热液矿床中含钙矿物的Sm-Nd同位素定年  

Sm-Nd Isotope Dating of Some Ca-bearing Minerals in Hydrothermal Deposits

作　　者：彭建堂[1] 符亚洲[1] 袁顺达[1] 沈能平[1] 张东亮[1] 

机构地区：[1]中国科学院地球化学研究所矿床地球化学国家重点实验室,贵阳550002

出　　处：《地质论评》2006年第5期662-667,共6页Geological Review

基　　金：国家自然科学基金资助项目(编号40472053)的成果。

摘　　要：Sm、Nd的离子半径相似、化学性质很相近,母体衰变形成的子体易在矿物晶格中保存下来,故矿物或岩石中的Sm-Nd同位素体系易保持封闭,具有较强的抗风化、抗蚀变能力,是一种有效的定年工具。但长期以来,Sm-Nd同位素体系主要用于前寒武纪地质年代学研究,研究对象主要限于陨石、月球岩石、古老的基性、超基性岩和前寒武纪老地层等。近年的研究表明,热液矿床中一些含钙矿物,其REE含量较高,Sm/Nd分馏明显,是很有潜力的Sm-Nd同位素定年对象,能对矿床的成矿时间进行精确制约。本文对萤石、白钨矿、方解石、电气石等常见热液含钙矿物的Sm-Nd同位素研究现状进行归纳总结,并对该方法在中国热液矿床中进一步的应用前景进行了展望,以期促进Sm-Nd同位素成矿年代学在我国的推广和应用。Both Sm and Nd are similar in ionic radius and in chemical properties, the daughter ^143 Nd decayed by the parent ^147 Sm through α- process can occupy the same site in mineral lattice as its parent, thus Sm-Nd isotope systematics is easily be closed and can resist later alteration and weathering. However, Sm-Nd chronometer has predominately been applied in Precambrian geochronological studies in the past, few similar applications have been carried out on hydrothermal mineralization, and the dated objectives are mainly restricted in meteorite, lunar rocks, ancient ultrabasic and basic rocks, and Precambrian metamorphic or sedimentary rocks. Some researches in recent years indicate that, some hydrothermal Ca-bearing minerals display relatively high REE concentrations and obvious Sm/Nd fractionation, and show great potentials in precisely dating various hydrothermal mineralization. Sm-Nd isotope dating studies on fluorite, scheelite, calcite and tourmaline are summarized in this paper, and their further application in hydrothermal deposits are expected, which aims to promote the development of Sm-Nd isotope geochronology in China.

关 键 词：Sm—Nd同位素体系 成矿年代学 含钙矿物 热液矿床 

分 类 号：P611[天文地球—矿床学] P597.3[天文地球—地质学]