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Grain-size features of a Miocene loess-soil sequence at Qinan: Implications on its origin

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Science China Earth sciences 2006年第7期49卷 731-738页

作者： QIAO Yansong1,3, GUO Zhengtang2,1, HAO Qingzhen1, YIN Qiuzhen1, YUAN Baoyin1 & LIU Tungsheng1 1. institute of geology and geophysics, chinese academy of sciences,{4., China 2. institute of Earth Environment, chinese academy of sciences, Xi’an 710075, China 3. institute of Geomechanics, chinese academy of Geological sciences, beijing 100081, China 1. institute of geology and geophysics Chinese Academy of Sciences Beijing 100029 China 3. institute of Geomechanics Chinese Academy of Geological Sciences Beijing 100081 China 2. institute of Earth Environment Chinese Academy of Sciences Xi’an 710075 China

In this study, grain-size of 507 bulk samples from the QA-I Mioceneloess-soil sequence at Qinan were analyzed, and the grain-size features are compared with those oftypical Quaternary loess and soil samples, representative lacustrine and fluvial samples. Theresults indicate that the grain-size distribution pattern of the Miocene loess is essentiallysimilar to that of Quaternary loess, but greatly differs from the lacustrine and fluvial *** layers are regularly coarser than soil layers, indicating cyclical climate changes. Mediangrain-size along the 253.1 m sequence varies from 6 to 13 μm and the > 63 μm fraction representsonly 5.3% in maximum, 0.9% in average. Long-term grain-size variations are consistent with the loessaccumulation rate at Qinan and with the eolian mass accumulation rate in the North Pacific. Thesefeatures firmly indicate an eolian origin of the studied sequence, and also reveal a coeval changesbetween the long-term changes of eolian grain-size and continental aridity in the dust sourceregions.

关键词： Qinan, Miocene loess-soil sequence, grain-size, eolian origin.

Chronological record of the Early Mesozoic underplating in the northern margin of North China—U-Pb chronometry of zircons in the Late Mesozoic andesite from Western Liaoning

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Progress in Natural Science:Materials International 2007年第8期17卷 943-947页

作者： Shao ji'an~(1,2**) Zhang Hongfu~2 Liu Xiaoming~3 Li Zhitong~4.(1.School of Earth and Space sciences,Peking University,beijing 100871,China 2.institute of geology and {4. and Key Laboratory of Mineral Resources,chinese academy of sciences,beijing 100029,China 3.Key Laboratory of Continental Dynamics,Northwestern University,Xi'an 710069,China 4.institute of geology and Mineral Resources of Shenyang,Shenyang 110032,China) [a]School of Earth and Space sciences Peking University Beijing China [b]Laboratory of Mineral Resources Chinese Academy of Sciences Institute of Geology and Continental Dynamics Beijing China [c]Key Laboratory of Continental Dynamics Northwestern university Xi'an China [d]institute of geology and Mineral Resources of Shenyang Shenyang China

Cathodoluminescence spectroscopic analysis of zircons in the uppermost sanukites of the early Cretaceous Yixian Forma- tion in Western Liaoning reveals zoning structures of the zircons in the volcanic rocks. LA-ICP-MS chronometry shows that the central part of the zircons is remnant zircon with a U-Pb dating of 254.Ma,which is consistent with the age of the Early Mesozoic underplating granulites,and that the periphery is zircon crystallizing out of the host magma with a U-Pb dating of 116 Ma,which is highly consistent with the Ar-Ar dating of the host volcanic *** of the clinopyroxenes xenocrystals in the sanukites are similar to those of the clinopyroxenes in the underplating granulites,indicating that the granulites accreted to the lower crust in the Early Mesozoic have been reformed and disrupted by the upwelling diapers of the asthenosphere and taken part in formation of the sanukites in the Late Mesozoic.

关键词： northern margin of North China Mesozoic volcanic rock U-Pb chronometry of zircon underplating granulite

2002:The extra-strong warm winter event in North Asia and its accompanying anomalous atmospheric circulation

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chinese Science Bulletin 2003年第10期48卷 1031-1033页

作者： WANG Huijun LASG, institute of Atmospheric Physics, chinese academy of sciences, beijing 100029, China LASG Institute of Atmospheric Physics Chinese Academy of Science China

Features of an extra-strong warm winter event in North Asia in 2002 and its accompanying anomalous atmospheric circulation were studied through diagnosis on the atmospheric reanalysis data set. Results show that the winter of 2002 is of the warmest in the recent 54.years in North Asia, which was caused by both decadal scale and interannual scale variability. The interannual variability is proved to be as the main cause for the event, and it is related to the global scale atmospheric circulation anomalies, with the strongest of them in the Eastern Hemisphere and in the middle and high latitude region of the Southern Hemisphere.

关键词：大气环流亚洲北部高强度暖冬现象天气资料

The high-resolution climate recorded in the δ^(18)O of Porites lutea from the Nansha Islands of China

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chinese Science Bulletin 2001年第24期46卷 2097-2102页

作者： YU Kefu, CHEN Tegu, HUANG Dingcheng, ZHAO Huanting, ZHONG Jinliang & LIU Dongsheng (LIU Tungsheng)South China Sea institute of Oceanoiogy, chinese academy of sciences. Guangzhou 510301, China:geology and geophysics institute. chinese academy of sciences, beijing 100029, China South China Sea institute of Oceanology Chinese Academy of Sciences Guangzhou China geology and geophysics institute Chinese Academy of Sciences Beijing China

A Porites lutea core from Yongshu Reef of Nansha Islands covering 50 years growth history was ana-ly/ed for oxygen isotopic composition with monthly and seasonally resolution. The calibration of the δ18O with the instrumental temperature indicated that the coral δ18O is a good indicator for sea surface temperature (SST) and air temperature (t). It can be used to reconstruct the SST and air temperature of the Yongshu Reef sea area. In addition, the coral δ18O provides signatures for the intensity of the East Asia monsoon and it is a record for the activities of El Nino events. With the calibrated SST and air temperature formulas, the most recent fifty years SST and air temperature were reconstructed based on the coral δ18O, thus back up the understanding of the climate of Nansha Islands to 1950. far beyond the limit of the instrumental recording since September 1988. It was found that, in general, increasing 1℃ air temperature results in 0.24.decrease in skeletal δ18O.

关键词： Nansha Islands Porites lutea δ18O sea surface tem-perature East Asia monsoon.

Cold Thermal Anomalous Structure within Lower Mantle and Its Geodynamic Implications

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Journal of China University of Geosciences 2001年第2期12卷 160-164页

作者： Xiong Xiong institute of Geodesy and geophysics, chinese academy of sciences, Wuhan 4.0077 institute of {4. and geophysics, chinese academy of sciences, beijing 100101 Hsu Houtze institute of Geodesy and geophysics, chinese academy of sciences institute of Geodesy and geophysics Chinese Academy of Sciences institute of geology and geophysics Chinese Academy of Sciences

The lateral temperature anomalous structure of the lower mantle is reconstructed from the seismic tomographical model and high temperature and high pressure laboratory results. A significant correlation between the distribution of the cold anomaly and the location of past subduction belts shows that the shallower anomaly corresponds to the younger subduction sites, while the deeper anomaly to the older ones. This correlation also suggests that the cold anomaly may have come from the subduction slabs and the scale of mantle convection may have been completed. The coldest and largest anomaly is concentrated near the core mantle boundary (CMB). Few cold anomalies float in the shallower and middle parts of the lower mantle, suggesting that the downward migration of the subduction slabs, discontinuous and step like, may be divided into the following three stages: subduction, stagnation at the 670 km discontinuity due to the phase transition, and disintegration when the size exceeds the critical point.

关键词： lower mantle cold thermal anomaly geodynamic implication.

SEISMIC STUDIES OF MARINE GAS HYDRATES

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化工学报 2003年第Z1期54卷 47-56页

作者： SONG Haibin (institute of geology and geophysics, CAS, beijing 100029, China) institute of geology and geophysics CAS Beijing 100029 China

We give a brief introduction of developments of seismic methods in the studies of marine gas hydrates. Then we give an example of seismic data processing for BSRs in western Nankai accretionary prism, a typical gas hydrate distribution region. Seismic data processing is proved to be important to obtain better images of BSRs distribution. Studies of velocity structure of hydrated sediments are useful for better understanding the distribution of gas hydrates. Using full waveform inversion, we successfully derived high-resolution velocity model of a double BSR in eastern Nankai Trough area. Recent survey and research show that gas hydrates occur in the marine sediments of the South China Sea and East China *** we would like to say seismic researches on gas hydrate in China are very preliminary.

关键词： gas hydrates, bottom-simulating reflector, seismic, full waveform inversion, Nankai Trough

Digital image analysis of palaeoenvironmental records and applications

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chinese Science Bulletin 2002年第23期47卷 1957-1963,2025-2026页

作者： SUN Donghuai1,2, LIU Yu2 & TAN Ming31. South China Sea institute of Oceanology, chinese academy of sciences. Guangzhou 510301, China 2. State Key Laboratory of Loess and Quaternary geology, Earth Environmental institute, chinese academy of sciences, Xi’an 710075, China 3. institute of geology and geophysics, chinese academy of sciences, beijing 100029, China South China Sea institute of Oceanology Chinese Academy of Sciences Guangzhou China State Key Laboratory of Loess and Quaternary geology Earth Environmental Institute Chinese Academy of Sciences Xi’an China institute of geology and geophysics Chinese Academy of Sciences Beijing China

Environmental change signals in geological or biological records are commonly reflected on their reflecting or transmitting images. These environmental signals can be extracted through digital image analysis. The analysis principle involves section line selection, color value reading and calculating environmental proxy index along the section lines, layer identification, auto-chronology and investigation of structure evolution of growth bands. On detailed illustrations of the image technique, this note provides image analyzing procedures of coral, tree-ring and stalagmite records. The environmental implications of the proxy index from image analysis are accordingly given through application demonstration of the image technique.

关键词： digital image environmental records.

Si-and alkali-rich melt inclusions in minerals of mantle peridotites from eastern China:Implication for lithospheric evolution

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Science China Earth sciences 2006年第1期49卷 43-49页

作者： FAN Qicheng1, SUI Jianli2, XU Ping2, LI Ni1, SUN Qian1 & WANG Tuanhua1 1. institute of geology, China Seismological Bureau, beijing 100029, China 2. institute of geology and geophysics, chinese academy of sciences, beijing 100029, China 1. institute of geology China Seismological Bureau Beijing 100029 China 2. institute of geology and geophysics Chinese Academy of Sciences Beijing 100029 China

Minerals of spinel- and garnet-facies mantle xenoliths entrained in Cenozoicbasalts from eastern China (North China, Northeastern China and Southeastern China coastal area)contains lots of melt inclusions. Studies on these melt inclusions show that the glass inclusionsare rich in SiO_2 (60%—68%) and alkalis (K_2O+Na_2O = 5%—11%, especially for K_2O) as well asvolatiles such as H_2O and CO_2 (2%—7%), which belong to dacites and andesites of the high-K calcicalkali series rocks with few shoshonites. High Al and Ca diopside in melt inclusion is the productof melt crystallization at high temperature and pressure, rather than the product ofdevitrification. Results show that these K-rich (in general K_2O > 3%) intermediate-acidic silicatemelt inclusions have characteristics of continent without a genetical link to host basalts and theirphenocrystic minerals. Thus, these trapped melt inclusions represent melts of Mesozoic lithosphericmantle-crust interaction and imply that the continental lithospheric mantle beneath eastern Chinahad undergone fragmentation and recreation processes during the Mesozoic and Cenozoic periods. Thisresult undoubtly provides important implication for the evolution of sub-continental lithospherebeneath eastern China. We propose that these Si- and alkalis-rich melts should be responsible forthe mantle chemical heterogeneity underneath eastern China.

关键词： Si- and alkali-rich melt inclusion, mantle peridotite, lithospheric evolution, eastern China.

Semi-analytical analysis of the response of the air temperature over the land surface to the global vegetation distribution

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chinese Science Bulletin 2009年第14期54卷 2499-2505页

作者： LIU Fei1,2 & CHAO JiPing3,4.1 institute of Atmospheric Physics, chinese academy of sciences, beijing 100029, China 2 Graduate University of chinese academy of sciences, {4. 10004., China 3 National Marine Environmental Forecasting Center, {4. 100081, China 4.First institute of Oceanography, State Oceanic Administration of China, Qingdao 266061, China institute of Atmospheric Physics chinese academy of sciences Beijing 100029 China Graduate University of chinese academy of sciences Beijing 100049 China National Marine Environmental Forecasting Center Beijing 100081 China First institute of Oceanography State Oceanic Administration of China Qingdao 266061 China

Response of the air temperature over the land surface to the global vegetation distribution is investigated, using a three-dimensional governing equation to simulate the steady, large-scale, limited amplitude perturbation of the free, inviscid and adiabatic atmosphere. The adoption of the static equation leads to a temperature governing equation in the terrain following coordinate. With the prescribed temperature as the upper boundary condition and the radiation balance as the lower boundary condition, the semi-analytical solution of the global circulation temperature can be calculated. In this article, only the air temperature (at 2 m height) over the land surface is analyzed, and the result suggests that this model can simulate the air temperature pattern over the land surface reasonably. A better simulation occurs when a simple feedback of the albedo on the temperature is included. Two sensitivity experiments are analyzed through this model. One suggests that the air temperature over the land surface descends obviously when the land surface is covered with ice all over, while another suggests that the air temperature rises a little when the land surface is covered with forest except the ice-covered area. This model appears to be a good tool to study the response of the air temperature to the vegetation distribution. Limitations of the model are also discussed.

关键词：空气温度植被分布陆地表面反应解析分析模拟模式控制方程边界条件