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Australasian microtektites across the Antarctic continent: Evidence from the Sør Rondane Mountain range (East Antarctica)

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Geoscience Frontiers 2021年第4期12卷 202-214页

作者： Bastien Soens Matthias van Ginneken Stepan Chernonozhkin Nicolas Slotte Vinciane Debaille Frank Vanhaecke Herman Terryn Philippe Claeys Steven Goderis Analytical Environmentaland Geo-ChemistryVrije Universiteit BrusselPleinlaan 2BE-1050 BrusselsBelgium Laboratoire G-Time UniversitéLibre de Bruxelles 50Av.F.D.Roosevelt CP 160/02BE-1050 BrusselsBelgium Centre for Astrophysics and Planetary Science University of KentCT27NZCanterburyKentUnited Kingdom Atomic&Mass Spectrometry–A&MS Research Unit Department of ChemistryGhent UniversityCampus SterreKrijgslaan 281–S12BE-9000 GhentBelgium Electrochemical and Surface Engineering Vrije Universiteit BrusselPleinlaan 2BE-1050 BrusselsBelgium

The~790 ka Australasian(micro)tektite strewn field is one of the most recent and best-known examples of impact ejecta emplacement as the result of a large-scale cratering event across a considerable part of Earth's surface(>10%in area).The Australasian strewn field is characterized by a tri-lobe pattern consisting of a large central distribution lobe,and two smaller side lobes extending to the west and ***,we report on the discovery of microtektite-like particles in sedimentary traps,containing abundant micrometeorite material,in the Sør Rondane Mountain(SRM)range of East *** thirty-three glassy particles display a characteristic pale yellowcolor and are predominantly spherical in shape,except for a single dumbbell-shaped *** vitreous spherules range in size from220 to 570μm,with an average diameter of~370μ*** compares relatively well with the size distribution(75–778μm)of Australasian microtektites previously recovered from the TransantarcticMountains(TAM)and located ca.2500–3000 km fromthe *** addition,the chemical composition of the SRM particles exhibits limited variation and is nearly identical to the‘normal-type’(i.e.,microtektites and the Australasian tektite strewn field in ***,Sr isotope ratios and Nd model ages suggest that the target material of the SRM particles was composed of a plagioclase-or carbonate-rich lithology derived from a Paleo-or Mesoproterozoic crustal *** affiliation to the Australasian strewn field requires long-range transportation,with estimated great circle distances of ca.11,600 km from the hypothetical source crater,provided transportation occurred along the central distribution *** is in agreement with the observations made for the Australasian microtektites recovered from Victoria Land(ca.11,000 km)and Larkman Nunatak(ca.12,000 km),w

关键词： Impact cratering Impact ejecta Target stratigraphy Volatilization Antarctica microtektites

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microtektites in the Middle Pleistocene deep-sea sediments of the South China Sea

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Science China Earth Sciences 1999年第5期42卷 531-535页

作者：赵泉鸿翦知湣李保华成鑫荣汪品先

This is a preliminary study on the microtektites that were found in large numbers from the interval between 7.80 and 8.10 m depth of core S095-17957-2 (10°53.9’N, 115°18.3’E, water depth 2 195 m), northern Nansha area of the South China Sea. The microtektites vary in shape, with spherules predominating, and are commonly less than 1 mm in diameter, transparent or semitransparent, brownish in color, with bubbles inside. Based on coarse fraction stratigraphy and foraminifera/nanofossil biostratigraphical events the microtektite layer was assigned to nearly the Bm-hes/Matuyama magnetic reversal boundary (some 0.78 MaBP). Obviously, the present microtektites, and those found from the middle Pleistocene of the Indian Ocean, Australia and loess of northern China, were products of the same impact event and therefore, are useful as a reliable mark in Quaternary stratigraphy, as well as in paleoclimatic studies.

关键词： microtektites coarse fraction geological age South China Sea.

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Age estimation of the mid-Pleistocene microtektite event in the South China Sea: A case showing the complexity of the sea-land correlation

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Chinese Science Bulletin 2000年第24期45卷 2277-2280页

作者： Jiliang Wang Quanhong Zhao Xinrong Cheng Rujian Wang Pinxian Wang Tongji Univ MOE Lab Marine Geol Shanghai 200092 Peoples R China

The present study confirms the stratigraphical position of microtektite layer being clearly located below the Brunhes/Matuyama (B/M) boundary. Based on the sedimentation rate derived from the stable isotopic and magnetic data of ODP Site 772A, cores 17957 and 17959 in the South China Sea, the age of the mid-Pleistocene impact event was estimated at 10-12 ka earlier than the Brunhes-Matuyama polarity reversal. However, the microtektites were found above the measured B/M boundary in the loess profile due to the downward deviation of the measured B/M boundary from its true position. This demonstrates the complexity of paleo-magnetic records in the loess profiles which, in turn, causes the confusion in the sea-land stratigraphic correlation.

关键词： microtektites Brunhes/Matuyama (B/M) boundary mid-Pleistocene sea-land correlation.

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A STUDY ON THE BLACK MICROSPHERULES WITH MAGNETISM IN SOIL FROM DONGLING MOUNTAIN, BEIJING

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Chinese Science Bulletin 1992年第19期37卷 1647-1652页

作者：张宝民李容全游长江贾铁飞 Department of Geography Beijing Normal University Beijing 100875 PRC

Dongling Mountain is the highest one of the Beijing West Mountains. There is a layer of subalpine meadow soil about 0.50 m thick at the top of the mountain, of which the basement rock is the Jurassic andesite. A secti... 详细信息

关键词： black microspherules with magnetism microtektites cosmic spherules

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Microspherules-Bearing White Sandstone: Implication of Cosmic Impact Event near Jurassic-Cretaceous Boundary in West Central Sinai, Egypt

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Journal of Geoscience and Environment Protection 2016年第7期4卷 53-65页

作者： Hanan S. Badawy Ahmed M. Zayed Mohamed G. Shahien Geology Department Faculty of Science Beni-Suef University Beni-Suef Egypt

The presence of glass microspherules enclosing relict grains, shattered quartz and silicon carbide in white sandstone beds near the Jurassic-Cretaceous boundary in west central Sinai indicates a cosmic impact event. Characterization of the impact microspherules and proposing a reasonable scenario for their origin are the aims of this work. Field observations, optical, binocular, scanning electron and high-resolution transmitted electron microscopy investigations and chemical analyses were carried out. The study revealed that glass microspherules have high Al2O3 and FeO contents and low CaO and MgO contents. The high content of Al2O3 indicates that the source of microtektite-like microspherules is attributed to the melting of a clay-rich sandstone and carbonaceous matter, while the high content of FeO indicates admixing with projectile matter. The reaction between silica and carbon was carried out under conditions of high temperature (T > 1000°C) and carbon (C/Si > 1) which resulted in the production of silicon carbide with microdiamond intergrowth. Consequently, this intergrowth is in accordance with the impact origin via rapid condensation and growth within a vapor phase. In spite of the fact that no source crater has been recognized to date in the study area, the authors propose at least a single cosmic impact event scenario for the recorded glass microspherules in west central Sinai. The impact excavated the Paleozoic siliciclastic sedimentary rocks and then the glass microspherules showered the area of study. The deposition of microtektite-like glass particles within the white sandstone beds of the Malha Formation took place in the fluvial plain terrestrial environment. This setting precluded severe post-depositional reworking, yielding preservation of the glass particles in a primary layer. Eventually, lateral migration of the braided channels led to the reworking of the microspherules layer and the spatial disper

关键词： Impact Glass microtektites Ejecta Nubian Sandstone SiC

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