Ordovician crustal thickening and syn-collisional magmatism of Iran: Gondwanan basement along the north of the Yazd Block (Central Iran)
Ordovician crustal thickening and syn-collisional magmatism of Iran: Gondwanan basement along the north of the Yazd Block (Central Iran)
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伊朗奥陶纪地壳增厚和同碰撞岩浆作用：亚兹德地块（伊朗中部）北部的冈瓦纳基底
DOI：
10.1080/00206814.2021.1972352
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发表时间：
2021
影响因子：
2.6
通讯作者：
Kawabata Hiroshi
中科院分区：
文献类型：
--
作者：
Samadi Ramin;Torabi Ghodrat;Dantas Elton Luiz;Morishita Tomoaki;Kawabata Hiroshi
本文研究了伊朗中东部微大陆（CEIM）西北部意外露头的冈瓦南花岗岩基底的遗迹，并将其纳入蛇绿岩质模子岩中。根据岩相学（白云母高模态含量（~10 vol.%）、角闪石不存在、继承锆石（>541 Ma））、地球化学(过铝和钙碱性s型亲和、高硅、高轻稀土元素（LREE)/重稀土元素（HREE）比值、负Nb和Ti异常）和年代学（岩浆锆石年龄~448 Ma）结果，认为该花岗岩为同碰撞背景下地壳增厚过程中沉积源形成的奥陶系深熔花岗岩。在泥盆纪（~410 Ma）表现出可能发育的变质变形特征（碎裂组构、石英胀形再结晶和片理）。该花岗岩的U-Pb锆石年龄与中欧其他与奥陶系碰撞相关的岩浆事件（Chahak - Airekan, Balvard）相似。研究结果证实，冈瓦纳超大陆以北的原特提斯洋在奥陶纪碰撞岩浆活动和泥盆纪-石炭纪区域变质作用中发生了卡多米期俯冲和闭合，导致地壳增厚。
This study investigates relicts of some granitic Gondwanan basement unexpectedly outcropping in the northwest of Central-East Iranian Microcontinent (CEIM) and incorporated into an ophiolitic mélange. Based on petrographical (e.g. high modal content of muscovite (~10 vol.%), absence of hornblende, inherited zircons (>541 Ma)), geochemical (peraluminous and calc-alkaline S-type affinity, high silica, high ‘light rare earth element (LREE)/heavy rare earth element (HREE)’ ratios, negative Nb and Ti anomalies), and geochronological (magmatic zircon age ~448 Ma) results, it is an Ordovician anatectic granite formed from a sedimentary source during crustal thickening in a syn-collisional setting. It shows some signatures of metamorphic deformation (cataclastic fabric, quartz bulging recrystallization, and foliation) likely developed in the Devonian (~410 Ma). The U-Pb zircon ages from this granite are analogous to the other Ordovician collision-related magmatic events in the CEIM (Chahak to Airekan, Balvard). Our results confirm that Cadomian subduction and closure of the Proto-Tethys Ocean to the north of the Gondwana supercontinent resulted in crustal thickening during Ordovician collision-related magmatism and Devonian-Carboniferous regional metamorphism in the CEIM.