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Apatite fission-track thermochronology data elucidate the cooling/exhumation history of the Qinling (Qin Mountains), which contain a Paleozoic-Mesozoic orogenic collage north of the Sichuan Basin and northeast of the Tibetan Plateau. In particular, we examine the extent to which the Qinling were affected by the rising plateau. The northern and eastern Qinling show continuous cooling and slow exhumation since the Cretaceous. In contrast, in the southwestern Qinling, rapid cooling initiated at 9-4 Ma, a few million years later than in the eastern Tibetan Plateau. A compilation of major Cenozoic faults in the eastern Tibetan Plateau and the Qinling, and their kinematic and dynamic characterization, shows that deformation in the Qinling has predominantly been strike slip. Active sinistral and dextral strike-slip faults delineate an area of eastward rock flow and bound the area of rapid late Cenozoic cooling outlined by apatite fission-track thermochronology. These data can be interpreted to indicate that lower crustal flow has been diverted around the Longmen Shan and beneath the southwestern Qinling, causing active plateau uplift in this area. Alternatively, northeastern Tibet may be growing eastward faster in the western Qinling than the entire South China Block is extruding to the east. Keywords: Tibet, Qinling, plateau growth, fission track, structural geology,

It is difficult to study solid bitumen because of the complexity of bitumen component and the variability of formation mechanism and influencing factor. It is very important that a lot of thick-layer anthraxolites from Tanjianshan Group in Lianhegou area, the northern of Qaidam Basin were discovered. Through field geological survey, organic geochemical analysis and basin simulation, the spatial distribution, geoehemical characteristics and origin of anthraxolite were discussed. The results show that anthraxolite is distributed in sandstone and limestone of member a of Tanjianshan Group with NW-SE trend; contents of chloroform asphalt "A" are low in anthraxolite, contents of saturated and aromatic hydrocarbons are also low in group component, but contents of non-hydrocarbon and asphaltene are high; carbon isotope compositions of saturated and aromatic hydrocarbons are light, and anthraxolite is at the stage of over-maturity with the equivalent vitrinite reflectance of 3.74%-4-72%; gas chromatogram of saturated hydrocarbon has single peak and odd carbon preference at the range of high carbon number; according to the oil-rock correlation, anihraxnliie is not comparable with Carboniferous and Jurassic hydrocarbon source rocks. but is comparable with mudstone from member a of Tanjianshan Group, the origin of anihraxolite is related to Late Devonian and Early Permian magmatic intrusion events, which make crude oil generated by hydrocarbon source rock to heavy oil, bitumen and even anthraxolite. [ABSTRACT FROM AUTHOR]

There is great exploration potential of natural gas in the western Qaidam Basin, however the gas generation depressions, major source rocks and critical moment of gas accumulation are not clear, and the present situations restrict the gas exploration process. The Paleogene and Neogene three-dimensional geological model for western Qaidam Basin was established by using the software PetroMod, which is most widely used in the petroleum system simulation. After entering the relevant parameters and running the program, the following maps were obtained, such as maturity distribution the gas generation intensity of each source rock, gas migration directions and gas-generation quantity. According to the above maps, it is determined that the major source rocks are the upper member of the Lower Ganchaigou Formation (E23) and the Upper Ganchaigou Formation (N1). It is also pointed out that the distribution of natural gas is controlled by the source rock maturity and the natural gas is located in the mature and high mature source rock area, and main gas-generation depressions are Hongshi, Xiaoliangshan and eastern Mangya Depressions. Structural high parts around the depressions are the gas migration directions, and the main gas generation periods are Quaternary (Q1+2) and Late Pliocene (N32) and the critical moment is at the end of N22. On the basis of the above research, favorable zones for natural gas distribution can be predicted that the Shizigou-Youshashan-Yingdong-Dawusi, Youquanzi-Kaitemilike-Youdunzi, and Xiaoliangshan-Nanyishan-Dafengshan structural belts are favorable zones for natural gas accumulation. [ABSTRACT FROM AUTHOR]