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The committee on the Paleogene of the U. S. S. R. presents a tabulation of the lithologic and faunal characteristics of a complete Paleogene section in the Crimea. The Committee proposes that this section serve as a new type of section for the Paleogene of Europe. — C.G. Tillman.  相似文献   

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张宏仁 《地质论评》2007,53(6):725-725
徐霞客是我国明末的一位伟大的地球科学家。然而徐霞客对地球科学的贡献只是经过丁文江先生的大力推介才广为世人所知。我国乃至世界上徐学研究能有今天这样的大好局面,丁文江先生功不可没。[第一段]  相似文献   

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在模拟回转和提升负载条件下,对异步电机和变频器组成的驱动系统在地质钻机上的适应性作了比较全面系统地实验研究。实验结果表明:交流变频驱动系统其调速范围宽,驱动特性好,可实现带载频繁启动;具有限定最大输出转矩、设定加减速时间等多项可选择的功能。系统运行可靠、效率高。在钻机上使用,可简化钻机传动机构,利于优化钻井和安全钻井;便于实现钻探设备的自动化。因此,交通变频驱动在钻机上有很好的应用前提,是一项值得  相似文献   

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The compilation of statistical data for 269 seismic crustal sections (total length: 81,000 km) which are available in the U.S.S.R. has shown that the preliminary conclusions drawn on relations between the elevation of the surface relief and Bouguer anomalies on one hand and crustal thickness (depth to the M-discontinuity) on the other hand are not fulfilled for the continental part of the U.S.S.R. The level of isostatic compensation has been found to be much deeper than the base of the earth's crust due to density inhomogeneities of the crust and upper mantle down to a depth of 150 km.

The results of seismic investigations have revealed a great diversity of relations between shallow geological and deep crustal structures:

Changes in the relief of the M-discontinuity have been found within the ancient platforms which are conformable with the Precambrian structures and which can exceed 20 km. In the North Caspian syneclise, extended areas devoid of the “granitic” layer have been discovered for the first time in continents. The crust was found to be thicker in the syneclises and anteclises of the Turanian EpiHercynian plate. In the West Siberian platforms these relations are reversed to a great extent.

Substantial differences in crustal structure and thickness were found in the crust of the Palaeo zoides and Mesozoides. Regions of substantial neotectonic activity in the Tien-Shan Palaeozoides do not greatly differ in crustal thickness if compared to the Kazakhstan Palaeozoides which were little active in Cenozoic time. The same is true for the South Siberian Palaeozoides.

The Alpides of the southern areas in the U.S.S.R. display a sharply differing surface relief and a strongly varying crustal structure. Mountains with roots (Greater Caucasus, Crimea) and without roots (Kopet-Dagh, Lesser Caucasus) were found there.

The Cenozoides of the Far East are characterized by a rugged topography of the M-discontinuity, a thinner crust and a less-pronounced “granitic” layer. A relatively small thickness of the crust was discovered in the Baikal rift zone.

The effective thickness of the magnetized domains of the crust as well as other calculations show that the temperature at the depth of the M-discontinuity (i.e., at depths of 40–50 km) is not higher than 300–400° C for most parts of the U.S.S.R.  相似文献   


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The Committee on Ordovician and Silurian Stratigraphy of the U. S. S. R. defines a number of time-stratigraphic subdivisions of the Russian Ordovician and Silurian Systems. — C.G. Tillman.  相似文献   

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