华南前寒武系基底变质杂岩和中-新生代地幔岩的稀有气体同位素组成及其大地构造意义          下载免费PDF全文

谢窦克  邢光福  陆志刚  陈荣  周宇章 《地质科学》2008,43(1):175-204

对华南前寒武系变质岩浆杂岩稀有气体He、Ne、Ar和Xe的系统研究表明:扬子克拉通基底为含高³He的下地壳"原始岩石层",(³He/⁴He)×10^-6比值为2.8～4.6;而华夏板块基底变质岩浆杂岩则是在缺乏³He、低(³He/⁴He)×10^-8比值(3.15～17.7)的构造环境下形成的大陆中-上地壳变质岩浆杂岩层,反映出两者基底性质迥然不同。华南中-新生代爆破岩筒He同位素组成相反,相对稳定的扬子克拉通(³He/⁴He)×10^-8比值仅0.18～4.22,而郯庐-四会-吴川断裂以东,中-新生代活动地块(太平洋构造域)(³He/⁴He)×10^-8比值高达3.7～20.5。He同位素表明郯庐-四会-吴川断裂带为切割深至地幔的边界深大断裂,是扬子克拉通与华夏板块间的边界且控制了燕山期火山-侵入岩浆向西扩展。Ar同位素组成表明华南大陆中-新生代地幔形成接近"均一"的地幔组份。¹³⁶Xe/¹³⁰Xe-¹²⁹Xe/¹³⁰Xe相关组份表明它们具有地幔柱岩石同位素组成特征。  相似文献   

试论雁荡山岩石地貌     

陶奎元  沈加林  姜杨  余明刚 《岩石学报》2008,24(11):2647-2656

雁荡山岩石地貌由叠嶂、方山、石门、柱峰、锐峰、岩洞、天生桥和峡谷、涧溪、瀑、潭、湖等岩石地貌组合而成。其形成的地质学、岩石学基础是白垩破火山岩相与构造。不同类型地貌景观反映了这一破火山构造。断裂切割、重力崩塌与流水侵蚀是形成此类地貌的主要外动力地质作用。雁荡山岩石地貌在形态、成因和审美学意义上均有别于我国砂砾岩岩石地貌、碳酸岩岩石地貌和花岗岩岩石地貌。雁荡山地貌可作为流纹质火山岩地貌的代表。  相似文献   

Chronology and cooling history of the Tianmenshan pluton in South Jiangxi Province and their geological significance     

Qingtao Zeng  Jianren Mao  Qing Hu  Xilin Zhao  Haimin Ye 《中国地球化学学报》2008,27(3):276-284

Geochronological studies on the crust-derived Tianmenshan pluton were undertaken by SHRIMP zircon U-Pb dating and Ar-Ar dating of biotite, muscovite and K-feldspar, giving a petrogenetic age of 167 Ma. Owing to the closure systems in different minerals, the cooling history of the pluton can be determined with an age-temperature diagram. The late hydrothermal event has been recognized, which is related probably with mineralization. In terms of the comparative geochronological and petrologic records, it is concluded that there are some constrains on tectonic evolution and that the formation of the Tianmenshan pluton proceeded in a transition period from Indosinian post-orogeny extension to strong compressive tectonics. And the timing of the hydrothermal event matches the compressive climax of the Yanshanian orogeny. The temporal gap between granite emplacement and wolframite mineralization could last 10-20 Ma owing to the low cooling rate of the pluton.  相似文献   

浙江五亩山地区钨矿容矿构造及找矿方向   总被引：1，自引：0，他引：1       下载免费PDF全文

李春海  吴昌志  郭坤一  包超民  邢光福 《地质找矿论丛》2008,23(1):22-26

五亩山地区燕山期花岗岩侵入活动后,形成了高温热液裂隙石英脉型黑钨矿(白钨矿)矿床.矿化脉体多分布在区域断裂的裂隙构造中,矿化体在地表以中(或低)角度产出,向下以高角度产出,或者两者交替产出形成类似于倾斜的"阶梯"状.通过对含矿裂隙的测量和统计,确定了成矿前或成矿期的裂隙,NE向裂隙为钨矿的容矿构造,并提出了找矿方向.  相似文献   

Water leaching of cesium from selected cesium mineral analogues     

《Applied Geochemistry》2006,21(3):405-418

Recently, a new mica phase Cs-tetra-ferri-annite has been synthesized and studied. This phase has been investigated because its high structural stability and assumed associated low leachability for Cs suggest that it may be a suitable waste form for immobilization of Cs. Further, synthesis, under hydrothermal conditions, is possible under conditions typical of an industrial-scale immobilization plant. Consequently, cesium-tetra-ferri-annite can be considered as a waste form for the fixation of Cs from solid radioactive waste. In this study, Cs immobilization in Cs-tetra-ferri-annite and CsAlSiO₄, as well as sorption onto montmorillonite and zeolite 13X, have been studied. Experiments were carried out to determine the influence of pH, temperature, time and leaching technique on the extent of release of Cs from these solids. These leaching studies have confirmed the limited leachability of Cs-tetra-ferri-annite, which was found to be more stable than CsAlSiO₄ by a factor of 3.7 at ambient temperature and near-neutral pH. These waste forms have also been found to be more effective in retaining Cs than Cs-montmorillonite and Cs-zeolite 13X. The relative release of Cs from all of the studied phases exhibits a similar trend with pH, temperature, time and techniques of leaching used in this study. For these phases, the leachability of Cs increases with acidity (pH 3) or alkalinity (pH 11) of the leachates as well as with increasing temperature and time of leaching. For CsAlSiO₄, the Cs-leachability was most strongly affected by increasing temperature. Cesium releases from this phase increased by a factor of about 6 when the temperature was raised from 20 to 100 °C. This increase with temperature was 3–6 times higher than that measured for the other phases. Under the present leaching conditions, Cs is released more than the matrix elements. Elements present in tetrahedral positions of CsAlSiO₄, Cs-montmorillonite and Cs-zeolite 13X leach much easier than elements in octahedral positions.  相似文献   

蒙脱石脱水作用与地面沉降关系的研究展望   总被引：7，自引：0，他引：7  

杨献忠杨祝良  陈敬中胡存礼袁平  魏乃颐 《岩石矿物学杂志》2005,24(6):659-665

粘土矿物在地面沉降中的作用、粘土矿物的脱水作用对地面沉降的影响等日益成为评价和防治地质、工程、水文、环境等问题的关键,也一直是相关领域的研究难题而逐渐引起高度重视。本文回顾了蒙脱石层间水性质、层间水化膨胀和脱水收缩的影响因素,提出蒙脱石层间的固溶体特征,在总结蒙脱石脱水作用与地面沉降关系研究成果的基础上,提出了用蒙脱石脱水作用研究地面沉降的思路。最后讨论了用蒙脱石的脱水作用研究地面滞后沉降及沉降趋势预测的可能性。  相似文献   

Geology, Geochemistry and Genesis of the Hongshijing Gold Deposit in Ruoqiang,Xinjiang     

肖惠良  周济元  王鹤年  崔炳芳  陈世忠 《中国地球化学学报》2003,22(3):280-288

1IntroductionTheHongshijinggolddepositislocatedinthenorthofLuobupouLakeofRuoqiang ,about 30 0kmsouthwestofHamiCity ,Xinjiang .ItwasdiscoveredbytheSixthGeologicalTeamofXinjiangduringgeo chemicalexploration .TheHongshijinggolddeposit,whichoccursinthegold bearingformationcomposedofMiddleandLateCarboniferousvolcanicandpyroclasticrocks ,isabrittle ductileshearzonetypegolddepositcontrolledbyariftbelt.TheHongshijinggolddepositislocatedinthesouthwestoftheHongshi jing -Maotoushanmineralizationb…  相似文献   

Caledonian Low-Temperature Granulite-Facies Metamorphism in the West Kunlun Orogenic Belt—SHRIMP Chronological Evidence from Zircon     

Zhang Chuanlin  Shen Jialin  Wang Aiguo  Zhao Yu  Guo Kunyi  Li Chunhai 《中国地球化学学报》2003,22(4):345-351

The West Kunlun orogenic belt is located at the conjunction of the paleo-Asian tectonic system and the Tethys tectonic system. Petrological and mineralogical studies of the Early Cambrian metamorphic surface crust in this region have shown that in case the metamorphism reached low-temperature granulate facies, the typical mineral assemblage is biotite-garnet-silimanite-K feldspar-plagioclase-quartz. The peak metamorphic temperatures are within the range of 720–740°C and the pressure is 0.6 GPa ±. Three types of metamorphic zircon have been detected in the metamorphic rocks: the complex inclusion-bearing type ; the early relic zircon inclusion-bearing type; and the inclusion-free type. SHRIMP age determination of these three types of metamorphic zircon have revealed that these zircons were formed principally during 400–460 Ma, indicating that pre-Cambrian metamorphic surface crust rocks underwent low-temperature granulite facies metamorphism during the Caledonian. In combination with the geological characteristics of this region, it is considered that when the oceanic basin was closed, there occurred intense intracontinental subduction (type A), bringing part of the Early Cambrian metamorphic basement in this region downwards to the lower crust. Meanwhile, there were accompanied with tectonic deformation at deep levels and medium- to high-grade metamorphism. This study provided important chronological and mineralogical evidence for the exploration of the evolutionary mechanism and process of the West Kunlun Early Paleozoic. Part of the results from the research project “ Research on the West Kunlun pre-Cambrian tectonic events” under the program “ Research on the important geological problems of China’ s pre-Cambrian” (No. 200113900070) sponsored by the China National Geological Surveying Bureau.  相似文献   

Meteoric diagenesis in Pleistocene reef limestones of Xisha Islands, China     

Liu Jian  Ye Zhizheng  Han Chunrui  Liu Xinbo  Qu Gaosheng 《Journal of Asian Earth Sciences》1997,15(6):465

This paper focuses on a borehole, Xichen-1 well, drilled on the Chenhang Island, Xisha Islands in the South China Sea. Mineralogical, petrographic, stable isotopic and minor-element data from the Holocene to Pleistocene interval (0–179 m ) in the Xichen-1 well are discussed in detail. The 400-m-long core is divisible into four mineralogical facies: a high-Mg calcitic aragonite facies (0–16.91 m, Holocene), an aragonitic low- Mg calcite facies (16.91–30.60 m, Late Pleistocene), a low- Mg calcitic facies (30.60–179 m, Middle-Early Pleistocene) and a low- Mg calcitic and dolomitic facies (179–400 m, Early Pleistocene–Late Miocene). The Holocene section has much higher whole-rock δ¹⁸O and δ¹³C values and Mg and Sr content than the non-dolomitized Pleistocene limestones (16.91–179 m). The 16.91–165 m interval is characterized by a relatively invariant oxygen isotopic composition and very heterogeneous carbon isotopic composition. Between 165 and 179 m, there is a positively correlated increase of whole-rock δ¹⁸O and δ¹⁸C with depth, and Mg content also shows a gradual increase with depth. Petrographic data demonstrate that the Pleistocene reef sequence has been extensively affected by meteoric waters. We conclude that the Late Pleistocene section (16.91–30.60 m) and the Middle-Early Pleistocene section (30.60–165 m) have suffered incomplete and complete meteoric diagenesis, respectively, and that the Early Pleistocene interval (165–179 m) was diagenetically altered in a meteoric–marine mixing environment.  相似文献   

ICP—AES法同时测定高纯氧化钇中稀土及非稀土杂质元素方法研究     

吕宝源  裘丽雯 《高校地质学报》1997,3(1):106-110

本文提出了用ＩＣＰ－ＡＥＳ法直接同时测定高纯氧化钇中１４个稀土和１６个非稀土杂质元素的分析方法，对被测元素的 谱线、氧化钇基本及背景影响进行了研究，用标准加入法测出氧化钇基准中的微量杂质元素，消除了由于忽略基准中的杂质元素含量给高纯氧化钇分析测定带来的误差，同时对工作条件进行了优化。方法中各被测元素的检出限为0.003～1.31ug/g，能够满足生产过程中的质量控制及进出口商品检验  相似文献