Abstract

Diverse geological complexes that form the crystalline basement of the East Antarctic Platform crop out in the Prince Charles Mountains. The Ruker Group is a member of the metasedimentary complexes that make up the Paleoproterozoic through Neoproterozoic suprastructure of the Ruker Terrane. It is divided into two sequences consisting of highly deformed and greenschist facies metamorphosed sedimentary and volcanic rocks. The mineral and major element compositions of metavolcanic rocks have been studied and physicochemical modeling of mineral parageneses has been performed to reconstruct the P–T parameters of metamorphism. The dependence of the mineralogy of metabasic schists on the protolith composition and the ratio of components in the H₂O–CO₂ fluid involved in the phase reactions were analyzed. The calculated mole fraction of CO₂ in the fluid equilibrated with carbonate-bearing parageneses is 0.13–0.27. It is assumed that chloritoid schist consists of metamorphosed laterites derived from basalt. Modeling and the data of chlorite–phengite thermobarometry indicate that the Ruker Group rocks were metamorphosed under conditions of the high-pressure part of the greenschist facies (300–450°C, 7–8 kb). These conditions are significantly higher than the stable continental geotherm and are close to those in the zone of a slow subduction geotherm. According to the available geological data, a similar geodynamic setting could be caused by the evolution of the Neoproterozoic intraplate sedimentary basin in connection with deep-sinking basement blocks as a result of tectonic aggregation during the closure of the basin.

中文翻译：

---

南极东部查尔斯王子山南部鲁克群的矿物共生模型和高温火山岩热压法

摘要

形成东南极平台结晶基底的各种地质​​复合体在查尔斯王子山中生长。Ruker小组是通过Ruker Terrane的新元古代超结构组成古元古代的准沉积复合物的成员。它分为两个序列，由高度变形的绿岩相和变质的沉积岩和火山岩组成。已经研究了超火山岩的矿物和主要元素组成，并进行了矿物共生物的物理化学建模，以重建变质作用的PT参数。陆生片岩的矿物学特征对原岩成分和H ₂ O–CO ₂中各组分的比例的依赖性分析了参与相反应的流体。计算出的CO ₂摩尔分数含碳酸盐的亚型平衡的流体中的总磷为0.13-0.27。假定类藻酸盐片岩由衍生自玄武岩的变质红土组成。绿泥石-辉石热压法的建模和数据表明，Ruker Group岩石是在绿片岩​​相高压部分（300-450°C，7-8 kb）的条件下变质的。这些条件明显高于稳定的大陆地热，并且接近缓慢俯冲地热的区域。根据现有的地质数据，由于盆地封闭期间的构造聚集，新元古代板块内沉积盆地与深沉的基底块的演化可能导致类似的地球动力学环境。