DOCSLIB.ORG

Pleistocene Organic Matter Modified by the Hiawatha Impact, Northwest Greenland Adam A

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Pleistocene Organic Matter Modified by the Hiawatha Impact, Northwest Greenland Adam A https://doi.org/10.1130/G47432.1 Manuscript received 23 January 2020 Revised manuscript received 2 April 2020 Manuscript accepted 8 April 2020 © 2020 The Authors. Gold Open Access: This paper is published under the terms of the CC-BY license. Published online 29 May 2020 Pleistocene organic matter modified by the Hiawatha impact, northwest Greenland Adam A. Garde1, Anne Sofie Søndergaard2, Carsten Guvad1, Jette Dahl-Møller3, Gernot Nehrke4, Hamed Sanei2, Christian Weikusat4, Svend Funder3, Kurt H. Kjær3 and Nicolaj Krog Larsen3 1 Geological Survey of Denmark and Greenland, Øster Voldgade 10, 1350 Copenhagen K, Denmark 2 Lithospheric Organic Carbon (LOC) Group, Department of Geoscience, Aarhus University, Høegh Guldbergs Gade 2, 8000 Aarhus, Denmark 3 Globe Institute, University of Copenhagen, Øster Voldgade 5–7, 1350 Copenhagen K, Denmark 4 Alfred Wegener Institute, Am Handelshafen, 27570 Bremerhaven, Germany ABSTRACT an iron meteorite (Kjær et al., 2018). The bulk The 31-km-wide Hiawatha impact crater was recently discovered under the ice sheet mineral assemblage and chemical composi- in northwest Greenland, but its age remains uncertain. Here we investigate solid organic tion of the sand indicate sourcing from gran- matter found at the tip of the Hiawatha Glacier to determine its thermal degradation, ulite-grade rocks similar to Paleoproterozoic provenance, and age, and hence a maximum age of the impact. Impactite grains of micro- paragneiss exposed in the ice-free foreland brecchia and shock-melted glass in glaciofluvial sand contain abundant dispersed carbon, to the crater (locally including sulfidic parag- and gravel-sized charcoal particles are common on the outwash plain in front of the crater. neiss with graphite flakes; Dawes, 2004). The The organic matter is depleted in the thermally sensitive, labile bio-macromolecule proto- crater has not been directly dated but is tenta- hydrocarbons. Pebble-sized lumps of lignite collected close to the sand sample consist largely tively referred to the Pleistocene and possibly of fragments of conifers such as Pinus or Picea, with greatly expanded cork cells and desic- as young as the last glacial period, based on cation cracks which suggest rapid, heat-induced expansion and contraction. Pinus and Picea indirect evidence such as preservation of the are today extinct from North Greenland but are known from late Pliocene deposits in the subglacial crater topography, a strongly dis- Canadian Arctic Archipelago and early Pleistocene deposits at Kap København in eastern turbed pre-Holocene ice stratigraphy over the North Greenland. The thermally degraded organic material yields a maximum age for the crater identified by airborne radar imaging, impact, providing the first firm evidence that the Hiawatha crater is the youngest known and an anomalously high modern-day volume large impact structure on Earth. of melt water draining from the impacted area (Kjær et al., 2018). INTRODUCTION raneous vegetation (Howard et al., 2013), and In this study, we investigate organic matter Most terrestrial impact structures contain the small, twin ca. 3.2 ka Kaali craters, Estonia, and its thermal degradation in the impactite only little organic carbon, recycled from target contain locally derived charcoal (Losiak et al., grains, charcoal, lignite, and bulk sediment in rocks. The ca. 35 Ma Popigai crater, Siberia, 2016, 2019). proglacial outwash from the Hiawatha crater contains diamonds transformed from target- With a diameter of 31 km, the newly dis- floor. We identify the wood fragments to gen- rock graphite (Masaitis et al., 1975). Ejecta covered Hiawatha crater under the Greenland era level and discuss the implications of our from the ca. 23 Ma Haughton crater, Canada Ice Sheet in northwest Greenland is one of the findings for the maximum age of the Hiawatha (Parnell et al., 2007), and the ca. 15 Ma Ries 25 largest impact structures on Earth (Fig. 1; impact. crater, Germany (Osinski 2003), contain organic Kjær et al., 2018; Impact Earth, 2020, https:// carbon derived from sedimentary target rocks, impact.uwo.ca/). A large variety of sand-sized METHODS and drill core from the 66 Ma Chicxulub crater, impactite grains originating from the crater Sediment samples described by Kjær et al. Mexico, contains particles of charcoal (Gulick floor were found in a glaciofluvial outwash (2018), and charcoal and lignite collected by us et al., 2019). If the source of the carbon can be sediment sample (HW21-2016 of Kjær et al.; from in front of the Hiawatha Glacier were inves- identified, it may serve to constrain the maxi- see their table S1 with sample information) tigated by standard optical and backscattered elec- mum age of cratering. For instance, dispersed deposited at the front of the Hiawatha Gla- tron scanning electron microscopy (SEM-BSE; graphitic carbon in the ca. 500 Ma Gardnos cier just outside the crater rim (Fig. 1). The Geological Survey of Denmark and Greenland, crater in Norway stems from Cambrian Alum sand contains shocked quartz, microbreccias, Copenhagen, Denmark), pyrolysis, and Raman Shale (Gilmour et al., 2003; Parnell and Lind- shock-melted mineral glasses, and micromag- spectra. The Raman spectra were obtained with gren 2006). Carbon inclusions in impact glasses matic aggregates; elevated Pt contents and a WITec alpha300 R system and a 488 nm laser linked to the purported ca. 0.8 Ma Darwin crater, anomalous platinum-group element ratios in at the Alfred Wegener institute (Bremerhaven, Tasmania, preserve biomarkers from contempo- this sediment suggest that the impactor was Germany); see the Supplemental Material1 for CITATION: Garde, A.A., et al., 2020, Pleistocene organic matter modified by the Hiawatha impact, northwest Greenland: Geology, v. 48, p. 867–871, https://doi.org/10.1130/G47432.1 Geological Society of America | GEOLOGY | Volume 48 | Number 9 | www.gsapubs.org 867 Downloaded from http://pubs.geoscienceworld.org/gsa/geology/article-pdf/48/9/867/5135263/867.pdf by guest on 26 September 2021 A Charcoal and Lignite Sand- and gravel-sized pieces of charcoal from sample HW21-2016 have a largely amor- phous structure (“glassy coal”) but also preserve relict cell structures (Fig. 3A). Their reflectance in incident white light is high (Ro ≤ 3.5%), within the range of modern charcoal (Braad- baart and Poole, 2008; McParland et al., 2009). Pebble-sized lumps of lignite collected at Figure 1. (A) Location of the Hiawatha crater the eastern Hiawatha Glacier front (Fig. 3B) and Kap København in have cellular structures and a low random Greenland. (B) Elevation reflectance (Ro ∼0.2%–0.5%). The ash con- map showing circular tent is only ∼0.5 wt%. One of these lumps depression of the crater, yielded a non-finite 14C age of >43,500 yr B.P. covered by the Greenland Ice Sheet (semitranspar- (our sample Beta-471661). Most of the lignite ent), and positions of consists of woody material with rows of well- glaciofluvial sand sample preserved, even-sized cells with central voids, HW21-2016 (78.83305°N, spiraled fibrous cell walls, and bordered pit pairs 67.13653 W) and two ° (Fig. 3C); layers of cork cells have filled inte- B older reference samples from the outwash plain riors. Alternating growth zones of spring and (HW12-2016, 78.84183°N, summer wood are up to a dozen cells thick. 67.29250°W; and HW13- These cell structures are diagnostic of conifer 2016, 78.88696°N , wood, most likely Pinus or Picea, whereas few 65.99227°W) from Kjær et al. (2018). Modified from fragments contain wood cells of uneven size Kjær et al. (2018). and distinct perforation plates, which is the characteristic of the angiosperm genus Betula (Hoadley, 1990). Some conifer cork layers have greatly inflated cells with numerous spherical voids (Fig. 3D), which we interpret as results of expansion by heating with sudden release of volatile components from the lipid-rich cork cells. Common branching and tapering systems of shrinkage cracks are likewise interpreted as evidence of rapid loss of volatile components by heating (Fig. 3E). Other lumps display flattened details. Organic carbon geochemistry in bulk front of the Hiawatha Glacier. The macroscale cells with homogeneous (gelatinous) interiors sediment sample HW21-2016 and two refer- organic matter comprises angular, sand- to and low reflectance (Ro = 0.1%–0.2%; Fig. 3C), ence samples was obtained by Hawk pyrolysis gravel-sized particles of charcoal in sample interpreted as remnants of decaying and mildly at Aarhus University (Aarhus, Denmark) follow- HW21-2016, as well as pebble-sized lumps compacted wood. Conglomerate-like masses ing Carrie et al. (2012), measuring the quantity of of lignite rounded by water transport on the of variably decomposed and disrupted wood total organic carbon (TOC, in weight percent) and eastern side of the glacier front; small twigs particles mixed with small vitrinous particles proto-hydrocarbons (S2, in milligrams thermally from dwarf bushes unrelated to the impact (Fig. 3F) are interpreted as results of normal sensitive, labile bio-macromolecule hydrocarbons occur locally on the glacial outwash plain. degradation of lignite and/or impact-related per gram sediment) released between 300 and The microscale, finely dispersed organic car- mixing and redeposition. Only very sporadic 650 °C from the preserved humic matter. Three bon was identified in the impactite grains of remnants of plant spores and/or algae have been grain-size fractions of each sample were mea- sample HW21-2016. found, and no leaf cuticula. sured to check potential variability with grain size. The lignite was dated by the Beta Analytic Organic Matter in the Impactite Grains Carbon Ordering and Organic Carbon Dating Service (https://www.radiocar- Microbreccia grains contain splinters of sili- Geochemistry bon.com/) with calendar-year calibration using cate minerals including shocked quartz as well The organic matter was characterized using OxCal v. 4.3 with the IntCal13 calibration curve as partially melted mineral fragments, set in an laser Raman spectrography (Figs.
Load more

Recommended publications
  • Terrestrial Impact Structures Provide the Only Ground Truth Against Which Computational and Experimental Results Can Be Com­ Pared
    Ann. Rev. Earth Planet. Sci. 1987. 15:245-70 Copyright([;; /987 by Annual Reviews Inc. All rights reserved TERRESTRIAL IMI!ACT STRUCTURES ··- Richard A. F. Grieve Geophysics Division, Geological Survey of Canada, Ottawa, Ontario KIA OY3, Canada INTRODUCTION Impact structures are the dominant landform on planets that have retained portions of their earliest crust. The present surface of the Earth, however, has comparatively few recognized impact structures. This is due to its relative youthfulness and the dynamic nature of the terrestrial geosphere, both of which serve to obscure and remove the impact record. Although not generally viewed as an important terrestrial (as opposed to planetary) geologic process, the role of impact in Earth evolution is now receiving mounting consideration. For example, large-scale impact events may hav~~ been responsible for such phenomena as the formation of the Earth's moon and certain mass extinctions in the biologic record. The importance of the terrestrial impact record is greater than the relatively small number of known structures would indicate. Impact is a highly transient, high-energy event. It is inherently difficult to study through experimentation because of the problem of scale. In addition, sophisticated finite-element code calculations of impact cratering are gen­ erally limited to relatively early-time phenomena as a result of high com­ putational costs. Terrestrial impact structures provide the only ground truth against which computational and experimental results can be com­ pared. These structures provide information on aspects of the third dimen­ sion, the pre- and postimpact distribution of target lithologies, and the nature of the lithologic and mineralogic changes produced by the passage of a shock wave.
    [Show full text]
  • Earth in Upheaval – Velikovsky
    KANSAS CITY, MO PUBLIC LIBRARY MAR 1989 JALS DATE DUE Earth in upheaval. 1 955 . Books by Immarvjel Velikoviky Earth in Upheaval Worlds in Collision Published by POCKET BOOKS Most Pot Ian Books arc available at special quantify discounts for hulk purchases for sales promotions premiums or fund raising SpeciaJ books* or txx)k e\( erj)ts can also tx.' created to ht specific needs FordetaJs write the office of the Vice President of Special Markets, Pocket Books, 12;K) Avenue of the Arm-mas New York New York 10020 EARTH IN UPHEAVAL Smnianue! Velikovsky F'OCKET BOOKS, a division of Simon & Schuster, IMC 1230 Avenue of the Americas, New York, N Y 10020 Copyright 1955 by Immanuel Vehkovskv Published by arrangement with Doubledav tx Compauv, 1m Library of Congiess Catalog Card Number 55-11339 All rights reserved, including the right to reproduce this book or portions thereof in any form whatsoever For information address 6r Inc. Doubledav Company, , 245 Park Avenue, New York, N Y' 10017 ISBN 0-fi71-524f>5-tt Fust Pocket Books punting September 1977 10 9 H 7 6 POCKET and colophon ae registered trademarks of Simon & Schuster, luc Printed in the USA ACKNOWLEDGMENTS WORKING ON Earth in Upheaval and on the essay (Address before the Graduate College Forum of Princeton University) added at the end of this volume, I have incurred a debt of gratitude to several scientists. Professor Walter S. Adams, for many years director of Mount Wilson Observatory, gave me all the in- formation and instruction for which I asked concern- ing the atmospheres of the planets, a field in which he is the outstanding authority.
    [Show full text]
  • Putative Microbial Mediation in NASA Lunar Sample Set: Microtextural Features at High Magnification
    EPSC Abstracts Vol. 13, EPSC-DPS2019-1-1, 2019 EPSC-DPS Joint Meeting 2019 c Author(s) 2019. CC Attribution 4.0 license. Putative microbial mediation in NASA lunar sample set: microtextural features at high magnification Szaniszló Bérczi (1), Márta Polgári (2,3), Ildikó Gyollai (2), Arnold Gucsik A.(3) (1) Eötvös University, Institute of Physics, Dept. Materials Physics, Cosmic Materials Space Res. Group, H-1117 Bu-dapest, Pázmány Péter sétány 1/a. Hungary, ([email protected]), (2) Institute for Geological and Geochemical Research, RCAES, Biogeochemical Working Group, HAS, H-1112 Budapest, Budaörsi u. 45, Hungary, ([email protected]), ([email protected]), (3) Eszterházy Károly University, Department of Natural Geography and Geoinformatics, 3300 Eger, Leányka str. 6, Hungary ([email protected]). Abstract 60025 lunar sample is a coarse grained brecciated (cata- The NASA Lunar Educational Set is since 25 year in clastic) anorthosite, in which rarely pyroxene is spotted. In Hungary, curating by B. Sz. at Eötvös University. As non- the vicinity of the pyroxenes the texture was interwoven by destructive method, only high resolution optical mi-crobial-like filamentous biosignatures (Fig. 3). microscopy is allowed by NASA. This method is good for microtextural studies of processes, where we found 2. Results and Discussion putative microbial features. To determination of microbial Optical microscopy is the allowed study form for the signatures Raman and FTIR spectroscopy would be NASA educational samples. We used it in extremely large requires to identify fine-grained biominerals and organic magnifica-tion capacity in order to see the texture in fine material, as the authors did by other meteorite and details [3, 4, 5, 6, 7].
    [Show full text]
  • 18Th EANA Conference European Astrobiology Network Association
    18th EANA Conference European Astrobiology Network Association Abstract book 24-28 September 2018 Freie Universität Berlin, Germany Sponsors: Detectability of biosignatures in martian sedimentary systems A. H. Stevens1, A. McDonald2, and C. S. Cockell1 (1) UK Centre for Astrobiology, University of Edinburgh, UK ([email protected]) (2) Bioimaging Facility, School of Engineering, University of Edinburgh, UK Presentation: Tuesday 12:45-13:00 Session: Traces of life, biosignatures, life detection Abstract: Some of the most promising potential sampling sites for astrobiology are the numerous sedimentary areas on Mars such as those explored by MSL. As sedimentary systems have a high relative likelihood to have been habitable in the past and are known on Earth to preserve biosignatures well, the remains of martian sedimentary systems are an attractive target for exploration, for example by sample return caching rovers [1]. To learn how best to look for evidence of life in these environments, we must carefully understand their context. While recent measurements have raised the upper limit for organic carbon measured in martian sediments [2], our exploration to date shows no evidence for a terrestrial-like biosphere on Mars. We used an analogue of a martian mudstone (Y-Mars[3]) to investigate how best to look for biosignatures in martian sedimentary environments. The mudstone was inoculated with a relevant microbial community and cultured over several months under martian conditions to select for the most Mars-relevant microbes. We sequenced the microbial community over a number of transfers to try and understand what types microbes might be expected to exist in these environments and assess whether they might leave behind any specific biosignatures.
    [Show full text]
  • Rocks, Soils and Surfaces: Teacher Guide
    National Aeronautics and Space Administration ROCKS, SOILS, AND SURFACES Planetary Sample and Impact Cratering Unit Teacher Guide Goal: This activity is designed to introduce students to rocks, “soils”, and surfaces on planetary worlds, through the exploration of lunar samples collected by Apollo astronauts and the study of the most dominant geologic process across the Solar System, the impact process. Students will gain an understanding of how the study of collected samples and impact craters can help improve our understanding of the history of the Moon, Earth, and our Solar System. Additionally, this activity will enable students to gain experience with scientific practices and the nature of science as they model skills and practices used by professional scientists. Objectives: Students will: 1. Make observations of rocks, “soil”, and surface features 2. Gain background information on rocks, “soil”, and surface features on Earth and the Moon 3. Apply background knowledge related to rocks, soils, and surfaces on Earth toward gaining a better understanding of these aspects of the Moon. This includes having students: a. Identify common lunar surface features b. Create a model lunar surface c. Identify the three classifications of lunar rocks d. Simulate the development of lunar regolith e. Identify the causes and formation of impact craters 4. Design and conduct an experiment on impact craters 5. Create a plan to investigate craters on Earth and on the Moon 6. Gain an understanding of the nature of science and scientific practices by: a. Making initial observations b. Asking preliminary questions c. Applying background knowledge d. Displaying data e. Analyzing and interpreting data Grade Level: 6 – 8* *Grade Level Adaptations: This activity can also be used with students in grades 5 and 9-12.
    [Show full text]
  • Appendix a Recovery of Ejecta Material from Confirmed, Probable
    Appendix A Recovery of Ejecta Material from Confirmed, Probable, or Possible Distal Ejecta Layers A.1 Introduction In this appendix we discuss the methods that we have used to recover and study ejecta found in various types of sediment and rock. The processes used to recover ejecta material vary with the degree of lithification. We thus discuss sample processing for unconsolidated, semiconsolidated, and consolidated material separately. The type of sediment or rock is also important as, for example, carbonate sediment or rock is processed differently from siliciclastic sediment or rock. The methods used to take and process samples will also vary according to the objectives of the study and the background of the investigator. We summarize below the methods that we have found useful in our studies of distal impact ejecta layers for those who are just beginning such studies. One of the authors (BPG) was trained as a marine geologist and the other (BMS) as a hard rock geologist. Our approaches to processing and studying impact ejecta differ accordingly. The methods used to recover ejecta from unconsolidated sediments have been successfully employed by BPG for more than 40 years. A.2 Taking and Handling Samples A.2.1 Introduction The size, number, and type of samples will depend on the objective of the study and nature of the sediment/rock, but there a few guidelines that should be followed regardless of the objective or rock type. All outcrops, especially those near industrialized areas or transportation routes (e.g., highways, train tracks) need to be cleaned off (i.e., the surface layer removed) prior to sampling.
    [Show full text]
  • Geochemistry of Darwin Glass and Target Rocks from Darwin Crater, Tasmania, Australia
    Meteoritics & Planetary Science 43, Nr 3, 479–496 (2008) AUTHOR’S Abstract available online at http://meteoritics.org PROOF Geochemistry of Darwin glass and target rocks from Darwin crater, Tasmania, Australia Kieren T. HOWARD School of Earth Sciences, University of Tasmania, Hobart, Tasmania 7000, Australia Present address: Impacts and Astromaterials Research Centre, Department of Mineralogy, The Natural History Museum, Cromwell Road, London SW7 5BD, UK Corresponding author. E-mail: [email protected] (Received 1 March 2007; revision accepted 25 July 2007) Abstract–Darwin glass formed about 800,000 years ago in western Tasmania, Australia. Target rocks at Darwin crater are quartzites and slates (Siluro-Devonian, Eldon Group). Analyses show 2 groups of glass, Average group 1 is composed of: SiO2 (85%), Al2O3 (7.3%), TiO2 (0.05%), FeO (2.2%), MgO (0.9%), and K2O (1.8%). Group 2 has lower average SiO2 (81.1%) and higher average Al2O3 (8.2%). Group 2 is enriched in FeO (+1.5%), MgO (+1.3%) and Ni, Co, and Cr. Average Ni (416 ppm), Co (31 ppm), and Cr (162 ppm) in group 2 are beyond the range of sedimentary rocks. Glass and target rocks have concordant REE patterns (La/Lu = 5.9–10; Eu/Eu* = 0.55–0.65) and overlapping trace element abundances. 87Sr/86Sr ratios for the glasses (0.80778–0.81605) fall in the range (0.76481–1.1212) defined by the rock samples. ε-Nd results range from −13.57 to −15.86. Nd model ages range from 1.2–1.9 Ga (CHUR) and the glasses (1.2–1.5 Ga) fall within the range defined by the target samples.
    [Show full text]
  • Cretaceous) Mass Extinction Earle G
    http://www.nap.edu/catalog/4762.html We ship printed books within 1 business day; personal PDFs are available immediately. Effects of Past Global Change on Life Panel on Effects of Past Global Change on Life, National Research Council ISBN: 0-309-55261-3, 272 pages, 8.5 x 11, (1995) This PDF is available from the National Academies Press at: http://www.nap.edu/catalog/4762.html Visit the National Academies Press online, the authoritative source for all books from the National Academy of Sciences, the National Academy of Engineering, the Institute of Medicine, and the National Research Council: • Download hundreds of free books in PDF • Read thousands of books online for free • Explore our innovative research tools – try the “Research Dashboard” now! • Sign up to be notified when new books are published • Purchase printed books and selected PDF files Thank you for downloading this PDF. If you have comments, questions or just want more information about the books published by the National Academies Press, you may contact our customer service department toll- free at 888-624-8373, visit us online, or send an email to [email protected]. This book plus thousands more are available at http://www.nap.edu. Copyright © National Academy of Sciences. All rights reserved. Unless otherwise indicated, all materials in this PDF File are copyrighted by the National Academy of Sciences. Distribution, posting, or copying is strictly prohibited without written permission of the National Academies Press. Request reprint permission for this book. ue r i ease l P are t ed. STUDIES IN GEOPHYSICS insert age breaks ally P Effects of Past Global Change on Life iles.
    [Show full text]
  • Physical Distribution Trends in Darwin Glass
    Physical distribution trends in Darwin glass Item Type Article; text Authors Howard, Kieren T. Citation Howard, K. T. (2009). Physical distribution trends in Darwin glass. Meteoritics & Planetary Science, 44(1), 115-129. DOI 10.1111/j.1945-5100.2009.tb00722.x Publisher The Meteoritical Society Journal Meteoritics & Planetary Science Rights Copyright © The Meteoritical Society Download date 11/10/2021 08:24:44 Item License http://rightsstatements.org/vocab/InC/1.0/ Version Final published version Link to Item http://hdl.handle.net/10150/656530 Meteoritics & Planetary Science 44, Nr 1, 115–129 (2009) Abstract available online at http://meteoritics.org Physical distribution trends in Darwin glass Kieren T. HOWARD Impacts and Astromaterials Research Centre (IARC), Mineralogy Department, The Natural History Museum, Cromwell Road, London SW7 5BD, UK Corresponding author. E-mail: [email protected] (Received 25 January 2008; revision accepted 26 September 2008) Abstract–Darwin glass formed by impact melting, probably during excavation of the 1.2 km diameter Darwin crater, Tasmania, Australia. The glass was ejected up to 20 km from the source crater and forms a strewn field of >400 km2. There is at least 11,250 m3 of glass in the strewn field and relative to the size of the crater this is the most abundant ejected impact glass on Earth. The glass population can be subdivided on the basis of shape (74% irregular, 20% ropy, 0.5% spheroid, 6% droplet, and 0.7% elongate) and color (53% dark green, 31% light green, 11% black, and 5% white). The white glasses contain up to 92 wt% SiO2 and are formed from melting of quartzite.
    [Show full text]
  • Meteorite Impacts, Earth, and the Solar System
    Traces of Catastrophe A Handbook of Shock-Metamorphic Effects in Terrestrial Meteorite Impact Structures Bevan M. French Research Collaborator Department of Mineral Sciences, MRC-119 Smithsonian Institution Washington DC 20560 LPI Contribution No. 954 i Copyright © 1998 by LUNAR AND PLANETARY INSTITUTE The Institute is operated by the Universities Space Research Association under Contract No. NASW-4574 with the National Aeronautics and Space Administration. Material in this volume may be copied without restraint for library, abstract service, education, or personal research purposes; however, republication of any portion thereof requires the written permission of the Insti- tute as well as the appropriate acknowledgment of this publication. Figures 3.1, 3.2, and 3.5 used by permission of the publisher, Oxford University Press, Inc. Figures 3.13, 4.16, 4.28, 4.32, and 4.33 used by permission of the publisher, Springer-Verlag. Figure 4.25 used by permission of the publisher, Yale University. Figure 5.1 used by permission of the publisher, Geological Society of America. See individual captions for reference citations. This volume may be cited as French B. M. (1998) Traces of Catastrophe:A Handbook of Shock-Metamorphic Effects in Terrestrial Meteorite Impact Structures. LPI Contribution No. 954, Lunar and Planetary Institute, Houston. 120 pp. This volume is distributed by ORDER DEPARTMENT Lunar and Planetary Institute 3600 Bay Area Boulevard Houston TX 77058-1113, USA Phone:281-486-2172 Fax:281-486-2186 E-mail:[email protected] Mail order requestors will be invoiced for the cost of shipping and handling. Cover Art.“One Minute After the End of the Cretaceous.” This artist’s view shows the ancestral Gulf of Mexico near the present Yucatán peninsula as it was 65 m.y.
    [Show full text]
  • Did Bering Strait People Initiate the Thule Migration?
    Alaska Journal of Anthropology Volume 4, Numbers 1-2 Did Bering Strait People Initiate the Thule Migration? Hans Christian Gulløv National Museum of Denmark ([email protected]) Robert McGhee Canadian Museum of Civilization ([email protected]) Abstract: Th e Ruin Island phase of northwestern Greenland and adjacent Ellesmere Island is associated with artifact assemblages that resemble those of western Alaskan Punuk, rather than Canadian Th ule culture or the North Alaskan Th ule tradition, the supposed source for the Inuit expansion eastward across North America. Ruin Island assemblages also contain numerous artifacts obtained through contact with the medieval Norse. Th e re-evaluation of radiocarbon series associated with Eastern Arctic Th ule culture suggests temporal priority for the Ruin Island phase, with a probably thirteenth century assignment. Th e role of iron is assessed as a motive for instigating the initial movement of Inuit from Alaska to the Eastern Arctic, and it is concluded that this was possibly a commercially-motivated enterprise undertaken by peoples whose ancestors had long engaged in the metal trade across Bering Strait Keywords: Greenland archaeology, Punuk culture, Inuit origins When Erik Holtved (1944, 1954) excavated early Inuit Th e temporal placement of the Ruin Island complex winter houses at Ruin Island and other locations in the Th ule was established with greater certainty by radiocarbon dates District of far northwestern Greenland, he recovered arti- obtained from sites on eastern Ellesmere Island, excavated fact assemblages that were signifi cantly diff erent from those during the 1970s and 1980s by Karen McCullough and Pe- excavated earlier by Mathiassen (1927) from Th ule culture ter Schledermann.
    [Show full text]
  • The Geological Record of Meteorite Impacts
    THE GEOLOGICAL RECORD OF METEORITE IMPACTS Gordon R. Osinski Canadian Space Agency, 6767 Route de l'Aeroport, St-Hubert, QC J3Y 8Y9 Canada, Email: [email protected] ABSTRACT 2. FORMATION OF METEORITE IMPACT STRUCTURES Meteorite impact structures are found on all planetary bodies in the Solar System with a solid The formation of hypervelocity impact craters has surface. On the Moon, Mercury, and much of Mars, been divided, somewhat arbitrarily, into three main impact craters are the dominant landform. On Earth, stages [3] (Fig. 2): (1) contact and compression, (2) 174 impact sites have been recognized, with several excavation, and (3) modification. A further stage of more new craters being discovered each year. The “hydrothermal and chemical alteration” is also terrestrial impact cratering record is critical for our considered as a separate, final stage in the cratering understanding of impacts as it currently provides the process (e.g., [4]), and is also described below. only ground-truth data on which to base interpretations of the cratering record of other planets and moons. In this contribution, I summarize the processes and products of impact cratering and provide and an up-to-date assessment of the geological record of meteorite impacts. 1. INTRODUCTION It is now widely recognized that impact cratering is a ubiquitous geological process that affects all planetary objects with a solid surface (e.g., [1]). One only has to look up on a clear night to see that impact structures are the dominant landform on the Moon. The same can be said of all the rocky and icy bodies in the solar system that have retained portions of their earliest crust.
    [Show full text]