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Adakite在地球化学上具明显特征的火山岩和深成花岗岩类岩石 ,见于洋内岛孤环境和大陆孤 ,如安底斯孤。在洋内岛孤 ,由热的消减的年轻大洋岩石圈熔融形成 (叫做“板片熔融”) ,而在大陆孤 ,熔融曾发生在构造或岩浆加厚的下地壳底(叫做“下地壳熔融”)。在这两种产状环境中 ,adakite的鲜明地球化学特征被认为是起因于 ,一种不同程度含水的变质基性原岩在足够深度上的部分熔融 ;这里的足够深度是指可使石榴子石在残余结晶组合 (即石榴角闪石和 /或榴辉石的残余 )中保持稳定的深度。“原始”或“母”adakite熔体一旦形成 ,便可能在其向上运移和侵位到中上地壳期间受到同化作用 (或是地幔 ,或是大陆物质 )和结晶分异作用的改造。中国东部晚中生代 (早中白垩世 ,16 0 - 110 Ma)的 adakite,与见于同一地区和其它地方的钠质 adakite相比 ,通常富含钾 (K2 O)和其它大离子亲石元素 (如 Ba、Th、U) ,有较低的 Na2 O/K2 O比值 (～ 1.0 - 1.1) ,类似于玄武岩在石榴角闪岩 -榴辉岩相含水熔融实验中所产生的 adakite熔体 ,要么是由洋壳板片熔融所形成 ,要么是由不同成分的玄武质下地壳原岩部分熔融所形成。尽管有这些成分差异 ,它们的总体化学特征仍然可将中国东部的富钾花岗岩类岩石定为adakite。我们把这些富钾的 ad
Adakite geochemically distinctive volcanic rocks and deep granitic rocks, found in the Inland Islands solitary environment and the mainland solitary, such as Andes solitary. On the intracontinental orbiting island, it is formed by the subduction of the hot, subducting, young oceanic lithosphere (called “plate melting”), whereas on the mainland alone the melting took place at the bottom of the structurally or magma thickened lower crust (called “lower crustal melting ”). In both environments, the distinct geochemical characteristics of adakite are thought to result from the partial melting of a varying degree of hydrous metamorphic basement rocks to a sufficient depth; the deep enough here means that the pomegranate Stones maintain a constant depth in the residual crystalline assemblage (ie, the remnants of garnet amphibole and / or eclogite). Once formed, the “primitive” or “mother” adakite melt may be modified by assimilation (or mantle, or continental matter) and crystallization segregation during its uplift and emplacement into the mid-upper crust. The Late Mesozoic (Early Cretaceous, 160-110 Ma) adakites in eastern China are generally rich in potassium (K2O) and other large ionophilic elements compared to sodium adakite found in the same area and elsewhere Ba, Th, U), with a lower Na2 O / K2 O ratio (~1.0-1.1), similar to the adakite melt of basalt that was produced in the amphibolite- eclogite hydrous melt experiments, either It is formed by the melting of the oceanic shell plates, or by the partial melting of the original rock of the basaltic lower crust of different compositions. Despite these compositional differences, their overall chemical characteristics still allow the adulteration of potassium-rich granitoids in eastern China. We put these potassium-rich ad