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81.
When, where and from which hominoid the human originated has been one of the key subjects in the study of human natural history. It is therefore very important to learn the chronological, geographical and taxonomic distribution of all hominoids. Yunnan Pr…  相似文献   
82.
In order to understand the effect of different land use on soil physics and nutrients properties of the debris flow bottomland, a case study at Daqing gully (in Xiaojiang Basin, Yunnan) was conducted in 2004. Soil samples were taken at depth of 0-10,10-20,20-40,40-60,60-80 cm under three land use patterns crop bottomland (CL), forest bottomland (FL), and barren bottomland(BL). The results showed that the developing bottomland to CL promoted soil toaccumulate total phosphorus (TP) and available phosphorus (AP), pH value transferred from neutral to alkalescency, and organic matter decreased significantly. Furthermore, the contents of total nitrogen (TN) and available nitrogen (AN) in CL were lower than that of FL and BL because the growth of crops consumed more nutrients in soil. The results also showed that the contents of TP, AP and available potassium (AK) in soil were positively correlated with soil particle.  相似文献   
83.
柴西南区古近系层序地层特征及岩性圈闭发育模式   总被引:1,自引:0,他引:1  
应用层序地层学理论,利用地震、钻井和测井资料,对柴西南地区古近系层序地层框架进行系统分析.古近系处在以中新统内不整合面(T2′)和古新统合新生界之间的不整合面(TR)为顶底界的二级层序中,共发育有3个三级层序:即路乐河层序(SA)、下干柴沟层序(SB)和上干柴沟层序(SC).重点分析了下干柴沟层序及上干柴沟层序,认为下干柴沟层序由3个体系域组成:即低位体系域、湖侵体系域及高位体系域.上干柴沟层序由于低位体系域不发育,故将其划分为湖侵体系域和湖退体系域两个体系域.另外,分析了柴西南地区不同的体系域中岩性圈闭可能发育位置,并且建立了隐蔽圈闭的分布模式.  相似文献   
84.
结合黄河流域水生态的现状,分析了影响当今水生态环境问题的自然和人为因素,提出了保护黄河流域水生态环境的对策。  相似文献   
85.
鄂尔多斯盆地北部下石盒子组 -山西组是天然气的重点勘探层位 ,根据薄片研究、阴极发光显微镜研究、粘土矿物分析、同位素分析 ,对鄂尔多斯盆地北部下石盒子组 -山西组的岩石学特征和成岩作用进行了分析 ,认为研究层位的岩石类型主要为岩屑砂岩 ,少量的长石岩屑砂岩。储层砂岩的成岩作用主要有长石的高岭石化、压实作用、自生矿物的形成作用、胶结作用及交代作用。最后根据成岩作用的特征 ,建立了研究区储层砂岩的成岩演化序列  相似文献   
86.
在综合研究野外露头、钻井剖面及室内编图、地层对比的基础上 ,指出鄂尔多斯盆地冲积扇 -河流沉积体系是侏罗纪富县期主要的古地理格局 ,富县期沉积受与古地貌密切相关的五条河谷控制。认为鄂尔多斯盆地侏罗纪富县期冲积扇沉积具进积型特征 ,其形成与古地形密切相关 ,分布于古甘陕、庆西河谷内  相似文献   
87.
羌塘盆地构造单元划分及含油气远景评价   总被引:11,自引:0,他引:11  
对14条近4000km的大地电磁测探资料进行了一维及二维连续介质反演,根据反演结果及地面地质资料解释确定了侏罗系、上三叠统底界面海拨高度图以及前泥盆系顶界面海拔高度图,并根据以上研究结果以及地质资料对羌塘盆地进行了构造单元划分以及含油气远景评价。  相似文献   
88.
The analysis of the flux observation dada from the Huaihe River Basin Experiment (HUBEX) shows that, in semi-humid monsoon regions, latent heat flux is as important as sensible heat flux in most situations. Moreover, it can even dominate the sensible heat flux in cropland and paddy field. This is distinct from that for arid and semi-arid regions where the sensible heat flux is dominant. Under clear sky conditions, the soil temperatures in different vertical layers all exhibit certain diurnal variations, and the magnitude decreases with depth to less than 1°C at a depth of 60 cm. This depth is considered as the transition layer for the soil moisture variation. On the other hand, the vertical profile of soil water content varies with the soil texture and even weather conditions, and the layer with maximum soil water content can also be found in Jiangji station during June 1998.  相似文献   
89.
Based on detailed studies, this paper proposesthat in the Tarim Basin, hydrocarbon reservoirs widespreadeither in vertical sequences or in plane and high-porosity andhigh-permeability reservoirs are developed all over the basin.However, obvious difference and heterogeneity exist amongdifferent kinds of reservoirs. The lithologic characteristics,reservoir space types and reservoir properties in variousstrata have been probed. The result indicates that althoughthe Paleozoic carbonates have been deeply buried for a longperiod, high-quality reservoirs with the porosity of up to 5%—8% (12% as the maximum) and the permeability of10×10-3—100×10-3 μm2 (1000×10-3 μm2 as the maximum)can be found in certain areas. These include the area withthe development of reefs and carbonate beaches, the weath-ered-crust buried-hill belts that have undergone thelong-term exposure, weathering and leaching, the area withthe development of dolomitization, and those areas that haveexperienced the resolution of carbonic acid and organic acidgenerated by the maturity of the organic matter. Finally, thegenesis of the high-porosity and high-permeability reservoirsin deep-buried conditions (with the depth more than 3500 m)have been investigated thoroughly.  相似文献   
90.
<正> Based on the analyses of hydrocarbon inclu-sions, K-Ar dating of authigenic illites and oil/gas-watercontact retrospection as well as other methods, the marineprimary reservoirs in the cratonic region of the Tarim Basinare found to have been formed in the late Caledonian toearly Hercynian, late Hercynian, and Himalayan, and oil andgas adjusted and redistributed in the Yanshanian (Jurassic toCretaceous) and Himalayan (Tertiary). The analyses alsoshow that the remaining primary oil accumulations aremostly formed in the late Hercynian, and the secondary oilreservoirs resulted from the adjustment and redistribution ofthe earlier accumulations during the Yanshanian and Hima-layan (especially late Himalayan), of which the Himalayan isalso the major stage of gas accumulation. The primary oilreservoirs formed in the late Hercynian mostly occur withinthe Paleozoic formation, whereas the secondary reservoirsformed in the Himalayan in the Mesozoic. The late adjust-ment and redistribution of reservoirs in the craton region ofthe Tarim Basin is ubiquitous because of the intensified tec-tonic movements since the Mesozoic, especially Cenozoic andintrusion of the high- to over-mature gas. Furthermore, thelower amplitude of reservoirs in the craton region also makesthem easier to be adjusted and redistributed. Therefore, theremaining paleo-uplift and palaeo-slope developed in rela-tively stable tectonic regions are the main potential areas forthe middle-large marine reservoirs in the Tarim Basin.  相似文献   
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