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

作　　者：Bastien Soens Matthias van Ginneken Stepan Chernonozhkin Nicolas Slotte Vinciane Debaille Frank Vanhaecke Herman Terryn Philippe Claeys Steven Goderis 

机构地区：[1]Analytical,Environmental,and Geo-Chemistry,Vrije Universiteit Brussel,Pleinlaan 2,BE-1050 Brussels,Belgium [2]Laboratoire G-Time,UniversitéLibre de Bruxelles 50,Av.F.D.Roosevelt CP 160/02,BE-1050 Brussels,Belgium [3]Centre for Astrophysics and Planetary Science,University of Kent,CT27NZ,Canterbury,Kent,United Kingdom [4]Atomic&Mass Spectrometry–A&MS Research Unit,Department of Chemistry,Ghent University,Campus Sterre,Krijgslaan 281–S12,BE-9000 Ghent,Belgium [5]Electrochemical and Surface Engineering,Vrije Universiteit Brussel,Pleinlaan 2,BE-1050 Brussels,Belgium

出　　处：《Geoscience Frontiers》2021年第4期202-214,共13页地学前缘（英文版）

基　　金：the Research Foundation Flanders (FWO)for funding this PhD research to BS;the support by the Belgian Science Policy (BELSPO) through BELAM,Amundsen and BAMM projects;the Research Foundation-Flanders (FWO–Vlaanderen) and the VUB strategic research;the support from the FWO–FNRS “Excellence of Science (EoS)” project ET–Ho ME (ID30442502);the FRS–FNRS for support.

摘　　要：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 east.Here,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 Antarctica.The thirty-three glassy particles display a characteristic pale yellowcolor and are predominantly spherical in shape,except for a single dumbbell-shaped particle.The vitreous spherules range in size from220 to 570μm,with an average diameter of~370μm.This 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 SRM.In addition,the chemical composition of the SRM particles exhibits limited variation and is nearly identical to the‘normal-type’(i.e.,<6%MgO)TAM microtektites.The Sr and Nd isotope systematics for a single batch of SRM particles(n=26)strongly support their affiliation with TAMmicrotektites and the Australasian tektite strewn field in general.Furthermore,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 unit.The 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 lobe.This 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),which,on average,decrease in size and

关 键 词：Impact cratering Impact ejecta Target stratigraphy VOLATILIZATION ANTARCTICA MICROTEKTITES 

分 类 号：P941.61[天文地球—自然地理学] P539