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Showing results for tags 'meteorite impact'.
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Controversy over impact origin of Maniitsoq structure (West Greeland) continues
Oxytropidoceras posted a topic in Geology
World's oldest meteor crater isn't what it seems By Harry Baker, Live Science, March 24, 2021 New controversial claim suggests it's not a meteor crater at all. Science Tech Daily, March 26, 2021 The paper is: Yakymchuk, C., Kirkland, C.L., Cavosie, A.J., Szilas, K., Hollis, J., Gardiner, N.J., Waterton, P., Steenfelt, A. and Martin, L., 2021. Stirred not shaken; critical evaluation of a proposed Archean meteorite impact in West Greenland. Earth and Planetary Science Letters, 557, no. 116730. PDF file of above paper on Researchgate Yours, Paul H.- 1 reply
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- archean
- asteroid impact
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Meteorite strikes may create unexpected form of silica Carnegie Institution for Science, August 26, 2020 The paper is: Sally June Tracy, Stefan J. Turneaure, Thomas S. Duffy. Structural response of α-quartz under plate-impact shock compression. Science Advances, 2020; 6 (35): eabb3913 Yours Paul H.
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- hypervelocity impact
- impactite
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Volcanic origin for Younger Dryas geochemical anomalies ca. 12,900 cal B.P.
Oxytropidoceras posted a topic in Fossil News
Texas cave sediment upends meteorite explanation for global cooling by Baylor University August 1, 2020 https://phys.org/news/2020-07-texas-cave-sediment-upends-meteorite.html The paper is: Sun, N, Brandon, A.D., Forman, S.L., Waters, M.R. and Befus, K.S., 2020. Volcanic origin for Younger Dryas geochemical anomalies ca. 12,900 cal B.P. Science Advances, 6(31), eaax8587 https://advances.sciencemag.org/content/6/31/eaax8587 Related papers: Holliday, V.T., Bartlein, P.J., Scott, A.C. and Marlon, J.R., 2020. Extraordinary biomass-burning episode and impact winter triggered by the Younger Dryas cosmic impact∼ 12,800 years ago, parts 1 and 2: a discussion. The Journal of Geology, 128(1), pp.69-94. https://www.journals.uchicago.edu/doi/abs/10.1086/706264 Wolbach, W.S., Ballard, J.P., Mayewski, P.A., Kurbatov, A., Bunch, T.E., LeCompte, M.A., Adedeji, V., Israde-Alcántara, I., Firestone, R.B., Mahaney, W.C. and Melott, A.L., 2020. Extraordinary Biomass-Burning Episode and Impact Winter Triggered by the Younger Dryas Cosmic Impact∼ 12,800 Years Ago: A Reply. The Journal of Geology, 128(1), pp.95-107. https://www.journals.uchicago.edu/doi/abs/10.1086/706265 Yours, Paul H.-
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- caves
- geochemical anomalies
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New Investigation of a Greenland ice core platinum anomaly near the Bølling-Allerød/Younger Dryas boundary
Oxytropidoceras posted a topic in Fossil News
Green, C. E., 2019. Investigating the origin of a Greenland ice core geochemical anomaly near the Bølling-Allerød/Younger Dryas boundary (Doctoral dissertation, Durham University). http://etheses.dur.ac.uk/13490/ http://etheses.dur.ac.uk/13490/1/C_Green_thesis_final_CORRECTIONS.pdf Green (2019) noted: "The source of a platinum peak identified in the Greenland Ice Sheet Project 2 (GISP2) ice core associated with high platinum/iridium (Pt/Ir) and platinum/aluminium (Pt/Al) ratios, and previous research attributed the anomaly to an unusual iron-rich Ir-poor meteorite impact." Green (2019) concluded: I. the Laacher See eruption is not the Pt spike source because: A. the Laacher See tephra has low Pt concentrations, B. the Laacher See tephra’s geochemical ratios are dissimilar to the GISP2 Pt spike and C. conversion of the Pt spike timing to the newest ice core age-depth model shows a chronological offset of ~60 years between the two events. II. The event resulting in the Pt spike occurred ~60 years after GS-1 cooling, and was therefore not the primary trigger. III. and the Pt spike origin is interpreted as either: A. a noncataclysmic impact of an undiscovered iron meteorite B. or an unidentified Pt-rich volcanic eruption contemporaneous with the anomaly, whose aerosol fractionated in the atmosphere or ice. Yours, Paul H.-
- bølling-allerød
- extraterrestrial impact
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