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High-resolution climate variability of southwest china during 57―70 ka reflected in a stalagmite δ^(18)O record from Xinya Cave

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Science china Earth sciences 2007年第8期50卷 1202-1208页

作者： LI TingYong1, YUAN DaoXian1,2, LI HongChun1,3 ,YANG Yan2, WANG JianLi1, WANG XinYa1, LI JunYun1, QIN JiaMing2, ZHANG MeiLiang2 & LIN YuShi2 1 College of Geographical Science, Southwest University, Chongqing 400715, china 2.karst dynamics laboratory, institute of karst geology, chinese academy of geological sciences, guilin 541004, china 3 Department of Earth sciences, Cheng-Kung University, Tainan 70101, Taiwan, china College of Geographical Science Southwest University Chongqing China karst dynamics laboratory Institute of Karst Geology Chinese Academy of Geological Sciences Guilin China Department of Earth sciences Cheng-Kung University Tainan Taiwan China

A 26-cm-long stalagmite (XY2) from Xinya Cave in northeastern Chongqing of china has been ICP-MS 230Th/U dated, showing a depositional hiatus at 2.3 cm depth from the top. The growth of the 2.3―26 cm interval determined by four dates was between 57 ka and 70 ka, with a linear growth rate of 0.023 mm/a. We have analyzed 190 samples for δ 18O and δ 13C, mostly in the 2.3―26 cm part. The δ 18O and δ 13C values between 57 ka and 70 ka reveal decadal-to-centennial climatic variability during the glacial in-terval of Marine Isotope Stage 4 (MIS4), exhibiting much higher resolution than that of the published Hulu and Dongge records during this interval. Speleothem δ 18O in eastern china, including our study area can be used as a proxy of summer monsoon strength, with lighter values pointing to stronger summer monsoon and higher precipitation, and vice versa. Two decreases in the δ 18O signature of XY2 record around 59.5 and 64.5 Ka are argued to correspond to the Dansgaard-Oeschger (D-O) events 17 and 18 respectively. The Heinrich event 6 (H6) can be identified in the record as a heavy δ 18O peak around 60 ka, indicating significant weakening of the monsoon in Chongqing during the cold period. The XY2 δ 18O record shows very rapid change toward to the interstadial condition of the D-O event, but more gradual change toward to the cold stadial condition. This phenomenon found in the Greenland ice core records is rarely observed so clearly in previously published speleothem records. According to SPECMAP δ 18O record, the glacial maximum of MIS 4 was around 64.5 ka with the boundary of MIS 3/4 around 60 ka. Unlike the marine record, the speleothem record of XY2, china, exhibits much high fre-quency variations without an apparent glacial maximum during MIS 4. However, the timing of MIS 3/4 boundary seems to be around 60 ka when the H6 terminated, in agreement with the marine chronology. The growth period of sample XY2 during glacial times probably reflects a local karstic routi

关键词： stalagmite U-series dating oxygen isotope records MIS4 D-O cycles H6 event Chongqing china

Reform of Carbonate Rock Subsurface by Crustose Lichens and Its Environmental Significance

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Acta Geologica Sinica(English Edition) 1998年第1期72卷 94-99页

作者： CAO Jianhua and WANG Fuxinginstitute of karst geology, chinese academy of geological sciences, guilin, Guanxi 541004 Xiao Pinfang Liu Xinzhu chinese Acad Geol Sci Inst Karst Geol Guilin 541004 Guanxi Peoples R China

Crustose lichens are distributed extensively in karst areas in Southern china. They can be found on the surface of carbonate rocks. Through biophysical and biochemical processes, crustose lichens reform the subsurface of carbonate rocks and in the meanwhile change their physical and chemical properties: (1) the mechanical strength decreases by 17.04° on average (up to 33.2°); (2) the chemical solution surface area increases from 28.26% to 75.36% (lichen microholes considered only); and (3) the water-holding capacity is greatly improved. Comparative field experiments between biokarst samples underneath crustose lichens and fresh rock samples with the same composition and texture show that the corrosional rate of carbonate rocks of the former is 1.264–1.643 times higher than that of the latter. Crustose lichens are considered as an activator of the surface corrosion of carbonate rocks.

关键词： crustose lichen carbonate rock biokarst corrosion environmental significance

The Formation Mechanism of Hydrogeochemical Features in a karst System During Storm Events as Revealed by Principal Component Analysis

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地学前缘 2009年第S1期16卷 33-34页

作者： Pingheng Yang Daoxian Yuan Kuang Yinglun,Wenhao Yuan,Peng Jia,Qiufang He 1.School of Geographical sciences,Southwest University,Chongqing 400715,china. 2.laboratory of Geochemistry and Isotope,Southwest University,Chongqing 400715,china 3.The karst dynamics laboratory,Ministry of Land and Resources,institute of karst geology,chinese academy of geological sciences,guilin 541004,china

The hydrogeochemical parameters of Jiangjia Spring,the outlet of Qingrnuguan underground river system(QURS) in Chongqing,were found responding rapidly to storm events in late April,2008.A total of 20 kinds of hydrogeo... 详细信息

关键词： rainfall principal component analysis(PCA) soil erosion agricultural activities karst hydrogeochemical feature Qingmuguan

A DESIGN FOR THE GLOBAL karst INFORMATION MANAGEMENT SYSTEM

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中国岩溶 1992年第S1期11卷 232-238页

作者： Lin Xinhong The institute of karst geology, guilin, china

"The Global karst Information Management System (GKIMS)" is a sub-project of International geological Correlation Program Project 299 "geology, Climate, Hydrology and karst Formation". GKIMS is developed on AST-386 mi... 详细信息

关键词： FORTRAN Correlation supporting stored karst BASIC latter hardware convenient distinguished

The δ^(18)O variation of a stalagmite from Qixing Cave,Guizhou Province and indi-cated climate change during the Holocene

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chinese Science Bulletin 2001年第22期46卷 1904-1908页

作者： CAI Yanjun, ZHANG Meiliang, PENG Zicheng, LIN Yushi, AN Zhisheng, ZHANG Zhaofeng & CAO YunningState Key laboratory of Loess and Quaternary geology, institute of Earth Environment, chinese academy of sciences, Xi’an 710054, china karst dynamics laboratory, Ministry of Land and Resources, guilin 541003, china Department of Earth and Space Science, University of Science & Technology of china, Hefei 230023, china State Key laboratory of Loess and Quaternary geology Institute of Earth Environment Chinese Academy of Sciences Xi’an China karst dynamics laboratory Ministry of Land and Resources Guilin China Department of Earth and Space Science University of Science & Technology of China Hefei China

A stalagmite from Qixing Cave, Guizhou Province was dated with the TIMS U-series method and its oxygen isotope composition was analyzed. On the basis of the ages and the variations of the δ18O of the stalagmite, the climate change of the last 7.7 ka has been reconstructed in this area: 7.7-5.8 ka, summer monsoon maximum period; 5.8-3.8 ka summer monsoon weakening period; 3.8-0.15 ka, weakened summer monsoon and high amplitude climate fluctuations period. We put forward that the increasing trend of δ18O of the stalagmite reflected not only the weakening of the summer monsoon, which was caused by the decreasing of solar radiation in the Northern Hemisphere, but also the possibly decreasing contribution of the southwest monsoon to the rainfall of this area. These results are consistent with the output of the numerical climate-model modeling. The high amplitude fluctuation of the δ18O may imply the quick shift of the contributions of different moisture sources to the precipitation in this area.

关键词： stalagmite Holocene southwest monsoon.

Kinematics and dynamics of the Mesozoic orogeny and late-orogenic extensional collapse in the Sino-Mongolian border areas

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Science china Earth sciences 2005年第7期48卷 849-862页

作者： ZHENG Yadong 1 & WANG Tao2 1. Key laboratory of Orogenic Belts and Crustal Evolution (Peking University), Ministry of Education, Beijing 100871, china 2. institute of geology, chinese academy of geological sciences, Beijing 100037, china Key laboratory of Orogenic Belts and Crustal Evolution (Peking University) Ministry of Education Beijing 100871 China institute of geology Chinese Academy of Geological Sciences Beijinq 100037 China

The Sino-Mongolian border areas underwent two important tectonic events during Mesozoic time after late Paleozoic orogeny: a late Triassic to earlier Jurassic contractional event that resulted in a large-scale south-vergent thrust during the orogeny and a late Jurassic-earlier Cretaceous extensional event in a north-south direction that formed a metamorphic core complex. The kinematic and dynamic analyses show that the thrust sheet moved southwards with a kinematic vorticity number of ca. -0.10 and sub-horizontal maximum compressive stress axis that belongs to a contraction-thickening shear. The upper plate of the late-orogenic detachment relatively moved in a 165°direction. The average kinematic vorticity in its earlier stage was 0.74 that belongs to simple shear dominated shearing and related to the maximum compressive stress axes dipping at ～66°, while the later average kinematic vorticity was ～0.55°that belongs to pure shear dominated shearing with sub-vertical maximum compressive stress axes. This suggests that the thrusting led to the crust thickened and the lower plate rocks that were originally located in the upper crust depressed through a brittle-ductile transition zone into the lower crust and became warmer. The heated rocks trended to uplift since their increasing volume and decreasing density while the loading of the upper-plate rocks increased due to the structural thickening. Under the combined effect of the loading and the thermal-uplifting, the ductile shear zone in between increased in its component of vertical pure shear. Once its pure-shear component exceeded its simple-shear one the ductile shear zone became an extension-thinned shear zone. This progressive transitional process reflects internal and essential temporal and spatial relationships: the extensional factor nucleated during the crust thickening by thrusting and increase of the extensional factor finally led to late-orogenic collapse.

关键词： Mesozoic thrusting,late-orogenic collapse,kinematic vorticity number,stress state.

Role of Carbonic Anhydrase as an Activator in Carbonate Rock Dissolution and Its Implication for Atmospheric CO2 Sink

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Role of Carbonic Anhydrase as an Activator in Carbonate Rock...

Northernmost paleo-tethyan oceanic basin in Tibet:Geo-chronological evidence from ^(40)Ar/^(39)Ar age dating of Dur'ngoi ophiolite

The First International Conference on Sustainable Development in karst Regions & International Working Group Meeting of IGCP 448 World Correlation of karst Ecosystems

作者： LIU Zaihuakarst dynamics laboratory of MLR, institute of karst geology chinese academy of geological sciences, 50 Qixing Road, guilin 541004

The conversion of CO into H and is a relatively slow ***,itskinetics may be rate determining in carbonate rock *** anhydrasc（CA）,whichis widespread in nature,was used to catalyze the CO conversion process in dissolutionexperiments of limestone and *** was found that the rate of dissolution increases by afactor of about 10 after the addition of CA at a high CO partial pressure（Pco）for limestone andabout 3 at low Pco for *** shows that reappraisal is necessaty for the importance ofchemical weathering（including carbonate rock dissolution and silicate weathering）in theatmospheric CO sink and the mysterious missing sink in carbon *** is doubtless thatprevious studies of weathering underestimated weathering rates due to the ignorance of CA as anactivator in weathering,thus the contribution of weathering to the atmospheric CO sink is *** finding also shows the need to examine the situ distribution and activity ofCA in different waters and to investigate the role of CA in weathering.

关键词： carbonic anhydrase, CO2 conversion, carbonate rock dissolution, atmospheric CO2 sink

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chinese Science Bulletin 2001年第14期46卷 1203-1205页

作者： CHEN Liang, SUN Yong, PEI Xianzhi, GAO Ming, FENG Tao, ZHANG Zhongqing & CHEN Wen1. laboratory of Continental dynamics, Northwest University, Xi’an 710069, china 2. Department of geology, Northwest University, Xi’an, 710069, china 3. institute of geology, chinese academy of geological sciences, Beijing, 100037, china laboratory of Continental dynamics Northwest University Xi’an China Department of geology Northwest University Xi’an China institute of geology Chinese Academy of Geological Sciences Beijing China

Whole rock 40Ar/39Ar age dating has been conducted on a basalt sample from Dur’ngoi ophiolite, Qinghai Province, which was reported to be the northernmost pa-leo-tethyan oceanic basin in Tibet. A high temperature pla-teau age (345.3±7.9 Ma) with an isochorn age (336.6±7.1 Ma) has been obtained, representing the eruption time of oceanic crust Considering related geological settings, the new age provides constraints on the northernmost pa-leo-tethyan suture zone in Tibet and the tectonic evolution of Paleo-tethys in Northeast Tibet and adjacent areas.

关键词： Dur’ngoi ophlolite 40Ar -39Ar age Paleo-tethys.

Developing on the karst dynamics Theory and the foundation of the International Research Center on karst under the Auspice of UNESCO

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中国岩溶 2009年第2期28卷 100-102页

作者： YUAN Daoxian(institute of karst geology,CAGS The Kars dynamics laboratory,MLR,guilin,Guangxi 541004,china)

Since 1990,four karst related IGCP Projects(IGCP 299,IGCP 379,IGCP 448 and IGCP 513)have been implemented successively by the author from the institute of karst geology,CAGS,as Leader of the International Working *** these four projects have provided opportunities for karst research communities worldwide to study together and solve resources and environment problems in the fields of karst formation,carbon cycle,

关键词： Dy Developing on the karst dynamics Theory and the foundation of the International Research Center on karst under the Auspice of UNESCO IGCP UNESCO