青海交通社矿区碱长花岗岩锆石U-Pb年龄、岩石地球化学特征及成因探讨
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摘要
交通社铌钽矿床位于阿尔金造山带,是该带近年来新发现的一个铌钽矿床。论文以该矿床为研究对象,通过开展矿床地质特征调查,利用锆石U-Pb年代学、岩石地球化学特征,探讨了与成矿密切相关的碱长花岗岩岩石成因类型及成岩成矿构造背景,探讨矿床成因。锆石LA-ICP-MS U-Pb同位素定年龄结果显示,碱长花岗岩为(453±4) Ma,属于高钾钙碱性系列,岩浆演化程度高;碱长花岗岩构造背景为后碰撞构造环境。微量元素表现为轻重稀土分馏不明显,稀土元素配分图显示,轻重稀土均相对平坦,具有明显Eu/Eu~*负异常。结合主量元素判别,同位素分析得出成岩、成矿物质为壳幔混合源。通过对比研究,结合矿床大地构造环境、成矿条件,认为交通社铌钽矿床形成于晚奥陶世,碱长花岗岩的侵入导致矿床的形成。矿床类型初步定为碱性花岗岩型铌钽矿床。
The Jiaotongshe niobium and tantalum deposit is located in the aljin orogenic belt, which is a newly discovered niobium and tantalum deposit in recent years. This paper takes this deposit as the research object, conducts a survey on the geological characteristics of the deposit, and USES zircon u-pb chronology and petrogeochemical characteristics to explore the genetic types of alkalifeldspathic rocks closely related to mineralization and the diagenetic and ore-forming tectonic background, so as to explore the genesis of the deposit. Zircon la-icp-ms u-pb isotope dating results show that the alkali feldspar is 4531±4 Ma,and the alkali feldspar belongs to the high kali-calc-alkali series with a high degree of magma evolution. The alkali feldspar tectonic background is the post-collision tectonic environment. The trace elements showed that the light and light rare earth fractionation was not obvious, and the rare earth elements partition diagram showed that the light and light rare earth elements were relatively flat with obvious Eu/Eu * negative anomaly.Combined with the identification of the main elements, isotopic analysis shows that the diagenesis and mineralization materials are mixed sources of crust and mantle. Through comparative study, combined with the geotectonic environment and metallogenic conditions of the deposit, it is concluded that the jiaotong she niobium tantalum deposit was formed in the late ordovician, and the intrusion of alkali feldspar resulted in the formation of the deposit. The deposit type is preliminarily defined as alkali granite-type niobium tantalum deposit.
The Jiaotongshe niobium and tantalum deposit is located in the aljin orogenic belt, which is a newly discovered niobium and tantalum deposit in recent years. This paper takes this deposit as the research object, conducts a survey on the geological characteristics of the deposit, and USES zircon u-pb chronology and petrogeochemical characteristics to explore the genetic types of alkalifeldspathic rocks closely related to mineralization and the diagenetic and ore-forming tectonic background, so as to explore the genesis of the deposit. Zircon la-icp-ms u-pb isotope dating results show that the alkali feldspar is 4531±4 Ma,and the alkali feldspar belongs to the high kali-calc-alkali series with a high degree of magma evolution. The alkali feldspar tectonic background is the post-collision tectonic environment. The trace elements showed that the light and light rare earth fractionation was not obvious, and the rare earth elements partition diagram showed that the light and light rare earth elements were relatively flat with obvious Eu/Eu * negative anomaly.Combined with the identification of the main elements, isotopic analysis shows that the diagenesis and mineralization materials are mixed sources of crust and mantle. Through comparative study, combined with the geotectonic environment and metallogenic conditions of the deposit, it is concluded that the jiaotong she niobium tantalum deposit was formed in the late ordovician, and the intrusion of alkali feldspar resulted in the formation of the deposit. The deposit type is preliminarily defined as alkali granite-type niobium tantalum deposit.
引文
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杨泽黎,邱检生,邢光福,等.2014.江西宜春雅山花岗岩体的成因与演化及其对成矿的制约[J].地质学报,2014,88(5):850-868.
尹蓉,王汝成,张爱铖,等.2013.新疆可可托海1号伟晶岩脉铌钽矿物研究与岩浆-热液演化关系//[C].中国矿物岩石地球化学学会第12届学术年会论文集.
曾兴洪,胡玉华,彭大勇.2012.四川省壤塘县斯约武锂、铌钽矿床地质特征及成因研究[J].四川有色金属.(02):18-21.
张培善,陶克捷,杨主明,等.2001.白云鄂博稀土、铌钽矿物及其成因探讨[J].中国稀土学报.(02):97-102.
李洁,黄小龙.2013.江西雅山花岗岩岩浆演化及其Ta-Nb富集机制[J].岩石学报,29(12):4311-4322.
史明魁,孙恭安.1981.广西栗木稀有金属花岗岩的岩石学和地球化学特征[J].宜昌地质矿产研究所所刊,(3):96-107.
王汾连,赵太平,陈伟.2012.铌钽矿研究进展和攀西地区铌钽矿成因初探[J].矿床地质,2012,31(2):293-308.
王汾连,赵太平,王焰.2015.攀西地区二叠纪赋存铌钽矿的正长岩脉的成因探讨[J].岩石学报.2015(06):1797-1805.
杨武斌,单强,赵振华,等.2011.巴尔哲地区碱性花岗岩的成岩和成矿作用:矿化和未矿化岩体的比较[J].吉林大学学报(地球科学版),41(6):1689-1704.
杨泽黎,邱检生,邢光福,等.2014.江西宜春雅山花岗岩体的成因与演化及其对成矿的制约[J].地质学报,2014,88(5):850-868.
尹蓉,王汝成,张爱铖,等.2013.新疆可可托海1号伟晶岩脉铌钽矿物研究与岩浆-热液演化关系//[C].中国矿物岩石地球化学学会第12届学术年会论文集.
曾兴洪,胡玉华,彭大勇.2012.四川省壤塘县斯约武锂、铌钽矿床地质特征及成因研究[J].四川有色金属.(02):18-21.
张培善,陶克捷,杨主明,等.2001.白云鄂博稀土、铌钽矿物及其成因探讨[J].中国稀土学报.(02):97-102.