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主要矿物(例如,普通辉石、钙镁闪石)和共存的熔体之间的微量元素分配系数(Ds~*)对俯冲带中岩浆的产生模式的确定是重要的。近来对含水富集Nb,Ta的碧玄岩和微量元素(Rb、Ba、Sr、Y、Nb、Ta和REE)胶状的硅酸盐-碳酸盐岩混合物进行合成实验,在1000～1050℃和2.0～2.5GPa条件下,在淬火的基质中形成了普通辉石和钙镁闪石。晶体和基质的范围足以进行微量元素的显微质子探针分析和D值的测定C>30μ)(表1)。 相似文献
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Identifying connections in a fractured rock aquifer using ADFTs 总被引：1，自引：0，他引：1
Fractured rock aquifers are difficult to characterize because of their extremely heterogeneous nature. Developing an understanding of fracture network hydraulic properties in these aquifers is difficult and time consuming, and field testing techniques for determining the location and connectivity of fractures in these aquifers are limited. In the Clare Valley, South Australia, well interference is an important issue for a major viticultural area that uses a fractured aquifer. Five fracture sets exist in the aquifer, all dipping > 25 degrees . In this setting, we evaluate the ability of steady-state asymmetric dipole-flow tests (ADFTs) to determine the connections between a test well and a set of piezometers. The procedure involves dividing a test well into two chambers using a single packer and pumping fluid from the upper chamber to the lower chamber. By conducting a series of tests at different packer elevations, an "input" signal is generated in fracture zones connected to the test well. By monitoring the "output" response of the hydraulic dipole field at piezometers, the connectivity of the fractures between the test well and piezometers can be determined. Results indicate the test well used in this study is connected in a complex three-dimensional geometry, with drawdown occurring above and below areas of potentiometric buildup. The ADFT method demonstrates that the aquifer evaluated in this study cannot be modeled effectively on the well scale using continuum flow models. 相似文献
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用氧同位素温度计测定了西阿尔卑斯ＤｏｒａＭａｉｒａ地块含柯石英—镁铝榴石白片岩的峰期变质温度。石英（柯石英较变后）的δ￣（１８）Ｏ（８．１‰～８．６‰，ｎ＝６），多硅白云母的（６．２‰～６．４‰，ｎ＝３）、蓝晶石的（６．１‰，ｎ＝２）、石榴石的（５．５‰～５．８‰，ｎ＝９）、ｅｌｌｅｎｂｅｒｇｅｒｉｔｅ的（６；３‰，ｎ＝１）和金红石的（３。３‰～３．６‰，ｎ＝３）δ￣（１８）Ｏ（ＳＭＯＷ）值反映了同位素平衡。以石英—石榴石—金红石分馏为基础测定的温度为７００～７５０℃。以对压力敏感的反应：镁铝榴石＋朽石英＝蓝晶石十顽火辉石为依据确定的最小压力为３．１～３．２ＧＰａ。为了通过对温度敏感的脱水反应：滑石十蓝晶石＝镁铝榴石十柯石英十水，来稳定镁铝榴石和柯石英，在７００～７５０℃时，α（Ｈ＿２Ｏ）必须减小到０．４～０。７５。当镁铝榴石在ｘ（ＣＯ＿２）＞０．０２（Ｔ＝７５０℃，Ｐ＝３．０ＧＰａ）不稳定时，α（Ｈ＿２Ｏ）的减少不会是由于ＣＯ＿２的稀释所引起的。当缺乏较多的外来流体稀释剂（即ＣＨ＿４或Ｎ＿２时，就需要有熔体相）。在α（Ｈ＿２Ｏ）＝１．Ｏ时，花岗岩的固相线温度为６８０℃／３．０ＧＰａ，在α（Ｈ＿２Ｏ）＝０． 相似文献
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欧亚板块东部边缘的火山岩(日本西南、日本海和中国东北部)表现出富集型同位素的特点(EMI)。日本海的Ulreung和Dog岛呈典型的DUPAL异常特征,△~(208/204)pb值极高(高达143),而且富集Nd和Sr同位素组分(ε_(Nd)=-3～-5,~(87)Sr/~(86)Sr=-0.705)。△~(208/204)pb值(高达140)和南半球与DUPAL异常有关的火山岩相似。由于日本海玄武岩的EMI特征比日本西南部和中国内陆的玄武岩更明显,我们认为,古老的地幔岩石圈早 相似文献
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Identification and imaging of soil and soil-pile deformation in the presence of liquefaction 总被引：1，自引：0，他引：1
M. Zeghal P. V. Kallou C. Oskay T. Abdoun M. K. Sharp 《地震工程与工程振动(英文版)》2006,5(2):171-182
1 Introduction Soil and soil-structure systems exhibit complex response patterns during earthquake-induced liquefaction. These patterns depend on geotechnical properties, in-situ stress conditions and interaction with subsurface structural elements. Seismic records of full- scale systems during case histories provide a valuable source of information on the associated response mechanisms. However, the response of these systems is commonly monitored at sparsely distributed locations only, mostly… 相似文献
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采自板块构造环境已知的现代玄武质岩石的地球化学特征,包括同位素特征,为判定古代类似岩石形成的构造环境提供了基本的佐证。这些应用通常包括下列一种或多种技术:a.利用几种特征元素的绝对丰度或比值进行定性比较;b.经验式地采用二元和三元构造辨别图解,这些辨别图解以相对于活动的相容元素(如Cr、Ni)和高场强的不相容元素(Ti、zr、P、Nb、Ta、Y)尤其是不相容元素的比值为依据;c.稀土模式;d.利用由平均 相似文献
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橄榄石是幔源原始岩浆中最早结晶的一种矿物,而且其化学成分可以提供源区橄榄岩性质的信息。地幔橄榄岩中橄榄石的100Mg/(Mg+Fe)值(Fo)范围较宽,从94到85,而NiO的含量约为0.4％(wt,以下同)。橄榄石Fo值的微小差异导致对原始岩浆MgO含量估计的较大不同。例如,原始的洋中脊玄武岩中橄榄石的Fo值相当于92、90和88,而MgO的含量分别约为16、12.5和10％。因此,在估计原始岩浆组分时,关键在于得到源区中橄榄石Fo的精确值。 相似文献