南海北部大陆架盆地热结构

南海北部大陆架盆地地热研究发现,各盆地深部温度结构和地壳热流在地表热流中所占比例不均一。其中,珠江口盆地地壳热流贡献小于25%,由陆向洋方向递减;莺歌海盆地中部地壳热流贡献小于30%,向NE方向递增;北部湾盆地地壳热流贡献在38%~42%之间稳定变化。分析表明,此区各盆地热结构的不均一性与大陆架地壳减薄、软流圈热物质上涌等因素有关。      

济阳坳陷地幔热流和深部温度

济阳坳陷深部地热状况对于分析岩石圈深部结构特征、探索该盆地形成和演化的地球动力学过程具有重要意义.依据济阳坳陷最新的钻探资料和深部地球物理探测结果, 按沉积盖层、上、中、下地壳4层结构, 建立了分别代表该区凹陷部位和凸起及斜坡带上的2种地壳结构模型.通过多道能谱分析, 测试了区内4 3块岩心样品的放射性元素U、Th、40K含量, 统计得出了济阳坳陷沉积盖层的平均生热率为(1.40±0.26) μW/m3.在研究大地热流分布的基础上, 结合济阳坳陷地壳各岩层放射性生热率, 采用“剥层”法, 从地表开始, 由浅到深逐步扣除各层段所提供的热量, 得到了济阳坳陷的地幔热流.并且采用相似的方法, 利用一维稳态热传导方程, 分析了地壳上地幔顶部的温度状况.结果表明, 济阳坳陷的地幔热流约为38.4~39.2 mW/m2, 占整个地表总热流量的5 8%;地幔顶部温度约为602~636℃.与世界上其他各类地质构造单元相比, 济阳坳陷无论是地幔热流值或其与地表热流之比值都是比较高的, 其深部地热状态具有介于稳定地区和构造活动区之间的特点.      

挪威和瑞典前寒武纪地层的重向生热率分布及地热意义

南斯堪的纳维亚（Scandivnavia)的地质情况为深部和中部地壳的取样提供了独特的条件，以进行热流和生热率研究。在南挪威中部地区，闪岩相的地体看来是位于更深的壳层枯部，这些更深的壳层在其西部和东部边缘出露。作者从文献中选用这个地区所有岩类的大量的地球化学数据来计算各种岩相的放射性生热率。用同一地区的热流约束得到了一个可靠的地壳生热率分布模型。麻粒岩相地体的平均生热率是0．4μW/m^3。这个地盾也包含了由后期构造事件形成的生热元素富集的花岗岩，地表岩石总的平均生热率是2．7μW/m^3。根据10个测点的热流和生热率的数据，这个地区的剩余热流为22±2mW/m^2，这相当于28km厚的深地壳岩相层顶的热流，预示了地幔热流可能只有10mW/m^2的低值。整个地壳平均的放射性热贡献为31mW/m^2。     

鄂尔多斯盆地热流场特征

鄂尔多斯盆地系统Ｕ、Ｋ、Ｔｈ含量和地壳结构分层的综合研究表明，盆地莫霍面的热流平均值为０．３７ＨＦＵ，比华北地洼型活化盆地（０．６４～０．９７ＨＦＵ）要低得多，尚有稳定构造区的热流特点。盆地地表平均热流值为１．４４６ＨＦＵ，与全球大陆中生代地洼型造山区（１．４５ＨＦＵ）很接近，说明鄂尔多斯残留地台型盆地，从大地构造性质角度上看，正趋于向活化的方向发展。从地表到莫霍面，各界面现今热流的分布形式一致，热流的变化梯度和趋势也一致，表明研究区热流场的表现形式，受上地幔热场格局的控制。盆地各界面现今热流北西低、南东高，在吴旗－靖边及其往两端延伸一线，存在一个明显的ＮＥＥ向梯度带，是油气在热动力驱使下而分散或富集的重要场所。     

中国东北地区地热资源及热结构分析

在我国东北地区，盆地的热流高而在山区和地台区（额尔古纳和佳木斯地台）热流较低，通过对该区的研究发现，在地壳和上地幔中莫霍面埋深，高导层埋深和热流值之间存在着密切的联系，通过对该区热流数据分析我们可以得到这样的结论：该区的地壳和上地幔的热结构引起了热流分布的变化。计算结果还表明，该区地台的地幔热流，地壳中10km以下和10km以上的热流对地表热流的贡献不同。该区松辽盆地中广泛分布着传导型中低温地热资源，对松辽盆地地热资源的开发利用有着广泛的前景。最后结合已有的地质和物探资料，还给出了长白山天池火山地区长白温泉地热系统的概念性模型。     

青藏高原及周边地区下地壳地球物理异常及成因

青藏高原及周边地区下地壳普遍发育电性高导层、波速低速层和热流密度值异常区.下地壳电性结构和速度结构明显具有纵向分层和横向分块的特点,其热流密度值具有明显的南北条带性和东西分块性.下地壳高导层、低速层和热流密度值异常区与青藏高原及周边地区各构造单元有一定的匹配性,异常区的形成与青藏高原和周边盆地耦合过程中下地壳岩石的热软化以及韧性流动有关.下地壳层流是下地壳岩石热软化和韧性流动的结果,青藏高原的隆升是层流作用的表现,目前层流作用的动力来源于恒河盆地下地壳,层流方向由恒河盆地流入青藏高原.     

缅因州的热流与基底放射性生热的关系：最初结果与初步解释

在缅因州新近取得的70个钻孔的热流值（a)在33－83mWm^-2范围，45个地点的放射性热产率值（A）在0．08－8．74μWm^-3之间。综合岩体中所测得的数据，用线性最小二乘法确定的直线斜率和截距分别在5．0－6．5km和35－39mWm^-2范围内。这些直线进一步证实大陆地块的Q和A值之间存在的线性关系。也证实了正常的剩余热流值是纽约和新英格兰地区具特征性的地热参数。重力、地震和地热模式都显示出缅因州岩体厚度和近地表放射性元素分布的复杂性。因此，在一些地区很难用简单的或指数递减的垂向热产率分布模式来解释这种Q－A线性关系。缅因州正常的剩余热流指示着这个区经历了古生代和侏罗纪的构造事件后，岩石圈就达到了平衡。在缅因州和中部新汉普群，8－10km的地壳厚度差别而引起的Moho高的温度变化不会超过150℃，这种变化对地幔性质的影响也是很微弱的。     

渤海盆地现今岩石圈热结构及新生代构造-热演化史

依据236口井共2 706组的静温数据以及25口井的系统测温数据,分析计算了渤海盆地地温梯度及大地热流;建立地壳分层结构模型,利用回剥法计算现今地幔热流、深部温度以及岩石圈厚度;在此基础上,利用地球动力学方法恢复本区热流演化史。结果表明：渤海盆地背景地温梯度为322 ℃/km,热流值为648 mW/m2;盆地现今热岩石圈厚度在61~69 km之间,地幔热流占地表热流的比例在60%左右,属于“热幔冷壳”型岩石圈热结构,盆地地壳底部或莫霍面温度变动在548~749 ℃之间;热流演化的特征与盆地的构造演化背景吻合,新生代以来盆地经历了3期岩石圈减薄并加热的过程,在东营组沉积末期热流达到最高(70~83 mW/m2）,这期间盆地内产出多期碱性玄武岩,表明盆地经历了波及地幔的裂谷过程,随后进入热沉降期,热流逐渐降低,盆地向坳陷型转变。     

东海陆架盆地西湖凹陷岩石圈热流变性质

为了探讨东海陆架盆地西湖凹陷岩石圈热流变性质,本文以实测地温数据为依据,模拟西湖凹陷岩石圈热结构,在此基础上,应用流变学原理模拟确定西湖凹陷岩石圈流变性质。结果表明,西湖凹陷岩石圈为一个冷地壳-热地幔、强地壳-弱地幔的"奶油蛋糕"型岩石圈。西湖凹陷平均地表热流密度为71 m W/m~2,地幔热流密度为40~65 m W/m~2,对地表热流密度的贡献度达73%~79%,地表热流受地幔热流控制,莫霍面温度在700℃左右,热岩石圈平均厚度为66 km。西湖凹陷岩石圈流变分层明显,上、中地壳基本为脆性层,下地壳和岩石圈上地幔为韧性层,岩石圈总流变强度平均约为2.65′10~(12) N/m,其中地壳流变强度为2.12′10~(12) N/m,地幔流变强度为5.29′10~(11) N/m,有效弹性厚度为11.7~14.5 km,地壳的流变性质控制了岩石圈的流变行为。此外,西湖凹陷岩石圈总强度较低,在构造应力作用下易于变形,且存在壳幔解耦现象。西湖凹陷岩石圈热状态及流变性质决定了西湖凹陷东部地区主要以浅部地壳的断层滑动和地层破裂来调节深部的构造应力。     

大陆岩石圈有效弹性厚度的计算及其地质意义

大陆范围内Te值有很大的范围，不同构造单元有不同的Te值。Te值的大小与岩石圈的热结构（热年龄）、壳幔耦合等因素有关。同时Te值和地壳厚度、地表有关矿产的分布、岩石圈地幔的物质组成等也有一定关系。     

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.     

Définition d'une limite multicritère ; stratigraphie du passage Campanien–Maastrichtien du site géologique de Tercis (Landes,SW France)Definition of a multi-criteria boundary; stratigraphy of the Campanian–Maastrichtian interval of the geological site at Tercis (Landes,SW France)

Lithostratigraphy, physicochemical stratigraphy, biostratigraphy, and geochronology of the 77–70 Ma old series bracketing the Campanian–Maastrichtian boundary have been investigated by 70 experts. For the first time, direct relationships between macro- and microfossils have been established, as well as direct and indirect relationships between chemo-physical and biostratigraphical tools. A combination of criteria for selecting the boundary level, duration estimates, uncertainties on durations and on the location of biohorizons have been considered; new chronostratigraphic units are proposed. The geological site at Tercis is accepted by the Commission on Stratigraphy as the international reference for the stratigraphy of the studied interval. To cite this article: G.S. Odin, C. R. Geoscience 334 (2002) 409–414.     

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.)