Petrogenesis and tectonomagmatic significance of Eocene mafic intrusions from the Neotethyan suture zone in the Muslim Bagh–Khanozai region, Pakistan

New geochemical data for mafic intrusions within the Eocene Nisai Formation along the suture zone between the Indian and Eurasian
plates are used to constrain their petrogenesis and assess the local tectonics and mantle dynamics. Petrological and geochemical
data indicate that these alkalic intrusions have moderately enriched incompatible trace element compositions similar to ocean
island basalt magmatism. Modelling suggests that these intrusions are the result of 1–5% melting of a deep, enriched, predominantly
garnet lherzolite, with a small amount of subduction-derived fluids. These melts then underwent fractional crystallization
at lithospheric depths of c. 30 km.
Supplementary materials: Detailed information on each analysed sample including field notes and latitude and longitude, replicate analysis of standards,
and fractional crystallization modelling are available at http://www.geolsoc.org.uk/SUP18893.

本项研究利用印度板块与欧亚板块缝合带内白垩纪尼赛伊组基性侵入岩的新地质化学数据，旨在限制其成因，并评估当地的构造活动和地幔动力学。岩石学和地质化学数据表明，这些碱性侵入岩具有中等程度富集的不相容微量元素组成，类似于海洋岛玄武岩岩浆活动。模型分析显示，这些侵入岩的形成源于1至5%的深部、富集、以石榴石橄榄岩为主的熔融作用，并伴有少量俯冲带来源的流体。随后，这些熔岩在约30公里的地壳深处经历了分凝结晶过程。补充材料：包括野外笔记、经纬度、标准物质的复分析以及分凝结晶模型在内的每个分析样本的详细信息均可在http://www.geolsoc.org.uk/SUP18893找到。