Towards a Unified Nomenclature of Metamorphic Petrology
Total Page:16
File Type:pdf, Size:1020Kb
Load more
Recommended publications
-
Structure Characterization of Impact Natural Diamond from Popigai Crater
80th Annual Meeting of the Meteoritical Society 2017 (LPI Contrib. No. 1987) 6191.pdf STRUCTURE CHARACTERIZATION OF IMPACT NATURAL DIAMOND FROM POPIGAI CRATER Mara Murri1, Adrian P. Jones2, Paul F. McMillan3, Christoph G. Salzmann3, Matteo Alvaro1, M. Chiara Domeneghetti1, Fabrizio Nestola4, Mauro Prencipe5, David Dobson2, Rachael Hazael3, Moreton Moore6, Sergei A. Vishnevsky7, Alla M. Logvinova7, Nikolay V. Sobolev7 1 Earth and Environmental Science University of Pavia, Via Ferrata 1, Italy ([email protected]), 2 Department of Earth Sciences, University College London, WC1E 6BT, UK ([email protected]), 3 Department of Chemistry, University College London, WC1E 6BT, UK, 4 Department of Geosciences, University of Padua, Italy 5 Earth Sciences Department, University of Torino, Italy, 6 Royal Holloway, University of London, TW20 0EX, UK, 7 Institute of Geology and Mineralogy, Siberian Branch of Russian Academy of Sciences, Koptyug Ave., 3, 630090, Novosibirsk, Russia Introduction: Impact cratering is undoubtedly one of the most frequent high-energetic and potentially catastrophic event occurring at the earth surface and in the planetary system. For example, the energy released from an impact occurring on the Earth’s surface as calculated even for a small impact crater appears to be 3 orders of magnitudes higher than the Hiroshima atomic bomb. These enormous energies and the very short duration can cause unique irreversible changes to rocks and minerals (eg. deformations, phase transformations, melting and vaporization) and are compatible with P and T conditions required to transform graphite into diamond (4.5GPa at 1000°C) and are also enough to induce deformation in the newly formed diamonds. -
The Popigai Crater in the Capacity of Interplanetary Structural Analog
EPSC Abstracts Vol. 5, EPSC2010-217, 2010 European Planetary Science Congress 2010 c Author(s) 2010 The Popigai crater in the capacity of interplanetary structural analog. G.Dolnikov (1), O.Korablev (1), O.Roste (1) and N. Evdokimova (1) (1) Space Research Institute (IKI), Russia, ([email protected] / Fax: +7-495-3332566) Abstract Popigai crater was formed into two-layer target of Archaean crystalline rocks of the Anabar Shields, In central Arctic Siberia of Russia is situated one of and overlying Proterozoic to Mesozoic sedimentary interesting placing our planet crater Popigai. It is the sequences. Basement rocks are represented by the 4th largest impact crater on Earth but the best Verkhne-Anabar (lower layer up to 10 km thick) and exposed, the three other craters are larger, but they the Khapchan (about 800-1200 m) series [3]. are either buried (Chicxulub), strongly deformed (Sudbury), or deformed and severely eroded (Vredefort). The crater is filled with melted and shuttered material, including microdiamonds and other high pressure minerals characteristic of ultra- high pressure formed during the catastrophic impact. 1. Introduction One of very interesting astroblem of Earth is one hundred kilometres Popigai structure, centred at 7134'N, 11112'E in central Arctic Siberia (Fig. 1, 2), that has been ascribed as nature conservation Figure 2: Space image of Popigai meteorite crater. object of our planet of significant first value [1], [2]. Сlearly showed the inner part about 80 km with a darker tone of forest. In Western and North-Western 2. Popigai astroblem sectors of crater clearly showed exits fragments of bottom old crater and melt rocks (tagamites). -
Shocked Quartz, Ir, Sr, and OS Anomalies Found in the Late
LPS XXVII 239 Shocked Quartz, Ir, Sr, and 0sanomalies found in the Late Eocene at Massignano (Ancona, Italy): clear evidence of a bolide impact. Aron K. Clymer, Dept. of Geology and Geophysics, University of California, Berkeley, California 94720; Hubert B. Vonhof, Research School of Sedimentary Geology (NSG), Inst. of Earth Sciences, Vrije Universiteit, de Boelelaan 1085, 1018 HV, Amsterdam, Netherlands; Thomas Meisel, Dept. of Geology, University of Maryland, College Park, MD 20742; David M. Bice, Dept. of Geology, Carleton College, Northfield, MN 55057; Alessandm Montanari, Osservatorio Geologico di Coldigioco, 62020 Frontale (MC), Italy. Shock metamorphosed quartz grains coincident with a positive Ir anomaly of 199 +I- 19 ppb, a positive 87Srl86Sr anomaly, and a negative 187W 1880s anomaly of about 0.3 5 have been found in a marly layer of the Late Eocene Scagha Variegata formation at Massignano (Ancona), which clearly indicates a large impact with an interpolated radiometric age of 35.7 +I- 0.4 Ma. The Popigai crater (Siberia, - 100 km diameter) and the recently discovered Chesapeake Bay Crater (Eastern U. S., - 80 km diameter) are the only known giant craters from the Late Eocene and are prime candidates for the event that distributed the shocked quartz and geochemical anomalies found at Massignano. Although the Middle and Late Eocene are characterized by signrficant stepwise extinctions, the only evidence of a biotic response at Massignano to an impact is a cooler water shift in the dinocyst assemblage associated with the impact layer. Therefore the effects of the impact on this region of the Late Eocene Tethys appears mild, and the global ramification s of the Late Eocene impacts on climate and life remains unclear. -
Candidates for Multiple Impact Craters: Popigai and Chicxulub As Seen by EGM08, a Global 50×50 Gravitational Model
Solid Earth Discuss., 2, 69–103, 2010 Solid Earth www.solid-earth-discuss.net/2/69/2010/ Discussions © Author(s) 2010. This work is distributed under the Creative Commons Attribution 3.0 License. This discussion paper is/has been under review for the journal Solid Earth (SE). Please refer to the corresponding final paper in SE if available. Candidates for multiple impact craters: popigai and chicxulub as seen by EGM08, a global 50×50 gravitational model J. Klokocnˇ ´ık1, J. Kostelecky´ 2,3, I. Pesekˇ 3, P. Novak´ 2,4, C. A. Wagner5, and J. Sebera1,3 1Astronomical Institute, Academy of Sciences of the Czech Republic, Czech Republic 2Research Institute for Geodesy, Topography and Cartography, Czech Republic 3Department of Advanced Geodesy, Czech Technical University, Czech Republic 4Department of Math, Faculty of Applied Sciences, University of West Bohemia, Czech Republic 5Laboratory for Satellite Altimetry, NOAA, USA Received: 15 January 2010 – Accepted: 25 February 2010 – Published: 9 March 2010 Correspondence to: J. Klokocnˇ ´ık ([email protected]) Published by Copernicus Publications on behalf of the European Geosciences Union. 69 Abstract In 2008 the new Earth Gravitational Model (EGM08) was released. It contains a com- plete set of spherical harmonic coefficients of the Earth’s gravitational potential (Stokes parameters) to degree 2190 and order 2159 that can be used for evaluation of various 5 potential quantities with both the unprecedented accuracy and high spatial resolution. Two such quantities, the gravity anomaly and second-order radial derivative of the dis- turbing potential, were computed over selected areas with known impact craters. The displays of these derivatives for two such sites clearly show not only the strong circular- like features known to be associated with them but also other symmetrical structures 10 which appear to make them multiple impact sites. -
The Recognition of Terrestrial Impact Structures
Bulletin of the Czech Geological Survey, Vol. 77, No. 4, 253–263, 2002 © Czech Geological Survey, ISSN 1210-3527 The recognition of terrestrial impact structures ANN M. THERRIAULT – RICHARD A. F. GRIEVE – MARK PILKINGTON Natural Resources Canada, Booth Street, Ottawa, Ontario, KIA 0ES Canada; e-mail: [email protected] Abstract. The Earth is the most endogenically active of the terrestrial planets and, thus, has retained the poorest sample of impacts that have occurred throughout geological time. The current known sample consists of approximately 160 impact structures or crater fields. Approximately 30% of known impact structures are buried and were initially detected as geophysical anomalies and subsequently drilled to provide geologic samples. The recognition of terrestrial impact structures may, or may not, come from the discovery of an anomalous quasi-circular topographic, geologic or geo- physical feature. In the geologically active terrestrial environment, anomalous quasi-circular features, however, do not automatically equate with an impact origin. Specific samples must be acquired and the occurrence of shock metamorphism, or, in the case of small craters, meteoritic fragments, must be demonstrated before an impact origin can be confirmed. Shock metamorphism is defined by a progressive destruction of the original rock and mineral structure with increasing shock pressure. Peak shock pressures and temperatures produced by an impact event may reach several hundreds of gigaPascals and several thousand degrees Kelvin, which are far outside the range of endogenic metamorphism. In addition, the application of shock- wave pressures is both sudden and brief. Shock metamorphic effects result from high strain rates, well above the rates of norma l tectonic processes. -
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. -
Carlyle Smith Beals Fonds (R15735) Finding Aid No MSS2580 MIKAN
Date: 15/06/2017 Carlyle Smith Beals fonds (R15735) Page 1 Finding aid no MSS2580 Y:\App\Impromptu\Mikan\Reports\Description_reports\finding_aids_&_subcontainers_simplelist.imr MIKAN Container File/Item Cr. file/item Hierarchy Title, etc Date of/de Extent/Media/Dim/Access cde # Contenant Dos./pièce Dos./item cr. Hiérarchie Titre, etc création Support ou Média / Dim. / Accès 4938572 Series Personnal papers [textual record, graphic material] 1922-1978 4941473 1 1 File Personal papers 1947-1972 Textual records / 90 S&C : Biographical information, genealogical information on the Beals family. Contains also a passeport and a manual with french expressions and vocabulary. 4941474 1 2 File Personal correspondence 1965-1978 Textual records / 90 S&C : Correspondence not related to the professional activities of C.S. Beals. Contains also several postal cards. 4941475 1 3 File Scholarship records, Degrees, Honors and letters of 1922-1977 Textual records / 90 recommendation S&C : Contains a scholarship record of Yale University for 1922, letters from the University of London that certify the reception of two Ph.D. by C.S. Beals in 1926 and 1934. Contains the certification of the registrar's Office of the University of Toronto for the M.A. of 1923. Contains also letters of recommendation from the different schools attented by C.S. Beals. Contains also a letter from the Royal Society of Canada informing C..S. Beals.that he'll be recommended as fellow of the RSC, a letter from The Profesionnal Institute of the Public Service of Canada for the reception of the Institute's Gold Medal (1977), correspondence and documentation concerning the reception of a Honorary Degree from Queen's University in Kingston in 1960 and a certificate of the Royal Society of Canada certifying 45 years of membership. -
Establishing the Link Between the Chesapeake Bay Impact Structure and the North American Tektite Strewn Field: the Sr-Nd Isotopic Evidence
Meteoritics & Planetary Science 41, Nr 5, 689–703 (2006) Abstract available online at http://meteoritics.org Establishing the link between the Chesapeake Bay impact structure and the North American tektite strewn field: The Sr-Nd isotopic evidence Alexander DEUTSCH1, 2* and Christian KOEBERL3 1Institut f¸r Planetologie (IfP), Westfälische Wilhelms-Universität Münster (WWU), Wilhelm-Klemm-Str. 10, D-48149 M¸nster, Germany 2Zentrallabor f¸r Geochronologie (ZLG), WWU, Corrensstr. 24, D-48149 M¸nster, Germany 3Department of Geological Sciences, University of Vienna, Althanstrasse 14, A-1090 Vienna, Austria *Corresponding author. E-mail: [email protected] (Received 09 November 2004; revision accepted 21 December 2005) Abstract–The Chesapeake Bay impact structure, which is about 35 Ma old, has previously been proposed as the possible source crater of the North American tektites (NAT). Here we report major and trace element data as well as the first Sr-Nd isotope data for drill core and outcrop samples of target lithologies, crater fill breccias, and post-impact sediments of the Chesapeake Bay impact ε t = 35.7 Ma structure. The unconsolidated sediments, Cretaceous to middle Eocene in age, have Sr of + + ε t = 35.7 Ma − − 54 to 272, and Nd ranging from 6.5 to 10.8; one sample from the granitic basement Nd ε t = 35.7 Ma + ε t = 35.7 Ma − with a T CHUR model age of 1.36 Ga yielded an Sr of 188 and an Nd of 5.7. The Exmore breccia (crater fill) can be explained as a mix of the measured target sediments and the granite, plus an as-yet undetermined component. -
Designing Global Climate and Atmospheric Chemistry Simulations for 1 and 10 Km Diameter Asteroid Impacts Using the Properties of Ejecta from the K-Pg Impact
Atmos. Chem. Phys., 16, 13185–13212, 2016 www.atmos-chem-phys.net/16/13185/2016/ doi:10.5194/acp-16-13185-2016 © Author(s) 2016. CC Attribution 3.0 License. Designing global climate and atmospheric chemistry simulations for 1 and 10 km diameter asteroid impacts using the properties of ejecta from the K-Pg impact Owen B. Toon1, Charles Bardeen2, and Rolando Garcia2 1Department of Atmospheric and Oceanic Science, Laboratory for Atmospheric and Space Physics, University of Colorado, Boulder, CO, USA 2National Center for Atmospheric Research, Boulder, CO, USA Correspondence to: Owen B. Toon ([email protected]) Received: 15 April 2016 – Published in Atmos. Chem. Phys. Discuss.: 17 May 2016 Revised: 28 August 2016 – Accepted: 29 September 2016 – Published: 27 October 2016 Abstract. About 66 million years ago, an asteroid about surface. Nanometer-sized iron particles are also present glob- 10 km in diameter struck the Yucatan Peninsula creating the ally. Theory suggests these particles might be remnants of the Chicxulub crater. The crater has been dated and found to be vaporized asteroid and target that initially remained as va- coincident with the Cretaceous–Paleogene (K-Pg) mass ex- por rather than condensing on the hundred-micron spherules tinction event, one of six great mass extinctions in the last when they entered the atmosphere. If present in the great- 600 million years. This event precipitated one of the largest est abundance allowed by theory, their optical depth would episodes of rapid climate change in Earth’s history, yet no have exceeded 1000. Clastics may be present globally, but modern three-dimensional climate calculations have simu- only the quartz fraction can be quantified since shock fea- lated the event. -
Astroblemes, Scientific America~?-, Vol
Waste Isolation Pilot Plant Compliance Certification Application Reference 176 Dietz, R.S., August 1961. Astroblemes, Scientific America~?-, Vol. 205, #2, p 50-58. Submitted in accordance with 40 CFR § 194.13, Submission of Reference Materials. .. ~H ..\TTER COXE rour inrhes hi~h is one or many in igneous rork XEST OF COXES in dolomite. a tn~ or lime~tone. is rrom Wrlls or the \·rederort Ring in South ..\rrira. a strurture that i& prob Creek Ba~in ~trurture in Tenllt"'-"ft'. Thi& ~roup i~ II iMhet hi~h. ably the remains or tl1e large>l meteorite crater known on earth. Shork pre~~ur~ generated by meteorite imparl rreate ourh ron~. (;J..\.XT SH.-\TTER COXF., over rour reea long. i& !ihown in 1•lare amons jumbled rorks in a Rat. geolor:iralJy underormrd terrain at the Kentland Jime~tone quarry in Indiana. These c·ones round indirate that the quarry i~ an anrienl meteorite-im:-t ,ite. UMI Article Clearinghouse has reproduced this material with SO perLmLi'~-s~on of the copyright owner. Further reproduction IS Thi~ newly. ('Oined w·ord refers to anctent scars left in the earth·~ cru~t by huge tneteoriteH. The evidence for such itnpacts is largely the h igh-pre~~ure tnineral coesite and ~~shatter cones~' in the rocks b,· Hobert S. Dietz t is ;m awesome experience to stand authorih· was such that it took more than fall every 10,000 years, some 50,000 on the rim of B;minger Crater in :30 years' to re\·erse his judgment. But the giant meteorites must have struck the I Arizona and reflect on the cosmic scienc.-es progress not so much by the dis earth during the past 500 million ~·ears. -
Provincial Plaques Across Ontario
An inventory of provincial plaques across Ontario Last updated: May 25, 2021 An inventory of provincial plaques across Ontario Title Plaque text Location County/District/ Latitude Longitude Municipality "Canada First" Movement, Canada First was the name and slogan of a patriotic movement that At the entrance to the Greater Toronto Area, City of 43.6493473 -79.3802768 The originated in Ottawa in 1868. By 1874, the group was based in Toronto and National Club, 303 Bay Toronto (District), City of had founded the National Club as its headquarters. Street, Toronto Toronto "Cariboo" Cameron 1820- Born in this township, John Angus "Cariboo" Cameron married Margaret On the grounds of his former Eastern Ontario, United 45.05601541 -74.56770762 1888 Sophia Groves in 1860. Accompanied by his wife and daughter, he went to home, Fairfield, which now Counties of Stormont, British Columbia in 1862 to prospect in the Cariboo gold fields. That year at houses Legionaries of Christ, Dundas and Glengarry, Williams Creek he struck a rich gold deposit. While there his wife died of County Road 2 and County Township of South Glengarry typhoid fever and, in order to fulfil her dying wish to be buried at home, he Road 27, west of transported her body in an alcohol-filled coffin some 8,600 miles by sea via Summerstown the Isthmus of Panama to Cornwall. She is buried in the nearby Salem Church cemetery. Cameron built this house, "Fairfield", in 1865, and in 1886 returned to the B.C. gold fields. He is buried near Barkerville, B.C. "Colored Corps" 1812-1815, Anxious to preserve their freedom and prove their loyalty to Britain, people of On Queenston Heights, near Niagara Falls and Region, 43.160132 -79.053059 The African descent living in Niagara offered to raise their own militia unit in 1812. -
Shock-Metamorphosed Zircon in Terrestrial Impact Craters
Meteoritics & Planetary Science 41, Nr 3, 433–454 (2006) Abstract available online at http://meteoritics.org Shock-metamorphosed zircon in terrestrial impact craters A. WITTMANN*, T. KENKMANN, R. T. SCHMITT, and D. ST÷FFLER Institut f¸r Mineralogie, Museum f¸r Naturkunde, Humboldt Universit‰t zu Berlin, Invalidenstrasse 43, 10115 Berlin, Germany *Corresponding author. E-mail: [email protected] (Received 06 June 2005; revision accepted 11 October 2005) Abstract–To ascertain the progressive stages of shock metamorphism of zircon, samples from three well-studied impact craters were analyzed by optical microscopy, scanning electron microscopy (SEM), and Raman spectroscopy in thin section and grain separates. These samples are comprised of well-preserved, rapidly quenched impactites from the Ries crater, Germany, strongly annealed impactites from the Popigai crater, Siberia, and altered, variably quenched impactites from the Chicxulub crater, Mexico. The natural samples were compared with samples of experimentally shock-metamorphosed zircon. Below 20 GPa, zircon exhibits no distinct shock features. Above 20 GPa, optically resolvable planar microstructures occur together with the high-pressure polymorph reidite, which was only retained in the Ries samples. Decomposition of zircon to ZrO2 only occurs in shock stage IV melt fragments that were rapidly quenched. This is not only a result of post-shock temperatures in excess of ∼1700 °C but could also be shock pressure–induced, which is indicated by possible relics of a high-pressure polymorph of ZrO2. However, ZrO2 was found to revert to zircon with a granular texture during devitrification of impact melts. Other granular textures represent recrystallized amorphous ZrSiO4 and reidite that reverted to zircon.