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991.
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通过归纳黔西北地区的区域地质背景,典型矿床的地质特征,比较矿床中矿石和含矿地层的Pb/盈比值和REE配分模式,分析构造展布、矿床(点)的分布和物探异常之间的关系,提出构造是区域的主要控矿因素,从而强调研究构造体系是综合找矿工作的重点。 相似文献
993.
数字高程模型(DEM)不仅可以实现三维地形可视化,而且还能由其进一步获得与高程有关的地形要素。针对青藏高原DEM生成和应用过程中碰到的数据量大、区域广阔、应用难度大等问题,本文给出了相应的解决方案,提出一套DEM制作和应用流程:以1:25万地形图矢量等高线数据内插方式生成青藏高原DEM数据,在此基础上,运用Mask处理后相交分析思想与多级金字塔、DEM水淹分析、高程分带等处理技术实现了青藏高原三维地形可视化、三维遥感影像制作、及其它生态地质环境因素的变化分析。基于此方法生成的青藏高原DEM数据,不仅精度高,三维地形可视化效果好,而且解决了海量DEM数据与其它资料综合分析的问题。 相似文献
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The distribution of uranium was studied in supergene phosphorites from the zones of the weathering of sedimentary and endogenous rocks, as well as in nonmarine coprolitic phosphorites and, to a lesser extent, phosphorites from ocean islands. These phosphorites show a diversity of the composition of their carbonate-apatite and structural characteristics. The uranium content ranges mostly from 5 to 100 ppm, with minimum and maximum values of 0.5 and 790 ppm. There is no correlation between the uranium content of a phosphorite and the type of rock with which it is connected. Lacustrine coprolitic phosphorites show elevated uranium contents (about 200 ppm). The maximum uranium content was detected in finely laminated phosphorite encrustations. The correlation analysis of the whole data set (63 samples) showed that uranium content is not correlated with any other component of phosphorites at a confidence level of 0.95. In contrast, there is a correlation between U and P2O5, CaO, and F for the combined set of samples from southern Siberian deposits. The significant correlation of U with Na2O and CO2 is variable both for southern Siberia on the whole and for particular deposits from this region. 相似文献
999.
Upper Cretaceous and Cenozoic formations of the western Transbaikal and southeastern Baikal regions are considered. Molasses and molassoids (molasse-type sediments) were included into these formations in previous works. In our opinion, the following formations are developed in these regions: plain fan formation divided into the terrigenous (Upper Cretaceous) and coaliferous (Upper Oligocene-Lower Pliocene) subformations; plain fine-clastic formation (Paleogene, except the Upper Oligocene); and orogenic molasse formation (Upper Pliocene-Holocene) divided into the lower red-colored and upper gray-colored subformations. Main textural features of these formations are considered. Paleogeographic and paleotectonic settings of their accumulation are reconstructed. It is shown that coarse-clastic sediments of fan formations accumulated in grabens among ancient denudation plains due to the destruction of rocks in near-wall benches. These plains probably hosted in some areas remnants of the mountainous relief. Origination and development of the Baikal rift zone was the main geological event in the Baikal region during the Late Cretaceous and Cenozoic. Based on study of the southeastern Baikal region with the thickest and most representative Cenozoic sections, the prerifting and rifting stages of this zone and correlative events in the adjacent (relatively stable) areas of the western Transbaikal region are characterized. 相似文献
1000.
A. Yu. Lein A. S. Savvichev I. I. Rusanov G. A. Pavlova N. A. Belyaev K. Craine N. V. Pimenov M. V. Ivanov 《Lithology and Mineral Resources》2007,42(3):221-239
Study of biogeochemical processes in water and sediments of the Chukchi Sea in August 2004 revealed atypical maximums of the concentration of biogenic elements (N, P, and Si) and the rate of microbial sulfate reduction in the surface layer (0–3 cm) of marine sediments. The C: N: P ratio in the organic matter (OM) of this layer does not fit the Redfield-Richards stoichiometric model. Specific features of biogeochemical processes in sea are likely related to the complex dynamics of water, high primary productivity (110–1400 mg C/(m2 day)), low depth of basin (<50 m in 60% of the water area), reduced food chain due to low population of zooplankton, high density of zoobenthos (up to 4230 g m?2), and high activity of microbial processes. Drastic decrease in the concentration of biogenic elements, iodine, total alkalinity (Alk), and population of microorganisms beneath the 0–3 cm layer testify to a large-scale OM decay at the water-seafloor barrier. Our original experimental data support the high annual rate of OM mineralization at the bottom of the Chukchi Sea. 相似文献