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281.
研究地层是有效寻找沉积矿产的重要基础,将龙永煤田内关于的层位及分带性与大区域上的相似层位作了对比,并论述了本煤田的特征与变迁的基本过程。最后,结合多年来的研究成果,就煤田内的产出情况,作了两点必要的说明。 相似文献
282.
RMR法与Q法是国内外八、九十年代岩体质量和参数估算的常用方法,然而RMR法和Q法对质量较差的岩体不太实用,而RMi法是一种既适用于软岩又适用于硬岩的岩体质量评价和参数估算方法。本文在介绍RMi法基本原理的基础上,对贵州省鱼简河水库坝基岩体变形模量进行确定。 相似文献
283.
ZHUWenbin MARuishi GUOLingzhi SUNYan XUMingjie HUDezhao 《大地构造与成矿学(英文版)》2003,27(1):179-190
The central structure belt in Turpan-Hami basin is composed of the Huoyanshan structure and Qiketai structure formed in late Triassic-early Jurassic, and is characterized by extensional tectonics. The thickness of strata in the hanging wall of the growth fault is obviously larger than that in the footwall, and a deposition center was evolved in the Taibei sag where the hanging wall of the fault is located. In late Jurassic the collision between Lhasa block and Eurasia continent resulted in the transformation of the Turpan-Hami basin from an extensional structure into a compressional structure, and consequently in the tectonic inversion of the central structure belt of the Turpan-Hami basin from the extensional normal fault in the earlier stage to the compressive thrust fault in the later stage. The Tertiary collision between the Indian plate and the Eurasian plate occurred around 55Ma, and this Himalayan orogenic event has played a profound role in shaping the Tianshan area, only the effect of the collision to this area was delayed since it culminated here approximately in late Oligocene-early Miocene. The central structure belt was strongly deformed and thrusted above the ground as a result of this tectonic event. 相似文献
284.
LIUZhifei WANGChengshan AlainTRENTESAUX ZHAOXixi YIHaisheng HUXiumian JINWei 《《地质学报》英文版》2003,77(4):504-513
Sedimentological, cyclic-stratigraphic, paleomagnetic, and clay-mineralogical studies on the early Oligocene Yaxicuo Group in the Hoh Xil Basin, the largest Cenozoic sedimentary basin in the hinterland of the Tibetan Plateau, provide abundant information of paleoclimate changes. A 350-m thick section in the middle-lower Yaxicuo Group was analyzed to reveal the climatic history that occurred in the Hoh Xil region during the early Oligocene interval 31.30-30.35 Ma, dated with the paleomagnetic chronostratigraphy. The results indicate that add and cold climate dominated the Hoh Xil region during the early Oligocene in general, being related to the global cooling and drying events that occurred in the earliest Oligocene. Within this period, relatively warm and wet climate accompanied by strong tectonic activity occurred in the 31.05-30.75 Ma interval; while add and cold climate and relatively inactive tectonics occurred in the 31.30-31.05 and 30.75-30.35 Ma intervals. Furthermore, spectral analyses of high-temporal resolution paleoclimatic records show orbital periods including eccentricity, obliquity, and precession. It is concluded that paleoclimate changes during the early Oligocene in the Hoh Xil region were forced by both tectonic activity and orbital periods. 相似文献
285.
Despite growing evidence for environmental oscillations during the last glacial–interglacial transition from high latitude, terrestrial sites of the North Pacific rim, oxygen-isotopic records of these oscillations remain sparse. The lack of data is due partially to the paucity of lakes that contain carbonate sediment suitable for oxygen-isotopic analysis. We report here the first record of oxygen-isotopic composition in diatom silica (δ18OSi) from a lake in that region. δ18OSi increases gradually from 19.0 to 23.5‰ between 12,340 and 11,000 14C yr B.P., reflecting marked climatic warming at the end of the last glaciation. Around 11,000 14C yr B.P., δ18OSi decreases by 1.7‰, suggesting a temperature decrease of 3.5–8.9 °C at the onset of the Younger Dryas (YD) in southwestern Alaska. Climatic recovery began ca. 10,740 14C yr B.P., as inferred from the increase of δ18OSi to a maximum of 23.9‰ near the end of the YD. Our data reveal that a YD climatic reversal in southwestern coastal areas of Alaska occurred, but the YD climate did not return to full-glacial conditions. 相似文献
286.
Development of Geological Data Warehouse 总被引:2,自引:0,他引:2
LiZhenhua HuGuangdao ZhangZhenfei 《中国地质大学学报(英文版)》2003,14(3):261-264
Data warehouse (DW), a new technology invented in 1990s, is more useful for integrating and analyzing massive data than traditional database. Its application in geology field can be divided into 3 phrases: 1992-1996, commercial data warehouse (CDW) appeared; 1996-1999, geological data warehouse (GDW) appeared and the geologists or geographers realized the importance of DW and began the studies on it, but the practical DW still followed the framework of DB; 2000 to present, geological data warehouse grows, and the theory of geo-spatial data warehouse (GSDW) has been developed but the research in geological area is still deficient except that in geography. Although some developments of GDW have been made, its core still follows the CDW-organizing data by time and brings about 3 problems: difficult to integrate the geological data, for the data feature more space than time; hard to store the massive data in fifferent levels due to the same reason; hardly support the spatial analysis if the data are organized by time as CDW does. So the GDW should be redesigned by organizing data by scale in order to store mass data in different levels and synthesize the data in different granularities, and choosing space control points to replace the former time control points so as to integrate different types of data by the method of storing one type data as one layer and then to superpose the layers. In addition, data cube, a wide used technology in CDW, will be no use in GDW, for the causality among the geological data is not so obvious as commercial data, as the data are the mixed result of many complex rules, and their analysis needs the special geological methods and software; on the other hand, data cube for mass and complex geo-data will devour too much store space to be practical. On this point, the main purpose of GDW may be fit for data integration unlike CDW for data analysis. 相似文献
287.
288.
利用2000年6月1日~8月11日北京地区地基全球定位系统(Globe Positioning System)网遥感大气总水汽量试验的观测资料,分析了北京地区夏季大气总水汽量的时空变化,研究了大气总水汽量与日平均温度、地面水汽压和降水的关系.研究结果表明:大气总水汽量存在明显的时空变化,对于地理位置基本相近的台站,海拔高度的影响比较明显,一般情况下高山站的水汽总量低于平原站;在晴天,地面水汽压与大气总水汽量有较好的相关性,而在云雨日,由于高低层大气湿度的变化常常不同步,用地面水汽压估算的大气总水汽量具有较大的偏差;大气总水汽量短时间内的快速增加往往对应有降水过程出现,但总水汽量的大小与降水量之间并没有明显的相关,在降水预报中应综合考虑总水汽量的前期平均水平、短时的增幅和峰值大小等条件的影响. 相似文献
289.
290.