Contrasting metamorphic records and their implications for tectonic process in the central Sør Rondane Mountains, eastern Dronning Maud Land, East Antarctica
Contrasting metamorphic records and their implications for tectonic process in the central Sør Rondane Mountains, eastern Dronning Maud Land, East Antarctica
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南极洲东部 Dronning Maud 地东部 Sør Rondane 山脉中部的对比变质记录及其对构造过程的影响
DOI：
10.1144/sp383.4
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发表时间：
2013
期刊：
影响因子：
--
通讯作者：
T
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文献类型：
--
作者：
Adachi;T.;Hokada;T.;Osanai;Y.;Nakano;N.;Baba;S. and Toyoshima;T
根据岩石学特征，将东南极洲德龙宁毛德地东部南龙格岭中段的变质岩划分为三种类型。(i)该地区保留了C。800 ℃和0.5-0.6 GPa的峰值变质条件，随后减压和随后的等压冷却和后期水化（A型）。(ii)Brattnipene和东部Menipa地区保留了c. 800 ℃和0.7-0.8 GPa，随后进行等压冷却和随后的水合（B型）。(iii)包括Lunckeryggen、Walnumfjella南部和Menipa西部在内的区域保留了角闪岩相的峰期变质条件，并具有典型的退变质作用（L型）特征，这些特征通常不受退水事件的影响。A型和B型岩石的峰期麻粒岩相变质作用在c. 640-600 Ma，但它们之间P-T轨迹的差异可以用A型岩石单元逆冲到B型岩石单元上来解释。相比之下，L型岩石的变质作用的时间是显着年轻的c。550 Ma，可能与伟晶岩和花岗岩类的侵入有关。这些在Sør Ronaldo山脉中部的变质记录可以作为与冈瓦纳形成有关的造山带的区域构造过程的试验场。
Metamorphic rocks in the central part of Sør Rondane Mountains, eastern Dronning Maud Land, East Antarctica, are classified into three types based on petrological characteristics.(i) The Austkampane area preserves c. 800 C and 0.5–0.6 GPa peak metamorphic conditions followed by decompression and subsequent isobaric cooling and later hydration (A-type).(ii) The Brattnipene and eastern Menipa area preserve peak P–T conditions of c. 800 C and 0.7–0.8 GPa with subsequent isobaric cooling and later hydration (B-type).(iii) The area including Lunckeryggen, southern Walnumfjella and western Menipa preserves an amphibolite–facies peak metamorphic condition with signatures of prograde metamorphism (L-type), which are typically unaffected by the retrograde hydration event. Peak granulite–facies metamorphism of A-and B-type rocks are contemporaneous at c. 640–600 Ma, but a difference in the P–T paths between these rocks can be explained by thrusting of the A-type rock unit onto the B-type rock unit. By contrast, the timing of the metamorphism of the L-type rocks is significantly younger at c. 550 Ma, possibly related to the intrusion of pegmatites and granitoids. These metamorphic records in the central part of the Sør Rondane Mountains can be a test ground for the regional tectonic processes proposed for the orogeny related to Gondwana formation.