Crustal anatexis and formation of two types of granitic magmas in the Kontum massif, central Vietnam: Implications for magma processes in collision zones
Crustal anatexis and formation of two types of granitic magmas in the Kontum massif, central Vietnam: Implications for magma processes in collision zones
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DOI：
10.1016/j.gr.2006.11.001
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发表时间：
2007-11
影响因子：
6.1
通讯作者：
M. Owada;Y. Osanai;N. Nakano;T. Matsushita;T. N. Nam;T. Tsunogae;T. Toyoshima;Pham Binh;H. K
中科院分区：
文献类型：
--
作者：
M. Owada;Y. Osanai;N. Nakano;T. Matsushita;T. N. Nam;T. Tsunogae;T. Toyoshima;Pham Binh;H. K
亚洲在晚二叠世由于一些微大陆的碰撞而成长。沿着大陆碰撞带发生同碰撞-碰撞后岩浆作用。本文报道了越南中部Kontum Gulf地区两种类型的花岗质岩石，即石榴石花岗岩（Grt花岗岩）和斜方辉石花岗岩（Opx花岗岩）。这些花岗岩形成于约。250 Ma时，高温（HT）和超高温（UHT）变质作用发生在同一带。根据岩石学和地球化学特征，并与前人的实验结果进行对比，认为含石榴子石花岗岩是由泥质片麻岩经部分熔融形成的，而含斜方辉石花岗岩则是由含石榴子石的镁铁质麻粒岩经部分熔融形成的。我们推断，一个显着高的地热梯度需要产生越南花岗岩岩浆作用和相关的HT超高温变质作用。这种地热可能归因于晚二叠世Kontum Bagraf下的上涌地幔柱。
Asia grew in the Late Permian by the collision of a number of micro-continents. Syn- to post-collisional magmatism occurred along the continental collision zones . In this study, we report two types of granitic rocks, garnet granite (Grt granite) and orthopyroxene granite (Opx granite), from the Kontum massif, central Vietnam, which is situated on the continental collision zone between the South China and Indochina cratons. These granitic rocks were formed at ca. 250 Ma when high-temperature (HT) and ultrahigh-temperature (UHT) metamorphism took place in the same zone. Based on the petrological and geochemical features compared with previously reported experimental results, garnet-bearing granite is derived from pelitic gneisses by partial melting, whereas orthopyroxene-bearing granite is produced by the partial melting of garnet-bearing mafic granulites. We inferred that a significantly high-geothermal gradient is required to produce Vietnamese granitic magmatism and related HT to UHT metamorphism. This geotherm may be attributed to upwelling mantle plume beneath the Kontum massif during the Late Permian.