Grenvillian and early Paleozoic polyphase metamorphism recorded by eclogite and host garnet mica schist in the North Qaidam orogenic belt
Grenvillian and early Paleozoic polyphase metamorphism recorded by eclogite and host garnet mica schist in the North Qaidam orogenic belt
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柴达木北造山带榴辉岩和寄主石榴石云母片岩记录的格伦维尔期和早古生代多期变质作用
DOI：
10.1016/j.gsf.2021.101170
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发表时间：
2021-02
影响因子：
8.9
通讯作者：
Bai Bowen
中科院分区：
文献类型：
--
作者：
Ren Yunfei;Chen Danling;Wang Haijie;Zhu Xiaohui;Bai Bowen
柴北缘造山带一般被认为是早古生代超压变质带，但越来越多的新元古代岩浆和变质事件的报道表明，柴北缘造山带可能也经历了Rodinia的组装。然而，由于新元古代变质作用的记录稀少和性质模糊，新元古代NQOB的演化并没有得到很好的约束。为了揭示华北造山带的多期造山历史，对产于玉卡-落凤坡造山带的绿帘榴辉岩和寄主石榴云母片岩进行了岩石学、相平衡模拟和年代学综合研究。新的锆石和独居石U-Pb年龄表明，石榴云母片岩的原岩形成于994-920 Ma，经历了新元古代（920-915 Ma）和早古生代（451-447 Ma）的多期变质作用，并伴随榴辉岩的形成。首次在石榴云母片岩中的石榴子石和早古生代锆石中发现残留绿辉石包裹体，为云母片岩早古生代榴辉岩相变质作用提供了有力证据。石榴云母片岩和包封榴辉岩的P-T峰值条件相似，分别为>27.4 kbar/613-670 °C和30.2-30.8 kbar/646-655 °C，表明该区榴辉岩及其寄主副片麻岩在早古生代经历了大陆深俯冲，成为一种相干的变质杂岩。根据P-T假剖面中新元古代锆石域矿物包裹体稳定性场、残余石榴石芯成分和锆石中钛温度计，新元古代变质作用的峰温条件大致限定在7.7-12.0 kbar和634-680 °C。根据我们目前和以往研究的P-T条件所确定的高的热梯度（16-37 °C/km）表明新元古代变质作用可能发生在>945-890 Ma的大陆碰撞环境中。自格伦维尔期同造山期花岗岩岩浆作用和变质作用（约。1.0- 0.9Ga），表明柴达木地块新元古代可能位于Rodinia北缘。
The North Qaidam orogenic belt (NQOB) is generally considered to be an early Paleozoic ultrahigh pressure metamorphic belt, but increasing reports of the Neoproterozoic magmatic and metamorphic events indicate that the NQOB probably also experienced the assembly of the Rodinia. However, the Neoproterozoic evolution of the NQOB is not well constrained due to the sparse records and ambiguous nature of the Neoproterozoic metamorphism. In order to reveal the multi-orogenic history of the NQOB, an integrated study of petrology, phase equilibrium modelling and geochronology was conducted on an epidote eclogite and host garnet mica schist from the Yuka–Luofengpo terrane. New zircon and monazite U–Pb ages show that the protolith of the garnet mica schist was deposited during 994–920 Ma and experienced Neoproterozoic (920–915 Ma) and early Paleozoic (451–447 Ma) polyphase metamorphism together with the enclosed eclogite. Relic omphacite inclusions were first identified in garnet and early Paleozoic zircon domains from the garnet mica schist, which provide solid evidence for the early Paleozoic eclogite facies metamorphism of the mica schist. Similar early Paleozoic peakP–Tconditions of >27.4 kbar/613–670 °C and 30.2–30.8 kbar/646–655 °C were obtained for the garnet mica schist and enclosed eclogite, respectively, indicating that eclogites and their host paragneisses in this region underwent continental deep subduction as a coherent metamorphic terrane in early Paleozoic. The peakP–Tconditions of the Neoproterozoic metamorphism were roughly constrained at 7.7–12.0 kbar and 634–680 °C for the garnet mica schist, based on stability field of mineral inclusions in Neoproterozoic zircons domains inP–Tpseudosection, the relic garnet core composition and Ti-in-zircon thermometer. The high thermal gradients (16–37 °C/km) defined by presently our and previously reportedP–Tconditions indicate that the Neoproterozoic metamorphism likely occurred in continental collision setting at >945–890 Ma. Since the Grenvillian syn-orogenic granitic magmatism and metamorphism (ca. 1.0–0.9 Ga) in the NQOB are much younger than the Grenvillian orogeny in the central part of Rodinia, the Qaidam Block was probably located at the north margin of Rodinia in Neoproterozoic.
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影响因子：
4.5
作者：
D. Rubatto;J. Hermann
通讯作者：
D. Rubatto;J. Hermann
DOI：
--
发表时间：
2006
期刊：
--
影响因子：
--
作者：
Cheng Dan-ling
通讯作者：
Cheng Dan-ling
尤卡·落风坡地体榴辉岩记录的两次造山旋回:对柴达木北造山带中元古代至早古生代构造演化的启示.
影响因子：
3.8
作者：
Ren Y F;Chen D L;Zhu X H;Ren Z L;Gong X K;Luo F H
通讯作者：
Luo F H
影响因子：
--
作者：
C. Yakymchuk;C. Clark;R. White
通讯作者：
C. Yakymchuk;C. Clark;R. White
影响因子：
--
作者：
L. Eymard;A. Weill;D. Bourras;C. Guérin;P. Borgne;J. Lefèvre
通讯作者：
L. Eymard;A. Weill;D. Bourras;C. Guérin;P. Borgne;J. Lefèvre