Contrasting metamorphic P–T path between Schirmacher Hills and Mühlig-Hofmannfjella, central Dronning Maud Land, East Antarctica
Contrasting metamorphic P–T path between Schirmacher Hills and Mühlig-Hofmannfjella, central Dronning Maud Land, East Antarctica
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DOI：
10.1144/sp308.20
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发表时间：
2008
期刊：
影响因子：
--
通讯作者：
S. Baba;M. Owada;K. Shiraishi
中科院分区：
文献类型：
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作者：
S. Baba;M. Owada;K. Shiraishi
摘要研究了德龙宁毛德地中部三个地区含石榴辉石基性片麻岩的退变质P-T轨迹。三个地区的岩石所估计的P-T条件没有差异，它们都在c. 6-8 kbar，750-830 ℃。然而，在Mühlig-Hofmann山脉（Filchnerfjella和Jutulsessen）的地方保存了具有矿物结构的岩石，表明近等温减压历史。在Schirmacher山，阿斯特丽德公主海岸的一个孤立的曝光，在镁铁质片麻岩中观察到的变质结构是等压冷却历史的指示。结合他们的P-T路径和年龄测定表明，Schirmacher山是一个单独的大陆，连同今天的东南非洲，而格伦维尔时代的东西向CDML内陆冰原岛峰地区的特点是等温减压变质历史的最后合并的冈瓦纳。
Abstract Retrograde metamorphic P–T paths of garnet–pyroxene-bearing mafic gneisses from three regions in central Dronning Maud Land (CDML) were examined. No difference in P–T conditions estimated from rocks of the three regions was recognized, and they are within the range of c. 6–8 kbar, 750–830 °C. However, localities in the Mühlig-Hofmann Range (Filchnerfjella and Jutulsessen) preserve rocks with mineral textures that indicate near-isothermal decompressional histories. In the Schirmacher Hills, an isolated exposure on the Princess Astrid Coast, metamorphic texture observed in mafic gneiss is indicative of an isobaric cooling history. Combining their P–T paths and age determinations suggests that the Schirmacher Hills was a separate terrane, together with present-day SE Africa, whereas the Grenvillian-age east–west-trending CDML inland nunatak regions are characterized by an isothermal decompressional metamorphic history related to the final amalgamation of Gondwana.