地质通报2025，Vol.44Issue(9)：1694-1712,19.DOI:10.12097/gbc.2024.10.039
华北克拉通北缘西沙德盖岩体成因及其对钼矿化的制约
Petrogenesis of the Xishadegai intrusion on the northern margin of the North China Craton and its constraints on molybdenum mineralization
摘要
Abstract
[Objective]The Xishadegai molybdenum deposit,located on the northern margin of the North China Craton,is a medium-sized porphyry-type Mo deposit.Its formation exhibits close temporal,spatial,and genetic links with syenogranite intrusions.The rock geochemical characteristics of this syenogranite and its constraints on mineralization warrant further investigation.[Methods]This study conducted zircon U-Pb dating,whole-rock major and trace element analysis,as well as strontium(Sr),neodymium(Nd),and hafnium(Hf)isotopic analyses on the syenogranites.[Results]LA-MC-ICP-MS zircon U-Pb dating yielded a weighted mean 206Pb/238U age of 220.2±1.8 Ma,indicating emplacement of the intrusion during the Late Triassic.Geochemically,the rocks exhibit high silica(SiO2=75.09%～77.06%),alkalinity(K2O+Na2O=7.76%～8.34%),and peraluminous character(A/CNK>1),coupled with low Ti,Fe,Mn,Mg,Ca,and P concentrations.They are enriched in Rb,Th,and U,and depleted in Ba,Sr,and Eu.The syenogranites possess low initial 87Sr/86Sr ratios((87Sr/86Sr)i=0.703954～0.705263),strongly negative εNd(t)values(-14.91～-13.40)and zircon εHf(t)values(-16.42～-13.30),and ancient two-stage Nd and Hf model ages(2207～2087 Ma,2292～2103 Ma).[Conclusions]The syenogranites are identified as highly fractionated,high-K calc-alkaline I-type granites.They were derived primarily from ancient lower crustal sources.The emplacement occurred under a post-collisional extensional tectonic setting following the collision between the North China Craton and the Siberian Plate.Significant fractional crystallization and moderate degrees of crustal assimilation occurred during magma ascending.Integrated geochemical and zircon-based oxygen fugacity analyses suggest that the highly evolved nature and elevated oxygen fugacity of the magmatic system were key factors controlling the formation of the Xishadegai Mo deposit.关键词
高钾钙碱性Ⅰ型花岗岩/岩浆氧逸度/含矿斑岩/钼矿/华北克拉通北缘Key words
high-K calc-alkaline Ⅰ-type granite/magmatic oxygen fugacity/ore-bearing porphyry/molybdenum deposit/the northern margin of the North China Craton分类
天文与地球科学引用本文复制引用
王梁,贾丽琼,陈英富,颜宏伟..华北克拉通北缘西沙德盖岩体成因及其对钼矿化的制约[J].地质通报,2025,44(9):1694-1712,19.基金项目
中国地质调查局项目《佳木斯-兴凯地块基础地质综合研究》(编号:DD20230253)、《内蒙古哈达门沟金矿田深部矿产远景调查》(编号:12120113072200)、《应用地质调查成果集成与规划部署研究》(编号:DD20230597) Supported by the projects of China Geological Survey(Nos.DD20230253,12120113072200,DD20230597) （编号:DD20230253）
