Zircon ages of the Bayankhongor ophiolite mélange and associated rocks: Time constraints on Neoproterozoic to Cambrian accretionary and collisional orogenesis in Central Mongolia
Zircon ages of the Bayankhongor ophiolite mélange and associated rocks: Time constraints on Neoproterozoic to Cambrian accretionary and collisional orogenesis in Central Mongolia
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巴彦洪戈尔蛇绿混杂岩及伴生岩的锆石年龄：蒙古中部新元古代至寒武纪增生和碰撞造山作用的时间限制
DOI：
10.1016/j.precamres.2009.11.009
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发表时间：
2010-02
影响因子：
3.8
通讯作者：
Ping Jian
中科院分区：
文献类型：
--
作者：
Dondov Tomurhuu;Laicheng Miao;Brian F. Windley;Fuqin Zhang;Wei Zhang;Alfred Krönera,;Dunyi Liu;Yurao Shi;Ping Jian
蒙古中部的地质特征是一个增生的海洋陆块与一个弧-微大陆碰撞带紧密并置。本文对来自大洋陆块的巴音洪岗蛇绿岩和来自弧-微大陆带的正长斑岩进行了新的U-Pb锆石年龄和地球化学分析，为该区新元古代晚期至早寒武世的演化提供了重要的约束条件。与层状辉长岩相关的斜长岩（655±4Ma）、交代层状辉长岩（647±6Ma）和高水平各向同性角孔辉长岩（647±7Ma）为蛇绿岩的深成岩部分提供了最古老的锆石年龄。角闪洞辉长岩中的斜花岗岩脉的年龄为636±6Ma，是蛇绿岩中最年轻的年龄。该深成层序形成时间长（约20Ma），具有海底扩张演化的特征，其Nd - sr同位素组成(Nd(t)=+7.6 ~ +4.7；initial87Sr/86Sr比值= 0.70279-0.70327)指向洋中脊起源。正长斑岩年龄为523±2Ma，记录了造山末期或后碰撞期。巴彦淖尔洋岩石圈从形成到增生至少经历了92Ma的漂移。
Central Mongolia is geologically characterized by close juxtaposition of an accreted oceanic terrane with an arc-microcontinent collision zone. We present new U–Pb zircon ages and geochemical data for the Bayankhongor ophiolite mélange from the oceanic terrane and for a syenite porphyry pluton from the arc-microcontinent zone, providing critical constraints on the regional evolution in late Neoproterozoic to early Cambrian times. An anorthosite (655±4Ma) associated with layered gabbro, a rodingite (metasomatized layered gabbro) (647±6Ma), and a high-level isotropic amphibole gabbro (647±7Ma) yielded the oldest zircon ages for the plutonic part of the ophiolite. A plagiogranite dike in the amphibole gabbro yielded an age of 636±6Ma, which is the youngest date obtained for the ophiolitic rocks. We suggest that the long duration (ca. 20Ma) for formation of this plutonic sequence characterizes the sea-floor spreading evolution, and the Nd–Sr isotopic composition (ɛNd(t)=+7.6 to +4.7; initial87Sr/86Sr ratio=0.70279–0.70327) points to a mid-ocean-ridge origin. The syenite porphyry, dated at 523±2Ma, records the terminal or post-collisional phase of orogeny. The Bayankhongor oceanic lithosphere experienced at least 92Ma of drift between its formation and accretion.
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影响因子：
1.1
作者：
I. Kozakov;A. Kotov;E. Sal’nikova;V. Kovach;A. Natman;E. Bibikova;T. Kirnozova;W. Todt;A. Krönder;S. Yakovleva;V. I. Lebede;A. M. Sugorakova
通讯作者：
I. Kozakov;A. Kotov;E. Sal’nikova;V. Kovach;A. Natman;E. Bibikova;T. Kirnozova;W. Todt;A. Krönder;S. Yakovleva;V. I. Lebede;A. M. Sugorakova
影响因子：
5.3
作者：
STEIGER, RH;JAGER, E
通讯作者：
JAGER, E
影响因子：
3.9
作者：
E. Dubińska;P. Bylina;A. Kozłowski;W. Dörr;K. Nejbert;Janina Schastok;C. Kulicki
通讯作者：
E. Dubińska;P. Bylina;A. Kozłowski;W. Dörr;K. Nejbert;Janina Schastok;C. Kulicki
影响因子：
2.9
作者：
R. Arenas;J. Catalán
通讯作者：
R. Arenas;J. Catalán
DOI：
10.1144/gsl.sp.2003.218.01.22
发表时间：
2003
期刊：
Geological Society, London, Special Publications
影响因子：
--
作者：
J. Wakabayashi;Y. Dilek
通讯作者：
J. Wakabayashi;Y. Dilek