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The crustal structure under Sanjiang and its dynamic implications:Revealed by seismic reflection/refraction profile between Zhefang and Binchuan,Yunnan

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Science China earth sciences 2005年第9期48卷 1329-1336页

作者： ZHANG Zhongjie1, BAI Zhiming1, WANG Chunyong2. TENG Jiwen1, Lü Qingtian3. LI Jiliang1, LIU Yifeng1 & LIU Zhenkuan4 1. institute of Geology and Geophysics, Chinese academy of {2., Beijing 10002., China 2. institute of Geophysics, China Seismological Bureau, Beijing 100085, China 3. institute of Deposition Resource, Chinese academy of Geo{2., Beijing 10003., China 4. School of Exploration and Information, China University of Geo{2., Beijing 100083. China 1. institute of Geology and Geophysics Chinese Academy of Sciences 100029 Beijing China 2. institute of Geophysics China Seismological Bureau 100085 Beijing China 3. institute of Deposition Resource Chinese Academy of Geosciences 100037 Beijing China 4. School of Exploration and Information China University of Geosciences 100083 Beijing China

The fault belts in Sanjiang mainly include Jinshajiang-Honghe fault, Lancangjiang fault and Nujiang fault (called Sanjiang faults) in western Yunnan Province, China. By interpreting the wide-angle seismic reflection/refraction profile between Zhefang and Binchuan, which crosses Tengchong and Baoshan blocks in Dianxi (western Yunnan) tectonic zone, we recon- struct the crustal structure with seismic traveltime tomography for crustal P-wave velocity and the seismic scattering image for crustal seismic reflection structure. In this paper, we firstly present the crustal structure images of P-wave velocity and seismic reflection under the wide-angle seismic profile. These results demonstrate that, the crustal velocity structure and seismic reflec- tion structure along the profile can be divided into 3.segments, and there is an obvious difference of crustal structure among the eastern, the western and the middle segment. Generally, crustal P-wave velocities in the Baoshan segment are 0.1―0.2.km/s slower and seismic reflection am- plitudes from Moho discontinuity are stronger than the other 2.segments. In the studied area, crustal thickness is about 40 km, and shows the thickening tendency from west to east along the profile. Additionally, it can be seen that there is one strong-amplitude seismic reflection event as bright points at the depths of 8―10 km, along the segment of 80―115 km of the profile (south- ward of Tengchong); and seismic reflection wave-field from Moho discontinuity varies obviously along the lateral direction. Finally, we make some discussions on the crustal thickening pattern in the Sanjiang fault belt, structural {3. of earthquake development and the contact rela- tionship between the Tengchong block, Banshan block and Luxi trough.

关键词： Sanjiang area wide-angle seismic profile crustal structure.

Characteristic Rainfall for Warning of Debris Flows

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Journal of Mountain Science 2010年第3期7卷 207-214页

作者： HU Kaiheng Cui Peng Wang Chuanchang Li Yong Lu xiaobing Key Laboratory of Mountain Hazards and earth Surface Processes Chinese Academy of Sciences Chengdu 610041 China institute of Mountain Hazards and environment Chinese Academy of Sciences & Ministry of Water Conservancy Chengdu 610041 China institute of Mechanics Chinese Academy of Sciences Beijing 100080 China

A characteristic rainfall is introduced to overcome the difficulties encountered in determining a critical rainfall value for triggering debris *** characteristic value is defined as the rainfall at which debris-flow occurrence probability shows a rapid increase,and can be used as a warning rainfall threshold for debris *** of recorded debris flows and 2.-hour rainfall data at Jiangjia basin,Yunnan Province,in southwestern China,demonstrates the existence of such a characteristic *** was found that the characteristic rainfall corresponds to the daily rainfall of 90% cumulative probability by analyzing the basin's daily rainfall *** result provides a simple and useful method for estimating a debris-flow warning rainfall threshold from the daily rainfall *** was applied to estimate the debris-flow warning rainfall threshold for the Subaohe basin,a watershed in the 2.08 Wenchuan {3.quake zone with many physical characteristics similar to those of the Jiangjia basin.

关键词： Debris flow Wenchuan earthquake warning rainfall threshold statistics of daily rainfalldistribution

A zooarchaeological study of bone assemblages from the Ma'anshan Paleolithic site

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Science China earth sciences 2010年第3期53卷 395-402页

作者： ZHANG Yue1,2.3. WANG ChunXue1,2. ZHANG ShuangQuan1,2.& GAO {3.ng1,2.1 institute of Vertebrate Paleontology and Paleoanthropology, Chinese academy of {2., Beijing 100044 2.Joint Laboratory of Human Evolution and Archaeometry, Chinese academy of {2., Beijing 100044 3.State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing 2.0008 1. institute of Vertebrate Paleontology and Paleoanthropology Chinese Academy of Sciences Beijing 100044 China2. Joint Laboratory of Human Evolution and Archaeometry Chinese Academy of Sciences Beijing 100044 China3. State Key Laboratory of Palaeobiology and Stratigraphy Nanjing 210008 China

Ten thousands of bone fragments were recovered from the Ma’anshan Paleolithic site, of which 43.8 pieces can be identified to skeletal elements or species. In this research, the bone assemblages are quantified based on elements of MNI, MNE, and MAU. Then bone surface modifications and skeletal element profiles of the bone assemblages are studied to understand shlepping behaviors and reveal the technique of disarticulating and defleshing the animals’ bodies, etc. Based on the analyses of bone assemblages and the comparative study with the ethnoarchaeological as well as experimental data, it is assumed that later hominids at the site made fuller use of the game animals than the earlier hominids. Incorporating the lines of evidence from chronological dating, paleoenvironment, and polished bone tools between the two cultural layers, here we propose three hypotheses suggesting that the changes of environment, the migrations of the hominids from the North, or the demographic pulses may cause such a behavioral difference. However, it is yet to be determined which hypothesis can better explain the changes.

关键词： Ma’anshan site zooarchaeology Paleolithic hominid behavior

Carbon Dioxide Fluxes and Concentrations in a Cotton Field in Northwestern China:Effects of Plastic Mulching and Drip Irrigation

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Pedosphere 2011年第2期21卷 178-185页

作者： LI Zhi-Guo Key Laboratory of Oasis Ecology and Desert environment Xinjiang Institute of Ecology and Geography Chinese Academy ofSciences Urumqi 830011 (China) Graduate University of Chinese academy of sciences Beijing 100049 (China) institute of Soil Science Chinese Academy of Sciences Nanjing 210008 (China) earth System Science Interdisciplinary Center University of Maryland College Park MD 20740 (USA)

In northwestern China, there has been a change from traditional cultivation system （TC） with no mulching and flood irrigation to a more modern cultivation system （MC） using plastic film mulching with drip irrigation. A field study was conducted to compare soil ＇C02.concentrations and soil surface COs fluxes between TC and MC systems during a cotton growing season. CO2.concentrations in the soil profile were higher in the MC system （3.07-92.2.L L-1） than in the TC system （1 2.5-8994 μL L-1） but the rate of CO2.flux was lower in the MC system. Possible reasons for this included decreased gas diffusion and higher soil moisture due to the mulching cover in the MC system, and the consumption of soil CO2.by weathering reactions. Over the whole cotton growing season, accumulated rates of CO2.flux were 3.0 and 3.4 g C m-2.for the MC and TC systems, respectively. When agricultural practices were converted from traditional cultivation to a plastic film mulching system, soil CO2.emissions could be reduced by approximately 100 g C m-2.year-1 in agricultural lands in arid and/or semi-arid areas of northern and northwestern China.

关键词： agricultural practice carbon cycle greenhouse gas emission soil respiration weathering reaction

Control of atmospheric CO_2.concentrations by 2.50: A calculation on the emission rights of different countries

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Science China earth sciences 2009年第10期52卷 1447-1469页

作者： DING ZhongLi1, DUAN xiaoNan2. GE QuanSheng3.& ZHANG ZhiQiang4 1 institute of Geology and Geophysics, Chinese {3. of {2., Beijing 10002., China 2.The General Office of Chinese {3. of {2., Beijing 100864, China 3.institute of Geographic {2. and Natural Resources Research, Chinese {3. of {2., Beijing 100101, China 4 The Lanzhou Branch of the National Science Library, the Scientific Information Center for Resources and {13., Lanzhou 73.000, China institute of Geology and Geophysics Chinese Academy of Sciences Beijing 100029 China The General Office of Chinese academy of sciences Beijing 100864 China institute of Geographic sciences and Natural Resources Research Chinese Academy

This paper is to provide quantitative data on some critical issues in anticipation of the forthcoming international negotiations in Denmark on the control of atmospheric CO2.concentrations. Instead of letting only a small number of countries dominate a few controversial dialogues about emissions reductions, a comprehensive global system must be established based on emissions allowances for different countries, to realize the long-term goal of controlling global atmospheric CO2.concentrations. That a system rooted in "cumulative emissions per capita," the best conception of the "common but differentiated responsibilities" principle affirmed by the Kyoto Protocol according to fundamental standards of fairness and justice, was demonstrated. Based on calculations of various countries' cumulative emissions per capita, estimates of their cumulative emissions from 1900 to 2.05, and their annual emissions allowances into the future (2.06―2.50), a 470 ppmv atmospheric CO2.concentration target was set. According to the following four objective indicators―total emissions allowance from 1900 to 2.50, actual emissions from 1900 to 2.05, emissions levels in 2.05, and the average growth rate of emissions from 1996 to 2.05―all countries and regions whose population was more than 3.0000 in 2.05 were divided into four main groups: countries with emissions deficits, countries and regions needing to reduce their gross emissions, countries and regions needing to reduce their emissions growth rates, and countries that can maintain the current emissions growth rates. Based on this proposal, most G8 countries by 2.05 had already expended their 2.50 emissions allowances. The accu-mulated financial value based on emissions has reached more than 5.5 trillion US dollars (2. dollars per ton of CO2.. Even if these countries could achieve their ambitious emissions reduction targets in the future, their per capita emissions from 2.06 to 2.50 would still be much higher than those of developing coun

关键词： international negotiations on climate change cumulative emissions per capita emission allowance

Geochemistry of high-Mg andesites from the early Cretaceous Yixian Formation, western Liaoning: Implications for lower crustal delamination and Sr/Y variations

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Science China earth sciences 2006年第9期49卷 904-914页

作者： WANG xiaorui1, GAO Shan1,2. LIU xiaoming1, YUAN Honglin1, HU Zhaochu1, ZHANG Hong1,3.& WANG Xuance4 1. State Key Laboratory of Continental Dynamics, Department of Geology, Northwest University, xi`an 710069, China 2. State Key Laboratory of Geological Processes and Mineral Resources, China University of Geosciences, Wuhan 43.074, China 3. Shenyang institute of Geology and Mineral Resources, Shenyang 11003.1} China 4. Guangzhou institute of Geochemistry, Chinese {3. of sciences, Guangzhou 510640, China 1. State Key Laboratory of Continental Dynamics Department of Geology Northwest University Xi’an 710069 China 2. State Key Laboratory of Geological Processes and Mineral Resources China University of Geosciences Wuhan 430074 China 3. Shenyang institute of Geology and Mineral Resources Shenyang 110032 China 4. Guangzhou institute of Geochemistry Chinese Academy of Sciences Guangzhou 510640 China

85 volcanic rocks of the Yixian Formation from the Sihetun type section werecollected and analyzed for geochemical and isotopic compositions. Major element compositionsindicate that the Sihetun volcanic rocks are high magnesium andesites with some basalts occurring atthe bottom of section. The Sihetun high magnesium andesites (SiO_2.= 52.82.59.3. wt%, Al_2._3.14.15-16.3.wt%) show many characteristics of adakites such as depletion in heavy rare-earth elements(HREE; Yb = 1.03.1.88 μg/g) and Y(12.2. μg/g) and high Sr (62.-13.1} μg/g) and Sr/Y(3.1}88), withhigh La_N/Yb_N ratio (10-2.). They share similar major and trace element characteristics to volcanicrocks from the xinglonggou Formation except their lower Nd isotope ratios (^(143.Nd/^(144)Nd(13.Ma) = 0.5118-0.5119, ε_(Nd) (13.Ma) = -11.6-13.8, ^(87)Sr/^(86)Sr (13. Ma) = *** were interpreted in a way that eclogite that formed at the base of thickened Archean lowercrust of the North China craton foundered into the convecting mantle and subsequently melted andinteracted with peridotite. However, compared to the xinglonggou volcanic rocks, the source of theSihetun magma contained more ancient continental crustal material in order to explain its evolved Ndisotopes. The age of the Sihetun Formation was 12. to 13. Ma, and this indicates that delaminationlasted to the early Cretaceous period. The Sr contents and Sr/Y ratios of the Sihetun high-Mgandesites show significant negative correlations with SiO_2.for samples with SiO_2.> 56%. Thesesuggest that the Sr and Sr/Y values were reduced due to fractional crystallization of ***, the effect of crystallization on volcanic Sr and Sr/Y ratio has to be taken intoaccount.

关键词： High-Mg andesite, Adakite, Yixian Formation, North China Craton, delamination.

Aridity/humidity status of land surface in China during the last three decades

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Science China earth sciences 2005年第9期48卷 1510-1518页

作者： WU Shaohong1, YIN Yunhe1,2. ZHENG Du1 & YANG Qinye1 1. institute of Geographical sciences and Natural Resources Research, Chinese {2. of sciences (CAS), Beijing 100101, China 2. Graduate School of the CAS, Beijing 10003., China 1. institute of Geographical sciences and Natural Resources Research Chinese Academy of Sciences (CAS) 100101 Beijing China 2. Graduate School of the CAS 100039 Beijing China

To clarify aridity/humidity status of land surface is helpful for studying environmental background and regional differences, seeking causes of environmental change, and providing a scientific basis for researches on climate change in the future. In this paper, the authors calcu- lated potential evapotranspiration of China using data from 616 meteorological stations during the period of 1971―2.00 with the Penman-Monteith model recommanded by FAO in 1998. Vy- sothkii’s model was used to calculate aridity/humidity index. Then the calculated results of sta- tions were interpolated to land surface using ArcGIS. Results show that the annual average po- tential evapotranspiration is 400―1500 mm in the whole country, 600―800 mm in most parts of it; and 3.0―1400 mm in growing season (April―Octobor), which is nearly 2.0 mm less than the annual average. According to the aridity/humidity indexes of 1.0, 1.5 and 4.0, the aridity/humidity status is categorized to four types, namely, humid, subhumid, semiarid and arid. A majority of stations (76%) are more humid in growing season than the annual average. Results of com- prisons between the distribution map of aridity/humidity index with that of precipitation and vegetation indicate a good consistence of aridity/humidity status with natural environment. Therefore potential evapotranspiration calculated with modified FAO’s Penman-Monteith model in combination with aridity/humidity index that considers water balance can more reasonably explain the actual land surface aridity/humidity status of China.

关键词： potential evapotranspiration, aridity/humidity status, land surface, regional differences, Penman-Monteith.

Planation Surfaces on the Tibet Plateau,China

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Journal of Mountain Science 2008年第4期5卷 310-317页

作者： ZHANG xinbao HE xiubin WANG Yangchun LONG Yi institute of Mountain Hazards and environment CAS Chengdu 610041 China State Key Laboratory of Loess and Quaternary Geology Institute of Earth Environment GAS Xi＇an 710075 China Graduate University of the Chinese Academic of sciences Beijing 100039 China

A planation hypothesis is proposed to explain landform evolution of the Tibet Plateau. A denudation threshold （T）, the maximum potential denudation rate for a certain type of rock, is introduced to explain the combined effects of lithology and tectonics on landform evolution. If the tectonic uplifting rate （U） is equal to or less than the threshold rate （U ≤ T）, the tectonic uplifting and terrain denudation are in dynamic equilibrium, and landforms are in a steady state. The end product should be planation surfaces whether the original landforms are flat plains or deeply dissected mountains. If U 〉 T, uplift and denudation are not able to reach a dynamic equilibrium state. The plateau surface is mostly underlain by soft rocks, such as the Mesozoic epimetamorphic argillites and Tertiary sedimentary rocks, while the mountain ranges comprise hard rocks, such as granite, gneiss and limestone. In soft rock regions, hills are low with a relative relief of mostly less than 100 m and the slopes are gentle at a gradient of 〈2.0. In contrast, hills can maintain steep slopes in hard rock regions. The Tibet Plateau has been under an equilibrium condition between tectonic uplifting and denudation except for the mountain ranges. The plateau might have reached the present altitudes before the Quaternary.

关键词： planation denudation threshold landform evolution Tibet Plateau China

Forecast Method of Multimode System for Debris Flow Risk Assessment in Qingping Town,Sichuan Province,China

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Journal of Mountain Science 2011年第4期8卷 592-602页

作者： KONG Jiming Key Laboratory of Mountain Hazards and earth Surface Processes Chinese Academy of Sciences institute of Mountain Hazards and environment Chinese Academy of Sciences

The Wenchuan earthquake of May 12.2.08 triggered large numbers of *** heavy rain on 13.August 2.10 triggered debris flows with total volume of more than 6 million cubic meters and the debris flows destroyed 500 houses and infrastructure built after the Wenchuan *** study area Qingping Town was located in the northwestern part of the Sichuan Basin of China,which needs the second reconstructions and the critical evaluation of debris *** study takes basin as the study unit and defines collapse,landslide and debris flow hazard as a geo-hazard system.A multimode system composed of principal series system and secondary parallel system were established to evaluate the hazard grade of debris flow in 13. drainage basins of Qingping *** evaluation result shows that 3..43. of study basins(42.basins) and 2..58% of study area,are in extremely high or high hazard grades,and both percentage of basin quantity and percentage of area in different hazard grades decrease with the increase of hazard *** to the geo-hazard data from the interpretation of unmanned plane image with a 0.5-m resolution and field investigation after the Wenchuan earthquake and 8.13.Big Debris Flow,the ratio of landslides and collapses increased after the Wenchuan earthquake and the ratios of extremely high or high hazard grades were more than moderate or low hazard grades obviously.2. geo-hazards after8.13.Big Debris Flow in Qingping town region all occurred in basins with extremely high or high hazard grades,and 9 debris flows were in basins with extremely high hazard *** model of multimode system for critical evaluation could forecast not only the collapse and landslide but also the debris flow precisely when the basin was taken as the study unit.

关键词： Multimode System Risk assessment Debris flow Landslide Wenchuan earthquake Qingping Town