Abstract:Basic volcanic rocks from Ke-Xia region of northwestern Junggar Basin were inves tigated systematically in such aspects as petrology, mineralogy, trace elements and Nd-Sr-Pb isotope geochemistry. Ke-Xia basic volcanic rocks belong to tholeiitic series and are characterized by low abundance of Ti, poor REE, slight enrichment of LREE, and significant enrichment of LILE relative to HFSE in the spider diagram, consistent with features of island arc tholeiitic melts. Ke-Xia basic volcanic rocks have positive εNd（t)(+7.2～+7.4), low values of （87Sr/86Sr)i(0.703717～0.704520) and HFSE/LILE, and steeper 206Pb/204Pb 207Pb/204Pb correlation gradient than that of MORB and OIB. These data show that Ke-Xia basic volcanic rocks might have been generated from the high-degree partial melting of depleted lithosphere mantle wedge above the subducted oceanic plate in the oceanic island arc, genetically related to the subduction of oceanic crust of western Junggar. It is thus consi_dered that the western Junggar arc-basin system extends eastward into the Jungaer Basin, and that the basement crust in northwestern Junggar Basin is a island arc type accreted block formed by ocean-continent collision.

Abstract:Several types of granites are distributed in Karamaili area of East Junggar, Xinjiang, which constitutes an important tin metallogenic zone.Biotite granites there have long been thought to be of S-type. Nevertheless, the study conducted by the authors shows that biotite granites in Sujiquan are actually typical aluminous A-type granites characterized by enrichment of LILE (such as Rb, K) and HFSE (such as Zr, Hf) as well as high FeO*/MgO and 10?000 Ga/Alratios. These features are obviously different from those observed for I- and S- type granites. Zircon U-Pb dating by LA-ICPMS shows that they were emplaced atabout 304±2Ma, close to the formation time of alkaline granites but later than the emplacement of calc-alkaline granitoids in this area. Although these biotite granites possess high εNd(t) values, they were not derived directly from a depleted mantle, but were most likely formed by partial melting of mantle-derived juvenile crustal materials which were subjected to deep burial and magmatic fractional crystallization. Trace element tectonic discriminant diagrams for granites reveal that biotite granites belong to post-collision granitoids, which marked the end of orogenic movement and the beginning of the intraplate evolution in Karamaili of East Junggar in late boniferous.

Abstract:Sangba granitoids are exposed near Sangba and Jianduo areas to the north of Jiali fault in Gangdese tectonic belt. The main rock types include granitite, porphyritic granitite and porphyritic granodiorite. The SHRIMP UPb dating results of zircons from porphyritic granodiorite (TW1530) and granitite (TW1637) are 117.2±1.6 Ma and 121.2±1.7 Ma, respectively, suggesting that Sangba granitoids were formed in early Cretaceous. Sangba granitoids belong to high K and calcalkalic rocks. According to geochemistry and the trace element discrimination diagrams for tectonic interpretation, the early Cretaceous granitoids are considered to be of the postcollision type formed in a transitional tectonic setting from the compressional system to the tensional system. The appearance of the early Cretaceous Sangba granitoids marked the end of the main orogenicevent in BangonghuNujiang suture. From early Cretaceous, Gangdese tectonic belt entered the tensional stage until the deposition of Jingzhushan Formation inlate Cretaceous.

Abstract:More than ten mafic-ultramafic intrusions are distributed in Kuwei area of the Altay orogenic belt, and the Kuwei intrusion is the biggest one in this area. The SHRIMP U-Pb zircon dating yields an age of 47±1 Ma, suggesting thatstrong uplift occurred in this area during Cenozoic. Compared with the mafic-ultramafic instrusions in other areas of the Altay Mountains, the Kuwei intrusion has some unique geochemical features in that it is characterized by low TiO2, REE and incompatible element contents, and high Al2O3 contents. The wide range of MgO contents (6.6%～20.1%) and the correlation between MgO contents, othermajor element [CM(46]contents and Ni contents imply that the fractional crystallization of olivine, orthopyroxene and clinopyroxene might have occurred. Its low REE and incompatible element contents, flat chondrite_normalized REE patterns and incompatible element ratios (e.g., La/Sm and Gd/Yb) indicate that the primary magma resulted from the high degree of melting of the depleted asthenospheric mantle (garnet peridotite). In addition, its high La/Nb ratios and the markedly positive Pb anomalies in the primitive mantle normalized trace element patterns suggest that the magma must have been subjected to the contamination of low crust materials in the magma chamber. The relatively low Ni contents probably resulted from the immiscible sulfide melt at a relatively deep level.

Abstract:Based on a detailed structural analysis and a preliminary study of major and rare earth elements in a suite of undeformed granites, mylonitized granites and leucogranitic dikes within the Yunmeng Mountains of northeastern Beijing, the authors have reached some conclusions: with increasing shear strain, SiO-2 decreases whereas Al_2O_3,TiO-2,H-2O,and LREE increase in mylonitized granites; compared with the undeformed granite, the leucogranitic dikes have lower LREE and P-2O-5 contents and (La/Gd)-N ratios, but elevated Sm/Nd ratios; and the REE distribution patterns of the mylonitized granites are parallel to the pattern of the undeformed granite, whereas the HREE distribution pattern of leucogranitic dike BH-2-5 and BH-2-6 is similar to that of the undeformed granite; the REE distribution pattern of BH-2-3 differs however from the patterns of all the other samples. The major and rare earth element geochemistry of BH-2-3 suggests that it was derived from partial melting of ancient metamorphic rocks. In such partial melting reactions, accessory phases that concentrated LREE like monazite occurred as residue phases, which resulted in extremely low LREE and P-2O-5 contents and elevated Sm/Nd ratios in the melts. The other two leucogranitic dikes may represent the latest crystallization differentiation product of the Mesozoic Yunmeng Mountain granites. The increasingly intense crystallization differentiation of a granitic magma resulted in the elevated SiO-2 and lowered LREE contents as well as the variation of Sm/Ndratios in the final silica saturated products .

Abstract:A series of prolonged granitic intrusions occur along the foliation of the Longquanguan ductile shear zone. Petrological and structural characteristics show that they are possibly syn-deformational granites resulting from partial melting of the country rock caused by shearing. The electronic microprobe dating of monazites from these granites shows that the major deformation episode took place at 1 877-1 846 Ma, the second deformation episode occurred at 1 812- 1 782 Ma, and the fluid activities happened in the late stage at about 1 725 Ma. The major deformation of the Longquanguan ductile shear zone occurred synchronously with the tectonic events in the central zone of the North China craton in the Late Paleoproterozoic, and this shear zone seems to have been one of the main shear zones formed by the collision of eastern and western blocks.

Abstract:The application of detrital geochemistry to determining tectonic setting and provenance attribute is an important means for basin analysis and also a helpful supplementary or verification method in using coarse detrital rocks to judge the background of provenance. Geochemical characteristics of 36 Tertiary mudstone samples from Kuqa depression show that the content of CaO is very high, which can somewhat dilute other major elements, trace elements and rare elements. Some reliable indicators for provenance analysis show the source rock nature of noncarbonate sediments. The REE distribution pattern is similar to that of the upper continental crust, characterized by enrichment of LREE and negative Eu anomalies. Some trace element ratios show that the source rocks are mainly felsic. According to K2O/Na2O-SiO2, La-Th - Sc and Th - Sc - Zr/10 discrimination diagrams, the tectonic setting of the provenance is similar to that of island arc. This result is different from the former research result on sandstones, suggesting that there exist specific characteristics between the orogenic inner plate and its foreland basin in sedimentary and tectonic coupling.

Abstract:The low reservoir productivity of Paleogene Shasan Member in Beitang sag is mainly attributed to its bad reservoir character. Based on large quantities of core and other geological data, the authors systematically discussed sedimentation, main reservoir characteristics of Shasan Member and the affecting factors. Sedimentary facies of Shasan Member in the study area are mainly fan delta deposition, gravity-slide deposition and lake deposition. The reservoirs belong to medium to bad reservoirs in size. Sedimentary facies, diagenetic actions such as compaction, cementation and dissolution, oil pool formation time, reservoir pressure and distribution of igneous rocks are major factors affecting the reservoir quality.

Abstract:Dongying depression is one of the most prolific hydrocarbon areas in China. The Paleogene stratum consists of underwater fan, littoral-shallow lacustrine and delta facies sandstones. Diagenesis and pore evolution have exerted great effects on the proporties of reservoir rocks. The study performed by the authors is of significance in finding favorable reservoir zones in Dongying depression. Many thin sections were analyzed by such means as standard petrographic microscope, X-ray diffraction and scanning electron microscope analysis so as to study the selected samples. Diagenetic complexity shows that compaction and cementation lead to decrease in porosity, whereas solution of unsteady minerals and carbonate cements result in increase in porosity. The evolution of organic materials and the sequence of clay minerals suggest that the diagenesis and the pore evolution of the sandstone in different structural belts varied obviously with the increase of the buried depth, and the reservoirs might be classified into three pore evolution zones, namely, the primary shallow pore zone, the primarysecondary transitional pore zone, and the secondary deep pore zone. The sandstones serve as well-developed secondary pore zones.

Abstract:Some samples were collected from Permian 10 th , 7 th and 3 rd coal seams in the Huaibei Coalfield, and the contents of 42 elements were determined by the instrumental neutron activation analysis (INNA). The distribution and variation ranges of the elements in the samples were compared with those of the Carboniferous- Permian coal from North China and the Chinese coals, and the relationship between the elements and ashes, the association characteristics and the distribution patterns were analyzed. The results show that the elements Ba, Co, Cr, Cu, Mo, Th, V, W, Zn and Ti are relatively abundant in the coal field. There exists a positive correlation between Al, Ti, K, Na and ashes, but things are quite opposite for Ca, Mg and Fe. Almost all rare earth elements are in a positive correlation with the ash and have similar distribution patterns, characterized by obvious Eu negative anomalies. It is thus concluded that the sources of the associated elements are terrigenous materials.

Abstract:Infrared reflectance spectrometry is an old and traditional experimental method characterized by rapid, simple, convenient and nondestructive operation. Nevertheless, this method has not yet been fully developed and applied. The experimental means, reflectance spectra characteristics and application prospects of this method are given in this paper.

Abstract:At present, the extraction of the soluble organic matter is mainly applied to sedimentary rocks for exploring oil and gas. The contents of the soluble organic matter in UHP metamorphic rocks from CCSD are usually at the level of trace amounts. It is therefore very important to prevent pollution from drilling mud, sample preparation and processing analysis and to improve extraction efficiency. This paper has dealt with the removal of external contaminants, the improvement of the extraction efficiency by ultrasonic wash, Soxhlet extraction and ultrasonic extraction, and the elimination of pollution in core samples by comparing total ion chromatogram between the samples and the pollutants.