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61.
兰州黄土在冻融过程中水热输运实验研究 总被引:6,自引:0,他引:6
实验表明,当上边界面温度按正弦变化,下边界面温度保持某一固定值时,冻结均匀的兰州黄土融化后,相变界面附近的含水量明显增大。同样,对初始均匀融化的兰州黄土试样,经冰融循环作用后,冰土层内最大融化深工附近的含水量大于附近区域的含水量。试样内水分在冻融作用下的这种积累特征,与天然情况下多年冻土上限附近出现的水分富积现象相类似。由于在冻结和融化过程中,水分将向相变界面附近迁移,多年冻土上限附近地下冰的形成 相似文献
62.
冀东地区麻粒岩相变质作用的演化 总被引:1,自引:2,他引:1
据冀东迁安-遵化一带麻粒岩相区的变质岩石、变质矿物及其组构特征、变质作用的温度、压力条件,结合同位素年代学资料,以及岩浆作用、构造变形作用和变质作用之间的关系,可将本区太古代变质作用划分为两期。太古代第一期变质作用只限于表壳岩包体岩石中,变质级为高角闪岩相和辉石麻粒岩相,第二期变质作用发生在晚太古代,早期变质阶段是在紫苏花岗岩侵位以后发生的辉石麻粒岩相变质作用,晚期变质阶段发生在稍后侵位的基性侵入岩体、英云闪长岩、奥长花岗岩等深成侵入体中,变质级达角闪麻粒岩相。早元古代第一期角闪石榴二辉麻粒岩型岩脉,遭受了辉石麻粒相变质作用,第二期角闪石榴斜长辉石岩型岩脉经历了角闪麻粒岩相变质作用。这些变质作用在早期岩石中都有不同程度的叠加。麻粒岩相变质作用的温度在700℃~920℃,压力在0.88~1.14GPa。变质作用的PTt演化呈现了逆时针近等压冷却的轨迹 相似文献
63.
河东煤田中南部煤层气地质及其勘探开发前景 总被引:1,自引:0,他引:1
通过对煤层生,储,盖,构造演化史及水文地质特征的研究,讨论了研究区煤层气开发的前景。结果表明:区内主要煤层具有良好的生气潜能,储集和盖层封盖性能,构造演化和水文地质条件是影响煤层气富集的主要因素;煤层气藏的浅部区主要以中小规模构造圈闭气藏的形式存在,深部区的较大规模的水动力圈团或复合圈闭气藏;柳林西南煤层600~1500m埋深区域是目前进行进一步开发工作的首选区域。 相似文献
64.
Geochemical enrichment and mineralization of indium 总被引:20,自引:0,他引:20
Indium occurs in a very dispersed manner in nature with enrichment of economic interest rarely known. The highly dispersed
nature of indium, among several other elements, has for a long time retarded our understanding of the regularities that control
their mineralization, which in turn has hindered exploitation and application of these elements. Recent studies of ours show
that no significant enrichment of indium can be recognized in various types of Pb-Zn sulphide deposits as well as in deposits
of copper, iron and manganese. Indium concentrations in ores of these deposits are generally below 10 × 10-6. In contrast, however, indium is found to be enriched to a significant extent in cassiterite-sulphide deposits and some tin-rich
Pb-Zn polymetallic deposits. The average content of indium in these deposits can be over 100 × 10-6, and more than 90% of it is concentrated in sphalerite. Generally, these deposits may be considered as large paragenic deposits
for indium and, therefore, there must be some regularities that govern the geochemical enrichment of the so-called “dispersed
element” indium.
This project was financially supported by the National Natural Science Foundation of China (No. 49633110). 相似文献
65.
67.
Halogen elements play an important role in the metallogenesis of metallic ore deposits and are involved in the whole process of remobilization, transport and precipitation of metallic elements. However, with the exception of fluorine, which, as a component of fluorite and mica minerals, can be occasionally concentrated in ores, Cl, Br and I are hard to enrich in the ores. Investigations have found that the halogen elements tend to diffuse toward country rocks with the development of hydrothermal alteration in the process of their involvement in metallogenesis, especially during the post-ore stage when extensive halogen diffusion halos over orebodies would be formed. Such halogen element diffusion halos over the Chadong As–Ag–Au deposit extend as widely as 200 m. The largest diffusion extent is for I and the diffusion halos of Br are most noticeable 50–130 m away from the orebodies. In areas of ore exposure and the strongly altered zone, the Cl, Br and I contents are close to those of the strata with a V-shaped distribution pattern in the periphery of the mining district. Comparatively speaking, in going away from the altered zone, the major metallic elements Au and Ag in the deposit tend to decrease suddenly to their normal contents in the strata. This variation feature of halogen elements can be used as geochemical indicators for exploring concealed orebodies at depth. In the Chadong ore deposit, halogen element anomalies can be used to predict concealed orebodies at the depth range of 0–200 m. 相似文献
68.
Geochemical characteristics of scandium are described with respect to its source,evolution and correlation with REE as observed in Late Sinian and Early Cambrian phosphorites and tuffs in Guizhou.Gomparison of chondrite-nomalized REE patterns and some other parameters between the phosphorite and tuff shows that scandium and REE are most likely to have been derived from earlier or contemporaneous marine volcanics or tuffs,with no indication of genetic link to the purple shales,silstones and dolomites in the area.The conditions under which the Sc-bearin phosphorites were formed are discussed in the light of sulfur isotopes and Eh-Ph constrains. 相似文献
69.
<正>The Bohai Bay Basin is a Mesozoic subsidence and Cenozoic rift basin in the North China Craton.Since the deposition of the Permo-Carboniferous hydrocarbon source rock,the basin has undergone many tectonic events.The source rocks have undergone non-uniform uplift,twisting,deep burying,and magmatism and that led to an interrupted or stepwise during the evolution of hydrocarbon source rocks.We have investigated the Permo-Carboniferous hydrocarbon source rocks history of burying,heating,and hydrocarbon generation,not only on the basis of tectonic disturbance and deeply buried but also with new studies on apatite fission track analysis,fluid inclusion measurements,and the application of the numerical simulation of EASY%R_o.The heating temperature of the source rocks continued to rise from the Indosinian to Himalayan stage and reached a maximum at the Late Himalayan.This led to the stepwise increases during organic maturation and multiple stages of hydrocarbon generation.The study delineated the tectonic stages, the intensity of hydrocarbon generation and spatial and temporal distribution of hydrocarbon generations.The hydrocarbon generation occurred during the Indosinian,Yanshanian,and particularly Late Himalayan.The hydrocarbon generation during the late Himalayan stage is the most important one for the Permo-Carboniferous source rocks of the Bohai Bay Basin in China. 相似文献
70.
海南岛红树植物的解剖生态研究及其地质意义 总被引:1,自引:0,他引:1
在对不同红树属种系统解剖的基础上,总结了红树植物根、茎、叶等不同营养器官的一般性解剖结构特征,探讨了红树植物解剖结构与生态适应间的关系,指出了现代红树植物解剖、生态的研究在古植物学和煤沉积学方面的意义。 相似文献