期刊
INTERNATIONAL JOURNAL OF EARTH SCIENCES
卷 112, 期 2, 页码 631-658出版社
SPRINGER
DOI: 10.1007/s00531-022-02258-2
关键词
Bohemian Massif; Moldanubian Zone; Thermobarometry; Anisotropy of magnetic susceptibility; Fabric pattern
This paper presents new structural, anisotropy of magnetic susceptibility (AMS), and petrological data in tandem with existing geochronological data to determine a polyphase Variscan tectonometamorphic event in the southwestern Moldanubian Zone of the Bohemian Massif. The study reveals the successive tectonometamorphic evolution of high-grade metamorphic rocks in this area, highlighting three main geodynamic episodes: collisional to exhumation, late-orogenic shortening, and late-orogenic extension.
This paper presents new structural, anisotropy of magnetic susceptibility (AMS), and petrological data in tandem with existing geochronological data to determine a polyphase Variscan tectonometamorphic event in the southwestern Moldanubian Zone of the Bohemian Massif. The high-grade metamorphic rocks of this Zone underwent the successive tectonometamorphic evolution (from ca. 360 to 310 Ma) that portrays three main geodynamic episodes: (a) The collisional to exhumation episode (ca. 360-335 Ma) recorded by the relict, steeply dipping, an similar to N(NNE) to S(SSW) striking foliation planes (S-1) developed at temperatures of 720-754 degrees C and pressures of ca. 790 MPa (M-1) and superimposed flat-lying foliation planes (S-2) under temperatures of 674 +27 degrees C and pressures of 680 +/- 110 MPa (M-2). (b) The late-orogenic similar to N-S oriented shortening (ca. 335-325 Ma) controlled by convergence of a crustal segment derived from the Gondwana continent (newly named as the Salzburgia Block) and the mostly consolidated Bohemian Massif. These collisional processes resulted in superimposition of the foliation planes (S-3) dipping steeply to moderately to the similar to N to similar to NNE(NE), re-heating and metamorphic overprint at temperatures of 770-830 degrees C and pressures of 450-530 MPa (M-3) and syn-tectonic emplacement of the numerous late-orogenic granitoids. (c) Subsequently, the switch in the paleostress regime from similar to N-S shortening to that of late-orogenic similar to ENE-WSW extension (ca. 325-310 Ma) led to the activation of regional right-lateral transtension and exhumation of the deep-seated rocks. Associated re-equilibration proceeded under temperatures of 662-701 degrees C and pressures of 362-437 MPa (M-4 event). In the latter stages of this episode, the synchronous reactivation of the regional similar to NW-SE striking right-lateral shear zones (Pfahl and Danube) and the almost perpendicular similar to NNE(NE)-SSW(SW) striking left-lateral shear zones took place.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据