万洋山-诸广山加里东期花岗岩的物质来源——Ⅰ.Sr-Nd-Pb-O多元同位素体系示踪

本文系统的Sr-Nd-Pb-O多元同位素体系示踪结果表明,万洋山-诸广山加里东期花岗岩类岩石是典型的壳型花岗岩,由区内未出露的中元古基底重熔形成,源岩的物质组成不均一.     

GEOCHRONOLOGY OF WANYANGSHAN-ZHUGUANGSHAN GRANITOID BATHOLITH:IMPLICATION FOR THE CRUST DEVELOPMENT

Single-grain zircon U-Pb analyses, combined with Sm--Nd, Rb--Sr, K--Ar and ~(40)Ar-~(39)Ar datingresults, suggest that there are four magmatic periods in Wanyangshan--Zhuguangshan granitoidbatholith, i.e. late Caledonian (414--434 Ma), Indosinian (220 Ma), middle Yanshanian (155 Ma)and late Yanshanian (105 Ma). The tectonic movement characterized by the unconformablecontact between Mid--Devonian and Pre--Devonian occurred about 380 Ma ago. Magmation istightly related to the regional crustal movement.     

中国某些花岗岩的Sr-O同位素体系

花岗岩类岩石δ~(18)O和~(87)Sr/~(86)Sr初始比值的关系可分为四种类型:封闭结果型:呈近于垂直的短线;硅铝物质重熔型:呈负相关关系;壳幔混合型:呈正相关关系;水-岩交换型:基本为无相关。     

万洋山-诸广山加里东期花岗岩的物质来源——Ⅱ.同位素多维空间的拓扑分析

Sr-Nd-O-Pb~3六维同位素空间的拓扑分析结果表明,万洋山-诸广山加里东期花岗岩的源岩主要由三端元物质组成,混合模式判别证明花岗岩是由三端元组分不同比例混合的产物,多元同位素体系和元素地球化学综合示踪研究表明,这三端元地壳成分为陆源沉积物、地槽沉积物和蚀变的基性火山岩。     

THREE-COMPONENT MIXING AND FOUR-SYSTEM RECYCLING MODELS FOR EXPLAINING Nd-Sr-Pb ISOTOPIC CORRELATIONS OF SUBOCEANIC AND SUBCONTINENTAL MANTLES

The Pb-Sr-Nd isotopic data of Cenozoic volcanic rocks from the continent of China show that there exist three main end members of the mantle, which are the enriched mantle of Wudalianchi in Northeast China, the depleted mantle in South China and the recycling mantle of Yunnan in southwestern China. A11 the data can well fit a curved surface of three-component mixing in Pb-Sr-Nd isotopic space. Seven major end members in the global mantle can be identified. Based on the intersection line between two curved surfaces of three-component mixing in the continent of China and the ocean, the Pb-Sr-Nd isotopic ratios in the primatire mantle can be calculated. In order to explain the genesis of seven end members of the mantle, four-and three-system recycling models were used. The theoretical results are well comparative with the isotopic distribution observed in global Cenozoic volcahics, and can provide useful constraints on the process of the geochemical evolution in the crust-mantle system.     

Source Rocks of the Caledonian-Age Granitoid Rocks in Wanyanshan-Zhuguangshan, Southeast China (Ⅱ)——Topological Analysis in Isotopic Multispace

Topological analysis in Sr-Nd-O-Pb_3 six-dimensional isotopic space suggests that the source rocks of the Caledonian-age granitoid rocks in Wanyangshan-Zhuguangshan, southeast China, comprise three end-member components. Isotopic mixing model discrimination indicates that the granitoid rocks were produced through mixing of the three componentsin varying proportions. Comprehensive study of multiple isotopic systems and geochemistry of the granitoid rocks suggests that the three end-member components were crustal rocks which are continent-derived sediments, geosycline sediments and altered basic volcanic rocks.     

激光熔蚀微探针-电感耦合等离子体质谱法--一种快速测定岩石样品中多个元素的新方法

利用激光探针与等离子体质谱联机技术(LAM-ICPMS)同时测定岩石样品中35个元素.对岩石标样的碱熔玻璃进行了系统的LAM-ICPMS方法研究.结果表明,采用散焦(defocus)激光束扫描法获得了连续稳定的分析信号,并提高了分析灵敏度和分析精密度.该法测定P的检出限为0.1%,Sc、Ti、V、Cr、Mn、Co及Ni的检出限为1.6×10-6～12×10-6,Ga、Rb、Sr及Ba的检出限为0.2×10-6～0.6×10-6,其余21个微量元素的检出限为10-9级;内部精度优于15%,外部精度优于10%.3个岩石标样(NTUG-1、NTUG-2及NTUG-3)的测量结果表明LAM-ICPMS是一种同时测定岩石样品多元素的快速有效方法.     

激光探针等离子质谱法分析岩石样品时相对元素响应及基体效应

研究了ＬＡＭ－ＩＣＰ－ＭＳ法分析岩石样品时以＾４３Ｃａ和＾５５Ｍｎ为内标的相对元素响应因子特征并进行了对比。以＾４３Ｃａ为内标不能消除ＬＡＭ－ＩＣＰ－ＭＳ分析中的基体效应,而以＾５５Ｍｎ为内标可明显地减弱基体效应的影响。测定了６个日本火成岩岩石标样中的３２个微量元素,除个别样品（如ＪＧ－３）和少数轻质量元素Ｐ、Ｓｃ、Ｃｒ以及重稀土元素Ｄｙ、Ｅｒ、Ｙｂ等外,绝大多数微量元素的分析值与标准植的相对偏差     

SOURCE ROCKS OF THE CALEDONIAN-AGE GRANITOID ROCKS IN WANYANGSHANZHUGUANGSHAN, SOUTHEAST GHINA (Ⅰ)——EVIDENCE FROM Sr-Nd-Pb-O ISOTOPIC CONSTRAINTS

Based on the systematic study by means of Sr-Nd-Pb-O isotopic constraints, the Caledonian-age granitoid rocks from Wanyangshan-Zhuguangshan, southeast China, were derived from the regional unexposed basement rocks of middle Proterozoic in age, belonging to the crust- (S-) type granite. Their source rocks were chemically and isotopically heterogeneous, and probably composed of more than two dominant end-members.     

电感耦合等离子体质谱法测定水中痕量元素

应用电感耦合等离子体质谱法测定了水样(地下水、地表水、饮用水等)中51项痕量元素,对分析条件包括测定同位素的选择、仪器的工作参数、方法的精密度及检出限的测试等进行了研究。应用此方法测定了混合标准中51项元素,所得测定值与标准值相符,相对偏差(除钨外)均小于±10%,回收率在90%~110%之间。,