岩石矿物学杂志2025，Vol.44Issue(3)：556-572,17.DOI:10.20086/j.cnki.yskw.2025.4150
冀北兰峡沟钼矿花岗岩成因及其成矿意义
The petrogenesis of granite and its significance on mineralization in Lanxiagou Mo deposit of northern Hebei
摘要
Abstract
The Lanxiagou molybdenum deposit,situated in northern Hebei Province within the western Yan-Liao Metallogenic Belt,primarily hosts molybdenite within granitic gneisses,with only sporadic mineralization in granitic intrusions.The influence of magmatic activity on molybdenum mineralization remains a key research focus.Zircon U-Pb dating reveals the granitic intrusion formed at 134.9±0.94 Ma(Early Cretaceous),coeval with regional mag-matic events.Geochemically,the Lanxiagou granite exhibits high SiO2(75.41％～76.21％),alkalis(Na2O+K2O=8.04％～8.73％),and Al2O3(12.19％～12.64％)with low CaO(0.44％～0.85％),classifying as high-K calc-alkaline,weakly peraluminous granite.It displays enrichment in LILEs(Rb,Th,U)and LREEs,depletion in HREEs and HFSEs(Nb,P,Ti),and moderate Eu anomalies(δEu=0.31～0.40).EPMA analyses indicate crust-derived fer-romagnesian biotite(high Mg,Fe,K;low Ca,Na)and albite(high Al,Na;low K,Ca).Mineralogical and geo-chemical signatures suggest a differentiated Ⅰ-type granite with crystallization differentiation of biotite,plagioclase,and apatite.Zircon εHf(t)values(-18.16 to-14.76)and tDM2(Hf)ages(2 570～2 117 Ma)indicate derivation from Paleoproterozoic lower crustal melting.The biotite in the intrusion exhibits relatively high oxygen fugacity(above the NNO buffer),with crystallization temperatures of 599～776℃,consolidation pressures of 164～260 MPa,and emplacement depths of 6.23～9.90 km,indicating formation under temperature and oxygen fugacity conditions favorable for molybdenum mineralization and significant exploration potential.关键词
冀北地区/锆石U-Pb年龄/全岩地球化学/矿物成分特征/兰峡沟钼矿床Key words
northern Hebei/zircon U-Pb dating/whole-rock geochemistry/mineral composition characteristics/Lanxiagou molybdenum deposit分类
天文与地球科学引用本文复制引用
任颖伟,王红,郑岩,孟柯柯,李红宾,张璨,梁景利,董国臣..冀北兰峡沟钼矿花岗岩成因及其成矿意义[J].岩石矿物学杂志,2025,44(3):556-572,17.基金项目
雄安新区科技创新专项(2023XAGG0068):河北省实物资料再开发项目 Xiong'an Science and Technology Innovation Project(2023XAGG0068) （2023XAGG0068）
Hebei Province Physical Data Redevelopment Project （）
