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971.
AbstractDuring the past 50 years, many geological and ore-deposit investigations have led to the discovery of the Fe–P–(Ti)-oxide deposits associated with mafic–ultramafic–carbonatite complexes in the Kuluketage block, northeastern Tarim Craton. In this paper, we discuss the genetic and ore-forming ages, tectonic setting, and the genesis of these deposits (Kawuliuke, Qieganbulake and Duosike). LA-ICP-MS zircon U–Pb dating yielded a weighted mean 206Pb/238U ages of 811?±?5?Ma, 811?±?4?Ma, and 840?±?5?Ma for Kawuliuke ore-bearing pyroxenite, Qieganbulake gabbro and Duosike ore-bearing pyroxenite, respectively. The CL images of the Kawuliuke apatite grains show core–rim structure, suggesting multi-phase crystallisation, whereas the apatite grains from Qieganbulake and Dusike deposits do not show any core–rim texture, suggesting a single-stage crystallisation. LA-ICP-MS apatite 207Pb-corrected U–Pb dating provided weighted mean 206Pb/238U ages of 814?±?21?Ma and 771?±?8?Ma for the Kawuliuke ores, and 810?±?7?Ma and 841?±?7?Ma for Qieganbulake and Duosike ores, respectively. The core–rim texture in apatite by CL imaging as well as two different ore-forming ages in the core and rim of the apatite indicate two metallogenic events for the Kawuliuke deposit. The first metallogenic period was magmatic in origin, and the second period was hydrothermal in origin. The initial ore-forming age of the Kawuliuke Fe–P–Ti mineralisation was ca 814?Ma and the second one was ca 771?Ma. On the other hand, the ore-forming ages of the Qieganbulake and Duosike deposits were ca 810?Ma and ca 841?Ma, respectively. Qieganbulake and Duosike deposits were of magmatic origin. Combined with previous geochronological data and the research on the tectonic background, we infer that the Kawuliuke, Qieganbulake and Duosike Fe–P–(Ti)-oxide deposits were formed in a subduction-related tectonic setting and were the product of subduction-related magmatism. 相似文献
972.
Employing long‐range correlation, complexity features and clustering, this study investigated the influence of dam and lake‐river systems on the Yangtze River flow. The impact of the Gezhouba Dam and the lake systems on streamflow was evaluated by analysing daily streamflow records at the Cuntan, the Yichang and the Datong station. Results indicated no evident influence of the Gezhouba Dam on streamflow changes. Distinct differences in scaling behaviour, long‐range correlation and clustering of streamflow at the Datong station when compared with those at the Cuntan and Yichang stations undoubtedly showed the influence of water storage and the buffering effect of the lake systems between the Datong station and other two hydrological stations on streamflow in the lower Yangtze River basin. Decreased regularity, enhanced long‐range correlation and increased clustering of streamflow in the lower Yangtze River basin due to the effect of water storage of the lake systems were corroborated. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
973.
974.
丹霞风景名胜区的旅游开发研究 总被引:14,自引:5,他引:14
本文以丹霞地貌、区域文化开发、景观美学、景观资源的保护和利用、旅游业开发等专题研究及区域旅游发展战略理论研究为基础,与风景旅游规划相结合,研究了自然景观和人文景观、景观资源综合评价和旅游开发总体规划等问题。据此研究成果上报,该风景区已被批准为第二批国家重点风景名胜区。 相似文献
975.
Mineralogy and geochemistry of a stratabound manganese deposit in the Tangganshan region of South China 总被引:1,自引:0,他引:1
The Tangganshan manganese ore deposit is a typical sedimentary-magmatic hydatopneumatogenic superimposed ore deposit. In this
paper this deposit is discussed in more detail from the following aspects: geology, ore mineralogy, and geochemistry. On the
basis of its occurrence, mineral assemblage, element geochemistry, isotopic geochemistry, and characteristics of organic matter
and fluid inclusions, the Tangganshan manganese ore deposit has proved to be a new-type manganese ore deposit that has been
enriched by magmatic-pneumatolic solutions. Most of the ore-forming elements were derived from the ore deposit itself, and
the rest from the magmatic-pneumatolitic solutions. 相似文献
976.
W. Chen 《Mineralium Deposita》1988,23(4):262-267
Mesozoic and Cenozoic sandstone-hosted copper deposits in South China are confined to the variegated rock formation of the faulted basins, the intermontane basins and piedmont basins around a copper-bearing old land. The variegated rock formation is generally of fluviolacustrine delta facies, shore facies and shore-cauce facies. The ore bodies are stratiform, occurring in the light-coloured beds of the variegated rock formation. The mineralization comprises chalcocite, bornite, chalcopyrite, native copper, covellite, pyrite and hematite, showing obvious zonation. The associated profitable elements in the ore are mainly silver, lead, zinc, molybdenum, selenium and uranium. The copper deposits are believed to have been formed through three processes of enrichment, i.e. weathering (copper-bearing weathered crust was formed as a result), deposition (source bed formed) and diagenesis (ore body formed). The variegated rocks with Cu, Ag, Pb, Zn, U, Mo, Cl and organic carbon anormalies and a great deal of pyrite, distributed in the faulted basins around the Cu-bearing old land, are recognized as the most favourable area for copper ore exploration. 相似文献
977.
本文研究了从5L水中用铁、铅、钡和铈作载体,系统分析~(234)U、~(238)U、~(228)Th、~(230)Th~(232)Th、~(224)Ra、~(226)Ra、~(228)Ra和~(210)Pb的含量或比值。铀、钍经Fe(OH)_3沉淀富集后用TBP萃淋树脂柱分离,用激光荧光和比色法测定,同位素比值用α谱仪测量,化学回收率在90%以上,测量下限分别为1μg/L和3μg/L。镭、铅经硫酸盐沉淀富集后,用EDTA在不同pH条件下分离,~(224)Ra和~(226)Ra用射气法测定,~(228)Ra和~(210)Pb分别用其β子体~(228)Ac和~(210)Bi在低本底β装置上测量,测量下限分别为2.5×10~(-2)、8×10~(-3)、4×10~(-3)和5×10~(-3)Bq/L。 相似文献
978.
979.
在1981年7月12日和13日,川西地区普降暴雨,井研县天云公社附近从7月12日夜间10时至7月13日午后6时,降雨量达到135毫米,可称为大暴雨。在井研县天云公社,1981年7月13日11时30分发生了一次地面沉陷(由降雨引起)。这次沉陷有明显的热异常前兆,沉陷后又出现了低温异常。 相似文献
980.
ON SOME KEY SEDIMENTATION PROBLEMS OF THREE GORGES PROJECT (TGP) 总被引:1,自引:0,他引:1
Lin Bingnan Dou Guoren Xie Jianheng Dai Dingzhong Chen Jisheng Tang Richang Zhang Ren 《国际泥沙研究》1989,(1)
I. INTRODUCTIONThe Three Gorges Project (TGP) being planned is to be located on the Yangtze River at Sandouplug, 44 km upstream of Yichang (Fig. l). A scheme studied in the feasibility stage has the crest ofthe dam placed at 185 m with a maximums height o… 相似文献