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Israde-Alcántara I, Bischoff JL, Domínguez-Vázquez G, Li HC, DeCarli PS, Bunch TE, Wittke JH, Weaver JC, Firestone RB, West A, Kennett JP, Mercer C, Xie S, Richman EK, Kinzie CR, Wolbach WS. Evidence from central Mexico supporting the Younger Dryas extraterrestrial impact hypothesis. Proc Natl Acad Sci U S A 2012; 109:E738-47. [PMID: 22392980 PMCID: PMC3324006 DOI: 10.1073/pnas.1110614109] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
We report the discovery in Lake Cuitzeo in central Mexico of a black, carbon-rich, lacustrine layer, containing nanodiamonds, microspherules, and other unusual materials that date to the early Younger Dryas and are interpreted to result from an extraterrestrial impact. These proxies were found in a 27-m-long core as part of an interdisciplinary effort to extract a paleoclimate record back through the previous interglacial. Our attention focused early on an anomalous, 10-cm-thick, carbon-rich layer at a depth of 2.8 m that dates to 12.9 ka and coincides with a suite of anomalous coeval environmental and biotic changes independently recognized in other regional lake sequences. Collectively, these changes have produced the most distinctive boundary layer in the late Quaternary record. This layer contains a diverse, abundant assemblage of impact-related markers, including nanodiamonds, carbon spherules, and magnetic spherules with rapid melting/quenching textures, all reaching synchronous peaks immediately beneath a layer containing the largest peak of charcoal in the core. Analyses by multiple methods demonstrate the presence of three allotropes of nanodiamond: n-diamond, i-carbon, and hexagonal nanodiamond (lonsdaleite), in order of estimated relative abundance. This nanodiamond-rich layer is consistent with the Younger Dryas boundary layer found at numerous sites across North America, Greenland, and Western Europe. We have examined multiple hypotheses to account for these observations and find the evidence cannot be explained by any known terrestrial mechanism. It is, however, consistent with the Younger Dryas boundary impact hypothesis postulating a major extraterrestrial impact involving multiple airburst(s) and and/or ground impact(s) at 12.9 ka.
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Affiliation(s)
- Isabel Israde-Alcántara
- Departamento de Geología y Mineralogía, Edif. U-4. Instituto de Investigaciones Metalúrgicas, Universidad Michoacana de San Nicólas de Hidalgo, C. P. 58060, Morelia, Michoacán, México
| | | | - Gabriela Domínguez-Vázquez
- Facultad de Biología, Universidad Michoacana de San Nicólas Hidalgo C. P. 58060, Morelia, Michoacán, México
| | - Hong-Chun Li
- Department of Geosciences, National Taiwan University, Taipei 106, Taiwan, Republic of China
| | | | - Ted E. Bunch
- Geology Program, School of Earth Science and Environmental Sustainability, Northern Arizona University, Flagstaff AZ 86011
| | - James H. Wittke
- Geology Program, School of Earth Science and Environmental Sustainability, Northern Arizona University, Flagstaff AZ 86011
| | - James C. Weaver
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Cambridge, MA 02138
| | | | | | - James P. Kennett
- />Department of Earth Science and Marine Science Institute, University of California, Santa Barbara, CA 93106
| | - Chris Mercer
- National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki, 305-0047, Japan
| | - Sujing Xie
- CAMCOR High Resolution and MicroAnalytical Facilities, University of Oregon, Eugene, OR 97403
| | - Eric K. Richman
- Materials Science Institute, University of Oregon, Eugene, Oregon 97403; and
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Wasson JT. Large aerial bursts: an important class of terrestrial accretionary events. ASTROBIOLOGY 2003; 3:163-179. [PMID: 12809134 DOI: 10.1089/153110703321632499] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Large aerial bursts similar to the 1908 Tunguska bolide but much larger in magnitude have surely been responsible for many catastrophic events in the history of the Earth. Because aerial bursts produce shallow (or even negligible) craters, their existence is difficult to document in the geological record. Even aerial bursts as small as Tunguska deposit enough energy to melt approximately 1mm of dry soil. Silica-rich glass formed in such melts has the potential to survive in the soil for many Ma, thus a potential indicator of large aerial bursts is glass that was formed as thick regions within silicate melt sheets. The layered tektites from Southeast Asia and the Libyan desert glass may have formed by a combination of sedimentation and downslope flow of silicate melt heated by radiation from large aerial bursts. The alternative, formation of layered tektites as crater ejecta, cannot account for observations such as uniformly high 10Be contents, the orientation of the magnetic remanence field, and the absence of splash-form (e.g., teardrop or dumbbell) tektites in regions where layered tektites are common. The largest asteroids or comets make craters no matter what their strength. Recent reviews suggest that, for events in the energy range up to 10(19)-10(20) J (about two orders of magnitude larger than the Meteor Crater impact), aerial bursts are more likely than cratering events, and the layered tektites of Southeast Asia imply the existence of aerial bursts one to two orders of magnitude larger still.
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Affiliation(s)
- John T Wasson
- Institute of Geophysics and Planetary Physics and Department of Earth and Space Sciences, University of California, Los Angeles 90095-1567, USA.
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Mukhopadhyay S, Farley KA, Montanari A. A short duration of the Cretaceous-Tertiary boundary event: evidence from extraterrestrial helium-3. Science 2001; 291:1952-5. [PMID: 11239153 DOI: 10.1126/science.291.5510.1952] [Citation(s) in RCA: 81] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Analyses of marine carbonates through the interval 63.9 to 65.4 million years ago indicate a near-constant flux of extraterrestrial helium-3, a tracer of the accretion rate of interplanetary dust to Earth. This observation indicates that the bolide associated with the Cretaceous-Tertiary (K-T) extinction event was not accompanied by enhanced solar system dustiness and so could not have been a member of a comet shower. The use of helium-3 as a constant-flux proxy of sedimentation rate implies deposition of the K-T boundary clay in (10 +/- 2) x 10(3) years, precluding the possibility of a long hiatus at the boundary and requiring extremely rapid faunal turnover.
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Affiliation(s)
- S Mukhopadhyay
- Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125, USA.
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