黑龙江平顶山金矿石英天然热发光特征     

刘福来 《吉林大学学报(地球科学版)》1992,(3)

对平顶山金矿中52件石英样品的天然热发光曲线特征研究表明,含金或富含金石英的热发光曲线以双峰或多峰为其主要特征,不含金的石英以单峰为其特征,石英热发光曲线特征可作为指示金矿化的一个重要标志.  相似文献   

载金石英的化学成分特征及其意义     

胡大千  贺义兴 《吉林大学学报(地球科学版)》1992,(1)

利用电子显微镜(EM)及能谱仪(EDS),分析研究了变生热液形成的载金石英的化学成分、离子扩散作用以及金在石英中的赋存状态等问题,探讨了它们的形成和变化机理。研究结果表明:Al~(3+)、Ti~(3+)、TFe、Na~(+)、K~(+)、Ca~(2+)等在石英中为类质同像混入物;石英和黄铁矿之间的离子相互扩散作用,表现为石英中Al离子的带出和Fe离子的带入,黄铁矿中Fe离子的带出和Al离子的带入;石英中呈分散状态分布的金主要为离子金,它们充填在石英结构中,起平衡电价的作用。  相似文献   

Silica mobility and fluid movement during metamorphism of the Connemara schists, Ireland   总被引：5，自引：1，他引：5  

B. W. D. YARDLEY  S. H. BOTTRELL 《Journal of Metamorphic Geology》1992,10(3):453-464

Quartz veins are developed in a wide range of metasediment types in the upper amphibolite facies rocks of Connemara, and attest to considerable migration of silica. Contrary to common assumptions, there is clear evidence that these veins do not primarily result from movement of fluid to regions of lower P–T down the regional geothermal gradient. Under amphibolite facies conditions, a dilute chloride fluid moving down temperature has the potential to alter 60g of plagioclase to muscovite for each gram of vein quartz precipitated, while cooling over the temperature interval from 650 to 500° C. The absence of significant metasomatic effects in the vein walls effectively precludes a simple origin from such through-flowing, externally derived fluids. The oxygen isotopic composition of matrix quartz shows considerable differences between different rock types (quartzite, pelite and marble), with a range of δ¹⁸O_SMOW from c.+ 11.5% (quartzite) to + 18.5% (marble). In each rock type, vein quartz compositions closely match those of the matrix quartz. These results demonstrate the importance of local segregation processes in the formation of veins, and suggest that fluid convection cells were not developed during metamorphism on a scale larger than the individual sedimentary formations, if at all. Both oxygen isotope data and the absence of metasomatism indicate that veins form primarily by segregation of quartz from the host lithologies, with only a relatively minor component of through flow of externally derived fluid. Veins are clearly not the major pathways of metamorphic dewatering. It is proposed that abundant veins in the predominantly pelitic Ballynakill Formation formed during peak metamorphic D3 folding because the formation was embrittled by high fluid pressures but was capped by impermeable marble. Hence the pelitic formation fractured repeatedly and the pore fluid drained through the fractures to form veins, while irreversible loss through the rest of the succession was a much less important process. In the central mountains of Connemara, rather pure, unreactive quartzites are cut by widely spaced, laterally extensive quartz veins that are axial planar to D3 folds. These veins may mark pathways whereby metamorphic fluid made its way through the massive impermeable quartzite from lower parts of the nappe pile, but here too, oxygen isotope data indicate considerable segregation of locally derived quartz, reflecting the importance of pumping of fluid between wail rocks and fractures relative to the component of through flow.  相似文献   

冀北水泉沟偏碱性杂岩体中云辉闪长岩的发现及其地质意义   总被引：6，自引：0，他引：6  

张招崇 《岩石矿物学杂志》1995,14(1):9-18

作者在冀北水泉沟偏碱性杂岩体中发现了一种钙碱性岩石──云辉闪长岩。根据其矿物组成，可能为一种新的岩石类型。该岩石由黑云母（约占１５％）、普通辉石（约占１５％）、更一中长石（约占６５％）、钾长石（约占５％）以及其它一些副矿物（＜１％）组成。与水泉沟杂岩体的其它岩类相比，该岩石以相对高含量的ＬＲＥＥ、高场强元素和Ｆｅ、Ｍｇ、Ｃａ等元素以及相对低的ＳｉＯ＿２、Ｋ＿２Ｏ＋Ｎａ＿２Ｏ和Ａｌ＿２Ｏ＿３为特征。  相似文献   

湘黔地区震旦纪菌藻硅质岩特征及形成机理探讨   总被引：7，自引：0，他引：7  

夏文杰  彭军 《矿物岩石》1993,13(3):21-28

湘黔地区震旦纪菌藻硅质岩化学成分纯净,硅质矿物含量95%以上,几乎都为泥晶—微晶石英,石英结晶度平均为6.35。岩石具菌藻生物结构,以纹层状构造为主。其中丰富的菌藻生物化石,按形态可划分为三种类型。岩石属原生沉积成因,二氧化硅的聚沉一方面通过菌藻有机体的硅化作用,另一方面是菌藻生物化学作用引起微环境变化而导致二氧化硅的聚沉。  相似文献   

湘西南石英脉型金矿矿物流体包裹体pH值和Eh值的估算   总被引：2，自引：0，他引：2  

吴湘滨  戴塔根  何绍勋 《大地构造与成矿学》1999,23(3):248-253

以湘西南石英脉型金矿床为例,研究ｐ Ｈ、Ｅｈ 估算值的结果表明利用围岩蚀变反应方程以及采用碱金属离子、卤素元素离子估算ｐＨ 值是不完善的。本文根据热力学原则（ 相平衡、电价中和） 提出了矿物流体包裹体成分体系计算ｐＨ 估算值的方法,并且讨论了测试包裹体时气体成分外逸是影响ｐＨ 和Ｅｈ 估算值的主要因素之一。  相似文献   

Oxygen isotope compositions of quartz grains (4–16 μm) from Chinese eolian deposits and their implications for provenance     

Shengshan?HouEmail author  Shiling?Yang  Jimin?Sun  Zhongli?Ding 《中国科学D辑(英文版)》2003,46(10):1003-1011

Oxygen isotope compositions were measured in quartz grains extracted from a 7.0 Ma red clay-loess sequence at Lingtai and six late Pleistocene loess sediments (Malan loess). Results show that the changes in oxygen isotope compositions of Malan loess are basically controlled by the geochemical characteristics of the source materials, while the effect of weathering process after dust deposition could be minor. The oxygen isotope distribution of quartz grains from red clay at Lingtai is similar to that of the overlying loess-paleosol sequence, thus indicating that the red clay at Lingtai has the same eolian origin as the loess-paleosol deposits. Furthermore, the oscillations of the isotope compositions in 4–16 μm-sized quartz grains may reflect the changes, to some extent, of the climatic systems of the source region.  相似文献   

吐哈盆地南缘彩霞山东石英闪长岩岩株锆石SHRIMP U-Pb测年   总被引：4，自引：1，他引：4  

任燕  郭宏  涂其军  冯新昌  李少贞  李嵩龄 《地质通报》2006,25(8):941-944

彩霞山东石英闪长岩岩株的锆石SHRIMP U-Pb年龄为267.8Ma±1.6Ma,结合克孜尔塔格岩体的同位素年龄综合分析,此年龄值介于王瑜等所研究剪切作用控制的克孜尔塔格岩体右行剪切年龄276～254Ma之间,表明该石英闪长岩岩株的侵位年龄比克孜尔塔格复式岩体晚,为中二叠世早期.  相似文献   

东天山大盐池西闪长岩锆石SHRIMP U-Pb测年——对伴生超基性岩时代下限的制约     

王德贵  李丽群  伏红霞 《地质通报》2006,25(8):963-965

大盐池西超基性岩一直缺乏可靠的年龄资料,因此时代厘定一直存在疑问.该超基性岩侵入于一个闪长岩体中,1∶5万区域地质矿产调查获得该闪长岩的年龄为303Ma±15Ma.这表明该超基性岩形成于晚石炭世以后.  相似文献   

浙江沐尘石英二长岩体的岩石地球化学特征及构造意义   总被引：5，自引：0，他引：5  

卢成忠 《地球化学》2007,36(5):457-466

出露于江山-绍兴断裂带西南段东南侧的沐尘岩体,以发育暗色包体和环斑长石为特征,具有显著的岩浆混合作用.寄主岩为二长岩-石英二长岩组合,包体岩石为二长闪长岩.二长岩组合.造岩矿物有钾长石、斜长石、石英、普通角闪石和黑云母.岩石富碱(Na2O K2O=6.58%～10.42%,平均8.41%)、高钾(K2O/Na2O=0.72～1.45,平均1.16)、贫钛(TiO2=0.37%～1.22%,平均0.76%)、富集大离子亲石元素和轻稀土元素,具有钾玄质系列的岩石地球化学特征.该岩体侵位于后碰撞弧构造环境,是早白垩世早期该区重要的构造.岩浆热事件的产物.  相似文献