文章基本信息

标题：Geological map of the ultra-high pressure Brossasco-Isasca unit (Western Alps, Italy)
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作者：Roberto Compagnoni ; Franco Rolfo ; Chiara Groppo 等
期刊名称：Journal of Maps
印刷版ISSN：1744-5647
出版年度：2012
卷号：8
期号：4
页码：465-472
DOI：10.1080/17445647.2012.744367
出版社：Journal of Maps
摘要：In the southern Dora-Maira Massif, Western Alps, slivers of continental crust with similar lithologies, but recrystallized during the Alpine orogeny at different peak- P conditions, are exposed. They include the Brossasco-Isasca Unit (BIU) where coesite was first discovered in continental crust. A new 1:20,000-scale geologic map and related cross-sections of the whole BIU and adjoining units is presented, in which the most significant features useful to infer the pre-Alpine history and the Alpine tectonic and metamorphic evolution, are summarized. Thanks to detailed petrography and petrology, the geologic map shows the precise location of ultra-high pressure (UH P ) minerals (such as coesite), and the locations of the most significant mineral assemblages (such as kyanite + jadeite). This innovative approach is used to distinguish the BIU from the adjacent units. Relict pre-Alpine structures (such as igneous intrusive contacts with basement xenoliths and metagranitoids) are summarized in a sketch illustrating the geologic setting of the UH P metamorphic unit as inferred before the Alpine orogeny.
关键词：ultra-high pressure metamorphism (UHPM); Dora-Maira Massif; Western Alps