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Inertial theory of the mean Hadley circulation under the condition of nonstatic equilibrium

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Science China earth {1. 2006年第5期49卷 546-553页

作者： CHAO Jiping1.& LIU Fei2,3.1. National Marine {1.al Forecasting Center, Beijing 1.0081. China 2. Key Laboratory Regional Climate-{1. for Temperate East Asia, institute of Atmospheric Physics, {3., Beijing 1.0029, China 3. Graduate University of {3., Beijing 1.0049, China 1. National Marine environmental Forecasting Center Beijing 100081 China 2. Key Laboratory Regional Climate-environment for Temperate East Asia Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China 3. Graduate University of {1. Beijing 100049 China

Tropical atmosphere is divided into two layers, the layer near the ground is the planet boundary layer, where the motion is linear, if the radiation equilibrium temperature is given at the top of the boundary layer, the vertical motion there can be obtained. It is the non-viscous ideal atmos- pheric layer above the boundary one, where the motion is nonlinear. After getting the conservation laws of angular momentum, potential temperature and potential vortex, the inertial theory of the Hadley circulation driven by the vertical motion of the boundary layer is established, followed by sev- eral examples of its application.

关键词： Hadley circulation, inertial theory, conservation laws of angular momentum, potential temperature and potential vortex.

Petrogenesis and dating of the Kangding complex,Sichuan Province

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Science China earth {1. 2005年第5期48卷 622-634页

作者： CHEN Yuelong 1 , LUO Zhaohua 1 , ZHAO Junxiang, LI Zhihong, ZHANG Hongfei & SONG Biao 3.1. Faculty of earth {1. and Natural Resources, China University of Geo{1., Beijing 100083. China 2. Faculty of earth {1., China University of Geo{1., Wuhan 43.074, China 3. Beijing SHRIMP Center, institute of Geology, chinese academy of Geological {1., Beijing 10003., China 1. Faculty of earth {1. and Natural Resources China University of Geosciences 100083 Beijing China 2. Faculty of earth {1. China University of Geosciences 430074 Wuhan China 3. Beijing SHRIMP Center Institute of Geology Chinese Academy of Geological Sciences 100037 Beijing China

An analysis of major and trace element geochemistry and SHRIMP U-Pb zircon dating of mafic, intermediate, and felsic rocks from the Mianning metamorphic complex of Si- chuan Province was conducted. One of our conclusions is that a majority of the zircons crystal- lized between 721.and 773.Ma in a magmatic regime. The complexes contain early to late Pa- leo-proterozoic relict zircons from ancient continental crust. The oldest age, 2468 Ma, may rep- resent the basement of the Yangtze block. Overgrowth zircon rims and palingenetic zircons have been observed and dated, and are believed to have formed after crystallization, during Paleozoic and Mesozoic metamorphic-anate{1.s. We also conclude that depletion of Nb, Ta, HREE, in a spider-diagram normalized to primitive mantle and calc-alkaline association, implies that they formed in island-arc or under-plating settings.

关键词： Kangding complex, zircons, SHRIMP, tectonic setting.

Geomorphologic evidence of phased uplift of the northeastern Qinghai-Tibet Plateau since 1. million years ago

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Science China earth {1. 2004年第9期47卷 822-833页

作者： LU Huayu1. WANG xiaoyong1. AN Zhisheng1. MIAO xiaodong1. ZHU Rixiang3. MA Haizhou2, LI Zhen4, TAN Hongbing2 & WANG xianyan1.1. State Key Laboratory of Loess and Quaternary Geology, institute of earth environment, {1., xi’an 71.075 China 2. Qinghai {3. of Salt Lakes, {1.. xining 81.008, China 3. {3. of Geology and Geophysics, {1., Beijing 1.0029, China 4. Department of Geography, Qinghai Normal University, xining 81.008, China chinese Acad Sci Inst Earth Environm State Key Lab Loess & Quaternary Geol Xian 710075 Peoples R China chinese Acad Sci Qinghai Inst Salt Lakes Xining 810008 Peoples R China chinese Acad Sci Inst Geol & Geophys Beijing 100029 Peoples R China Qinghai Normal Univ Dept Geog Xining 810008 Peoples R China

A typical sequence of fluvial terraces and aeolian deposits overlying these ter- races were multidisciplinary investigated. New evidences for uplift process of the northeastern Qinghai-Tibetan Plateau in the past 1. million years were obtained. At least 1. river terraces along Huangshui, the first-class tributary of Yellow River, at the xining-Huzhu region are identi- fied. While the first one (T1. is classified as an accumulation terrace, the others are all basement river terraces, which consist of the Tertiary sandstone and siltstone bedrock, fluvial gravel and pebbles and the overlying aeolian loess-Red Clay deposit. Samples from the aeolian deposits were examined for paleomagnetic stratigraphic reconstruction (1.{1. samples), luminescence dating (1. samples), magnetic susceptibility and grain-size distribution (more than 4000 sam- ples). The luminescence dating and stratigraphic correlation suggest that terraces of Tll, T1., T8, T7, T{1. T2, T1.were formed at 1., 1..{1. 1.55, 1.2, 0.1., 0.07 and 0.01.million years ago, re- spectively. Sedimentological analysis and geomorphological observation indicate that formation and evolution of these terraces were mainly driven by tectonic uplift. Therefore, the terrace se- quence provides an ideal geological record, of the uplift process of the northeastern during the past 1. million years, and the timings of the terraces formation are regarded as the timings of tectonic uplift. The significant uplifting events took place at 1., 1..{1. 1.2 and 0.1. mil- lion years ago, respectively. The fluvial incision at the xining-Huzhu region is less than 1.0 m during a period of ~1. million years in the Miocene era (between the Tll and T9), while the Huangshui River had incised 4{1. m during the past 1.2 million years (from T7 to the present floodplain). The river incision process clearly demonstrates that accelerated rising of the north- eastern Qinghai-Tibet Plateau during the late Cenozoic, and provides new evidence of previous thoughts

关键词： river terrace, tectonic uplift, loess-Red Clay, the past 1. million years, northeastern Qinghai-Tibet Plateau.

Crustal structure of Gondwana-and Yangtze-typed blocks:An example by wide-angle seismic profile from Menglian to Malong in western Yunnan

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Science China earth {1. 2005年第11期48卷 1828-1836页

作者： ZHANG Zhongjie1, BAI Zhiming1, WANG Chunyong2, TENG Jiwen1, Lü Qingtian3. LI Jiliang1, SUN Shanxue1 & WANG xinzheng1 1. institute of Geology and Geophysics, {1., Beijing 100029, China 2. institute of Geophysics, {3. Seismological Bureau, Beijing 100081, China 3. institute of Deposition Resource, {3. academy of Geological sciences, Beijing 10003., China 1. institute of Geology and Geophysics Chinese Academy of Sciences 100029 Beijing China 2. institute of Geophysics Chinese Seismological Bureau 100081 Beijing China 3. {1. of Deposition Resource Chinese Academy of Geological Sciences 100037 Beijing China

The wide-angle seismic profile between Menglian and Malong crosses the Baoshan block (Gondwana-typed), and Simao and southwestern Yangtze blocks (Yangtze-typed). By in-terpreting the wide-angle seismic data, we obtained the seismic crust/upper mantle structure of P-wave velocities together with the seismic reflections of these three blocks, Changning- Menglian and Mojiang suture zones among the mentioned three blocks. Our interpreting results demonstrate that the P-wave crustal velocity of Simao block is slower than that of Baoshan and southwestern Yangtze block and the crustal thickness gradually thickens from the Baoshan block, Simao to southwestern Yangtze block. Crustal reflection patterns of these three blocks have dis-tinct differences too. For the Gondwana-typed blocks, seismic reflections in the upper crust are well developed while in middle-lower crust they are very weak. The crustal reflections in the Yangtze block are very well developed. The crustal reflection patterns in Simao and southwest-ern Yangtze blocks are distinguishable. The average thickness of the crust in the studied area is about 40 km. And we make some discussions on the crustal thickening model of the three blocks in western Yunnan and tectonic setting of seismic developing and interaction of Gondwana and Yangtze blocks.

关键词： Gondwana blocks,Yangtze blocks,wide-angle profile,crustal structure,tectonic setting

Holocene grassland vegetation, climate and human impact in central eastern Inner Mongolia

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Science China earth {1. 2005年第7期48卷 1025-1039页

作者： HUANG Fei1. Kealhofer Lisa2, xiONG Shangfa{1.& HUANG Fengbao1.1. Nanjing institute of Geology and Paleontology,{1.,Nanjing 21.008,China 2. Anthropology and Sociology Department,Santa Clara University,CA 9505{1.USA {1. institute of Geology and Geophysics,{1.,Beijing 1.0029,China Nanjing institute of Geology and Paleontology Chinese Academy of Sciences Nanjing 210008 China Anthropology and Sociology Department Santa Clara University CA 95053 United States institute of Geology and Geoohysics Chinese Academy of Sciences Beijina 100029 China

Phytolith and pollen preserved in the Taipusi Banner paleosol profile, central eastern Inner Mongolia, provide evidence of Holocene grassland vegetation, climate and human impact. The combined phytolith and pollen records reveal a major change in vegetation composition about 5000 a BP. Before 5000 a BP, the vegetation was dominated by Aneurolepidium chinese-Stipa grandis grassland of C4 grasses. After 5000 a BP, C4 grasses rapidly retreated, indicating a shift to colder and more arid conditions. The gradual invasion of Stipa krylovii, Ag-ropyron desertorum, Ephedra, Chenopodiaceae and Caragana reveal the onset of grassland degeneration. Between 1.000 and 8720 a BP, the Aneurolepidium chinese-Stipa grandis grassland included a small proportion of Artemisia shrub and Echionopos type plants, implying a strong winter monsoon and very weak summer monsoon. From 8720 to 7000 a BP, C4 grasses were common, indicating a strengthening of the summer monsoon. Between 7000 and 5000 a BP, the Holocene thermal maximum was evident, with a significant expansion of C4 grasses and the presence of some trees (such as Pinus and Betula, and so on) in or near the study site. From 4200?000 a BP, a sandy grassland of Artemisia and Agropyron desertorum together with Aster-type taxa occurred. Precipitation amelioration took place between 3.00 and 21.0 a BP, with a rapid development of Echinops type plants and a small expansion of C4 grasses. From 21.0 a BP to present, human activities accelerated the process of grassland degeneration.

关键词： phytolith and pollen records grassland environment change human impact Holocene central eastern Inner Mongolia.

SHRIMP zircon U-Pb geochronology of early Mesozoic felsic igneous rocks from the southern Lancangjiang and its tectonic implications

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Science China earth {1. 2006年第10期49卷 1032-1042页

作者： PENG Touping1.2, WANG Yuejun1. FAN Weiming1. LIU Dunyi3. SHI Yuruo3.& MIAO Laicheng4 1. Key Laboratory of Isotope Geochronology and Geochemistry, Guangzhou institute of Geochemistry, {1., Guangzhou 51.640, China 2. Graduate University of {1., Beijing 1.003., China 3. SHRIMP isotope Laboratory, {3. academy of Geological sciences, Beijing 1.003., China 4. institute of Geology and Geophysics, {1., Beijing 1.0029, China Key Laboratory of Isotope Geochronology and Geochemistry Guangzhou Institute of Geochemistry Chinese Academy of Sciences Guangzhou China Graduate University of chinese academy of sciences Beijing China SHRIMP isotope Laboratory Chinese Academy of Geological Sciences Beijing China institute of Geology and Geophysics Chinese Academy of Sciences Beijing China

The SHRIMP zircon U-Pb geochronology of three typical samples, including two monzo nitic granites from the Lincang batholith and a rhyolite from the Manghuai Formation are presented in the southern Lancangjiang, western Yunnan Province. The analyses of zircons for the biotite monzonitic granites from the northern (02DX-1.0}) and southern (20JH-1.) Lincang batholith show the single and tight clusters on the concordia, and yield the weighted mean 206Pb/23.U ages of 229.4 ± 3.0 Ma and 23..4 ± 3.6 Ma, respectively, representing the crystallized ages of these granites. The zircons for the rhyolitic sample (02DX-95) from the Manghuai Formation give a weighted mean 206Pb/23.U age of 23..0 ± 5.0 Ma. These data suggest that the igneous rocks from the Lincang granitic batholith and Manghuai Formation have a similar crystallized age. In combination with other data, it is inferred that both were generated at a narrow age span (~23. Ma) and were originated from the postcollisional tectonic regime. An early Proterozoic 206Pb/23.U apparent age of 1.77±44 Ma is additionally obtained from one zircon from the biotite monzonitic granite (southern Lincang batholith), indicative of devel- opment of the early Proterozoic Yangtze basement in the region. These precisely geochronological data provide important constraints on better understanding the Paleozoic tectonic evolution of the Tethys, western Yunnan Province.

关键词： SHRIMP zircon U-Pb dating, Middle Triassic, Lincang granitic batholith, Manghuai Formation rhyolite, southern Lancangjiang.

Forcing mechanism of the Pleistocene east Asian monsoon variations in a phase perspective

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Science China earth {1. 2005年第10期48卷 1708-1717页

作者： TIAN Jun1.2, WANG Pinxian1. CHENG xinrong1. WANG Rujian1.& SUN xiangjun1.3.1. State Key Laboratory of Marine Geology, Tongji University, Shanghai 200092, China 2. institute of Geology and Geophysics, {1., Beijing 1.0029, China 3. institute of Botany, {1., Beijing 1.0093. China State Key Laboratory of Marine Geology Tongji University Shanghai China institute of Geology and Geophysics {1. Beijing China institute of Botany {1. Beijing China

The deep sea records from the ODP Sites 1.43.and 1.44 in the northern and southern South China Sea (SCS), including foraminiferal δ 1.O and δ 1.0}, Opal% and pollen percentage, reveal that the variations of the east Asian monsoon have been closely correlated with the variations of the earth’s orbital parameters (eccentricity, obliquity and precession) and the global ice volume on orbital scale. All the monsoonal proxies show strong 1.0 ka, 41.ka and 23.ka cycles. Although G. ruber δ 1.0} of Site 1.43.is coherent with the ETP (ETP= normalized (eccentricity + obliquity-precession) at eccentricity, obliquity and precession bands, most of the coherent relationship focuses on the precession band, and the other monsoonal proxies are coherent with the ETP only at the precession band, which indicate that precession dominates the Pleistocene tropical climate changes. The phase relationship of the monsoonal proxies with the foraminiferal δ 1.O implies that the global ice volume changes have played a significant role in modulating the east Asian monsoon climate, at least dominating the winter monsoon. This forcing mechanism of the east Asian monsoon is apparently different from that of the Indian ocean mon-soon. The variations of the east Asian monsoon at the precession band, at least that of the winter monsoon, have been controlled not only by the sensible heating but also by the latent heating of the surface water in the South China Sea.

关键词： South China Sea, ODP, east Asian monsoon, orbital forcing, global ice volume.

Distributions of fatty acids in a stalagmite related to paleoclimate change at Qingjiang in Hubei,southern China

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Science China earth {1. 2005年第9期48卷 1463-1469页

作者： xiE Shucheng1,HUANG Junhua1,WANG Hongmei2,YI Yi1,HU Chaoyong1, CAI Yanjun3.& CHENG Hai4 1. Faculty of earth Science,China University of Geo{1.,Wuhan 43.074,China 2. School of environmental Studies,China University of Geo{1.,Wuhan 43.074,China 3. skllqg,institute of earth environment,chinese academy of sciences,xi’an 71.075,China 4. Department of Geology and Geophysics,University of Minnesota,MN55455,USA 1. Faculty of earth Science China University of Geosciences 430074 Wuhan China 2. School of environmental Studies China University of Geosciences 430074 Wuhan China 3. skllqg Institute of Earth Environment Chinese Academy of Sciences 710075 Xi’an China 4. Department of Geology and Geophysics University of Minnesota 55455 MN USA

Fatty acids extracted from a subtropical stalagmite at Qingjiang in Southern China’s Hubei Province were analysed using gas chromatography-mass spectrometry. These n-alkanoic acids range from C1. to C26 in carbon number, maximizing at C1., with a second dominance at C22. In contrast to the stalagmite analysed, the overlying soils are characterized by the dominance of heavy-molecular-weight homologues (>C20). The n-fatty acids in the stalagmite were proposed to be contributed by both the soil ecosystems and the microbes harboring in the percolating water and the cave. The ratios of unsaturated to saturated n-fatty acids (C1.:1./C1.:0, C1.:1.C1.:0) appear to show trends comparable with the oxygen isotope records of the stalagmite carbonate, with enhanced values associated with the cold episode such as Heinrich event 1. This paleoclimate-dependent record of the n-fatty acids might reflect microbial changes in physiology and activity in response to the temperature. This record shows somewhat difference from the previous paleoclimate signal extracted from n-alkanols and n-alkan-2-ones of the same stalagmite. The acid record fails to document the well-known Younger Dryas event which was effectively shown by the latter two biomarkers derived from soil ecosystems. This discrepancy might result from the changing biogeochemical impact on different lipid fractions as well as the varied organism populations in different ecosystems.

关键词： biomarker, ecosystem, microbe, speleothem, paleoclimate, Quaternary.

Two possible mechanisms for vortex self-organization

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Science China earth {1. 2006年第2期49卷 202-211页

作者： LUO Zhexian2, ZHOU xiuji1.& GAO Shouting3.1. chinese {1. of Meteorological sciences, Beijing 1.0081. China 2. Department of Space Information Science, Nanjing University of Information Science and Technology, Nanjing 21.044, China 3. {3. of Atmospheric Physics, chinese academy of sciences, Beijing 1.0029, China 2. Department of environmental Science Nanjing University of Information Science and Technology Nanjing 210044 China 1. chinese {1. of Meteorological sciences Beijing 100081 China 3. {1. of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China

The vortex self-organization is investigated in this paper by four groups of numerical experiments within the framework of quasi-geostrophic model, and based on the experimental results two types of possible mechanisms for vortex self-organization are suggested. The meso-scale to-pography may enable separated vortices to merge into a larger scale vortex; and the interaction of meso-γ and meso-β scale systems may make separated vortices to self organize a typhoon-like vor-tex circulation.

关键词： vortex, self-organization, meso-scale topography, interaction of different scales.