Abstract

Geological, mineralogical–petrographic, and geochronological studies (U/Pb, Rb/Sr, and Ar/Ar isotope dating) of igneous complexes of the Dalat Zone identified two stages, which reflect a change in the geodynamic regime. The first, Late Jurassic, stage corresponded to a suprasubduction setting with formation of volcanic sequences of the Deobaoloc complex: calc-alkali basaltic andesites, andesites, dacites, their tuff breccias, and tuffs. The second, Albian–Coniacian, stage of the transform setting was related to a sliding zone of tectonic plates, activation of general left-lateral shear deformations at the continent–ocean boundary, and formation of paleovolcanic structures and related Dinhquan granitic batholiths (113 ± 0.6 Ma), Ancroet granites (97 ± 0.4 Ma), Deoca monzogranodiorites (90.4 ± 0.3 Ma), and Cana leucogranite–alaskites (86.8 ± 1.5 Ma). The thermochronological analysis and mathematical modeling indicate that the live period of parental granitic magma in a transform geodynamic setting was Δt of ~27 Ma and differentiation in the deep source resulted in origination of the final Cana leucogranite-alaskitic intrusive stocks with Au–Mo ± Cu mineralization.

中文翻译：

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越南东南部白垩纪岩浆作用的地质和热年代学

摘要

大叻地区火成岩的地质，矿物学，岩石学和地质年代学研究（U / Pb，Rb / Sr和Ar / Ar同位素测年）确定了两个阶段，这反映了地球动力学机制的变化。第一阶段是侏罗纪晚期，对应于俯冲带，形成了Deobaoloc复合体的火山序列：钙碱性玄武安山岩，安山岩，dacites，凝灰岩角砾岩和凝灰岩。转换设置的第二个阶段，即阿尔比亚－科尼亚古时代，与构造板块的滑动带，大陆－海洋边界处的一般左侧剪切变形的激活以及古火山构造和相关的定泉花岗岩基岩的形成有关（113± 0.6 Ma），Ancroet花岗岩（97±0.4 Ma），Deoca monzogranodiorites（90.4±0.3 Ma）和Cana白云石-阿拉斯基特（86.8±1.5 Ma）。吨〜27 Ma和在深源分化导致用Au-沫±铜矿最终卡纳淡色花岗岩-alaskitic侵入股的发起。