河南桐柏围山城地区变质岩中石榴石的研究

本文据我国河南桐柏围山城地区的石榴石的物理性质、化学成分、晶体结构（使用Ｘ射线分析、红外吸收光谱和穆斯堡尔谱）的研究，证实该区石榴石存在着铝榴石和钙榴石两个系列，并探索了变质岩原岩的组分；变质岩的形成温度为７２５－７５５℃原始变质岩为中等压力产物。多硅白云母形成时的温度和压力属于叠加变质作用的温压条件。本区的区域变质岩是多期变质作用叠加的产物。     

浙西南松阳地区斜长角闪岩变质作用演化及地质意义

位于浙西南松阳地区八都杂岩的斜长角闪岩是构成前寒武纪基底的主要变质岩之一,但其原岩类型与变质演化特点目前尚不明确.开展了岩相学、矿物微区化学成分及全岩主微量元素研究,发现该斜长角闪岩的原岩类型为高铁拉斑玄武岩,可能形成于岛弧构造环境.石榴石核部保存有进变质信息,峰期变质阶段(M1)矿物组合为石榴石(边部)+浅闪石+斜长...     

西昆仑铁克里克东一带赛图拉岩群变质岩特征及地质意义

新疆西昆仑铁克里克东一带长城系赛图拉岩群b岩组变质岩主要沿昆仑山呈近东西向展布,为一套区域动力热流变质作用形成的变质岩.本次工作采集了6件较有代表性的变质岩样品做硅酸盐、稀土、微量元素分析测试.原岩恢复相关判别图解显示其原岩是以粘土、杂砂岩的碎屑岩为主,还有一些火山岩,具有一定的复杂性;构造环境判别相关图解显示其为岛弧...     

南苏鲁造山带的超高压变质岩及岩石化学研究

在南苏鲁造山带核部，古老的表壳岩和花岗质侵人岩经历了三叠纪的超高压变质作用，在超高压变质岩石抬升过程中经历了强烈的角闪岩相退变质作用改造。据岩相学和岩石化学研究，可以区分出六大类典型超高压变质岩：榴辉岩、石榴石橄榄岩、石英硬玉岩、石榴石多硅白云母片岩、硬玉石英岩和石榴石绿辉石文石岩。这些岩石的角闪岩相退变质产物分别是斜长角闪岩、蛇纹岩、长英质片麻岩、长石石英云母片岩、石英岩和大理岩。地球化学研究揭示，榴辉岩的原岩很可能是形成在大陆内部构造环境的拉斑玄武岩，而石榴石橄榄岩可能是起源于亏损的残余地幔。石英硬玉岩原岩包括正变质的花岗岩和奥长花岗岩、副变质的酸性火山碎屑岩和长石石英砂岩。大面积分布的古老花岗岩很可能是形成在大陆或大陆边缘环境。长石石英云母片岩、石英岩和大理岩的原岩为沉积岩，与副变质的长英质片麻岩和基性火山岩—起构成了古老的表壳岩组合。双峰式的酸性和基性火山岩组合的存在也证明部分表壳岩是形成在大陆环境。因此，可以推测南苏鲁造山带核部的超高压变质岩原岩为形成在大陆板内环境的沉积岩—酸性和基性火山岩—花岗岩和奥长花岗岩建造。     

赣南地区变质岩离子吸附型稀土矿床地质特征及找矿方向

通过对赣南地区变质岩离子吸附型稀土矿床进行岩石学、稀土元素地球化学和矿床地质特征研究,探讨变质岩离子吸附型稀土矿床的控矿因素、矿床成因及下一步找矿方向。赣南地区变质岩的原岩时代主要为青白口纪—奥陶纪,变质岩的稀土元素丰度较高,属轻稀土富集型。已发现的离子吸附型稀土矿床主要赋存于震旦纪—青白口纪变质岩中,以青白口纪库里组和南华纪寻乌岩组为主。石城—宁都—瑞金浅变质岩区和会昌—安远—寻乌中深变质岩区可作为离子吸附型稀土矿勘查的首选地区。     

全国变质岩原岩恢复学术讨论会在烟台召开

由本会变质岩专业委员会和中国地质学会岩石专业委员会、山东省地质学会联合举办的全国变质岩原岩恢复学术讨论会,于1983年11月1日至7日在山东省烟台市召开。到会代表118人,分属22个省市的72个单位。会议共收到论文摘要126篇,论文65篇。内容包括变质岩原岩恢复的综合方法,各种岩石化学计算法、微量元素法、多种副矿物法、数学地质法、稀土地球化学法以及氧     

赣南宁都地区变质岩离子吸附型稀土矿床地球化学特征及找矿意义

赣南浅变质岩离子吸附型稀土矿床是江西省近些年来新发现的稀土矿类型。文章主要研究赣南地区新元古代青白口纪库里组和神山组浅变质岩稀土矿点,通过野外地质调查和室内综合研究,总结了该类稀土矿床的地球化学特征。结果表明:该区浅变质岩以SiO₂含量中等、K₂O/Na₂O值较高、全碱含量中等、TFe₂O₃+MgO及CaO较低为特点; 稀土元素总量较高,轻、重稀土元素分馏明显,轻稀土富集,Eu中等亏损,部分矿点已达到化学风化晚期阶段; 各矿点风化壳的稀土元素配分模式与原岩类似,稀土元素富集程度主要受控于原岩稀土元素丰度和风化指数CIA。     

相山铀矿田基底变质岩原岩恢复及构造环境判别

文章通过对相山铀矿田深部变质岩开展岩石学、矿物学及地球化学等方面的研究,以探讨相山基底变质岩原岩的属性和形成环境等特征。根据铀矿科学钻孔岩心样品地球化学分析显示,基底变质岩成熟度较高,显示高镁铁、富硅、富铝,低钠钾的特征,原岩总体呈中酸性。变质岩整体表现出相对富集Ba、U、Rb、K、Th等元素,亏损Nb、Sr、P、Ti等元素;轻、重稀土元素分馏较为明显,且轻稀土相对富集、重稀土相对亏损;δEu为0.6～1.1,平均为0.7,小于1,表现为负异常;δCe为2.9～3.9,平均为3.4,表现为正异常。根据变质岩稀土元素北美页岩标准化(NASC)蛛网图显示,样品稀土元素含量与北美页岩(NASC)含量相近,推测原岩具有沉积岩的特征。主量元素分布特征表明相山铀矿田基底变质岩原岩成分复杂,推测其原岩主要为一套陆源海相沉积泥质岩、砂岩及粉砂岩系列的浅变质作用类型的陆源碎屑岩,主要有岩屑砂岩、富镁沉积岩、泥质碳质硅质岩,可能有部分火山凝灰岩。根据主微量构造判别图,推测相山基底变质岩其原岩为大陆岛弧构造环境下形成的沉积碎屑岩。     

中国大陆科学钻探主孔榴辉岩中石榴石和绿辉石原位激光探针分析及其成岩成矿指示意义

本文以中国大陆科学钻探主孔0～2000m岩芯中的榴辉岩为对象,运用EMPA和LA-ICP-MS技术,系统测定了榴辉岩中石榴石和绿辉石的主量与微量元素组成,并据此讨论了它们的成岩成矿意义.研究结果表明,CCSD主孔榴辉岩中石榴石富重稀土和Sc、Y、Co,而绿辉石则富中稀土和Pb、Sr、V,石榴石和绿辉石的高场强元素(特别是Nb、Ta)含量均很低.石榴石存在不同程度的Ce负异常,指示榴辉岩的形成过程中卷入有地表氧化条件下形成的风化沉积物.石榴石具有低的Zr/Y比值,绿辉石普遍具有高的Sr含量,这些特征说明榴辉岩(特别是高钛榴辉岩)的原岩可能为遭受过壳源物质混染与交代的富集地幔部分熔融的产物.高钛与低钛榴辉岩中石榴石和绿辉石在主量及微量元素组成上存在一定差别,总体而言,高钛榴辉岩中石榴石具高的MgO含量和较高的MgO/TFeO比值,以及较高的稀土和Sc含量,而绿辉石则相对富TFeO、MnO,并具有较高的Sr、Zr、Hf含量.高钛榴辉岩中石榴石和绿辉石常出现不同程度的Eu正异常,Cr含量均显著低于低钛榴辉岩.综合分析表明,高钛榴辉岩的原岩最可能为富斜长石的辉长质侵入岩,原岩组成的差异应是导致二类榴辉岩中石榴石和绿辉石矿物化学组成存在差异的主要原因.     

西昆仑铁克里克东一带赛图拉岩群变质岩特征及地质意义

新疆西昆仑铁克里克东一带长城系赛图拉岩群b岩组变质岩主要沿昆仑山呈近东西向展布,为一套区域动力热流变质作用形成的变质岩。本次工作采集了6件较有代表性的变质岩样品做硅酸盐、稀土、微量元素分析测试。原岩恢复相关判别图解显示其原岩是以粘土、杂砂岩的碎屑岩为主,还有一些火山岩,具有一定的复杂性;构造环境判别相关图解显示其为岛弧环境和活动大陆边缘环境,碎屑物源复杂;赛图拉岩群原岩恢复及构造环境的重建,丰富了西昆仑铁克里克东一带板块发育的过程,为研究Rodinia超大陆形成演化历史提供了新资料。     

The terrestrial fauna of the Late Triassic Pant-y-ffynnon Quarry fissures,South Wales,UK and a new species of Clevosaurus (Lepidosauria: Rhynchocephalia)

Pant-y-ffynnon Quarry in South Wales yielded a rich cache of fossils in the early 1950s, including articulated specimens of new species (the small sauropodomorph dinosaur Pantydraco caducus and the crocodylomorph Terrestrisuchus gracilis), but no substantial study of the wider fauna of the Pant-y-ffynnon fissure systems has been published. Here, our overview of existing specimens, a few described but mostly undescribed, as well as freshly processed material, provides a comprehensive picture of the Pant-y-ffynnon palaeo-island of the Late Triassic. This was an island with a relatively impoverished fauna dominated by small clevosaurs (rhynchocephalians), including a new species, Clevosaurus cambrica, described here from a partially articulated specimen and isolated bones. The new species has a dental morphology that is intermediate between the Late Triassic Clevosaurus hudsoni, from Cromhall Quarry to the east, and the younger C. convallis from Pant Quarry to the west, suggesting adaptive radiation of clevosaurs in the palaeo-archipelago. The larger reptiles on the palaeo-island do not exceed 1.5?m in length, including a small carnivorous crocodylomorph, Terrestrisuchus, and a possible example of insular dwarfism in the basal dinosaur Pantydraco.     

The effect of water on accessory phase solubility in subaluminous and peralkaline granitic melts

The solubilities of columbite, tantalite, wolframite, rutile, zircon and hafnon were determined as a function of the water contents in peralkaline and subaluminous granite melts. All experiments were conducted at 1035 °C and 2 kbar and the water contents of the melts ranged from nominally dry to approximately 6 wt.% H₂O. Accessory phase solubilities are not affected by the water content of the peralkaline melt. By contrast, solubilities are affected by the water content of the subaluminous melt, where the solubilities of all the accessory phases examined increase with the water content of the melt, up to 2 wt.% H₂O. At higher water contents, solubilities are nearly constant. It can be concluded that water is not an important control of accessory phase solubility, although the water content will affect diffusivities of components in the melt, thus whether or not accessory phases will be present as restite material. The solubility behaviour in the subaluminous and peralkaline melts supports previous spectroscopic studies, which have observed differences in the coordination of high field strength elements in dry vs. wet subaluminous granitic glasses, but not for peralkaline granitic glasses. Lastly, the fact that wolframite solubility increases with increasing water content in the subaluminous melt suggests that tungsten dissolved as a hexavalent species.     

Quaternary stresses revealed by calcite twinning inversion: insights from observations in the Savonnières underground quarry (eastern France)

Calcite samples were extracted both from the rock matrix and the superficial coating of a karstified fault plane of an underground quarry, located in the eastern border of the Paris basin. The karstification is dated as Quaternary. Analysis of mechanical calcite twinning reveals that only the calcite matrix has also undergone a compression trending WNW that can be attributed to the Mio-Pliocene alpine collision. Both coating and matrix have undergone a strike-slip regime with σ₁ roughly trending north–south, that could correspond to the regional present-day state of stress, a strike-slip compression rather trending NNW, modified by local phenomena. To cite this article: M. Rocher et al., C. R. Geoscience 335 (2003).     

HYDROGEOLOGY

正20141756 Chen Ruige(Mathematical College,China University of Geosciences,Beijing100083,China);Zhou Xun Numerical Simulation of Groundwater Level Fluctuation in a Coastal Confined Aquifer with Sloping Initial Groundwater Level Induced by the Tide(Geological Bulletin of China,ISSN1671-2552,CN11-4648/P,32(7),2013,p.1099-1104,6 illus.,16 refs.) Key words:confined water,groundwater level     

METAMORPHIC PETROLOGY

正20141408 Cai Jia(Institute of Geology,Chinese Academy of Geological Sciences,Beijing100037,China);Liu Fulai Petrogenesis and Metamorphic P-T Conditions of Garnet-Spinel-Biotitebearing Paragneiss in Danangou Area,Daqingshan-Wulashan Metamorphic Complex Belt(Acta Petrologica Sinica,ISSN1000-0569,CN11-1922/P,29(7),     

SERIALS

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GEOPHYSICAL EXPLORATION

正20142386An Guoying(China Aero Geophysical Survey and Remote Sensing Center for Land and Resources,Beijing 100083,China)Application of Satellite Remote Sensing in Regional Hydrogeological Investigation:Taking Cenozoic Strata in Wenquan Sheet(1∶250 000)of Karakoram Range as an Example(Geosci-     

QUATERNARY GEOLOGY & GEOMORPHOLOGY

正20141016An Chengbang(Key Laboratory of Western China’s Environmental Systems,Ministry of Education,Lanzhou University,Lanzhou 730000,China);Zhao Yongtao Lake Records during the Last Glacial Maximum from Xinjiang,NW China and Their Climatic Impli-     

PETROLEUM GEOLOGY

正20141538 Cao Qing(School of Earth Sciences and Engineering,Xi’an Petroleum University,Xi’an 710065,China);Zhao Jingzhou Characteristics and Significance of Fluid Inclusions from Majiagou Formation,Yichuan Huangling Area,Ordos Basin(Advances in Earth Science,ISSN1001-8166,CN62-1091/P,28(7),2013,p.819-828,7 illus.,3 tables,43 refs.)     

GEOCHEMISTRY

正20142002 Wei Hualing(Institute of Geophysical and Geochemical Exploration,Chinese Academy of Geological Sciences,Langfang065000,China);Zhou Guohua Element Content and Mineral Compositions in Different Sizes of Soil in Tongling Area,Anhui Province(Geological Bulletin of China,ISSN1671-2552,CN11-4648/P,32(11),2013,p.1861