长坑金银矿床的铅,锶,硫同位素特征与矿化模式

长坑矿床金、银矿石的铅同位素组成具有一定的差异，前者的２０６Ｐｂ／２０４Ｐｂ比值变化大，后者较富２０７Ｐｂ／２０８Ｐｂ。金矿石中的铅为普通铅与放射成因铅混合而成的异常铅，银矿石中的铅则可能为三阶段铅混合的产物，且二者均为壳源。方解石的８７Ｓｒ／８６Ｓｒ比值显示锶来自地壳。金、银矿石硫化物的δ３４Ｓ值分别以分散（平均值为负）和较为集中（平均值为正）为特征，并与铅同位素组成之间存在相关关系。结合金、银的矿化分带现象，提出了铅同位素特征与氧化势不同的流体相互混合的成矿模式。     

基于数字频率合成技术的任意波形发生器设计与应用

介绍了直接数字合成技术的原理及其在任意波形发生器上的应用,设计了任意波形发生器和多类信号的 混合发生软件.并对任意波形发生器的性能进行了测试.测试结果表明,该仪器频率信号发生准确、可靠.将该仪器用于漆包线信号传输特性分析.得到了漆包线的频率特性.     

Granite gneiss basement on Flinders Island,South Australia

A U–Pb zircon age of 1762 ± 11 Ma is reported for granite gneiss located on Flinders Island, South Australia. This age is identical, within analytical uncertainty, to a previously reported age for schists of the Price Metasediments located 100 km to the southeast on the southwestern coast of the Eyre Peninsula. The outcrop represents the only known country rock to the Early Mesoproterozoic Calca Granite (Hiltaba Suite) of Flinders Island, the largest island of the Investigator Group of islands, in the southwestern Gawler Craton. The stratigraphic name Investigator Granite Gneiss is proposed for this rock unit. The discovery of the Investigator Granite Gneiss now considerably increases the extent of known Late Palaeoproterozoic rocks on the eastern side of the peninsula. The outcrop was previously included with the considerably younger St Peter Suite granite‐monzogranite, and grouped together with other islands in the Investigator Group. This new dating suggests that the geology on the other islands may require revision. For the first time, detailed major and trace‐element geochemistry is supplied for the granite gneiss on Flinders Island.     

SHRIMP U–Pb geochronology of authigenic xenotime and its potential for dating sedimentary basins

SHRIMP (Sensitive High‐Resolution Ion MicroProbe) analytical procedures have been developed to enable dating of the small, early diagenetic xenotime overgrowths that commonly occur on zircons in siliciclastic sedimentary rocks. The method will be particularly useful in Precambrian terranes, where diagenetic xenotime dating could play a role equivalent to biostratigraphic dating in the Phanerozoic. Reliable ²⁰⁷Pb/²⁰⁶Pb data are more readily obtained than ²⁰⁶Pb/²³⁸U, which also favours application to the Precambrian. However, it is demonstrated that ²⁰⁶Pb/²³⁸U dating of larger overgrowths (>10 μm) is also viable and applicable to Phanerozoic samples. SHRIMP Pb/Pb geochronology of authigenic xenotime in an unmetamorphosed Palaeoproterozoic sandstone in the Kimberley Basin has constrained diagenesis to a precision of ± 7 Ma. In contrast, greenschist‐facies metasediments of the Archaean Witwatersrand Basin, South Africa, contain both authigenic and alteration xenotime that record a complex history of growth from early diagenesis to the last major thermal event to affect the basin.     

An indirect lead isotope age determination of gold mineralization at the Corinthia mine,Yilgarn Block,Western Australia

The Corinthia lode‐gold deposit in amphibolite‐facies greenstone belt rocks in the Southern Cross Province of the Archaean Yilgarn Block contains a largely undeformed pegmatite dyke emplaced during the last phases of movement along the Fraser's‐Corinthia shear zone. Gold mineralization and shear zone development were synchronous, and a Pb‐Pb isochron age of 2620 ±6 Ma for pegmatite emplacement either indirectly dates mineralization, or places a minimum age constraint on the timing of mineralization. This age is in accord with a broadly synchronous dominant episode of Archaean lode‐gold mineralization throughout the Yilgarn Block.     

华南两类不同成因花岗岩的铅同位素组成特征

本文论述了华南两类不同成因花岗岩的铅同位素组成特征。不同类型的花岗岩,具有明显不同的铅同位素组成。改造型花岗岩相对富放射成因铅,其铅同位素比值较高,Pb/~(204)Pb>72;且相对富铀铅而贫钍铅,~(208)Pb/~(206)Pb<2.1。同熔型花岗岩则反之。利用有关的铅同位素图解和参数,可对花岗岩的成因类型进行划分。岩石的铅同位素组成与其成岩物质来源的关系,可从铀(钍)铅同位素的演化得到解释。研究结果表明,花岗岩的铅同位素组成特征,能够提供有关成岩物质来源的信息,从而作为划分花岗岩成因类型的又一个稳定同位素标志。     

金矿床定年方法进展及中国金矿床成矿时代

本文汇集和讨论了夹皮沟、辽宁、冀东、张家口、小秦岭、胶东、湘西、粤西－海南、滇西、北疆和台湾等我国主要金矿化集中区某些典型矿床的成矿年龄．在此基础上讨论了金矿床蚀变矿物、流体包裹体、石英、水热锆石、裂变径迹和矿石矿物同位素年龄测定新方法及热释发光技术在金矿床定年中的进展。普通铅模式年龄的定年意义是很有限的，但异常铅模式研究可用来示踪金矿化历史。＂成矿物质来源年龄老，矿床定位年龄新＂，即成矿作用具有明显继承性是中国金矿床最突出的特征。     

meso-四-(4-甲氧苯基)卟啉与铅的显色反应及其双波长和导数光谱行为研究

本文研究了meso-四-(4-甲氧苯基)卟啉与铅的高灵敏显色反应及双波长和导数光谱行为。当有Tween-80存在时,在强碱性介质中,于沸水浴上加热32min,显色反应能定量进行。该体系的表现摩尔吸光系数(ε_(466.5))为1.77×10~5,双波长的ε_(466.5/422)为3.16×10~5,四阶导数光谱的有效摩尔响应值为2.67×10~6。此显色体系用于合成样品中痕量Pb的测定,回收率在96.8～98.2％之间。     

秦岭泥盆系层控铅锌矿床成因模式探讨

在论述秦岭泥盆系层控铅锌矿床的黄铁矿微量元素,硫、铅、氢、氧同位素,矿物气液包裹体均一温度及成分.区域地层元素丰度等方面特征的基础上,提出了该类型属海底含矿热泉溢出沉积和隐伏含矿热泉贯入沉淀的成因模式.