Lower Continental Crusts Involved in the Alpine Orogeny:New Insight from the Santa Lucia Nappe Metasediments(Corsica,France)  

作　　者：Chiara FRASSI Maria DI ROSA Luca PANDOLFI Michele MARRONI 

机构地区：[1]Dipartimento di Scienze della Terra,Universitàdi Pisa,Via Santa Maria 53,56126 Pisa,Italy [2]Istituto di Geoscienze e Georisorse,IGG-CNR,Via Moruzzi,50124 Pisa,Italy

出　　处：《Acta Geologica Sinica(English Edition)》2024年第4期904-920,共17页地质学报（英文版）

基　　金：supported by the PRIN 2020(P.I.M.Marroni);Fondi Ateneo Grant by The University of Pisa。

摘　　要：In the Alpine Corsica(France),the Santa Lucia Nappe represents a peculiar unit preserving the unique relicts of Paleozoic lower to medium continental crust.It consists of composite basement affected by Permian granulite facies metamorphic conditions unconformably covered by a Late Cretaceous clastic sequence(Tomboni Conglomerate and Tralonca Flysch)affected by polyphase deformation and low-grade-metamorphism.In this work,we present a new reconstruction of the deformation events registered by the Tralonca Flysch during the Alpine orogeny.The D1 phase was testified by rare isoclinal folds.The D2 phase produced a continuous foliation and a map-scale sheath-fold with a top-to-W sense of shear.The D3 phase produced E-verging non-cylindrical folds and S3 crenulation cleavage that is not associated to metamorphic blastesis.We present the first temperature-pressure-deformation(P-T-d)path for the Tralonca Flysch,demonstrating that the Santa Lucia Nappe underwent accretion and then first stage exhumation in the Alpine wedge during the D1 phase with pressure and temperature peaks both occurred under blueschist metamorphic conditions.The D2 phase occurred at lower pressure-temperature conditions during a second stage exhumation.This pressure-temperaturedeformation path is comparable with those of the Lower Units(i.e.,the subducted continental units of Alpine Corsica)suggesting a common geodynamic history.

关 键 词：blueschist-facies metamorphism P-T-d path Santa Lucia Nappe CORSICA Alpine orogeny 

分 类 号：P548[天文地球—构造地质学]