; II) low-Cr aluminian pyroxene that occurs as megacrysts are high pressure phases (7-12 kb) being crystallized from an alkaline-like evolving magma; III) low-Cr aluminian diopside of crustal origin. Evidence of carbonatitic cryptic metasomatic enrichment is shown by clinopyroxenes of Groups I and II. The data do not support a kimberlitic affinity as it has been suggested for the diatremes. Rather, they are interpreted as vents related to the alkaline magmatism affecting the area in Late Cretaceous. The alkaline parental magma of the pyroxene megacrysts was generated from a metasomatized mantle at garnet facies that incorporated fragments of the surrounding still fertile mantle. Presumably at spinel-facies level the magma began to fractionate the megacrysts, whose crystallization proceeded over a large range of falling pressure and temperature. The chemical similarities between Group III clinopyroxenes and those from the differentiated lithotypes indicate that the magma carried this mineral phase on its evolution, at crustal conditions, towards a more evolved alkaline composition. Still, a non-cognate origin for the Group III clinopyroxenes cannot be discarded.
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Affiliation(s)
| | | | - Gianbosco Traversa
- Università di Roma La Sapienza, Italia; Università di Roma La Sapienza, Italia
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Romano PSR, Azevedo SAK. ARE EXTANT PODOCNEMIDID TURTLES RELICTS OF A WIDESPREAD CRETACEOUS ANCESTOR? SOUTH AMERICAN JOURNAL OF HERPETOLOGY 2006. [DOI: 10.2994/1808-9798(2006)1[175:aeptro]2.0.co;2] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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23
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McNeill CR, Watts B, Thomsen L, Belcher WJ, Greenham NC, Dastoor PC. Nanoscale quantitative chemical mapping of conjugated polymer blends. NANO LETTERS 2006; 6:1202-6. [PMID: 16771580 DOI: 10.1021/nl060583w] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Utilizing scanning transmission X-ray microscopy (STXM), we present a quantitative chemical analysis of the bulk composition of spin-coated blends of poly(9,9-dioctylfluorene-co-N-(4-butylphenyl)diphenylamine) (TFB) and poly(9,9'-dioctylfluorene-co-benzothiadiazole) (F8BT) used in efficient polymer light emitting diodes. With a lateral resolution of 50 nm, we reveal nanoscale subsurface chemical structure and show that in particular while blend composition remains constant within the TFB-rich domain, in the F8BT-rich phase there is an enrichment of F8BT at the domain interface.
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Bonotto DM, Mello CB. A combined method for evaluating radon and progeny in waters and its use at Guarani aquifer, São Paulo State, Brazil. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2006; 86:337-53. [PMID: 16337318 DOI: 10.1016/j.jenvrad.2005.10.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2005] [Revised: 10/10/2005] [Accepted: 10/23/2005] [Indexed: 05/05/2023]
Abstract
A combined method for evaluating radon (222Rn) and progeny (214Pb and 214Bi) in water was developed by using inexpensive alpha scintillation counting and gamma ray spectrometry through NaI(Tl) scintillation detectors. A groundwater sample collected at the Poços de Caldas alkaline massif in Brazil was submitted to the technique in order to assure its applicability by comparing the volumetric activities by different methods. Similar volumetric activity was determined for 214Pb and 214Bi in the sample analyzed that is compatible with the expected condition of radioactive equilibrium between these nuclides. The combined method was successfully used to analyze groundwater samples from Guarani aquifer in São Paulo State, Brazil, and the results of the measurements indicated that 214Pb and 214Bi provide useful information concerning the evaluation of the drinking water quality in terms of radiological aspects. This is because they are directly identified in the water samples, without the need of requiring the assumption of the establishment of the transient equilibrium condition with its parent 222Rn.
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Affiliation(s)
- D M Bonotto
- Departamento de Petrologia e Metalogenia, Universidade Estadual Paulista (UNESP), IGCE-Instituto de Geociencias e Ciencias Exatas, Av. 24-A, No. 1515, C.P. 178, CEP 13506-900, Rio Claro, São Paulo, Brazil.
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Ishizuka O, Uto K, Yuasa M. Volcanic history of the back-arc region of the Izu-Bonin (Ogasawara) arc. ACTA ACUST UNITED AC 2003. [DOI: 10.1144/gsl.sp.2003.219.01.09] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
AbstractThe laser-heating 40Ar/39Ar dating method was applied to volcanic rocks systematically collected from the back-arc region of the central part of the Izu-Bonin arc. Dating results combined with whole-rock chemistry and other geological information reveal the volcanic history of the back-arc region of the Izu-Bonin arc. In the back-arc seamount chains area, andesitic-basaltic volcanism initiated at c. 17 Ma, slightly before the Shikoku Basin ceased spreading, and continued until c. 3 Ma. Relatively old volcanism (>8 Ma) has been found only from the western part of the seamount chains, and younger volcanism mainly occurs in the eastern part of the chains, indicating the western margin of the active volcanic zone of the Izu-Bonin arc has migrated eastward with time. At around 2.8 Ma, volcanism initiated in the western part of the back-arc knolls zone. This volcanism is characterized by eruption of clinopyroxene-olivine basalt. In the first stage of rifting, this type of basalt erupted from N-S-trending fissures and/or vents aligned in this direction and formed N-S-trending ridges. Between 2.5 and 1 Ma, many small knolls were formed by eruption of basalt and minor felsic rocks. Volcanism younger than 1 Ma occurred only in the currently active rift zone and its adjacent area.The active volcanic zone in the back-arc seamount chains area converged to the volcanic front with time from 17 to 3 Ma. Active rifting and rifting-related volcanism also migrated or converged eastward after 1 Ma. The observed temporal variation of locus of volcanism may be explained by rapid retreat of the Philippine Sea Plate relative to the Pacific Plate and resulting steepening of the subducting slab.
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Affiliation(s)
- Osamu Ishizuka
- Institute of Geoscience, Geological Survey of Japan/AIST
Central 7, 1-1-1 Higashi, Tsukuba, Ibaraki, 305-8567, Japan
| | - Kozo Uto
- Institute of Geoscience, Geological Survey of Japan/AIST
Central 7, 1-1-1 Higashi, Tsukuba, Ibaraki, 305-8567, Japan
| | - Makoto Yuasa
- Geoinformation Division, Geological Survey of Japan//AIST, Central 7, 1-1-1 Higashi
Tsukuba, Ibaraki, 305-8567, Japan
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De Min A, Piccirillo EM, Marzoli A, Bellieni G, Renne PR, Ernesto M, Marques LS. The Central Atlantic Magmatic Province (CAMP) in Brazil: Petrology, geochemistry, 40Ar/39Ar ages, paleomagnetism and geodynamic implications. THE CENTRAL ATLANTIC MAGMATIC PROVINCE: INSIGHTS FROM FRAGMENTS OF PANGEA 2003. [DOI: 10.1029/136gm06] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
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27
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Rightor EG, Urquhart SG, Hitchcock AP, Ade H, Smith AP, Mitchell GE, Priester RD, Aneja A, Appel G, Wilkes G, Lidy WE. Identification and Quantitation of Urea Precipitates in Flexible Polyurethane Foam Formulations by X-ray Spectromicroscopy. Macromolecules 2002. [DOI: 10.1021/ma0122627] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- E. G. Rightor
- Analytical Sciences, The Dow Chemical Company, 1897 Building, Midland, Michigan 48667; Department of Physics, North Carolina State University, Raleigh, North Carolina 27695; Brockhouse Institute for Materials Research, McMaster University, Hamilton, ON L8S 4M1 Canada; Polyurethanes, Dow Chemical, Building B-1608, 2301 N. Brazosport Blvd., Freeport, Texas 77541; and Department of Chemical Engineering, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061
| | - S. G. Urquhart
- Analytical Sciences, The Dow Chemical Company, 1897 Building, Midland, Michigan 48667; Department of Physics, North Carolina State University, Raleigh, North Carolina 27695; Brockhouse Institute for Materials Research, McMaster University, Hamilton, ON L8S 4M1 Canada; Polyurethanes, Dow Chemical, Building B-1608, 2301 N. Brazosport Blvd., Freeport, Texas 77541; and Department of Chemical Engineering, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061
| | - A. P. Hitchcock
- Analytical Sciences, The Dow Chemical Company, 1897 Building, Midland, Michigan 48667; Department of Physics, North Carolina State University, Raleigh, North Carolina 27695; Brockhouse Institute for Materials Research, McMaster University, Hamilton, ON L8S 4M1 Canada; Polyurethanes, Dow Chemical, Building B-1608, 2301 N. Brazosport Blvd., Freeport, Texas 77541; and Department of Chemical Engineering, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061
| | - H. Ade
- Analytical Sciences, The Dow Chemical Company, 1897 Building, Midland, Michigan 48667; Department of Physics, North Carolina State University, Raleigh, North Carolina 27695; Brockhouse Institute for Materials Research, McMaster University, Hamilton, ON L8S 4M1 Canada; Polyurethanes, Dow Chemical, Building B-1608, 2301 N. Brazosport Blvd., Freeport, Texas 77541; and Department of Chemical Engineering, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061
| | - A. P. Smith
- Analytical Sciences, The Dow Chemical Company, 1897 Building, Midland, Michigan 48667; Department of Physics, North Carolina State University, Raleigh, North Carolina 27695; Brockhouse Institute for Materials Research, McMaster University, Hamilton, ON L8S 4M1 Canada; Polyurethanes, Dow Chemical, Building B-1608, 2301 N. Brazosport Blvd., Freeport, Texas 77541; and Department of Chemical Engineering, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061
| | - G. E. Mitchell
- Analytical Sciences, The Dow Chemical Company, 1897 Building, Midland, Michigan 48667; Department of Physics, North Carolina State University, Raleigh, North Carolina 27695; Brockhouse Institute for Materials Research, McMaster University, Hamilton, ON L8S 4M1 Canada; Polyurethanes, Dow Chemical, Building B-1608, 2301 N. Brazosport Blvd., Freeport, Texas 77541; and Department of Chemical Engineering, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061
| | - R. D. Priester
- Analytical Sciences, The Dow Chemical Company, 1897 Building, Midland, Michigan 48667; Department of Physics, North Carolina State University, Raleigh, North Carolina 27695; Brockhouse Institute for Materials Research, McMaster University, Hamilton, ON L8S 4M1 Canada; Polyurethanes, Dow Chemical, Building B-1608, 2301 N. Brazosport Blvd., Freeport, Texas 77541; and Department of Chemical Engineering, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061
| | - A. Aneja
- Analytical Sciences, The Dow Chemical Company, 1897 Building, Midland, Michigan 48667; Department of Physics, North Carolina State University, Raleigh, North Carolina 27695; Brockhouse Institute for Materials Research, McMaster University, Hamilton, ON L8S 4M1 Canada; Polyurethanes, Dow Chemical, Building B-1608, 2301 N. Brazosport Blvd., Freeport, Texas 77541; and Department of Chemical Engineering, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061
| | - G. Appel
- Analytical Sciences, The Dow Chemical Company, 1897 Building, Midland, Michigan 48667; Department of Physics, North Carolina State University, Raleigh, North Carolina 27695; Brockhouse Institute for Materials Research, McMaster University, Hamilton, ON L8S 4M1 Canada; Polyurethanes, Dow Chemical, Building B-1608, 2301 N. Brazosport Blvd., Freeport, Texas 77541; and Department of Chemical Engineering, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061
| | - G. Wilkes
- Analytical Sciences, The Dow Chemical Company, 1897 Building, Midland, Michigan 48667; Department of Physics, North Carolina State University, Raleigh, North Carolina 27695; Brockhouse Institute for Materials Research, McMaster University, Hamilton, ON L8S 4M1 Canada; Polyurethanes, Dow Chemical, Building B-1608, 2301 N. Brazosport Blvd., Freeport, Texas 77541; and Department of Chemical Engineering, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061
| | - W. E. Lidy
- Analytical Sciences, The Dow Chemical Company, 1897 Building, Midland, Michigan 48667; Department of Physics, North Carolina State University, Raleigh, North Carolina 27695; Brockhouse Institute for Materials Research, McMaster University, Hamilton, ON L8S 4M1 Canada; Polyurethanes, Dow Chemical, Building B-1608, 2301 N. Brazosport Blvd., Freeport, Texas 77541; and Department of Chemical Engineering, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061
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Mitchell GE, Wilson LR, Dineen MT, Urquhart SG, Hayes F, Rightor EG, Hitchcock AP, Ade H. Quantitative Characterization of Microscopic Variations in the Cross-Link Density of Gels. Macromolecules 2001. [DOI: 10.1021/ma010840d] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- G. E. Mitchell
- Analytical Sciences Laboratory, The Dow Chemical Company, 1897 Building, Midland, Michigan 48667; Superabsorbent Products R&D, The Dow Chemical Company, 1603 Building, Midland, Michigan 48667; Department of Physics, North Carolina State University, Raleigh, North Carolina 27695; and Brockhouse Institute for Materials Research, McMaster University, Hamilton, Ontario L8S 4M1, Canada
| | - L. R. Wilson
- Analytical Sciences Laboratory, The Dow Chemical Company, 1897 Building, Midland, Michigan 48667; Superabsorbent Products R&D, The Dow Chemical Company, 1603 Building, Midland, Michigan 48667; Department of Physics, North Carolina State University, Raleigh, North Carolina 27695; and Brockhouse Institute for Materials Research, McMaster University, Hamilton, Ontario L8S 4M1, Canada
| | - M. T. Dineen
- Analytical Sciences Laboratory, The Dow Chemical Company, 1897 Building, Midland, Michigan 48667; Superabsorbent Products R&D, The Dow Chemical Company, 1603 Building, Midland, Michigan 48667; Department of Physics, North Carolina State University, Raleigh, North Carolina 27695; and Brockhouse Institute for Materials Research, McMaster University, Hamilton, Ontario L8S 4M1, Canada
| | - S. G. Urquhart
- Analytical Sciences Laboratory, The Dow Chemical Company, 1897 Building, Midland, Michigan 48667; Superabsorbent Products R&D, The Dow Chemical Company, 1603 Building, Midland, Michigan 48667; Department of Physics, North Carolina State University, Raleigh, North Carolina 27695; and Brockhouse Institute for Materials Research, McMaster University, Hamilton, Ontario L8S 4M1, Canada
| | - F. Hayes
- Analytical Sciences Laboratory, The Dow Chemical Company, 1897 Building, Midland, Michigan 48667; Superabsorbent Products R&D, The Dow Chemical Company, 1603 Building, Midland, Michigan 48667; Department of Physics, North Carolina State University, Raleigh, North Carolina 27695; and Brockhouse Institute for Materials Research, McMaster University, Hamilton, Ontario L8S 4M1, Canada
| | - E. G. Rightor
- Analytical Sciences Laboratory, The Dow Chemical Company, 1897 Building, Midland, Michigan 48667; Superabsorbent Products R&D, The Dow Chemical Company, 1603 Building, Midland, Michigan 48667; Department of Physics, North Carolina State University, Raleigh, North Carolina 27695; and Brockhouse Institute for Materials Research, McMaster University, Hamilton, Ontario L8S 4M1, Canada
| | - A. P. Hitchcock
- Analytical Sciences Laboratory, The Dow Chemical Company, 1897 Building, Midland, Michigan 48667; Superabsorbent Products R&D, The Dow Chemical Company, 1603 Building, Midland, Michigan 48667; Department of Physics, North Carolina State University, Raleigh, North Carolina 27695; and Brockhouse Institute for Materials Research, McMaster University, Hamilton, Ontario L8S 4M1, Canada
| | - H. Ade
- Analytical Sciences Laboratory, The Dow Chemical Company, 1897 Building, Midland, Michigan 48667; Superabsorbent Products R&D, The Dow Chemical Company, 1603 Building, Midland, Michigan 48667; Department of Physics, North Carolina State University, Raleigh, North Carolina 27695; and Brockhouse Institute for Materials Research, McMaster University, Hamilton, Ontario L8S 4M1, Canada
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Koprinarov I, Hitchcock AP, Li WH, Heng YM, Stöver HDH. Quantitative Compositional Mapping of Core−Shell Polymer Microspheres by Soft X-ray Spectromicroscopy. Macromolecules 2001. [DOI: 10.1021/ma001626c] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- I. Koprinarov
- Department of Chemistry & BIMR, McMaster University, Hamilton, Ontario L8S 4M1, Canada
| | - A. P. Hitchcock
- Department of Chemistry & BIMR, McMaster University, Hamilton, Ontario L8S 4M1, Canada
| | - W. H. Li
- Department of Chemistry & BIMR, McMaster University, Hamilton, Ontario L8S 4M1, Canada
| | - Y. M. Heng
- Department of Chemistry & BIMR, McMaster University, Hamilton, Ontario L8S 4M1, Canada
| | - H. D. H. Stöver
- Department of Chemistry & BIMR, McMaster University, Hamilton, Ontario L8S 4M1, Canada
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Cracraft J. Avian evolution, Gondwana biogeography and the Cretaceous-Tertiary mass extinction event. Proc Biol Sci 2001; 268:459-69. [PMID: 11296857 PMCID: PMC1088628 DOI: 10.1098/rspb.2000.1368] [Citation(s) in RCA: 169] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The fossil record has been used to support the origin and radiation of modern birds (Neornithes) in Laurasia after the Cretaceous-Tertiary mass extinction event, whereas molecular clocks have suggested a Cretaceous origin for most avian orders. These alternative views of neornithine evolution are examined using an independent set of evidence, namely phylogenetic relationships and historical biogeography. Pylogenetic relationships of basal lineages of neornithines, including ratite birds and their allies (Palaleocognathae), galliforms and anseriforms (Galloanserae), as well as lineages of the more advanced Neoves (Gruiformes, (Capimulgiformes, Passeriformes and others) demonstrate pervasive trans-Antarctic distribution patterns. The temporal history of the neornithines can be inferred from fossil taxa and the ages of vicariance events, and along with their biogeographical patterns, leads to the conclusion that neornithines arose in Gondwana prior to the Cretaceous Tertiary extinction event.
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Affiliation(s)
- J Cracraft
- Department of Ornithology, American Museum of Natural History, New York, NY 10024, USA.
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31
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Cashman K, Pinkerton H, Stephenson J. Introduction to Special Section: Long Lava Flows. ACTA ACUST UNITED AC 1998. [DOI: 10.1029/98jb01820] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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32
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Kosterov AA, Perrin M, Glen JM, Coe RS. Paleointensity of the Earth's magnetic field in Early Cretaceous time: The Paraná Basalt, Brazil. ACTA ACUST UNITED AC 1998. [DOI: 10.1029/98jb00022] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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33
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Raia F, Spera FJ. Simulations of crustal anatexis: Implications for the growth and differentiation of continental crust. ACTA ACUST UNITED AC 1997. [DOI: 10.1029/97jb01589] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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34
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Duncan RA, Hooper PR, Rehacek J, Marsh JS, Duncan AR. The timing and duration of the Karoo igneous event, southern Gondwana. ACTA ACUST UNITED AC 1997. [DOI: 10.1029/97jb00972] [Citation(s) in RCA: 396] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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35
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Chapter 11 The owambo basin of northern namibia. ACTA ACUST UNITED AC 1997. [DOI: 10.1016/s1874-5997(97)80014-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/28/2023]
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36
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Turner S, Hawkesworth C, Gallagher K, Stewart K, Peate D, Mantovani M. Mantle plumes, flood basalts, and thermal models for melt generation beneath continents: Assessment of a conductive heating model and application to the Paraná. ACTA ACUST UNITED AC 1996. [DOI: 10.1029/96jb00430] [Citation(s) in RCA: 114] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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37
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Storey BC. The role of mantle plumes in continental breakup: case histories from Gondwanaland. Nature 1995. [DOI: 10.1038/377301a0] [Citation(s) in RCA: 493] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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38
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Basu AR, Poreda RJ, Renne PR, Teichmann F, Vasiliev YR, Sobolev NV, Turrin BD. High-
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He Plume Origin and Temporal-Spatial Evolution of the Siberian Flood Basalts. Science 1995; 269:822-5. [PMID: 17778742 DOI: 10.1126/science.269.5225.822] [Citation(s) in RCA: 126] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
An olivine nephelinite from the lower part of a thick alkalic ultrabasic and mafic sequence of volcanic rocks of the northeastern part of the Siberian flood basalt province (SFBP) yielded a (40)Ar/(39)Ar plateau age of 253.3 +/- 2.6 million years, distinctly older than the main tholeiitic pulse of the SFBP at 250.0 million years. Olivine phenocrysts of this rock showed (3)He/(4)He ratios up to 12.7 times the atmospheric ratio; these values suggest a lower mantle plume origin. The neodymium and strontium isotopes, rare earth element concentration patterns, and cerium/lead ratios of the associated rocks were also consistent with their derivation from a near-chondritic, primitive plume. Geochemical data from the 250-million-year-old volcanic rocks higher up in the sequence indicate interaction of this high-(3)He SFBP plume with a suboceanic-type upper mantle beneath Siberia.
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39
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Catastrophe: impact of comets and asteroids. ACTA ACUST UNITED AC 1995. [DOI: 10.1016/s0168-6321(06)80027-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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40
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Bercovici D, Mahoney J. Double Flood Basalts and Plume Head Separation at the 660-Kilometer Discontinuity. Science 1994; 266:1367-9. [PMID: 17772845 DOI: 10.1126/science.266.5189.1367] [Citation(s) in RCA: 102] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Several of the world's flood basalt provinces display two distinct times of major eruptions separated by between 20 million and 90 million years. These double flood basalts may occur because a starting mantle plume head can separate from its trailing conduit upon passing the interface between the upper mantle and the lower mantle. This detached plume head eventually triggers the first flood basalt event. The remaining conduit forms a new plume head, which causes the second eruptive event. The second plume head is predicted to arrive at the lithosphere at least 10 million years after the first plume head, in general agreement with observations regarding double flood basalts.
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Basu AR, Renne PR, Dasgupta DK, Teichmann F, Poreda RJ. Early and Late Alkali Igneous Pulses and a High-
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He Plume Origin for the Deccan Flood Basalts. Science 1993; 261:902-6. [PMID: 17783739 DOI: 10.1126/science.261.5123.902] [Citation(s) in RCA: 231] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Several alkalic igneous complexes of nephelinite-carbonatite affinities occur in extensional zones around a region of high heat flow and positive gravity anomaly within the continental flood basalt (CFB) province of Deccan, India. Biotites from two of the complexes yield (40)Ar/(39)Ar dates of 68.53 +/- 0.16 and 68.57 +/- 0.08 million years. Biotite from a third complex, which intrudes the flood basalts, yields an (40)Ar/(39)Ar date of 64.96 +/- 0.1 1 million years. The complexes thus represent early and late magmatism with respect to the main pulse of CFB volcanism 65 million years ago. Rocks from the older complexes show a (3)He/(4)He ratio of 14.0 times the air ratio, an initial (87)Sr/(86)Sr ratio of 0.70483, and other geochemical characteristics similar to ocean island basalts; the later alkalic pulse shows isotopic evidence of crustal contamination. The data document 3.5 million years of incubation of a primitive, high-(3)He mantle plume before the rapid eruption of the Deccan CFB.
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