New whole-rock geochemical analyses along with laser ablation multi-collector inductively coupled plasma mass spectrometry U–Pb zircon ages of the granite–rhyolite from the Karakoram Batholith, exposed along the Shyok Valley, NW India, have been performed to understand the timing and geochemical evolution of these magmatic bodies and their implications for the geodynamic evolution of the Karakoram Batholith. New geochronological data on granites and rhyolites along with previously published geochronological data indicate that the Karakoram Batholith evolved during Albian time (~110–100 Ma) owing to the subduction of Tethys oceanic lithosphere along the Shyok Suture Zone. This region witnessed a period of no magmatism during ~99–85 Ma. Following this, the Kohistan–Ladakh arc and Karakoram Batholith evolved as a single entity in Late Cretaceous and early Palaeogene times. Late Cretaceous (~85 Ma) rhyolite intrusions within the Karakoram Batholith show calc-alkaline subduction-related signatures with a highly peraluminous nature (molar A/CNK = 1.42–1.81). These intrusions may have resulted from c. ~13.8 % to ~34.5 % assimilation of pre-existing granites accompanied by fractional crystallization during the ascent of the magma. The contamination of mantle wedge-derived melts with crust of the active continental margin of the Karakoram most likely enhanced the high peraluminous nature of the rhyolite magma, as has been constrained by assimilation fractional crystallization modelling. Two granite samples from the contact of the Shyok Metamorphic Complex and Karakoram Batholith indicate that the post-collisional Miocene magmatism was not only confined along the Karakoram Fault zone but also extends ~30 km beyond the Shyok–Muglib strand.

中文翻译：

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喀喇昆仑东部 Shyok 缝合带印亚碰撞边缘的闭合：新的地球化学和锆石 U-Pb 年代学观测

新的全岩地球化学分析以及激光烧蚀多收集器电感耦合等离子体质谱法对来自印度西北部 Shyok 山谷的喀喇昆仑岩基的花岗岩-流纹岩的 U-Pb 锆石年龄进行了研究，以了解时间和这些岩浆体的地球化学演化及其对喀喇昆仑岩基地球动力学演化的影响。花岗岩和流纹岩的新年代学数据以及先前发表的年代学数据表明，由于特提斯海洋岩石圈沿 Shyok 缝合带俯冲，喀喇昆仑岩基在阿尔比时期（~110-100 Ma）演化。该地区在~99-85 Ma 期间经历了一段没有岩浆活动的时期。按照此，Kohistan-Ladakh arc 和 Karakoram Batholith 在白垩纪晚期和古近纪早期演化为一个整体。喀喇昆仑岩基内的晚白垩世（~85 Ma）流纹岩侵入体显示出具有高度过铝性质的钙碱性俯冲相关特征（摩尔 A/CNK = 1.42-1.81）。这些入侵可能是由于C. ~13.8% 到 ~34.5% 的预先存在的花岗岩同化伴随着岩浆上升过程中的分级结晶。由于受到同化分级结晶模型的限制，喀喇昆仑活动大陆边缘的地壳对地幔楔形熔体的污染很可能增强了流纹岩岩浆的高过铝性质。来自 Shyok 变质杂岩和喀喇昆仑岩基接触的两个花岗岩样品表明，后碰撞中新世岩浆活动不仅局限于喀喇昆仑断裂带，而且还延伸到 Shyok-Muglib 链之外约 30 公里。