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851.
Cenomanian-lower coniacian radiolarian assemblages from the Naiba reference section (Sakhalin) 总被引:2,自引:2,他引:0
L. G. Bragina 《Stratigraphy and Geological Correlation》2008,16(5):503-514
Reexamination of radiolarians from the Naiba and Bykovo formations of the Naiba reference section (West Sakhalin Mountains) is carried out. Distinguished in the section are the Cromyomma (?) nodosa-Amphipyndax sp. A (terminal early Cenomanian), Cuboctostylus kasinzovae-C. sakhalinensis (Middle Cenomanian), Cuboctostylus trifurcatus-Cassideus yoloensis (terminal middle-late Cenomanian), and Spongodiscus concentricus-Multastrum robustum (late Turonian to early Coniacian probably) assemblages. According to results of comparative analysis for North Pacific regions, concurrent radiolarian assemblages from the Naiba section and California contain up to 40% of species in common, whereas taxonomic similarity with assemblages from Japan is insignifican in contrast. 相似文献
852.
853.
G. L. Sivakumar Babu Satyanarayana Murthy Dasaka 《Geotechnical and Geological Engineering》2008,26(1):37-46
The effect of directional behaviour of correlation structure of cone tip resistance on the bearing capacity of shallow strip
footing resting on cohesionless soil deposit in 2-D random field is analysed using probabilistic approach. The results obtained
from the analysis show that the assumption of perfect (or infinite) correlation of cone tip resistance data leads to lower
values of probability of failure. In contrast, the isotropic assumption of correlation behaviour based on vertical scale of
fluctuation leads to higher values of probability of failure. The results also show that the transformation model would play
a major role in the evaluation of variability of design property. In conclusion, the need for a proper evaluation methodology
for calculation of correlation lengths of soil properties and their influence in foundation design is highlighted. 相似文献
854.
A petrographic study of 157 samples from the Early to Middle Eocene deep-marine sandy systems, Ainsa–Jaca basin, Spanish Pyrenees, shows that each system has a characteristic petrofacies. Three main petrofacies are recognized. Petrofacies 1 sandstones comprise mainly siliciclastic grains (≥80%), subordinate terrigenous carbonate grains and negligible intrabasinal grains. Petrofacies 2 hybrid arenites are characterized by significant amounts (≥10%) of intrabasinal carbonate grains. Petrofacies 3 calcilithites contain relatively abundant (≥10%) extrabasinal carbonate grains. On the basis of these petrofacies, a revised correlation of the sandy systems is proposed between the more proximal Ainsa basin, and the more distal Jaca basin sediments, now separated by the Boltaña anticline, across which it is impossible to actually trace out individual beds or sandstone packages between both basins. The arenite composition in the Ainsa and Jaca basins is interpreted as being controlled mainly by synsedimentary tectonic processes that led to changes in sediment sources during basin evolution. 相似文献
855.
在焦家金矿区地球化学测量的基础上,通过对不同矿化区段地球化学异常结构的因子分析,探讨矿致异常的元素组合特征.认为不同矿化区段公因子都为典型的热液矿床元素组合,其中成矿地段公因子变量数较少且相关性较大,公因子具有很强的代表性,而非矿化地段公因子中则变量相对较多,因子载荷较小;Co,Ni为典型的深源代表组分,仅在矿化地段表现为独立因子,且与主因子表现为明显的负相关;金元素在矿化地段各因子上均具有一定载荷,但集中分布在两个主因子上,而且与As,Hg,Ag,Pb元素的相关性较大,因此F1因子基本代表了矿化公因子的元素组合,是成矿预测最有效的指示标志. 相似文献
856.
The geochemical characteristics and origin of crude oils in the Kekeya Oilfield,Xinjiang, China 总被引:2,自引:2,他引:0
GC/MS and GC/MS/MS techniques were employed to describe the characteristics of biomarker assemblages in two sets of hydrocarbon source rocks, Jurassic and Permian, in southwestern Tarim, and the parameters for the classification of the two sets of hydrocarbon source rocks have been established. It is found that diahopane and C30-unknown terpane are abundant in Permian samples, the contents of diahopane in Jurassic samples are relatively low, and terpenoids have been detected in Jurassic samples but not in Permian source rock samples. Kekeya crude oils are abundant in diahopane and C30-unknown terpane. The results of fine oil-rock correlation indicated that Kekeya crude oils were derived mainly from the Permian hydrocarbon source rocks. However, a small amount of diterpenoid was detected in the crude oils, indicating that the Jurassic hydrocarbon source rocks also made a certain contribution to Kekeya crude oils. 相似文献
857.
The Occurrence of Oleananes in the Beibuwan Basin and Its Application to the Study of Maturity and Oil-Source Rock Correlation 总被引:3,自引:0,他引:3
LI Meijun WANG Tieguan State Key Laboratory of Petroleum Resource Prospecting Earth Sciences Geoinformatics School China University of Petroleum Beijing China LIU Ju ZHANG Meizhu MA Qinglin GAO Lihui Southern Oil Exploration Development Company PetroChina Guangzhou China LU Hong Guangzhou Institute of Geochemistry Chinese Academy of Sciences Guangzhou China 《《地质学报》英文版》2008,82(3):585-595
The oleanane parameter, i.e., OP (oleananes/(oleananes+C30hopanes)) in the two sedimentary columns of the Beibuwan Basin, South China Sea, can be used to delimit the top of oil generation window, with Ro (/%) of 0.53 in Well M1 and 0.55 in Wells H1/Hd1/Hd2, respectively. Comparing with vitrinite reflectance (Ro/%), the OP features a dynamic range and can indicate the oil generation window more precisely. By using OP and other geochemical indices, the oil-source correlation is also conducted. It suggests that the oils in wells M1 and M2 are derived from the source rocks in situ. The mudstone in Huachang uplift is not the main source rocks for oils in this area, The OP is also a useful oil-source correlation parameter in some Tertiary lacustrine basins. 相似文献
858.
结合地理国情监测与1∶50 000地形数据库更新的各作业工序,将可协同作业的部分提炼出来,以期为两个项目的顺利开展提供技术支撑。 相似文献
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860.