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Magnetic properties of Jiaxian red clay sequences from northern chinese Loess Plateau and its paleoclimatic significance

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Science China Earth sciences 2005年第8期48卷 1234-1245页

作者： QIANG Xiaoke, AN Zhisheng, LI Huamei, CHANG Hong & SONG Yougui 1. SKLLQG, Institute of Earth Environment, chinese academy of sciences, Xi’an 710075, China 2. guangzhou Institute of {2., chinese academy of sciences, guangzhou 510640, China 1. chinese academy of sciences SKLLQG Institute of Earth Environment 710075 Xi’an China 2. chinese academy of sciences Guangzhou Institute of Geochemistry 510640 Guangzhou China

Detailed rock magnetism investigation of the Jiaxian red clay sequences indicated that there are common magnetic mineralogy properties in red clay and loess-paleosol sequences from the chinese Loess Plateau as well as the marked properties of themselves, magnetic min-erals mainly with magnetite, maghemite, hematite, and possibly limonite/goethite contributing to the magnetic behavior. Meanwhile, it is found that the strong paleosol in red clay sequences has a lower coercivity and higher content of ultra-fine ferrimagnetic grains than that of the weak pa-leosol, which is similar to loess and paleosol in upper Wucheng Loess sequences, and indicates that humid conditions and relatively strong pedogenesis play a significant role in the increase of ultra-fine magnetic minerals and transformation of the magnetic minerals. This suggests that, like Quaternary loess-paleosols, the change of characteristics of paleoclimatic conditions of the late Tertiary red clay deposits is fluctuant. In addition, the results of magnetic hysteresis properties show that the applied saturated field for samples from the Jiaxian red clay sequences is higher than that of the samples from eastern and southern chinese Loess Plateau. It is obviously shown that there exist more hard magnetic minerals and relatively weak biochemical processes in the Jiaxian red clay sequences on northern chinese Loess Plateau. We conclude that the paleocli-matic environment is different between northern and eastern/southern chinese Loess Plateau, and it should be more arid in northern chinese Loess Plateau.

关键词： northern chinese Loess Plateau, red clay, magnetic property, paleoclimatic significance.

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The biomarkers of 2.6,10,15, 19-pentamethylicosenes and their carbon isotopic composition in the sediments from the Gulf of Mexico

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chinese Science Bulletin 2006年第14期51卷 1736-1740页

作者： SONG Zhiguang1,2.& WANG Cuiping1,3.. State Key Laboratory of Organic geochemistry, guangzhou Institute of geochemistry, chinese academy of sciences, guangzhou 510640, China 2. guangzhou Research Center of Gas Hydrate, chinese academy of sciences, guangzhou 510640, China 3. Graduate School of chinese academy of sciences, Beijing 10003., China State Key Laboratory of Organic geochemistry Guangzhou Institute of Geochemistry Chinese Academy of Sciences Guangzhou 510640 China guangzhou Research Center of Gas Hydrate Chinese Academy of Sciences Guangzhou 510640 China Graduate School of chinese academy of sciences Beijing 100039 China

A group of 2.6,10,15,19-pentamethyli- cosenes (PMIΔ) containing 1―5 unsaturated double bonds has been identified in the sea floor sediments from the Gulf of Mexico at the Green Canyon 2.8 *** PMIΔ compounds are distributed between nC2. and nC2. on the mass chromatogram of aliphatic fraction. Their δ 13. values are very much depleted in 13. and in the range of ?86.7‰ to ?115.5‰, whereas the δ 13. values of companion n-alkanes range from ?2..4‰ to ?3..6‰. These unsaturated PMIΔ com-pounds are typical biomarkers derived from the an-aerobic oxidation of methane mediated by meth-ane-oxidizing archaeal bacteria and indicative of the gas seeps or even the occurrence of gas hydrates in the deep sea sediments.

关键词：生物标志墨西哥湾沉积物 PMIA 天然气水化物

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The Juancheng chondrite──A new meteorite falling recently in China

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chinese Science Bulletin 1998年第21期43卷 1834-1837页

作者： CHEN Yongheng 1,2. WANG Daode+2.and WANG Ruitian+3.. Department of Chemistry, guangzhou Normal University, guangzhou 510400, China 2. guangzhou Institute of geochemistry, chinese academy of sciences, guangzhou 510640, China 3. Heze Bureau of Seismolo Department of Chemistry Guangzhou Normal University Guangzhou China guangzhou Institute of geochemistry Chinese Academy of Sciences Guangzhou China Heze Bureau of Seismology Shandong Province Heze China

The Juancheng chondrite, a new meteorite falling recently in Juancheng County, Shandong Province, China, is classified as an H5 (S2. chondrite based on the compositions of olivine (Fa= 19.2. σ Fa=0.46) and low-Ca pyroxene (Fs=16.9, σ Fa=0.4). The plagioclase in the Juancheng chondrite is rich in CaO, indicating a relatively high metamorphic temperature the parent body underwent.

关键词： Juancheng ordinary chondrite new meteorite.

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Nitric Oxide Emission Following Wetting of Dry Soils in Subtropical Humid Forests

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Pedosphere 2009年第6期19卷 692-699页

作者： LI De-Jun and WANG Xin-Ming 2.State Key Laboratory of Organic geochemistry, guangzhou Institute of geochemistry, chinese academy of sciences, guangzhou 510640 (China) [a]State Key Laboratory of Organic geochemistry Guangzhou Institute of Geochemistry Chinese Academy of Sciences Guangzhou 510640 (China)

Information about soil nitric oxide （NO） emissions from subtropical forests is quite limited, and even less is known about the pulse emission of NO when wetting soils after a long period of dryness. In this study, we measured NO fluxes following wetting of dry soft in a broadleaf forest and a pine forest in subtropical China. Large pulses of NO fluxes were observed after soil wetting in both forests. NO fluxes increased significantly within 0.5 h following wetting in both forests and reached peak 1 and 4 h after soil wetting in the pine forest and the broadleaf forest, respectively. In the broadleaf forest, averaged peak flux of NO pulses was 157 ng N m^-2.s^-1, which was 8 times the flux value before wetting, and in the pine forest, the averaged peak flux was 13. ng N m-2.s 1, which was 15.5 times the flux value before wetting. The total pulses-induced NO emissions during the dry season were roughly estimated to be 2..4 mg N m^-2.in the broadleaf forest and 2..2.mg N m^-2.in the pine forest or made up a proportion of 4.6% of the annual NO emission in the broadleaf forest and 5.3. in the pine forest.

关键词： dry season flux. NO. pulse subtropical China

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Kinetics of early methane generation from Green River shale

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chinese Science Bulletin 1998年第22期43卷 1908-1912页

作者： LIU Jinzhong\+1 and TANG Yongchun 2.1. Laboratory of Organic geochemistry, guangzhou Institute of geochemistry, chinese academy of sciences, guangzhou 510640, China 2. Chevron Petroleum Technology Company, CA 9063., USA Laborarory of Organic geochemistry Guangzhou Institute of Geochemistry Chinese Academy of Sciences Guangzhou China Chevron Petroleum Technology Company USA

During oil/gas exploration in an area, there is a question as to whether methane in the strata was generated \%in situ\% mainly by thermal degradation of local organic matter. The key to the question is whether the kerogen could produce methane of more than 80 mL/g TOC, when its \%R\%\-o increased from initial (0.3.%) to current value of 0.70% during thermal evolution. The authors have made efforts to answer this question by the kinetics method. First, a series of pyrolysis experiments were carried out to obtain data of methane yield and \%R\%\-o evolution, from which kinetic parameters of methane and \%R\%\-o were derived; then these parameters were extrapolated to the geological condition and finally, a methane yield, 96 mL/g TOC, was predicted. The result suggests that from the view of hydrocarbon generation, methane in the seam should be from thermal degradation of local kerogen.

关键词： methane kinetics pyrolysis organic geochemistry.

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Evaluation criteria for gas source rocks of marine carbonate in China

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Progress in Natural Science:Materials International 2005年第9期15卷 810-817页

作者： WANG Zhaoyun1**, ZHAO Wenzhi1 and WANG Yunpeng2.1. Research Institute of Petroleum Exploration & Development,PetroChina, Beijing 100083. China 2. guangzhou Institute of {3.,{2., guangzhou 510640, China) Research Institute of Petroleum Exploration & Development PetroChina Beijing 100083 China. guangzhou Institute of geochemistry Chinese Academy of Sciences Guangzhou 510640 China

Hydrocarbon generating and expulsion simulation experiments are carried out using samples artifically matched between the acid-dissolved residue of relatively low-maturity limestone and the original sample. This work makes up for the insufficiency of source rock samples with high abundance of organic matters and low maturity in China. The organic carbon content of the 10 prepared samples varies between 0.15% and 0.74%. Pyrolysis data and simulation experiment results of hydrocarbon generating and expulsion, which were obtained by a high-temperature and high-pressure open system, indicate that the lower limit of organic carbon content for marine carbonate rock to generate and expel hydrocarbons is 0.2.%—0.3.%. In combination with the numerical analysis of organic carbon in marine carbonate rocks from Tarim Basin, Sichuan Basin, Ordos Basin and North China, as well as the contribution of these gas source rocks to the discovered gas pools, we think that the organic carbon criterion for carbonate gas source rocks should be 0.3..

关键词： carbonate gas source rock gas-generating efficiency evaluation criteria simulation experiment.

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Relation between texture and chemical composition of peridotite xenoliths and its implications: An example from Wangqing, Jilin Province

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chinese Science Bulletin 1998年第10期43卷 837-840页

作者： XU Yigang guangzhou Institute of geochemistry,{2.,{3., China guangzhou Institute of geochemistry Chinese Academy of Sciences Guangzhou China

Spinel peridotite xenoliths from Wangqing, NE China exhibit correlative variations in texture, temperature, geochemistry and radiogenic isotopes. This suggests that the Wangqing xenoliths may come from a mantle diapir. It is possible that the fertile and undeformed lherzolites were situated in the interior of the diapir, whereas the refractory and deformed harzburgites and clinopyroxene_poor lherzolites were within the diapiric flanks.

关键词： peridotite xenoliths texture geochemistry Wangqing.

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Trace element characteristics and origin of intergranular components in mantle peridotites

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chinese Science Bulletin 2000年第7期45卷 643-649页

作者： XU Yigangguangzhou Institute of geochemistry,{2.,{3., China guangzhou Institute of geochemistry Chinese Academy of Sciences Guangzhou China

Leaching experiment has been carried out on mantle xenoliths with different petrographic features in order to directly characterize the nature of intergranular components. ICP-MS analyses of leachates show that they are characterized by high LREE concentrations with strong depletion of Ta. The total REE contents and whether the negative Rb, Ba and Nb anomalies are present or not in intergranular components are largely dependent upon the nature of mantle metasomatism experienced by its host rock. It is proposed that intergranular components may represent residues of small volume metasomatic melts.

关键词： peridotite xenoliths intergranular components trace elements upper mantle.

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Trace element geochemical characteristics of plants and their influence on the remote-sensing spectral properties in the North Jiangsu oil field

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chinese Science Bulletin 2000年第S1期45卷 26-34页

作者： WANG Yunpengguangzhou Institute of geochemistry,{2.,{3., China chinese Acad Sci Guangzhou Inst Geochem Guangzhou 510640 Peoples R China

This paper presents the contents of 17 kinds of trace elements in plant leaf samples collected from 4 sections in the North Jiangsu oil field, and the dada on their visible-near infrared spectra. By comparing the results of the inner and outer oil-gas remote-sensing anomaly areas, the plant trace element composition, and the enrichment characteristics and their influence on the plant spectral properties are described. The results indicated that the plant leaves had very strong enrichment ability toward some elements such as Mg, Ca, K, Na, Fe, Al, Mn, V, Zn and Cr. The plant leaves from the oil-gas abnormal areas were enriched in trace elements of the Fe-series, but depleted in alkali and alkali-earth metal elements. The plant trace elements had a strong influence on the 'blue-shift' strength and the reflectance of visible bands. And the ratios between Fe, Co and K, Na, Cd, Cu, Ba are the effective remote-sensing oil-indicating factors of plant trace elements. plant trace element, geochemistry, remote

关键词： plant trace element geochemistry remote sensing spectra North Jiangsu oil fleld.

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NaAlSi_3._8-hollandite and other high-pressure minerals in the shock melt veins of the Suizhou meteorite

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chinese Science Bulletin 2001年第13期46卷 1121-1126页

作者： XIE Xiande, CHEN Ming, WANG Deqiang & El Goresy A.1.guangzhou Institute of geochemistry,{2.,{3., China 2. Max-Planck-Institute fur Chemie, 5512. Mainz, Germany guangzhou Institute of geochemistry Chinese Academy of Sciences Guangzhou 510640 China Max-Planck-Institute für Chemie 55128 Mainz Germany

The Suizhou L6 chondrite contains a few very thin shock melt veins of 0.02.0.09 mm in width. In spite of small width of the veins, shock-induced high-pressure phases, such as coarse-grained NaAlSi3.8-hollandite, ringwoodite, majorite and fine-grained matrix majorite-pyropess have been discovered in these veins. NaAlSi3.8-hollandite, the high-pressure phase of plagioclase, in Suizhou shock veins occurs as a single phase mineral, no silicate glassy phase, such as albitic glass, was incorporated with it. The presence of above-mentioned high-pressure phases constrains the high pressure (up to 2.-2. GPa) and high temperature (up to 1900-2.00℃) regime in Suizhou shock veins, and indicates that the duration of high-pressure regime in the veins should be long enough (a few seconds) for phase transformation and crystallization of minerals under pressure. The discovery of the first natural single-phase crystalline NaAlSi3.8- holland-ite in Suizhou meteorite is of important significance in understanding the Earth’

关键词： high NaAlSi3.8-hollandite and other high-pressure minerals in the shock melt veins of the Suizhou meteorite

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