Abstract:Mafic dykes represent a possible event of crustal break-off and can constrain the time of land-rebuilding and dynamics in this area. The authors found rome unreported mafic dykes in the Qinling and Longshan Groups between the Qinling and the Qilian orogenic belts. A 440 Ma U-Pb age was measured for these dykes using zircon LA ICPMS, which indicates that a regional extension might have occurred in the Qinling and the Qilian orogenic belts. The data is very important in the study of the evolution and mineralization of the Qinling and the Qilian orogenic belts.

Abstract:Recently, a theory which considers that topaz may crystallize directly and mainly from the F_rich acid magma and/or the F-rich magmatic_hydrothermal transition fluid similar to magma in overall nature has given a vigorous challenge to the traditional ideas of single alteration origin for topaz. The high-ltrahigh-pressure metamorphic topaz has been reported time and again. On the basis of geological, geochemical and mineralogical characteristics of topaz-bearing rocks as well as related petrogenetic and metallogenic experimental data, a new petrogenetic and mineral-forming model for topaz has been established. The model does not negate the alteration and metamorphic origin of topaz. The authors hold that it is inadvisable to emphasize the role of metamorphism (including alteration) indiscriminately and exaggerate its ubiquity and its importance to petrogenesis and mineralization.

Abstract:In the process of 1:50000 geological survey for Hongling and two other sheets in Hongshishan area of the Beishan orogenic belt, the authors studied AR, NK/A, A/CNK and δEu values of Maanshanbei granite in the Beishan orogenic belt. Petrochemical and geochemical features all indicate that Maanshanbei granite is of the peraluminium to weakly peraluminium type in the transitional zone of calc-alkaline and K-high calc-alkaline series, with characteristics of the Sr-high granite. U-Pb dating of zircon from Maanshanbei granite_diorite yielded an average weighted 206Pb/238U age of (237.8±4.3) Ma. This isotope age of Maanshanbei granite-diorite-is of great significance in studying the tectonic evolution of Hongshishan area in the Beishan orogenic belt, Gansu Province.

Abstract:Based on geochemical characteristics and tectonic setting of intrusive rocks in Zhoukoudian complex and a comparison with adakites, the authors have revealed that these intrusive rocks are similar to adakites in petrological and geochemical characteristics. 143Nd/144Nd87Sr/86Sr diagram shows that the projections are in the EMⅠ-rich mantleregion, suggesting that their material sources are related to EMⅠ-rich mantle.Besides,εNd(t)I Sr figure proves that the projections are within granulites and pyroxenite xenoliths in Hannuoba basalts. Further research indicates that Zhoukoudian complex was formed by partial melting of young lower crust in the North China craton in Mesozoic

Abstract:Peperite is a special kind of volcaniclastic rock formed by the intermingling of magma with wet sediments. The formation of peperite is mainly controlled by the fuel-coolant interactions (FCI) or phreatomagmatism and the fluidization of the host sediments. Peperite usually occurs at the bottom and the frontal part of the lava flows and is also distributed around shallow intrusions. Based on the textures, the authors classified peperite in northwestern Hebei into two types, i.e., fluidal and blocky. The fluidal peperite is produced by the mingling of magma with fine sediments, while the blocky peperite is related to coarse sediments. Correct identification of the peperite is important in studying the chronology of magmatism and the evolution of basins.

Abstract:The saline lake is one of the most favorable environments for developing hydrocarbon source rocks. In this paper, a sample core from the Qinghai Lake was studied. Based on the relationship of the organic matter content and clay mineral content to the mineral surface area, the authors used the mineral component (or mineralogical phase) to analyze the preservation of organic matter in sediments. Organic matters from abundant terrigenous plants around the lake area composed mainly of microbes and algaes are very rich in the lake. The mineralogical phase indicates that clay minerals are up to 32.4% in sediments at the bottom of the Qinghai Lake, with illite being the main component part. Density fractionation reveals that organic matter content is closely relevant to clay mineral content and mineral surface area in the salified Lake, suggesting that clay mineral adsorption is the major mechanism in the preservation of organic matter in sediments of the Qinghai Lake.

Abstract:This paper has discussed composition characteristics and variation tendency of carbon and oxygen isotopes from carbonates in Dengying Formation. The δ13C values of the carbonates are between -2.11‰ and 2.71‰, andnegative anomalies are existent at the top and the bottom whereas the main part is relatively stable, with an insignificant decreasing tendency. The δ18O values are between -3.52‰ and -8.76‰, being relatively stable on the whole with a slight decreasing tendency from bottom to top. The composition characteristics and variation tendency are similar to those of the strata of the corresponding period in the world and hence have worldwide correlation significance. The variations of the isotopic content show that the sea level got lowered for a short span at the early stage of Dengying period and then became steady. At the end of Dengying period, the ocean environment in Jiangshan changed intensely, similar to things of the global paleoenvironment in the corresponding period.

Abstract:Pt-TiO-2 pillared clays were prepared by the Sol-gel method at a certain ratio of Ti(OC-4H-9)-4 to CH_3COOH modified by cationic surfactant cetyltrimethyl ammonium bromide (CTMAB). These composite catalysts were prepared by adding surfactant first, and then pillared with TiO-2 sol solution which was prepared in different Pt contents. Scanning electron microscopy (SEM), X-ray diffraction (XRD) and energy dispersive spectrometry (EDS) were used to investigate the texture of prepared catalysts, and their BET surface areas were also measured. The adsorption and photocatalytic performance of prepared pillared clays were studied by using methyl orange(MO) as a mode organic pollutant. The result indicated that the catalysts obtained layered struc-tures. And the different adsorptions with different contents of Pt were observed. Moreover,the conclusion is reached that Pt can act as separation centers which capture the photogenerated electrons and make a longer electron_hole pair separation lifetime. So it is found that different photocatalytic properties can be enhanced by preparing the catalyst with different Pt contents. An optimal content of 0.2% Pt can achieve the best photocatalytic performance of MO.

Abstract:Asteriscus otoliths of carps were collected from the Baiyangdian shallow lake and the Miyun reservoir, whose water environments are completely different. The former has been seriously polluted whereas the latter is nearly pure and has experienced no pollution. The otoliths were analyzed by Neutron Activation Analysis (NAA) for microchemical characteristics as indicators to hydrochemical changes. The contents of Sr, Zn, As, Au, Ba, K and Na in the otolith from the Baiyangdian shallow lake are obviously higher than those from the Miyun reservoir. Linear Discriminant Function Analysis (STATISTICA) was uses to classify carp collection sites. The discriminant functions show the major differences between the two sites are the differences in concentrations of Sr, Zn, As and Ba. Moreover, the variation ranges of As,Ba,Sr and Na in otolith from the Baiyangdian shallow lake are relatively larger than those from the Miyun reservoir, which is in accord with the fact that a seasonal and temporal influx of industrial waste into the Baiyangdian shallow lake drainage area causes the precipitation of these elements in some otolith growth increments. The differences of these elements in otoliths from these two areas are consistent with those in the carp living water. These conclusions are of significance in study_ing indicators to hydrochemical environments.

Abstract:Sulphoaluminate alite cements were successfully prepared fromfly ash, bauxite and CaF2 as a fluxing agent by designing MG and MS values, i.e., the controlling of CaO and CaSO4 content, and the sintering at 1150℃, 1200℃, 1250℃, 1300℃ and 1350℃ respectively. The effects of composition design and calcining temperature on the mineral phase of cement clinker were investigated by XRD and SEM, and the chemical reaction route and mechanism were discussed in this paper. The results indicate that the optimized mineral phase of cement clinker can be obtained under the following conditions: MG=1.05 and MS =0.95 at 1300℃, and the phase compositions of cement clinker are C4A3S 58.73%，C3S 23.99%, C2S2.87%, C11A7·CaF2/C12A714.07%，and f-CaO 0.35%. The main phase C4A3S in the cement clinker is well developed into regular and perfect rhombus-dodecahedron morphological crystals with sizes of 1～3μm, and the alite phase is developed into smaller hexagon crystals. 

Abstract:Being sensitive to surrounding environmental changes, reef corals have proved to be capable of recording such environmental information as temperature, salinity and pollution. Red tides, visible ‘blooms’of phytoplankton, badly affect reef ecosystems. During red tides, alkalinity (or pH value), dissolved oxygen and concentration of iron and manganese in sea water are abnormal. Furthermore, the algae accumulate in large quantities to discolor the water, shade submerged reefs, block the photosynthesis of zooxanthellae, the symbiosis algae in polyps, and cause oxygen depletion when dead algae begin to decompose. The changes may lead to the extensive death of reef. In theory, the reefs that survive the red tides can record these changes in water. We can analyze the geochemical changes in coral skeletons such as boron isotope and trace elements like iron and manganese and probe into characteristics of corals so as to investigate the historical red tides. At present, the researchers on the response of coral reef to red tides and the record of historical red tides in reef corals are only in the beginning stages. The combination of the mechanism, characteristics and ecological impacts of the red tides with the characteristics of corals can not only help the study of coral reef environment record but also open a new way to record historical red tides. 

Abstract:The intercalation of kaolinite is the key to the preparation of polymer layered silicate nanocomposites. In this paper, the research advances in intercalation mechanism of kaolinite are summarized, and the intercalation mechanism is discussed in detail, which includes several aspects of the reaction and orientation of the molecule in the lamella, the role of the water in the intercalating process, the absorption and intercalation, and the de-intercalation. In addition, the potential application of kaolinite/organic intercalated composites is described. On such a basis, the key points in this research field are indicated.