气候变化领域集成服务门户(CCPortal): Formation and evolution of a subduction-related melange: The example of the Rocca Canavese Thrust Sheets (Western Alps)

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DOI	10.1130/B35213.1
	Formation and evolution of a subduction-related melange: The example of the Rocca Canavese Thrust Sheets (Western Alps)
	Roda M.; Zucali M.; Regorda A.; Spalla M.I.
发表日期	2020
ISSN	167606
起始页码	884
结束页码	896
卷号	132 期号:2021-03-04
英文摘要	In the Sesia-Lanzo Zone, Western Alps, the Rocca Canavese Thrust Sheets (RCT) subunit is characterized by a mixture of mantle-and crust-derived lithologies, such as metapelites, metagranitoids, metabasics, and serpentinized mantle slices with sizes ranging from meters to hundreds of meters. Structural and metamorphic history suggests that the RCT rocks experienced a complex evolution. In particular, two different peak conditions were obtained for the metabasics, representing different tectono-metamorphic units (TMUs), namely, D1a under eclogite facies conditions and D1b under lawsoniteblueschist-facies conditions. The two TMUs were coupled during the syn-D2 exhumation stage under epidote-blueschist-facies conditions. The different rocks and metamorphic evolutions and the abundance of serpentinites in the tectonic mixture suggest a possible subduction-related melange origin for the RCT. To verify whether a subduction-related melange can record tectono-metamorphic histories similar to that inferred for the RCT, we compare the pressure-temperature evolutions with the results of a 2-D numerical model of ocean-continent subduction with mantle wedge serpentinization. The predictions of the numerical model fully reproduce the two peak conditions (D1a and D1b) and the successive exhumation history of the two TMUs within the subduction wedge. The degree of mixing estimated from field data is consistent with that predicted by the numerical simulation. Finally, the present-day location of the RCT, which marks the boundary between the orogenic wedge (Penninic and Austroalpine domains) and the southern hinterland (Southalpine domain) of the Alpine chain, is reproduced by the model at the end of the exhumation in the subduction wedge. Therefore, the comparison between natural data and the model results confirms the interpretation of the RCT as a subductionrelated melange that occurred during exhumation within a serpentinized mantle wedge. © 2019 Geological Society of America.
语种	英语
来源期刊	Bulletin of the Geological Society of America
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/184821
作者单位	Università degli Studi di Milano, Dipartimento di Scienze della Terra, Via Mangiagalli 34, Milano, 20133, Italy; University of Houston, Department of Earth and Atmospheric Sciences, Houston, TX 77204, United States; Università degli Studi di Milano, Dipartimento di Scienze della Terra, Via Cicognara 7, Milano, 20133, Italy
推荐引用方式 GB/T 7714	Roda M.,Zucali M.,Regorda A.,et al. Formation and evolution of a subduction-related melange: The example of the Rocca Canavese Thrust Sheets (Western Alps)[J],2020,132(2021-03-04).
APA	Roda M.,Zucali M.,Regorda A.,&Spalla M.I..(2020).Formation and evolution of a subduction-related melange: The example of the Rocca Canavese Thrust Sheets (Western Alps).Bulletin of the Geological Society of America,132(2021-03-04).
MLA	Roda M.,et al."Formation and evolution of a subduction-related melange: The example of the Rocca Canavese Thrust Sheets (Western Alps)".Bulletin of the Geological Society of America 132.2021-03-04(2020).