Strontium Isotope Analysis of Kimberlitic Groundmass Perovskite via LA-MC-ICP-MS   总被引：1，自引：0，他引：1  

Chad Paton  Jon D. Woodhead  Janet M. Hergt  David Phillips  Simon Shee 《Geostandards and Geoanalytical Research》2007,31(4):321-330

Strontium isotopic composition is a potentially powerful tracer in studies of kimberlitic rocks but the results from even the most carefully collected and stringently prepared bulk-rock samples are still hampered by contamination and alteration effects. Here we describe a LA-MC-ICP-MS technique which can obtain accurate, high precision Sr_i ratios from 50–150 μm kimberlitic groundmass perovskite without requiring time-consuming mineral separation procedures. Since perovskite is a robust magmatic phase with an extremely low Rb/Sr ratio, the effects of late-stage crustal contamination, post-emplacement alteration and age correction are minimised and results are more representative of primary melt compositions, while additionally preserving powerful grain-scale spatial and textural information. We demonstrate that the adopted protocol overcomes isobaric interferences from Kr⁺, Rb⁺, Er²⁺ and Yb²⁺, and that Ca dimers and Ca argides do not detectably affect the quality of ⁸⁷Sr/⁸⁶Sr ratios produced. To illustrate the utility of the technique, contrasting bulk-rock and in situ perovskite results from eleven Proterozoic kimberlites are documented.  相似文献   

四川盆地东部海相下—中三叠统界线的锶同位素年龄标定   总被引：5，自引：0，他引：5  

黄思静  裴昌蓉  卿海若  胡作维  吴素娟  孙治雷 《地质学报》2006,80(11):1691-1698

中国西南地区海相下—中三叠统以火山碎屑岩为其直观界线,该年龄的标定可为区域地层年表和国际地层委员会全球标准年表研究提供重要的下—中三叠统界线年龄参考值.基于此,本文测试了四川盆地东部华蓥山下—中三叠统界线火山碎屑岩附近的石膏和硬石膏样品87Sr/86Sr比值,以及相应的Si、Ca、Mg、Mn、Sr以及SO42-的含量,根据锶同位素地层学的原理,尝试对下—中三叠统界线进行了年龄标定;同时评估了样品的成岩蚀变性、对海水信息的代表性以及年龄标定结果的可靠性.火山碎屑岩附近5个样品的87Sr/86Sr比值变化在0.708243~0.708391之间,标定的年龄值在240.5~242.5Ma的范围内,2个紧靠火山碎屑岩样品的年龄值在242Ma左右(分别为241.9Ma和242.5Ma),从而为华南地区以火山碎屑岩作为海相下—中三叠统界线的合理性提供了重要的化学地层学依据,也为全球下—中三叠统界线提供了一个新的年龄值.  相似文献   

Strontium Isotope Composition and Characteristic Analysis of Cambrian-Ordovician Carbonate in the Region of Tazhong, Tarim Basin     

黄文辉 杨敏于炳松  樊太亮初广震万欢  朱井泉王旭 吴仕强 《中国地质大学学报(英文版)》2006,17(3):246-257

The Tarim basin, which is located in the Xin-jiang Autonomous Region in western China , is alarge-scale superi mposed basin situated between theTianshan Mountains to the north and the KunlunMountains to the south, with an area of 560 000km2. The Tazhong uplift ,locatedin the central partof the basin, has an area of 30 000 km2.It is sur-rounded by the Manjiaer depressionin the north,theTangguzibasi depressionin the south,the Bachu up-lift inthe west andthe Tadong saginthe east .It hasbeco…  相似文献   

Strontium isotope composition of the Arno River Valley waters （Tuscany, Italy） as a natural tracer of water-rock interaction and mixing processes     

Barbara Nisi Orlando Vaselli Antonella Buccianti Giulia Perini Angelo Minissale Giordano Montegrossi Franco Tassi 《中国地球化学学报》2006,25(B08):273-273

Sr isotope studies of surficial waters have highlighted that differences in the ^87Sr/^86Sr ratio and Sr concentration are primarily caused by mixing of waters of various origins with specific isotopic and chemical characteristics, resulting from water-rock interaction processes. In this paper we reported the first Sr isotopic ratios, coupled with water chemistry, the measurement was carried out on samples related to （1） the Amo River （Tuscany, central-northern Italy）, between the source and the mouth, （2） the most important tributaries and to （3） the thermal water discharges seeping out in the southern part of the basin. The main goals are： a） to use the ^87Sr/^86Sr ratio as a discriminative parameter of source areas, b） to define its variation along both the main course and principal tributaries, and c） to estimate the effects of the mixing process of the different end-embers. The outcropping rocks in the Amo River Basin are predominantly sedimentary, mainly made up of Mesozoic limestones, Oligocene sandstones and Plio-Pleistocene marine-lacustrine formations. Triassic and Mesosinian evaporites crop out in the Elsa and Era reaches, whereas Paleozoic quartzitic formations occur in the Mrs. Pisani area. Strontium isotopic composition is generally controlled by lithology and does not seem to be affected by anthropic input and flow rate. The ^87Sr/^86Sr ratios in the Arno Basin vary between 0.707963 and 0.712743, the highest ratios being related to waters circulating in the Palezoic rocks and Oligocene sandstone formations. Less radiogenic values pertain to the Elsa and Era tributaries where contributions related to the dissolution of evaporitic sequences, and mixing processes with the thermal discharges have been distinguished. The tributaries show that water samples in the pristine area have higher ^87Sr/^86Sr ratios than the respective tributaries from which water samples were collected near the confluence. Eventually, water samples collected along the Arno River, close to the mouth, tend to have Sr isotopic ratios similar to those of the present seawater.  相似文献   

Global correlation for strontium isotope curve in the Late Cretaceous of Tibet and dating marine sediments   总被引：7，自引：0，他引：7  

HUANG Sijing  SHI He  SHEN Licheng  ZHANG Meng & WU Wenhui State Key Laboratory of Oil/Gas Reservoir Geology  Exploitation  College of Geoscience  Chengdu University of Technology  Chengdu  China 《中国科学D辑(英文版)》2005,48(2):199-209

87Sr/86Sr ratios of marine carbonate samples collected from a sedimentary section of the Late Cretaceous in the south of Tibet were measured. Based on the absence of cathodo-luminescence and a very low Mn/Sr ratio (average 0.06) of the samples, it is thought that they contain information on the original seawater strontium isotope composition. The strontium isotope evolution curve of the Late Cretaceous in Tibet we established here, is consistent with other coeval curves from Europe, North America and Antarctica, supports the notion that the strontium isotope composition of seawater is governed by global events, which provides a new approach for the inter-continental and inter-basinal correlations of Late Cretaceous in the area and is a complementarity for biostratigraphy. In addition, we attempt to determine the age of the boundaries for Campanian/Santonian and Maastrichtian/Campanian by 87Sr/86Sr ratios for Gamba section in southern Tibet. The two boundaries are located in the thickness of 217 m (83.5 M  相似文献   

大沟谷钠长石岩型金矿床Pb、S、Sr同位素特征初探     

梁华英  王秀璋 《矿物学报》2001,21(2):246-250

大沟谷金矿床产于震旦系乐晶峡群钠长石岩带底部陡倾斜钠长石岩中。金矿床铅同位素组成变化大^206Pb/^204Pb17.356-19.306,^207Pb/^204Pb15.330-15.862,^208Pb/^204Pb37.532-39.957。u值在8.23-10.6之间，黄铁矿δ^34S值在5.1‰-13.4‰之间，铅同位素组成具线性相关关系，^206Pb/^204Pb与^207Pb/^204Pb线性方程y=0.24x 11.19,r=0.83,^206Pb/^204Pb与^208Pb/^204Pb方程为y=1.3x 14.8,r=0.93，黄铁矿铅硫同位素组成具负相关关系，钠长石岩Rb、Sr含量较低，^87Sr/^86Sr值为0.72263-0.73150，平均0.72595。综合铅、锶、硫同位素特征，可以认为大沟谷金矿床成矿物质主要来自高u值基底碎屑沉积岩及钠化基性火成岩。  相似文献   

全热解石墨管石墨炉原子吸收法测定痕量锶   总被引：2，自引：0，他引：2  

郑衍生  周采菊 《岩矿测试》1992,11(3):236-239

研究了热解涂层和全热解石墨管中Sr的原子吸收信号形状和原子化行为,讨论了CaCl_2、FeCl_3和HClO_4,抑制Sr吸收信号的原因。采用EDTA铵盐作基体改进剂,全热解石墨管石墨炉原子吸收法直接测定河泥中痕量Sr,方法的特征量为6.9pg/0.0044A。  相似文献   

DCS－偶氮胂光度法测定钛酸锶烧结物中游离的氧化锶     

胡浩  周宏实 《岩矿测试》1994,(4)

ＤＣＳ－偶氮胂光度法测定钛酸锶烧结物中游离的氧化锶胡浩，周宏实江苏海安磷肥厂２２６６００ＤＣＳ－偶氮肿［２－（２－胂酸基苯偶氮）－７－（２，６－二氯－４－磺酸基苯偶氮）－１，８－二羟基－３，６－二磺酸萘］属双偶氮变色酸类显色剂，主要用于稀土元素的高灵...  相似文献   

定襄七郎山锶－偏硅酸天然矿泉水水质特征     

杨国礼 《华北地质矿产杂志》1994,(4)

定襄七郎山矿泉水井，位于定襄无畏庄七郎山山脚下。含水层为滹沱群东冶亚群瑶池村组白云质灰岩和白云岩，为具有深循环远源补给的岩溶裂隙水。通过理化检测，天然水质优良，属锶（１．７２ｍｇ／Ｌ），偏硅酸（２５ｍｇ／Ｌ）天然矿泉水，开发前景良好。  相似文献   

榆次西窑饮用天然矿泉水的形成条件及水质特征     

周永昌  齐永生 《华北地质矿产杂志》1994,9(4):411-415

矿泉水赋存于沁水向斜北部东翼三叠系砂页岩地层中，１９８７年和１９９３年经山西地矿局和地矿部组织鉴定，水质符合《饮用天然矿泉水》国家标准（ＧＢ８５３７－８７），属含锶－偏硅酸重碳酸－钠钙型矿泉水。Ｙｈ＿１、井、Ｋ＿１井均已开发利用，生产瓶装天然矿泉水和矿泉水系列饮料。  相似文献