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Metamorphic stages in mountain belts during a Wilson cycle: A case study in the central Sanandaj-Sirjan zone (Zagros Mountains, Iran)

文献类型:期刊论文

作者Shakerardakani, Farzaneh1,2,3; Neubauer, Franz1; Bernroider, Manfred1; Finger, Fritz4; Hauzenberger, Christoph5; Genser, Johann1; Waitzinger, Michael4; Monfaredi, Behzad5
刊名GEOSCIENCE FRONTIERS
出版日期2022-03-01
卷号13期号:2页码:30
关键词Carboniferous Polyphase metamorphism Petrochronology Chemical Th-U-Pb age dating Ar-40/Ar-39 dating Collisional orogen
ISSN号1674-9871
DOI10.1016/j.gsf.2021.101272
英文摘要Polymetamorphic units are important constituents of continent-continent collisional orogens, and rift metamorphic assemblages are often overprinted by subsequent metamorphism during subduction and collision. This study reports the metamorphic conditions and evolution of the Dorud-Azna metamorphic units in the central part of the Sanandaj-Sirjan zone (SSZ), Iran. Here, new geothermobarometry results are integrated with Ar-40/Ar-39 mineral and Th-U-Pb monazite and thorite ages to provide new insight of polyphase metamorphism in the two different basement units of the SSZ, the lower Galeh-Doz orthogneiss and higher Amphibolite-Metagabbro units. In the Amphibolite-Metagabbro unit, staurolite micaschist underwent a prograde P-T evolution from 640 +/- 20 degrees C/6.2 +/- 0.8 kbar in garnet cores (M1) to 680 +/- 20 degrees C/7.2 +/- 1.0 kbar in garnet rims (M2). Three Th-U-Pb monazite ages of 306 +/- 5 Ma, 322 +/- 28 Ma and 336 +/- 39 Ma from the garnet-micaschists testify the Carboniferous age of M1 metamorphism. In the same unit, the metagabbro records P-T conditions of 4.0 +/- 0.8 kbar and 580 +/- 50 degrees C in the (magmatic) amphibole core (Late Carboniferous intrusion) to 7.5 +/- 0.7 kbar and 700 +/- 20 degrees C in the amphibole rim indicating a prograde P-T path during subsequent burial (M1). New (40) Ar/Ar-39 dating of white mica from the staurolite micaschist yielded a staircase pattern ranging from 36 +/- 12 Ma to 170 +/- 2 Ma. This implies polymetamorphism with a minimum Late Jurassic cooling age through the Ar retention temperature of ca. 425 +/- 25 degrees C after M2 metamorphism and a Paleogene low-grade metamorphic overprint (M3), while Ar-40/Ar-39 white mica dating of garnet micaschist yielded a plateau age of 137.84 +/- 0.65 Ma. We therefore interpret the amphibolite-grade metamorphism M2 to have predated 170 Ma and is likely between 180 and 200 Ma. Furthermore, it is overprinted at about 36 Ma under retrogressive low-grade M3 metamorphism (at temperatures of -350-240 degrees C) during final shortening and exhumation. In the underlying Galeh-Doz unit, the Panafrican granitic orthogneiss intruded at P-T conditions of 3.2 +/- 4 kbar and 700 +/- 20 degrees C, then it was metamorphosed and deformed at 600 +/- 50 degrees C and 2.0 +/- 0.8 kbar (metamorphic stage Ml) prior to Late Carboniferous intrusion of mafic dikes. Ar-40/Ar-39 dating of amphibole from the Galeh-Doz orthogneiss gave plateau-like steps between 260 and 270 Ma, representing the age of cooling through ca. 500 degrees C after the Ml metamorphic event. Interestingly, the results of this study demonstrate polyphase metamorphic histories in both the Galeh-Doz orthogneiss and Amphibolite-Metagabbro units at different P-T conditions and final thickskinned Paleogene emplacement of these units over the underlying low-grade metamorphic June Complex. Our findings suggest that both units are affected by high-Tflow-P Late Carboniferous orogenic metamorphism along with the bimodal magmatism, as result of rifting. We propose that the Early Jurassic amphibolite-grade M2 metamorphism of the SSZ is correlated with the initial subduction of the Neotethyan Ocean. Eventually, the investigated units reflect various stages of a Wilson cycle, from rifting to initiation of the subduction in final plate collision. (C) 2021 China University of Geosciences (Beijing) and Peking University. Production and hosting by Elsevier B.V.
WOS关键词PETROLOGICAL ELEMENTARY TOOLS ; CANYON SANIDINE STANDARD ; AL2SIO5 TRIPLE POINT ; K-40 DECAY CONSTANTS ; NW IRAN ; TECTONIC EVOLUTION ; WESTERN IRAN ; MONAZITE GEOCHRONOLOGY ; CONTINENTAL COLLISION ; JOINT DETERMINATION
资助项目Afro-Asiatisches Institut, Salzburg
WOS研究方向Geology
语种英语
WOS记录号WOS:000773521400006
出版者CHINA UNIV GEOSCIENCES, BEIJING
资助机构Afro-Asiatisches Institut, Salzburg ; Afro-Asiatisches Institut, Salzburg ; Afro-Asiatisches Institut, Salzburg ; Afro-Asiatisches Institut, Salzburg ; Afro-Asiatisches Institut, Salzburg ; Afro-Asiatisches Institut, Salzburg ; Afro-Asiatisches Institut, Salzburg ; Afro-Asiatisches Institut, Salzburg ; Afro-Asiatisches Institut, Salzburg ; Afro-Asiatisches Institut, Salzburg ; Afro-Asiatisches Institut, Salzburg ; Afro-Asiatisches Institut, Salzburg ; Afro-Asiatisches Institut, Salzburg ; Afro-Asiatisches Institut, Salzburg ; Afro-Asiatisches Institut, Salzburg ; Afro-Asiatisches Institut, Salzburg
源URL[http://ir.iggcas.ac.cn/handle/132A11/105039]  
专题地质与地球物理研究所_岩石圈演化国家重点实验室
通讯作者Shakerardakani, Farzaneh
作者单位1.Paris Lodron Univ Salzburg, Dept Geog & Geol, Hellbrunner Str 34, A-5020 Salzburg, Austria
2.Chinese Acad Sci, Inst Geol & Geophys, State Key Lab Lithospher Evolut, Beijing 100029, Peoples R China
3.Chinese Acad Sci, Innovat Acad Earth Sci, Beijing 100029, Peoples R China
4.Paris Lodron Univ Salzburg, Dept Chem & Phys Mat, Jakob Haringer Str 2a, A-5020 Salzburg, Austria
5.Karl Franzens Univ Graz, Inst Earth Sci, NAWI Graz Geoctr, Univ Pl 2, A-8010 Graz, Austria
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Shakerardakani, Farzaneh,Neubauer, Franz,Bernroider, Manfred,et al. Metamorphic stages in mountain belts during a Wilson cycle: A case study in the central Sanandaj-Sirjan zone (Zagros Mountains, Iran)[J]. GEOSCIENCE FRONTIERS,2022,13(2):30.
APA Shakerardakani, Farzaneh.,Neubauer, Franz.,Bernroider, Manfred.,Finger, Fritz.,Hauzenberger, Christoph.,...&Monfaredi, Behzad.(2022).Metamorphic stages in mountain belts during a Wilson cycle: A case study in the central Sanandaj-Sirjan zone (Zagros Mountains, Iran).GEOSCIENCE FRONTIERS,13(2),30.
MLA Shakerardakani, Farzaneh,et al."Metamorphic stages in mountain belts during a Wilson cycle: A case study in the central Sanandaj-Sirjan zone (Zagros Mountains, Iran)".GEOSCIENCE FRONTIERS 13.2(2022):30.

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来源:地质与地球物理研究所

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