Contrasting metamorphic records and their implications for tectonic process in the central Sør Rondane Mountains, eastern Dronning Maud Land, East Antarctica

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.

南极东部毛德皇后地（Dronning Maud Land）东部的瑟尔隆达讷山脉（Sør Rondane Mountains）中部区域的变质岩，可依据岩石学特征划分为三类：
(i) 奥斯特坎帕内地区（Austkampane area）保留了约800 ℃、0.5~0.6 GPa的峰值变质温压条件，后续经历减压、等压冷却及后期水化作用，划归为A型；
(ii) 布拉特尼佩讷（Brattnipene）与梅尼帕东部区域保留了约800 ℃、0.7~0.8 GPa的峰值变质温压条件，后续经历等压冷却及后期水化作用，划归为B型；
(iii) 伦克里根（Lunckeryggen）、瓦尔纳姆菲耶拉南部（Walnumfjella）及梅尼帕西部地区的岩石，保留了角闪岩相（amphibolite-facies）峰值变质条件，并显示出进变质作用的特征，且基本未受退变质水化事件的影响，划归为L型。
A型与B型岩石的麻粒岩相（granulite-facies）峰值变质作用时代同步，均为约640~600 Ma，但二者的温压路径差异可通过A型岩石单元逆冲推覆至B型岩石单元之上得到合理解释。与之相反，L型岩石的变质作用时代明显更年轻，约为550 Ma，推测与伟晶岩及花岗岩类（granitoids）的侵入活动相关。
瑟尔隆达讷山脉中部的上述变质作用记录，可作为检验与冈瓦纳（Gondwana）形成相关造山运动所提出的区域构造演化模型的试验场。