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Christ O, Nestola F, Alvaro M. Open questions on carbonaceous matter in meteorites. Commun Chem 2024; 7:118. [PMID: 38811753 DOI: 10.1038/s42004-024-01200-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2024] [Accepted: 05/14/2024] [Indexed: 05/31/2024] Open
Affiliation(s)
- Oliver Christ
- Department of Earth and Environmental Sciences, University of Pavia, 27100, Pavia, Italy.
| | - Fabrizio Nestola
- Department of Geosciences, University of Padua, 35131, Padua, Italy
| | - Matteo Alvaro
- Department of Earth and Environmental Sciences, University of Pavia, 27100, Pavia, Italy
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2
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Moore CR, Brooks MJ, Dunbar JS, Hemmings CA, Langworthy KA, West A, LeCompte MA, Adedeji V, Kennett JP, Feathers JK. Platinum and microspherule peaks as chronostratigraphic markers for onset of the Younger Dryas at Wakulla Springs, Florida. Sci Rep 2023; 13:22738. [PMID: 38123649 PMCID: PMC10733423 DOI: 10.1038/s41598-023-50074-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2023] [Accepted: 12/14/2023] [Indexed: 12/23/2023] Open
Abstract
Anomalous peak abundances of platinum and Fe-rich microspherules with high-temperature minerals have previously been demonstrated to be a chronostratigraphic marker for the lower Younger Dryas Boundary (YDB) dating to 12.8 ka. This study used Bayesian analyses to test this hypothesis in multiple sequences (units) of sandy, weakly stratified sediments at Wakulla Springs, Florida. Our investigations included platinum geochemistry, granulometry, optically stimulated luminescence (OSL) dating, and culturally dated lithics. In addition, sediments were analyzed using scanning electron microscopy and energy dispersive x-ray spectroscopy to investigate dendritic, iron-rich microspherules previously identified elsewhere in peak abundances at the onset of the Younger Dryas (YD) cool climatic episode. Our work has revealed this abundance peak in platinum and dendritic spherules in five sediment sequences at Wakulla Springs. A YDB age of ~ 12.8 ka for the platinum and spherule chronostratigraphic datum in these Wakulla Springs sequences is consistent with the archaeological data and OSL dating. This study confirms the utility of this YDB datum layer for intersequence correlation and for assessing relative ages of Paleoamerican artifacts, including those of likely Clovis, pre-Clovis, and post-Clovis age and their possible responses to environmental changes known to have occurred during the Younger Dryas cool climatic episode.
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Affiliation(s)
- Christopher R Moore
- South Carolina Institute of Archaeology and Anthropology, University of South Carolina, P.O. Box 400, New Ellenton, SC, 29809, USA.
| | - Mark J Brooks
- South Carolina Institute of Archaeology and Anthropology, University of South Carolina, P.O. Box 400, New Ellenton, SC, 29809, USA
| | - James S Dunbar
- Aucilla Research Institute Inc., 555 North Jefferson Street, Monticello, FL, 32344, USA
| | - C Andrew Hemmings
- Aucilla Research Institute Inc., 555 North Jefferson Street, Monticello, FL, 32344, USA
| | - Kurt A Langworthy
- CAMCOR, University of Oregon, 1443 E 13Th Ave, Eugene, OR, 97403, USA
| | | | - Malcolm A LeCompte
- Center of Excellence in Remote Sensing Education and Research, Elizabeth City State University, Elizabeth City, NC, 27909, USA
| | - Victor Adedeji
- Department of Natural Sciences, Elizabeth City State University, Elizabeth City, NC, 27909, USA
| | - James P Kennett
- Department of Earth Science and Marine Science Institute, University of California, Santa Barbara, CA, 93106, USA
| | - James K Feathers
- Luminescence Dating Laboratory, University of Washington, 125 Raitt Hall, Seattle, WA, 98195-3412, USA
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3
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Zhang J, Lu T, Xiao J, Du C, Chen H, Li R, Sui X, Pan Z, Xiao C, Zhao X, Yao J, Liu Y, Lei Y, Ruan Y, Zhang J, Li H, Zhang Q, Zhang Y, Cai J, Yang Y, Zheng J. MSC-derived extracellular vesicles as nanotherapeutics for promoting aged liver regeneration. J Control Release 2023; 356:402-415. [PMID: 36858264 DOI: 10.1016/j.jconrel.2023.02.032] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2022] [Revised: 02/22/2023] [Accepted: 02/23/2023] [Indexed: 03/03/2023]
Abstract
Aging is one of the critical factors to impair liver regeneration leading to a high incidence of severe complications after hepatic surgery in the elderly population without any effective treatment for clinical administration. As cell-free nanotherapeutics, mesenchymal stem cell-derived extracellular vesicles (MSC-EVs) have been demonstrated the therapeutic potentials on liver diseases. However, the effects of MSC-EVs on the proliferation of aged hepatocytes are largely unclear. In this study, we found MSCs could reduce the expression of senescence-associated markers in the liver and stimulate its regeneration in aged mice after receiving a two-thirds partial hepatectomy (PHx) through their secreted MSC-EVs. Using RNA-Seq and AAV9 vector, we mechanistically found that these effects of UC-MSC-EVs partially attributed to inducing Atg4B-related mitophagy. This effect repairs the mitochondrial status and functions of aged hepatocytes to promote their proliferation. And protein mass spectrum analysis uncovered that DEAD-Box Helicase 5 (DDX5) enriches in UC-MSC-EVs, which interacts with E2F1 to facilitate its nuclear translocation for activating the expression of Atg4B. Collectively, our data show that MSC-EVs act nanotherapeutic potentials in anti-senescence and promoting regeneration of aged liver by transferring DDX5 to regulate E2F1-Atg4B signaling pathway that induce mitophagy, which highlights the clinical application valuation of MSC-EVs for preventing severe complications in aged population receiving liver surgery.
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Affiliation(s)
- Jiebin Zhang
- Department of Hepatic Surgery and Liver Transplantation Center of the Third Affiliated Hospital of Sun Yat-sen University; Organ Transplantation Research Center of Guangdong Province, Guangdong Province Engineering Laboratory for Transplantation Medicine. Guangzhou 510630, China; Guangdong Key Laboratory of Liver Disease Research, Key Laboratory of Liver Disease Biotherapy and Translational Medicine of Guangdong Higher Education Institutes, the Third Affiliated Hospital of Sun Yat-sen University, Guangzhou 510630, China
| | - Tongyu Lu
- Department of Hepatic Surgery and Liver Transplantation Center of the Third Affiliated Hospital of Sun Yat-sen University; Organ Transplantation Research Center of Guangdong Province, Guangdong Province Engineering Laboratory for Transplantation Medicine. Guangzhou 510630, China; Guangdong Key Laboratory of Liver Disease Research, Key Laboratory of Liver Disease Biotherapy and Translational Medicine of Guangdong Higher Education Institutes, the Third Affiliated Hospital of Sun Yat-sen University, Guangzhou 510630, China
| | - Jiaqi Xiao
- Department of Hepatic Surgery and Liver Transplantation Center of the Third Affiliated Hospital of Sun Yat-sen University; Organ Transplantation Research Center of Guangdong Province, Guangdong Province Engineering Laboratory for Transplantation Medicine. Guangzhou 510630, China; Guangdong Key Laboratory of Liver Disease Research, Key Laboratory of Liver Disease Biotherapy and Translational Medicine of Guangdong Higher Education Institutes, the Third Affiliated Hospital of Sun Yat-sen University, Guangzhou 510630, China
| | - Cong Du
- Biological Treatment Center, the Third Affiliated Hospital of Sun Yat-sen University, Guangzhou 510630, China
| | - Haitian Chen
- Department of Hepatic Surgery and Liver Transplantation Center of the Third Affiliated Hospital of Sun Yat-sen University; Organ Transplantation Research Center of Guangdong Province, Guangdong Province Engineering Laboratory for Transplantation Medicine. Guangzhou 510630, China; Guangdong Key Laboratory of Liver Disease Research, Key Laboratory of Liver Disease Biotherapy and Translational Medicine of Guangdong Higher Education Institutes, the Third Affiliated Hospital of Sun Yat-sen University, Guangzhou 510630, China
| | - Rong Li
- Guangdong Key Laboratory of Liver Disease Research, Key Laboratory of Liver Disease Biotherapy and Translational Medicine of Guangdong Higher Education Institutes, the Third Affiliated Hospital of Sun Yat-sen University, Guangzhou 510630, China
| | - Xin Sui
- Surgical ICU, the Third Affiliated Hospital of Sun Yat-sen University, Guangzhou 510630, China
| | - Zihao Pan
- Department of Gastrointestinal Surgery, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou 510080, China
| | - Cuicui Xiao
- Guangdong Key Laboratory of Liver Disease Research, Key Laboratory of Liver Disease Biotherapy and Translational Medicine of Guangdong Higher Education Institutes, the Third Affiliated Hospital of Sun Yat-sen University, Guangzhou 510630, China; Department of Anesthesiology, the Third Affiliated Hospital of Sun Yat-sen University, Guangzhou 510630, China
| | - Xuegang Zhao
- Surgical ICU, the Third Affiliated Hospital of Sun Yat-sen University, Guangzhou 510630, China
| | - Jia Yao
- Department of Hepatic Surgery and Liver Transplantation Center of the Third Affiliated Hospital of Sun Yat-sen University; Organ Transplantation Research Center of Guangdong Province, Guangdong Province Engineering Laboratory for Transplantation Medicine. Guangzhou 510630, China; Guangdong Key Laboratory of Liver Disease Research, Key Laboratory of Liver Disease Biotherapy and Translational Medicine of Guangdong Higher Education Institutes, the Third Affiliated Hospital of Sun Yat-sen University, Guangzhou 510630, China
| | - Yasong Liu
- Department of Hepatic Surgery and Liver Transplantation Center of the Third Affiliated Hospital of Sun Yat-sen University; Organ Transplantation Research Center of Guangdong Province, Guangdong Province Engineering Laboratory for Transplantation Medicine. Guangzhou 510630, China; Guangdong Key Laboratory of Liver Disease Research, Key Laboratory of Liver Disease Biotherapy and Translational Medicine of Guangdong Higher Education Institutes, the Third Affiliated Hospital of Sun Yat-sen University, Guangzhou 510630, China
| | - Yunguo Lei
- Department of Hepatic Surgery and Liver Transplantation Center of the Third Affiliated Hospital of Sun Yat-sen University; Organ Transplantation Research Center of Guangdong Province, Guangdong Province Engineering Laboratory for Transplantation Medicine. Guangzhou 510630, China; Guangdong Key Laboratory of Liver Disease Research, Key Laboratory of Liver Disease Biotherapy and Translational Medicine of Guangdong Higher Education Institutes, the Third Affiliated Hospital of Sun Yat-sen University, Guangzhou 510630, China
| | - Ying Ruan
- Department of thyroid and breast surgery, the Third Affiliated Hospital of Sun Yat-sen University, Guangzhou 510630, China
| | - Jian Zhang
- Department of Hepatic Surgery and Liver Transplantation Center of the Third Affiliated Hospital of Sun Yat-sen University; Organ Transplantation Research Center of Guangdong Province, Guangdong Province Engineering Laboratory for Transplantation Medicine. Guangzhou 510630, China; Guangdong Key Laboratory of Liver Disease Research, Key Laboratory of Liver Disease Biotherapy and Translational Medicine of Guangdong Higher Education Institutes, the Third Affiliated Hospital of Sun Yat-sen University, Guangzhou 510630, China
| | - Hua Li
- Department of Hepatic Surgery and Liver Transplantation Center of the Third Affiliated Hospital of Sun Yat-sen University; Organ Transplantation Research Center of Guangdong Province, Guangdong Province Engineering Laboratory for Transplantation Medicine. Guangzhou 510630, China; Guangdong Key Laboratory of Liver Disease Research, Key Laboratory of Liver Disease Biotherapy and Translational Medicine of Guangdong Higher Education Institutes, the Third Affiliated Hospital of Sun Yat-sen University, Guangzhou 510630, China
| | - Qi Zhang
- Biological Treatment Center, the Third Affiliated Hospital of Sun Yat-sen University, Guangzhou 510630, China
| | - Yingcai Zhang
- Department of Hepatic Surgery and Liver Transplantation Center of the Third Affiliated Hospital of Sun Yat-sen University; Organ Transplantation Research Center of Guangdong Province, Guangdong Province Engineering Laboratory for Transplantation Medicine. Guangzhou 510630, China; Guangdong Key Laboratory of Liver Disease Research, Key Laboratory of Liver Disease Biotherapy and Translational Medicine of Guangdong Higher Education Institutes, the Third Affiliated Hospital of Sun Yat-sen University, Guangzhou 510630, China.
| | - Jianye Cai
- Department of Hepatic Surgery and Liver Transplantation Center of the Third Affiliated Hospital of Sun Yat-sen University; Organ Transplantation Research Center of Guangdong Province, Guangdong Province Engineering Laboratory for Transplantation Medicine. Guangzhou 510630, China; Guangdong Key Laboratory of Liver Disease Research, Key Laboratory of Liver Disease Biotherapy and Translational Medicine of Guangdong Higher Education Institutes, the Third Affiliated Hospital of Sun Yat-sen University, Guangzhou 510630, China.
| | - Yang Yang
- Department of Hepatic Surgery and Liver Transplantation Center of the Third Affiliated Hospital of Sun Yat-sen University; Organ Transplantation Research Center of Guangdong Province, Guangdong Province Engineering Laboratory for Transplantation Medicine. Guangzhou 510630, China; Guangdong Key Laboratory of Liver Disease Research, Key Laboratory of Liver Disease Biotherapy and Translational Medicine of Guangdong Higher Education Institutes, the Third Affiliated Hospital of Sun Yat-sen University, Guangzhou 510630, China.
| | - Jun Zheng
- Department of Hepatic Surgery and Liver Transplantation Center of the Third Affiliated Hospital of Sun Yat-sen University; Organ Transplantation Research Center of Guangdong Province, Guangdong Province Engineering Laboratory for Transplantation Medicine. Guangzhou 510630, China; Guangdong Key Laboratory of Liver Disease Research, Key Laboratory of Liver Disease Biotherapy and Translational Medicine of Guangdong Higher Education Institutes, the Third Affiliated Hospital of Sun Yat-sen University, Guangzhou 510630, China.
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El Mendili Y, Orberger B, Chateigner D, Bardeau JF, Gascoin S, Petit S. Raman investigations and ab initio calculations of natural diamond-lonsdaleite originating from New Caledonia. Chem Phys 2022. [DOI: 10.1016/j.chemphys.2022.111541] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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5
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Shen Y, Su S, Zhao W, Cheng S, Xu T, Yin K, Chen L, He L, Zhou Y, Bi H, Wan S, Zhang Q, Wang L, Ni Z, Banhart F, Botton GA, Ding F, Ruoff RS, Sun L. Sub-4 nm Nanodiamonds from Graphene-Oxide and Nitrated Polycyclic Aromatic Hydrocarbons at 423 K. ACS NANO 2021; 15:17392-17400. [PMID: 34128643 DOI: 10.1021/acsnano.1c00209] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Nanodiamonds are interesting materials from the point of view of their biocompatibility and their chemical, spectroscopic, and mechanical properties. Current synthetic methods for nanodiamonds involve harsh environments, which are potentially hazardous in addition to being expensive. We report a low-temperature (423 K) hydrothermal approach to form nanodiamonds by using graphene-oxide or nitrated polycyclic aromatic hydrocarbons (naphthalene, anthracene, phenanthrene, or pyrene) as a starting material. The reaction products contain single-crystalline or twinned nanodiamonds with average diameters in the 2-3 nm range. Theoretical calculations prove that, at the nanoscale, sub-4 nm nanodiamonds may adopt a structure that is more stable than graphene-oxide and nitrated polycyclic aromatic hydrocarbons. Our findings show that sp2 carbon in the polycyclic aromatic precursor can be converted to sp3 carbon under unexpectedly moderate temperature conditions by using nanoscale precursors and thus offer a low-temperature approach for the synthesis of sub-4 nm nanodiamonds.
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Affiliation(s)
- Yuting Shen
- SEU-FEI Nano-Pico Center, Key Lab of MEMS of Ministry of Education, Collaborative Innovation Center for Micro/Nano Fabrication, Device and System, Southeast University, Nanjing 210096, People's Republic of China
| | - Shi Su
- SEU-FEI Nano-Pico Center, Key Lab of MEMS of Ministry of Education, Collaborative Innovation Center for Micro/Nano Fabrication, Device and System, Southeast University, Nanjing 210096, People's Republic of China
- School of Aeronautic Engineering, Nanjing Vocational University of Industry Technology, Nanjing 210023, People's Republic of China
| | - Wen Zhao
- Center for Multidimensional Carbon Materials (CMCM), Institute for Basic Science (IBS), Ulsan 689-798, Republic of Korea
| | - Shaobo Cheng
- Department of Materials Science and Engineering and Canadian Centre for Electron Microscopy, McMaster University, Hamilton, ON, Canada L8S 4M1
| | - Tao Xu
- SEU-FEI Nano-Pico Center, Key Lab of MEMS of Ministry of Education, Collaborative Innovation Center for Micro/Nano Fabrication, Device and System, Southeast University, Nanjing 210096, People's Republic of China
| | - Kuibo Yin
- SEU-FEI Nano-Pico Center, Key Lab of MEMS of Ministry of Education, Collaborative Innovation Center for Micro/Nano Fabrication, Device and System, Southeast University, Nanjing 210096, People's Republic of China
| | - Linjiang Chen
- Department of Chemistry, University of Liverpool, Liverpool L69 7ZD, United Kingdom
| | - Longbing He
- SEU-FEI Nano-Pico Center, Key Lab of MEMS of Ministry of Education, Collaborative Innovation Center for Micro/Nano Fabrication, Device and System, Southeast University, Nanjing 210096, People's Republic of China
| | - Yilong Zhou
- SEU-FEI Nano-Pico Center, Key Lab of MEMS of Ministry of Education, Collaborative Innovation Center for Micro/Nano Fabrication, Device and System, Southeast University, Nanjing 210096, People's Republic of China
| | - Hengchang Bi
- SEU-FEI Nano-Pico Center, Key Lab of MEMS of Ministry of Education, Collaborative Innovation Center for Micro/Nano Fabrication, Device and System, Southeast University, Nanjing 210096, People's Republic of China
| | - Shu Wan
- SEU-FEI Nano-Pico Center, Key Lab of MEMS of Ministry of Education, Collaborative Innovation Center for Micro/Nano Fabrication, Device and System, Southeast University, Nanjing 210096, People's Republic of China
| | - Qiubo Zhang
- SEU-FEI Nano-Pico Center, Key Lab of MEMS of Ministry of Education, Collaborative Innovation Center for Micro/Nano Fabrication, Device and System, Southeast University, Nanjing 210096, People's Republic of China
| | - Liang Wang
- Institute of Nanochemistry and Nanobiology, Shanghai University, Shanghai 200444, People's Republic of China
| | - Zhenhua Ni
- Department of Physics, Southeast University, 211189, Nanjing, China
| | - Florian Banhart
- Institut de Physique et Chimie des Matériaux de Strasbourg (IPCMS), UMR 7504 Université de Strasbourg - CNRS, 23 rue du Loess, 67034 Strasbourg, France
| | - Gianluigi A Botton
- Department of Materials Science and Engineering and Canadian Centre for Electron Microscopy, McMaster University, Hamilton, ON, Canada L8S 4M1
| | - Feng Ding
- Center for Multidimensional Carbon Materials (CMCM), Institute for Basic Science (IBS), Ulsan 689-798, Republic of Korea
- School of Materials Science and Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan 689-798, Republic of Korea
| | - Rodney S Ruoff
- School of Materials Science and Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan 689-798, Republic of Korea
| | - Litao Sun
- SEU-FEI Nano-Pico Center, Key Lab of MEMS of Ministry of Education, Collaborative Innovation Center for Micro/Nano Fabrication, Device and System, Southeast University, Nanjing 210096, People's Republic of China
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A Tunguska sized airburst destroyed Tall el-Hammam a Middle Bronze Age city in the Jordan Valley near the Dead Sea. Sci Rep 2021; 11:18632. [PMID: 34545151 PMCID: PMC8452666 DOI: 10.1038/s41598-021-97778-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2021] [Accepted: 08/30/2021] [Indexed: 02/08/2023] Open
Abstract
We present evidence that in ~ 1650 BCE (~ 3600 years ago), a cosmic airburst destroyed Tall el-Hammam, a Middle-Bronze-Age city in the southern Jordan Valley northeast of the Dead Sea. The proposed airburst was larger than the 1908 explosion over Tunguska, Russia, where a ~ 50-m-wide bolide detonated with ~ 1000× more energy than the Hiroshima atomic bomb. A city-wide ~ 1.5-m-thick carbon-and-ash-rich destruction layer contains peak concentrations of shocked quartz (~ 5-10 GPa); melted pottery and mudbricks; diamond-like carbon; soot; Fe- and Si-rich spherules; CaCO3 spherules from melted plaster; and melted platinum, iridium, nickel, gold, silver, zircon, chromite, and quartz. Heating experiments indicate temperatures exceeded 2000 °C. Amid city-side devastation, the airburst demolished 12+ m of the 4-to-5-story palace complex and the massive 4-m-thick mudbrick rampart, while causing extreme disarticulation and skeletal fragmentation in nearby humans. An airburst-related influx of salt (~ 4 wt.%) produced hypersalinity, inhibited agriculture, and caused a ~ 300-600-year-long abandonment of ~ 120 regional settlements within a > 25-km radius. Tall el-Hammam may be the second oldest city/town destroyed by a cosmic airburst/impact, after Abu Hureyra, Syria, and possibly the earliest site with an oral tradition that was written down (Genesis). Tunguska-scale airbursts can devastate entire cities/regions and thus, pose a severe modern-day hazard.
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Moore AMT, Kennett JP, Napier WM, Bunch TE, Weaver JC, LeCompte M, Adedeji AV, Hackley P, Kletetschka G, Hermes RE, Wittke JH, Razink JJ, Gaultois MW, West A. Evidence of Cosmic Impact at Abu Hureyra, Syria at the Younger Dryas Onset (~12.8 ka): High-temperature melting at >2200 °C. Sci Rep 2020; 10:4185. [PMID: 32144395 PMCID: PMC7060197 DOI: 10.1038/s41598-020-60867-w] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2019] [Accepted: 02/18/2020] [Indexed: 11/09/2022] Open
Abstract
At Abu Hureyra (AH), Syria, the 12,800-year-old Younger Dryas boundary layer (YDB) contains peak abundances in meltglass, nanodiamonds, microspherules, and charcoal. AH meltglass comprises 1.6 wt.% of bulk sediment, and crossed polarizers indicate that the meltglass is isotropic. High YDB concentrations of iridium, platinum, nickel, and cobalt suggest mixing of melted local sediment with small quantities of meteoritic material. Approximately 40% of AH glass display carbon-infused, siliceous plant imprints that laboratory experiments show formed at a minimum of 1200°-1300 °C; however, reflectance-inferred temperatures for the encapsulated carbon were lower by up to 1000 °C. Alternately, melted grains of quartz, chromferide, and magnetite in AH glass suggest exposure to minimum temperatures of 1720 °C ranging to >2200 °C. This argues against formation of AH meltglass in thatched hut fires at 1100°-1200 °C, and low values of remanent magnetism indicate the meltglass was not created by lightning. Low meltglass water content (0.02-0.05% H2O) is consistent with a formation process similar to that of tektites and inconsistent with volcanism and anthropogenesis. The wide range of evidence supports the hypothesis that a cosmic event occurred at Abu Hureyra ~12,800 years ago, coeval with impacts that deposited high-temperature meltglass, melted microspherules, and/or platinum at other YDB sites on four continents.
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Affiliation(s)
- Andrew M T Moore
- College of Liberal Arts, Rochester Institute of Technology, Rochester, NY, 14623, USA
| | - James P Kennett
- Department of Earth Science and Marine Science Institute, University of California Santa Barbara, Santa Barbara, CA, 93106, USA
| | - William M Napier
- Armagh Observatory and Planetarium, College Hill, Armagh BT61 9DG, Northern Ireland, UK
| | - Ted E Bunch
- Geology Division, School of Earth and Sustainability, Northern Arizona University, Flagstaff, AZ, 86011, USA
| | - James C Weaver
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Cambridge, MA, 02138, USA
| | - Malcolm LeCompte
- Elizabeth City State University, Center of Excellence in Remote Sensing Education and Research, Elizabeth City, NC, 27909, USA
| | - A Victor Adedeji
- Department of Natural Sciences, Elizabeth City State University, Elizabeth City, NC, 27909, USA
| | - Paul Hackley
- U.S. Geological Survey (USGS), 12201 Sunrise Valley Drive, Reston, VA, 20192, USA
| | - Gunther Kletetschka
- Institute of Geology, Czech Academy of Science of the Czech Republic and, Charles University, Faculty of Science, Czech Republic, CZE; and University of Alaska Fairbanks, 903 Koyukuk Drive, Fairbanks, Alaska, 99775, USA
| | - Robert E Hermes
- Los Alamos National Laboratory (retired), White Rock, NM, 87547, USA
| | - James H Wittke
- Geology Division, School of Earth and Sustainability, Northern Arizona University, Flagstaff, AZ, 86011, USA
| | - Joshua J Razink
- Center for Advanced Materials Characterization at Oregon (CAMCOR), University of Oregon, Eugene, OR, 97403, USA
| | - Michael W Gaultois
- Leverhulme Research Centre for Functional Materials Design, The Materials Innovation Factory, Department of Chemistry, University of Liverpool, Liverpool, UK
| | - Allen West
- Comet Research Group, 2204 Lakewood Drive, Prescott, AZ, 86301, USA.
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Moore CR, Brooks MJ, Goodyear AC, Ferguson TA, Perrotti AG, Mitra S, Listecki AM, King BC, Mallinson DJ, Lane CS, Kapp JD, West A, Carlson DL, Wolbach WS, Them TR, Harris MS, Pyne-O'Donnell S. Sediment Cores from White Pond, South Carolina, contain a Platinum Anomaly, Pyrogenic Carbon Peak, and Coprophilous Spore Decline at 12.8 ka. Sci Rep 2019; 9:15121. [PMID: 31641142 PMCID: PMC6805854 DOI: 10.1038/s41598-019-51552-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2019] [Accepted: 09/27/2019] [Indexed: 11/19/2022] Open
Abstract
A widespread platinum (Pt) anomaly was recently documented in Greenland ice and 11 North American sedimentary sequences at the onset of the Younger Dryas (YD) event (~12,800 cal yr BP), consistent with the YD Impact Hypothesis. We report high-resolution analyses of a 1-meter section of a lake core from White Pond, South Carolina, USA. After developing a Bayesian age-depth model that brackets the late Pleistocene through early Holocene, we analyzed and quantified the following: (1) Pt and palladium (Pd) abundance, (2) geochemistry of 58 elements, (3) coprophilous spores, (4) sedimentary organic matter (OC and sedaDNA), (5) stable isotopes of C (δ13C) and N (δ15N), (6) soot, (7) aciniform carbon, (8) cryptotephra, (9) mercury (Hg), and (10) magnetic susceptibility. We identified large Pt and Pt/Pd anomalies within a 2-cm section dated to the YD onset (12,785 ± 58 cal yr BP). These anomalies precede a decline in coprophilous spores and correlate with an abrupt peak in soot and C/OC ratios, indicative of large-scale regional biomass burning. We also observed a relatively large excursion in δ15N values, indicating rapid climatic and environmental/hydrological changes at the YD onset. Our results are consistent with the YD Impact Hypothesis and impact-related environmental and ecological changes.
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Affiliation(s)
- Christopher R Moore
- Savannah River Archaeological Research Program, South Carolina Institute of Archaeology and Anthropology, University of South Carolina, P.O. Box 400, New Ellenton, SC, 29809, USA.
| | - Mark J Brooks
- Savannah River Archaeological Research Program, South Carolina Institute of Archaeology and Anthropology, University of South Carolina, P.O. Box 400, New Ellenton, SC, 29809, USA
| | - Albert C Goodyear
- South Carolina Institute of Archaeology and Anthropology, Columbia, SC, 29208, USA
| | - Terry A Ferguson
- Department of Environmental Studies, Wofford College, 429N Church Street, Spartanburg, SC, 29303-3663, USA
| | - Angelina G Perrotti
- University of Wisconsin, Geography Department, 550N Park Street, Madison, WI, 53707-1404, USA
| | - Siddhartha Mitra
- Department of Geological Sciences, East Carolina University, Greenville, NC, 27858-4353, USA
| | - Ashlyn M Listecki
- Department of Biology, East Carolina University, Greenville, NC, 27858-4353, USA
- Department of Chemistry, East Carolina University, Greenville, NC, 27858-4353, USA
| | - Bailey C King
- Department of Biology, East Carolina University, Greenville, NC, 27858-4353, USA
- Department of Chemistry, East Carolina University, Greenville, NC, 27858-4353, USA
| | - David J Mallinson
- Department of Geological Sciences, East Carolina University, Greenville, NC, 27858-4353, USA
| | - Chad S Lane
- Department of Earth and Ocean Sciences, University of North Carolina Wilmington, Wilmington, NC, 28411, USA
| | - Joshua D Kapp
- Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, CA, 95064, USA
| | | | - David L Carlson
- Department of Anthropology, Texas A&M University, College Station, TX, 77843-4352, USA
| | - Wendy S Wolbach
- Department of Chemistry and Biochemistry, DePaul University, Chicago, IL, 60614, USA
| | - Theodore R Them
- Department of Geology and Environmental Sciences, College of Charleston, Charleston, SC, 29424, USA
| | - M Scott Harris
- Department of Geology and Environmental Sciences, College of Charleston, Charleston, SC, 29424, USA
| | - Sean Pyne-O'Donnell
- Earth Observatory of Singapore and Asian School of the Environment, Nanyang Technological University, Singapore, Singapore
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9
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Sedimentary record from Patagonia, southern Chile supports cosmic-impact triggering of biomass burning, climate change, and megafaunal extinctions at 12.8 ka. Sci Rep 2019; 9:4413. [PMID: 30867437 PMCID: PMC6416299 DOI: 10.1038/s41598-018-38089-y] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Accepted: 12/19/2018] [Indexed: 11/09/2022] Open
Abstract
The Younger Dryas (YD) impact hypothesis posits that fragments of a large, disintegrating asteroid/comet struck North America, South America, Europe, and western Asia ~12,800 years ago. Multiple airbursts/impacts produced the YD boundary layer (YDB), depositing peak concentrations of platinum, high-temperature spherules, meltglass, and nanodiamonds, forming an isochronous datum at >50 sites across ~50 million km² of Earth's surface. This proposed event triggered extensive biomass burning, brief impact winter, YD climate change, and contributed to extinctions of late Pleistocene megafauna. In the most extensive investigation south of the equator, we report on a ~12,800-year-old sequence at Pilauco, Chile (~40°S), that exhibits peak YD boundary concentrations of platinum, gold, high-temperature iron- and chromium-rich spherules, and native iron particles rarely found in nature. A major peak in charcoal abundance marks an intense biomass-burning episode, synchronous with dramatic changes in vegetation, including a high-disturbance regime, seasonality in precipitation, and warmer conditions. This is anti-phased with northern-hemispheric cooling at the YD onset, whose rapidity suggests atmospheric linkage. The sudden disappearance of megafaunal remains and dung fungi in the YDB layer at Pilauco correlates with megafaunal extinctions across the Americas. The Pilauco record appears consistent with YDB impact evidence found at sites on four continents.
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10
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Tarasenka N, Stupak A, Tarasenko N, Chakrabarti S, Mariotti D. Structure and Optical Properties of Carbon Nanoparticles Generated by Laser Treatment of Graphite in Liquids. Chemphyschem 2017; 18:1074-1083. [DOI: 10.1002/cphc.201601182] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2016] [Revised: 12/22/2016] [Indexed: 01/06/2023]
Affiliation(s)
- Natalie Tarasenka
- B.I. Stepanov Institute of physics; National Academy of Sciences of Belarus; 68 Nezalezhnasti ave. 220072 Minsk Belarus
| | - Aleksandr Stupak
- B.I. Stepanov Institute of physics; National Academy of Sciences of Belarus; 68 Nezalezhnasti ave. 220072 Minsk Belarus
| | - Nikolai Tarasenko
- B.I. Stepanov Institute of physics; National Academy of Sciences of Belarus; 68 Nezalezhnasti ave. 220072 Minsk Belarus
| | - Supriya Chakrabarti
- Plasma Science and Nanoscale Engineering Group; Nanotechnology & Integrated Bio-Engineering Centre (NIBEC); Ulster University; Shore Road BT37 0QB Newtownabbey UK
| | - Davide Mariotti
- Plasma Science and Nanoscale Engineering Group; Nanotechnology & Integrated Bio-Engineering Centre (NIBEC); Ulster University; Shore Road BT37 0QB Newtownabbey UK
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11
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Holliday V, Surovell T, Johnson E. A Blind Test of the Younger Dryas Impact Hypothesis. PLoS One 2016; 11:e0155470. [PMID: 27391147 PMCID: PMC4938604 DOI: 10.1371/journal.pone.0155470] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2016] [Accepted: 04/22/2016] [Indexed: 11/19/2022] Open
Abstract
The Younger Dryas Impact Hypothesis (YDIH) states that North America was devastated by some sort of extraterrestrial event ~12,800 calendar years before present. Two fundamental questions persist in the debate over the YDIH: Can the results of analyses for purported impact indicators be reproduced? And are the indicators unique to the lower YD boundary (YDB), i.e., ~12.8k cal yrs BP? A test reported here presents the results of analyses that address these questions. Two different labs analyzed identical splits of samples collected at, above, and below the ~12.8ka zone at the Lubbock Lake archaeological site (LL) in northwest Texas. Both labs reported similar variation in levels of magnetic micrograins (>300 mg/kg >12.8ka and <11.5ka, but <150 mg/kg 12.8ka to 11.5ka). Analysis for magnetic microspheres in one split, reported elsewhere, produced very low to nonexistent levels throughout the section. In the other split, reported here, the levels of magnetic microspherules and nanodiamonds are low or nonexistent at, below, and above the YDB with the notable exception of a sample <11,500 cal years old. In that sample the claimed impact proxies were recovered at abundances two to four orders of magnitude above that from the other samples. Reproducibility of at least some analyses are problematic. In particular, no standard criteria exist for identification of magnetic spheres. Moreover, the purported impact proxies are not unique to the YDB.
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Affiliation(s)
- Vance Holliday
- School of Anthropology & Department of Geosciences, University of Arizona, Tucson, Arizona, United States of America
- * E-mail:
| | - Todd Surovell
- Department of Anthropology, University of Wyoming, Laramie, Wyoming, United States of America
| | - Eileen Johnson
- Museum of Texas Tech University, Lubbock, Texas, United States of America
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12
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Bogdanov KV, Osipov VY, Zhukovskaya MV, Jentgens C, Treussart F, Hayashi T, Takai K, Fedorov AV, Baranov AV. Size-dependent Raman and SiV-center luminescence in polycrystalline nanodiamonds produced by shock wave synthesis. RSC Adv 2016. [DOI: 10.1039/c6ra09317e] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
30 × 30 nm TEM image of diamond polycrystal consisting cubic nanodiamonds of different orientation doped by luminescent SiV centers with luminescent intensity depended on mean size of the polycrystals.
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Affiliation(s)
| | - V. Yu. Osipov
- Ioffe Physical-Technical Institute
- Saint-Petersburg 194021
- Russia
| | | | | | - F. Treussart
- Laboratoire Aimé Cotton
- CNRS
- Univ. Paris-Sud
- ENS Cachan
- Université Paris Saclay
| | - T. Hayashi
- Faculty of Engineering
- Shinshu University
- Nagano 380-8553
- Japan
| | - K. Takai
- Department of Chemical Science and Technology
- Hosei University
- Tokyo 184-8584
- Japan
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13
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Twinning of cubic diamond explains reported nanodiamond polymorphs. Sci Rep 2015; 5:18381. [PMID: 26671288 PMCID: PMC4680963 DOI: 10.1038/srep18381] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2015] [Accepted: 11/13/2015] [Indexed: 11/08/2022] Open
Abstract
The unusual physical properties and formation conditions attributed to h-, i-, m-, and n-nanodiamond polymorphs has resulted in their receiving much attention in the materials and planetary science literature. Their identification is based on diffraction features that are absent in ordinary cubic (c-) diamond (space group: Fd-3m). We show, using ultra-high-resolution transmission electron microscope (HRTEM) images of natural and synthetic nanodiamonds, that the diffraction features attributed to the reported polymorphs are consistent with c-diamond containing abundant defects. Combinations of {113} reflection and <011> rotation twins produce HRTEM images and d-spacings that match those attributed to h-, i-, and m-diamond. The diagnostic features of n-diamond in TEM images can arise from thickness effects of c-diamonds. Our data and interpretations strongly suggest that the reported nanodiamond polymorphs are in fact twinned c-diamond. We also report a new type of twin (<11> rotational), which can give rise to grains with dodecagonal symmetry. Our results show that twins are widespread in diamond nanocrystals. A high density of twins could strongly influence their applications.
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14
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Bayesian chronological analyses consistent with synchronous age of 12,835-12,735 Cal B.P. for Younger Dryas boundary on four continents. Proc Natl Acad Sci U S A 2015. [PMID: 26216981 DOI: 10.1073/pnas.1507146112] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The Younger Dryas impact hypothesis posits that a cosmic impact across much of the Northern Hemisphere deposited the Younger Dryas boundary (YDB) layer, containing peak abundances in a variable assemblage of proxies, including magnetic and glassy impact-related spherules, high-temperature minerals and melt glass, nanodiamonds, carbon spherules, aciniform carbon, platinum, and osmium. Bayesian chronological modeling was applied to 354 dates from 23 stratigraphic sections in 12 countries on four continents to establish a modeled YDB age range for this event of 12,835-12,735 Cal B.P. at 95% probability. This range overlaps that of a peak in extraterrestrial platinum in the Greenland Ice Sheet and of the earliest age of the Younger Dryas climate episode in six proxy records, suggesting a causal connection between the YDB impact event and the Younger Dryas. Two statistical tests indicate that both modeled and unmodeled ages in the 30 records are consistent with synchronous deposition of the YDB layer within the limits of dating uncertainty (∼ 100 y). The widespread distribution of the YDB layer suggests that it may serve as a datum layer.
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15
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Lonsdaleite is faulted and twinned cubic diamond and does not exist as a discrete material. Nat Commun 2014; 5:5447. [PMID: 25410324 DOI: 10.1038/ncomms6447] [Citation(s) in RCA: 173] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2014] [Accepted: 10/01/2014] [Indexed: 11/09/2022] Open
Abstract
Lonsdaleite, also called hexagonal diamond, has been widely used as a marker of asteroidal impacts. It is thought to play a central role during the graphite-to-diamond transformation, and calculations suggest that it possesses mechanical properties superior to diamond. However, despite extensive efforts, lonsdaleite has never been produced or described as a separate, pure material. Here we show that defects in cubic diamond provide an explanation for the characteristic d-spacings and reflections reported for lonsdaleite. Ultrahigh-resolution electron microscope images demonstrate that samples displaying features attributed to lonsdaleite consist of cubic diamond dominated by extensive {113} twins and {111} stacking faults. These defects give rise to nanometre-scale structural complexity. Our findings question the existence of lonsdaleite and point to the need for re-evaluating the interpretations of many lonsdaleite-related fundamental and applied studies.
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16
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Chronological evidence fails to support claim of an isochronous widespread layer of cosmic impact indicators dated to 12,800 years ago. Proc Natl Acad Sci U S A 2014; 111:E2162-71. [PMID: 24821789 DOI: 10.1073/pnas.1401150111] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
According to the Younger Dryas Impact Hypothesis (YDIH), ∼ 12,800 calendar years before present, North America experienced an extraterrestrial impact that triggered the Younger Dryas and devastated human populations and biotic communities on this continent and elsewhere. This supposed event is reportedly marked by multiple impact indicators, but critics have challenged this evidence, and considerable controversy now surrounds the YDIH. Proponents of the YDIH state that a key test of the hypothesis is whether those indicators are isochronous and securely dated to the Younger Dryas onset. They are not. We have examined the age basis of the supposed Younger Dryas boundary layer at the 29 sites and regions in North and South America, Europe, and the Middle East in which proponents report its occurrence. Several of the sites lack any age control, others have radiometric ages that are chronologically irrelevant, nearly a dozen have ages inferred by statistically and chronologically flawed age-depth interpolations, and in several the ages directly on the supposed impact layer are older or younger than ∼ 12,800 calendar years ago. Only 3 of the 29 sites fall within the temporal window of the YD onset as defined by YDIH proponents. The YDIH fails the critical chronological test of an isochronous event at the YD onset, which, coupled with the many published concerns about the extraterrestrial origin of the purported impact markers, renders the YDIH unsupported. There is no reason or compelling evidence to accept the claim that a cosmic impact occurred ∼ 12,800 y ago and caused the Younger Dryas.
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17
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Quantifying the distribution of nanodiamonds in pre-Younger Dryas to recent age deposits along Bull Creek, Oklahoma panhandle, USA. Proc Natl Acad Sci U S A 2014; 111:1726-31. [PMID: 24449875 DOI: 10.1073/pnas.1309734111] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
High levels of nanodiamonds (nds) have been used to support the transformative hypothesis that an extraterrestrial (ET) event (comet explosion) triggered Younger Dryas changes in temperature, flora and fauna assemblages, and human adaptations [Firestone RB, et al. (2007) Proc Natl Acad Sci USA 104(41):16016-16021]. We evaluate this hypothesis by establishing the distribution of nds within the Bull Creek drainage of the Beaver River basin in the Oklahoma panhandle. The earlier report of an abundance spike of nds in the Bull Creek I Younger Dryas boundary soil is confirmed, although no pure cubic diamonds were identified. The lack of hexagonal nds suggests Bull Creek I is not near any impact site. Potential hexagonal nds at Bull Creek were found to be more consistent with graphene/graphane. An additional nd spike is found in deposits of late Holocene through the modern age, indicating nds are not unique to the Younger Dryas boundary. Nd distributions do not correlate with depositional environment, pedogenesis, climate perturbations, periods of surface stability, or cultural activity.
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18
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Wu Y, Sharma M, LeCompte MA, Demitroff MN, Landis JD. Origin and provenance of spherules and magnetic grains at the Younger Dryas boundary. Proc Natl Acad Sci U S A 2013; 110:E3557-66. [PMID: 24009337 PMCID: PMC3780899 DOI: 10.1073/pnas.1304059110] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
One or more bolide impacts are hypothesized to have triggered the Younger Dryas cooling at ∼12.9 ka. In support of this hypothesis, varying peak abundances of magnetic grains with iridium and magnetic microspherules have been reported at the Younger Dryas boundary (YDB). We show that bulk sediment and/or magnetic grains/microspherules collected from the YDB sites in Arizona, Michigan, New Mexico, New Jersey, and Ohio have (187)Os/(188)Os ratios ≥1.0, similar to average upper continental crust (= 1.3), indicating a terrestrial origin of osmium (Os) in these samples. In contrast, bulk sediments from YDB sites in Belgium and Pennsylvania exhibit (187)Os/(188)Os ratios <<1.0 and at face value suggest mixing with extraterrestrial Os with (187)Os/(188)Os of ∼0.13. However, the Os concentration in bulk sample and magnetic grains from Belgium is 2.8 pg/g and 15 pg/g, respectively, much lower than that in average upper continental crust (=31 pg/g), indicating no meteoritic contribution. The YDB site in Pennsylvania is remarkable in yielding 2- to 5-mm diameter spherules containing minerals such as suessite (Fe-Ni silicide) that form at temperatures in excess of 2000 °C. Gross texture, mineralogy, and age of the spherules appear consistent with their formation as ejecta from an impact 12.9 ka ago. The (187)Os/(188)Os ratios of the spherules and their leachates are often low, but Os in these objects is likely terrestrially derived. The rare earth element patterns and Sr and Nd isotopes of the spherules indicate that their source lies in 1.5-Ga Quebecia terrain in the Grenville Province of northeastern North America.
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Affiliation(s)
- Yingzhe Wu
- Radiogenic Isotope Geochemistry Laboratory, Department of Earth Sciences, Dartmouth College, Hanover, NH 03755
| | - Mukul Sharma
- Radiogenic Isotope Geochemistry Laboratory, Department of Earth Sciences, Dartmouth College, Hanover, NH 03755
| | - Malcolm A. LeCompte
- Center of Excellence in Remote Sensing Education and Research, Elizabeth City State University, Elizabeth City, NC 27909; and
| | | | - Joshua D. Landis
- Radiogenic Isotope Geochemistry Laboratory, Department of Earth Sciences, Dartmouth College, Hanover, NH 03755
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19
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Evidence for deposition of 10 million tonnes of impact spherules across four continents 12,800 y ago. Proc Natl Acad Sci U S A 2013; 110:E2088-97. [PMID: 23690611 DOI: 10.1073/pnas.1301760110] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Airbursts/impacts by a fragmented comet or asteroid have been proposed at the Younger Dryas onset (12.80 ± 0.15 ka) based on identification of an assemblage of impact-related proxies, including microspherules, nanodiamonds, and iridium. Distributed across four continents at the Younger Dryas boundary (YDB), spherule peaks have been independently confirmed in eight studies, but unconfirmed in two others, resulting in continued dispute about their occurrence, distribution, and origin. To further address this dispute and better identify YDB spherules, we present results from one of the largest spherule investigations ever undertaken regarding spherule geochemistry, morphologies, origins, and processes of formation. We investigated 18 sites across North America, Europe, and the Middle East, performing nearly 700 analyses on spherules using energy dispersive X-ray spectroscopy for geochemical analyses and scanning electron microscopy for surface microstructural characterization. Twelve locations rank among the world's premier end-Pleistocene archaeological sites, where the YDB marks a hiatus in human occupation or major changes in site use. Our results are consistent with melting of sediments to temperatures >2,200 °C by the thermal radiation and air shocks produced by passage of an extraterrestrial object through the atmosphere; they are inconsistent with volcanic, cosmic, anthropogenic, lightning, or authigenic sources. We also produced spherules from wood in the laboratory at >1,730 °C, indicating that impact-related incineration of biomass may have contributed to spherule production. At 12.8 ka, an estimated 10 million tonnes of spherules were distributed across ∼50 million square kilometers, similar to well-known impact strewnfields and consistent with a major cosmic impact event.
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20
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Independent evaluation of conflicting microspherule results from different investigations of the Younger Dryas impact hypothesis. Proc Natl Acad Sci U S A 2012; 109:E2960-9. [PMID: 22988071 DOI: 10.1073/pnas.1208603109] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Firestone et al. sampled sedimentary sequences at many sites across North America, Europe, and Asia [Firestone RB, et al. (2007) Proc Natl Acad Sci USA 106:16016-16021]. In sediments dated to the Younger Dryas onset or Boundary (YDB) approximately 12,900 calendar years ago, Firestone et al. reported discovery of markers, including nanodiamonds, aciniform soot, high-temperature melt-glass, and magnetic microspherules attributed to cosmic impacts/airbursts. The microspherules were explained as either cosmic material ablation or terrestrial ejecta from a hypothesized North American impact that initiated the abrupt Younger Dryas cooling, contributed to megafaunal extinctions, and triggered human cultural shifts and population declines. A number of independent groups have confirmed the presence of YDB spherules, but two have not. One of them [Surovell TA, et al. (2009) Proc Natl Acad Sci USA 104:18155-18158] collected and analyzed samples from seven YDB sites, purportedly using the same protocol as Firestone et al., but did not find a single spherule in YDB sediments at two previously reported sites. To examine this discrepancy, we conducted an independent blind investigation of two sites common to both studies, and a third site investigated only by Surovell et al. We found abundant YDB microspherules at all three widely separated sites consistent with the results of Firestone et al. and conclude that the analytical protocol employed by Surovell et al. deviated significantly from that of Firestone et al. Morphological and geochemical analyses of YDB spherules suggest they are not cosmic, volcanic, authigenic, or anthropogenic in origin. Instead, they appear to have formed from abrupt melting and quenching of terrestrial materials.
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21
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Suspect cubic diamond "impact" proxy and a suspect lonsdaleite identification. Proc Natl Acad Sci U S A 2012; 109:E2242; author reply E2245-7. [PMID: 22829671 DOI: 10.1073/pnas.1206253109] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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22
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Paleoecological changes at Lake Cuitzeo were not consistent with an extraterrestrial impact. Proc Natl Acad Sci U S A 2012; 109:E2243; author reply E2245-7. [PMID: 22829674 DOI: 10.1073/pnas.1206196109] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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23
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Age models and the Younger Dryas Impact Hypothesis. Proc Natl Acad Sci U S A 2012; 109:E2240; author reply E2245-7. [PMID: 22829673 DOI: 10.1073/pnas.1206143109] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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24
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Inconsistent impact hypotheses for the Younger Dryas. Proc Natl Acad Sci U S A 2012; 109:E2241; author reply E2245-7. [PMID: 22829675 DOI: 10.1073/pnas.1206739109] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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25
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Inconsistent redefining of the carbon spherule "impact" proxy. Proc Natl Acad Sci U S A 2012; 109:E2244; author reply E2245-7. [PMID: 22829672 DOI: 10.1073/pnas.1206108109] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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26
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Reply to Blaauw et al., Boslough, Daulton, Gill et al., and Hardiman et al.: Younger Dryas impact proxies in Lake Cuitzeo, Mexico. Proc Natl Acad Sci U S A 2012. [DOI: 10.1073/pnas.1209463109] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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27
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Very high-temperature impact melt products as evidence for cosmic airbursts and impacts 12,900 years ago. Proc Natl Acad Sci U S A 2012; 109:E1903-12. [PMID: 22711809 DOI: 10.1073/pnas.1204453109] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
It has been proposed that fragments of an asteroid or comet impacted Earth, deposited silica- and iron-rich microspherules and other proxies across several continents, and triggered the Younger Dryas cooling episode 12,900 years ago. Although many independent groups have confirmed the impact evidence, the hypothesis remains controversial because some groups have failed to do so. We examined sediment sequences from 18 dated Younger Dryas boundary (YDB) sites across three continents (North America, Europe, and Asia), spanning 12,000 km around nearly one-third of the planet. All sites display abundant microspherules in the YDB with none or few above and below. In addition, three sites (Abu Hureyra, Syria; Melrose, Pennsylvania; and Blackville, South Carolina) display vesicular, high-temperature, siliceous scoria-like objects, or SLOs, that match the spherules geochemically. We compared YDB objects with melt products from a known cosmic impact (Meteor Crater, Arizona) and from the 1945 Trinity nuclear airburst in Socorro, New Mexico, and found that all of these high-energy events produced material that is geochemically and morphologically comparable, including: (i) high-temperature, rapidly quenched microspherules and SLOs; (ii) corundum, mullite, and suessite (Fe(3)Si), a rare meteoritic mineral that forms under high temperatures; (iii) melted SiO(2) glass, or lechatelierite, with flow textures (or schlieren) that form at > 2,200 °C; and (iv) particles with features indicative of high-energy interparticle collisions. These results are inconsistent with anthropogenic, volcanic, authigenic, and cosmic materials, yet consistent with cosmic ejecta, supporting the hypothesis of extraterrestrial airbursts/impacts 12,900 years ago. The wide geographic distribution of SLOs is consistent with multiple impactors.
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Nanodiamonds and wildfire evidence in the Usselo horizon postdate the Allerod-Younger Dryas boundary. Proc Natl Acad Sci U S A 2012; 109:7648-53. [PMID: 22547791 DOI: 10.1073/pnas.1120950109] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The controversial Younger Dryas impact hypothesis suggests that at the onset of the Younger Dryas an extraterrestrial impact over North America caused a global catastrophe. The main evidence for this impact--after the other markers proved to be neither reproducible nor consistent with an impact--is the alleged occurrence of several nanodiamond polymorphs, including the proposed presence of lonsdaleite, a shock polymorph of diamond. We examined the Usselo soil horizon at Geldrop-Aalsterhut (The Netherlands), which formed during the Allerød/Early Younger Dryas and would have captured such impact material. Our accelerator mass spectrometry radiocarbon dates of 14 individual charcoal particles are internally consistent and show that wildfires occurred well after the proposed impact. In addition we present evidence for the occurrence of cubic diamond in glass-like carbon. No lonsdaleite was found. The relation of the cubic nanodiamonds to glass-like carbon, which is produced during wildfires, suggests that these nanodiamonds might have formed after, rather than at the onset of, the Younger Dryas. Our analysis thus provides no support for the Younger Dryas impact hypothesis.
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29
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Accumulation of impact markers in desert wetlands and implications for the Younger Dryas impact hypothesis. Proc Natl Acad Sci U S A 2012; 109:7208-12. [PMID: 22529347 DOI: 10.1073/pnas.1200296109] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The Younger Dryas impact hypothesis contends that an extraterrestrial object exploded over North America at 12.9 ka, initiating the Younger Dryas cold event, the extinction of many North American megafauna, and the demise of the Clovis archeological culture. Although the exact nature and location of the proposed impact or explosion remain unclear, alleged evidence for the fallout comes from multiple sites across North America and a site in Belgium. At 6 of the 10 original sites (excluding the Carolina Bays), elevated concentrations of various "impact markers" were found in association with black mats that date to the onset of the Younger Dryas. Black mats are common features in paleowetland deposits and typically represent shallow marsh environments. In this study, we investigated black mats ranging in age from approximately 6 to more than 40 ka in the southwestern United States and the Atacama Desert of northern Chile. At 10 of 13 sites, we found elevated concentrations of iridium in bulk and magnetic sediments, magnetic spherules, and/or titanomagnetite grains within or at the base of black mats, regardless of their age or location, suggesting that elevated concentrations of these markers arise from processes common to wetland systems, and not a catastrophic extraterrestrial impact event.
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