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引用本文:马顺清1 陈 静2. 黑龙江鹿鸣钼矿区花岗岩锆石年龄、地球化学特征及其地质意义[J]. 中国地质, 2012, 39(5): 1162-1171.
MA Shun-qing1, CHEN Jing2. Geochronology and geochemistry of granite of the Luming molybdenum deposit in Heilongjiang and their geological significance[J]. Geology in China, 2012, 39(5): 1162-1171(in Chinese with English abstract).
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黑龙江鹿鸣钼矿区花岗岩锆石年龄、地球化学特征及其地质意义
马顺清1 陈 静21,2
1.中国地质大学(北京),北京 100083;2. 青海省地质调查院,青藏高原北部地质过程与矿产资源重点实验室,青海 西宁 810012
摘要:
提要:鹿鸣钼矿床位于伊春—延寿多金属成矿带中南段,是近年新发现的斑岩型钼矿床。矿区内成矿主岩为二长花岗岩-花岗斑岩,本文采用LA-ICP-MS微区原位同位素分析技术,测得锆石U-Pb年龄分别为(195.4±1.4)Ma和(197.6±1.3) Ma,形成于印支晚期—燕山早期。岩石地球化学数据表明花岗岩SiO2质量分数为70.74%~75.80%、K2O和Na2O质量分数分别为3.85%~7.02%和0.93%~2.95%,里特曼指数为0.9~3.1,分析显示属于高钾钙碱性-钾玄岩系列岩体;稀土总量(ΣREE)偏低、有较强烈的轻重稀土元素分馏(LaN/YbN=7.76~26.47),Eu负异常明显(Eu/Eu?鄢=0.34~0.62);微量元素富集Rb、Th、U、K,亏损Nb、Ta、Ti、Y和Yb等元素,这或者暗示其岩浆源区相对富水,或者反映岩浆源区可能遭受过俯冲带流体的交代作用,结合前人研究成果认为该矿床的形成与早中生代太平洋板块俯冲作用有关。
关键词:  鹿鸣钼矿  锆石U-Pb年龄  岩石地球化学  太平洋板块俯冲
DOI:
分类号:
基金项目:国土资源大调查项目(资[2010]矿评01-20-06)资助。
Geochronology and geochemistry of granite of the Luming molybdenum deposit in Heilongjiang and their geological significance
MA Shun-qing1, CHEN Jing21,2
1. China University of Geosciences, Beijing 100083, China;2. Northern Tibetan Plateau Geological Processes and Mineral Resources Laboratory, Qinghai Geological Survey Institute, Xining 810012, Qinghai, China
Abstract:
Abstract:The recently-discovered Lumin molybdenum deposit is located in the southern section of the Yichun-Yanshou polymetallic ore-forming belt. The ore-forming rocks mainly include adamellite -granite porphyry, and the LA -ICP - MS micro- situ isotopic analysis shows that their ages are195.4±1.4 Ma and 197.6±1.3 Ma, suggesting products of the late Indosinian - Early Yanshanian period. Geochemical studies indicate that SiO2 (wt%) values vary in the range of 3.36%~5.78%,whereas K2O and Na2O vary in the range of 3.36%~5.78% and 2.60%~3.78% respectively. Rittmann indexes vary between 0.9 and 3.1. Analysis shows that the intrusions belong to high-K calc-alkaline-shoshonitic series. The ΣREE values are low with a strong fractionation between light and heavy rare earth elements(LaN/YbN=7.76~26.47) and obvious Eu negative anomaly(Eu/Eu?鄢=0.34~0.62). Trace elements display enrichment of Rb, Th , U , K and depletion of Nb , Ta, Ti, Y, Yb , suggesting that the source might have been a relatively water-rich magma, or the magma might have suffered from metasomatism by subduction zone fluid. Combined with results of previous studies, it is concluded that the formation of the deposit was probably controlled by the subduction of Pacific plate in early Mesozoic.
Key words:  Luming molybdenum deposit  zircon U-Pb age  geochemistry  subduction of Pacific plate