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Authigenic gypsum found in gas hydrate-associated sediments from Hydrate Ridge, the eastern North pacific

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Science China Earth Sciences 2004年第3期47卷 280-288页

作者： Erwin Suess Dirk Rickert Department of Marine Environmental Geology Research Centre of Marine Geology University of Kiel Kiel D-24148 Germany Department of Marine Environmental Geology Research Centre of Marine Geology University of Kiel Kiel D-24148 Germany

Characteristic gypsum micro-sphere and granular mass were discovered by bin-ocular microscope in the gas hydrate-associated sediments at cores SO143-221 and SO143/TVG40-2A respectively on Hydrate Ridge of Cascadia margin, the eastern North pacific. XRD patterns and EPA analyses show both micro-sphere and granular mass of the crystals have the typical peaks and the typical main chemical compositions of gypsum, although their weight percents are slightly less than the others in the non-gas hydrate-associated marine regions. SEM pictures show that the gypsum crystals have clear crystal boundaries, planes, edges and cleav-ages of gypsum in form either of single crystal or of twin crystals. In view of the fact that there are meanwhile gas hydrate-associated authigenic carbonates and SO42--rich pore water in the same sediment cores, it could be inferred reasonably that the gypsums formed also authigenically in the gas hydrate-associated environment too, most probably at the interface between the down-ward advecting sulfate-rich seawater and the below gas hydrate, which spilled calcium during its formation on Hydrate Ridge. The two distinct forms of crystal intergrowth, which are the granular mass of series single gypsum crystals at core SO143/TVG40-2A and the microsphere of gypsum crystals accompanied with detrital components at core SO143-221 respectively, indicate that they precipitated most likely in different interstitial water dynamic environments. So, the distinct authigenic gypsums found in gas hydrate-associated sediments on Hydrate Ridge could also be believed as one of the parameters which could be used to indicate the presence of gas hydrate in an unknown marine sediment cores.

关键词： authigenic gypsum, gas hydrate-associated sediment, Hydrate Ridge, eastern North pacific.

Relationship between the tropical cyclone genesis over the Northwest pacific.and the sea surface temperature anomalies

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Progress in Natural Science:Materials International 2007年第10期17卷 1208-1212页

作者： Wang Jinbo, Qian Weihong and Zhang Xin(Monsoon and Environment Research Group, School of Physics, Peking University, Beijing 100871, China) Monsoon and Environment Research Group School of Physics Peking University Beijing 100871 China

Using the tropical cyclone (TC) data derived from the Joint Typhoon Warning Center (JTWC) and the sea surface temperature data derived from the Joint Environmental Data Analysis Center (JEDAC) at the Scripps Institute of Oceanography from January 1955 to December 2000, we analyzed the relationship between the TC genesis over the Northwest pacific.(NWP) and the sea surface temperature anomalies (SSTA) over the pacific.basin. A long-term trend indicated that the highest frequency of monthly TC genesis appeared earlier and the annual genesis sum increased gradually during the last half century with some oscillations. No significant synchronous correlation was found between the NWP TC events and the SSTA over the pacific.basin, while the annual sum of TC genesis was closely related with the SSTA averaged from the first three months (January, February and March) of the year in the equatorial western and eastern pacific.and over mid-high latitudes of the North pacific. The results implied that there are an interannual El Nio SSTA mode in the equatorial western and eastern pacific.and an interdecadal SSTA mode in the northern pacific. which affected the TC genesis. A regression analysis between the first three-month SSTA and the annual TC sum based on two time scales was conducted. The correlation coefficient between simulated and observed TC sums reached a high value of 0.77.

关键词： tropical cyclone long-term trend sea surface temperature pacific.

MAIN FACTORS STUDY OF THE CONTROLLING GEOCHEMICAL CHARACTERISTICS OF FERROMANGANESE NODULES (Ⅰ)——GEOCHEMICAL CHARACTERISTICS OF FERROMANGANESE NODULES

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Science China Chemistry 1992年第3期35卷 375-384页

作者：鲍根德 The Second Institute of Oceanography State Oceanic Administration Hangzhou 310012 PRC

The geochemical characteristics of ferromanganese nodules have been described in detail by the information study of major elements, trace elements, rare earth elements and infrared spectrophotometer, X-ray diffraction, electronic probing, electronic microscope analysis in 57 ferromanganese nodules of different types from the South China Sea and the Northern Central pacific.Basin. The result shows that (ⅰ) the different types of ferromanganese nodules have different geochemical characteristics; (ⅱ) there is a close relationship between Mn/Fe in ferromanganese nodules and their element content, mineral composition, nodule abundance, tenor (Cu+Co+Ni)%, growth Speed and sedimentary environment. It has suggested that Mn/Fe in nodules can be an indicator of classifying ferromanganese nodule types.

关键词： ferromanganese nodule geochemical characteristics the South China Sea the Northern Central pacific.

Late Holocene cooling event in the western pacific

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Science China Earth Sciences 1996年第5期39卷 543-550页

作者：翦知湣李保华 UwePflaumann 汪品先 Laboratory of Marine Geology Tongji University Shanghai 200092 China Also in Nanjing Institute of Geology and Paleontology Chinese Academy of Sciences Nanjing 210008 China Institute of Geology and Paleontology Kiel University Kiel 24118Germany

Cores 255, 170, 17940-2, raised from the Okinawa Trough and South China Sea, have been studied for planktonic foraminifers. Among all the species, Pulleniatina obliquiloculata is shown to be sensitive to winter sea surface temperature in the late Quaternary in the western pacific. Its relative abundance fluctuations are significant and correlatable between the cores. The most conspicuous change during Holocene is the P. obliquiloculata minimum zone around 4-2ka B. P., which correlates probably to the neoglacial cooling. The widespread occurrence of this cooling event in the western pacific.suggests that P. obliquiloculata is promising as a paleoceanographic and climatic monitor, possibly important for reconstructing sea-land correlation of climate.

关键词： cooling late Holocene Pulleniatina obliquiloculata the western pacific.