中国地质2025，Vol.52Issue(6)：1930-1949,20.DOI:10.12029/gc20230228001
青藏高原东北缘红岭北锂辉石花岗伟晶岩脉群的发现及找矿前景分析
Discovery of spodumene granite-pegmatite dike group in Northern Hongling area,northeastern margin of Qinghai-Xizang Plateau and its prospecting prospect
摘要
Abstract
This paper is the result of geological survey engineering. [Objective]The eastern part of Zongwulong tectonic belt is an important Indosinian Li-Be metallogenic belt newly discovered in recent years,and the existing prospecting discoveries and research are limited to the Chakabeishan area.In this study,52 granite pegmatite dikes were found in Northern Hongling area,30 km southeast of Li-Be deposit in Chakabeishan,among which 6 dikes have better ore-bearing property,and with lithology of beryl-bearing spodumene granite pegmatite and greisen albite spodumene pegmatite.The highest grade of Li2O is 3.56％-3.71％,and the grade of BeO is 0.031％-0.048％,which indicate good metallogenic potential.However,the age,source area and origin of these pegmatite veins are still unclear,which further restricts the regional prospecting potential.[Methods]The petrology,geochemistry and chronology of the newly discovered beryl-bearing spodumene granite pegmatite in the northern Hongling are systematically studied in this paper.[Results]The pegmatite is characterized by high SiO2(75.4％-84.2％),Al2O3(10.23％-16.15％),K2O(0.32％-3.02％)and Na2O(0.99％-3.45％),and is peraluminous rock;The total amount of rare earth elements in pegmatite is very low(∑RE E=0.15× 10-6-0.85× 10-6),with slight enrichment of LREE(LREE/HREE=2.7-11.4,(La/Yb)N=3.9-24.7),and δEu is mainly positive anomaly.Characterized by enrichment of Rb,Ta,P,Cs,Pb and loss of Ba,Th,La,Ce,Sr,Nd and Ti.The zircon U-Pb age of pegmatite and columbite-tantalite is(211.2±7)Ma and(223±1)Ma,which indicate the diagenetic and metallogenic age is 223-21 1Ma.The Hf isotope shows that the εHf(t)value is between-8.61 and-9.43,and the corresponding crustal model age(tDM2)of Hf isotope is between 1.801 Ga and 1.843 Ga.[Conclusions]The beryllite-bearing spodumene granitic pegmatite in the northern Hongling area belongs to LCT pegmatite,which suggest that may be formed by partial melting of metamorphic argillaceous rocks of palaeoproterozoic era based on the geochemical data.The Li-Be deposit was formed in the Indosinian period.The discovery of beryllite-bearing spodumene granite-pegmatite in the northern Hongling area further points out the direction of lithium beryllium ore prospecting in the eastern part of the Zongwulong structural belt,which has good metallogenic potential and is expected to provide a new lithium beryllium ore exploration base for the northeastern edge of the Qinghai-Xizang Plateau.关键词
锂辉石花岗伟晶岩/铌钽铁矿/U-Pb定年/Hf同位素/印支晚期/红岭北/宗务隆构造带/地质调查工程Key words
spodumene granite pegmatite/columbite tantalite/U-Pb dating/Hf isotope/Late Indosinian/Northern Hongling area/Zongwulong tectonic belt/geological survey engineering分类
天文与地球科学引用本文复制引用
刘建栋,张新远,王秉璋,李善平,李五福,曹锦山,辜平阳,曹华文,郑英,王春涛,金婷婷..青藏高原东北缘红岭北锂辉石花岗伟晶岩脉群的发现及找矿前景分析[J].中国地质,2025,52(6):1930-1949,20.基金项目
国家重点研发计划项目(2021YFC2901902)、青海省地质矿产勘查开发局项目(青地矿科[2021]61号)和中国地质调查局项目(DD20190069-[2019]107)联合资助. Supported by the National Key Research and Development Plan Project(No.2021YFC2901902),Qinghai Provincial Geological and Mineral Exploration and Development Bureau Project(No.QDKK[2001]No.61)and the project of China Geological Survey(No.DD20190069-[2019]107). （2021YFC2901902）
