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标题：Fracture dolomite as an archive of continental palaeo-environmental conditions
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作者：Andre Baldermann ; Florian Mittermayr ; Stefano M. Bernasconi 等
期刊名称：Communications Earth & Environment
电子版ISSN：2662-4435
出版年度：2020
卷号：1
期号：1
页码：1-12
DOI：10.1038/s43247-020-00040-3
语种：English
出版社：Nature Research
摘要：The origin of Quaternary dolomites in continental environments (e.g. karst and lakes) is barely constrained compared to marine dolomites in sedimentary records. Here we present a study of dolomite and aragonite formations infilling young fractures of the Erzberg' iron ore deposit, Austria, under continental-meteoric and low temperature conditions. Two dolomite generations formed shortly after the Last Glacial Maximum (~20 kyr BP): dolomite spheroids and matrix dolomite. Clumped isotope measurements and U/Th disequilibrium ages reveal formation temperatures of 0-3 C (6 C) and 3-20 C (5 C) for the both dolomite types, and depositional ages around 19.21 0.10 kyr BP and 13.97 0.08 kyr BP or younger, respectively. Meteoric solution and carbonate isotope compositions (18O, 13C and 87Sr/86Sr) indicate the dolomites formed via aragonite and high-Mg calcite precursors from CO2-degassed, Mg-rich solutions. Our study introduces low temperature dolomite formations and their application as a sedimentary-chemical archive. Palaeo-environmental conditions can be recorded in low-temperature continental archives, according to geochemical and isotopic analyses of dolomitic fracture infills at Erzberg, Austria.