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南江县赶场区实施“亲民工程”的调查报告
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作者 陈克福 《四川政报》 2001年第16期34-35,共2页
南江县赶场区就如何贯彻落实江总书记'三个代表'重要思想进行了一系列卓有成效的尝试和探索。他们根据本区的实际情况,制定并实施了'亲民五个一'工程,即:一封致农民朋友的公开信,一个业余演出队,一个下访工作组,一个定... 南江县赶场区就如何贯彻落实江总书记'三个代表'重要思想进行了一系列卓有成效的尝试和探索。他们根据本区的实际情况,制定并实施了'亲民五个一'工程,即:一封致农民朋友的公开信,一个业余演出队,一个下访工作组,一个定期接待日,一个义务监督队。取得了群众提高觉悟,干部转变作风,干群关系密切,经济社会全面发展的良好效果。为了宣传好江总书记'三个代表'的重要思想,探索、总结和推广新时期加强农村宣传思想政治工作,我先后两次对该区进行了专项调查。一、困境赶场区位于南江县北部边远山区,幅员面积323平方公里,辖7个乡、41个村、232个社,38700人。该区自然条件差,经济基础薄弱,农民增收缓慢,社会矛盾突出,尤其是干群关系较之其它地方显得更为紧张。集中表现为:一是班子不团结,凝聚力、战斗力、说服力。 展开更多
关键词 南江县赶场 "亲民工程" "三个代表" 农村思想政治工作
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创建绿化示范乡镇的体会
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作者 陈立群 《上海农业科技》 2002年第5期12-12,共1页
关键词 绿化示范乡镇 城乡绿化 组织领导 全民义务植树 上海 南江区 康桥镇
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“花”的启示
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作者 乐菡静 《语文世界(上旬刊)》 2000年第Z1期87-88,共2页
关键词 “花” 启示 蒲公英 审题构思 作文展示 南江区 文章中心 文章主题 日本作家 血雨
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邓子恢三到广西
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作者 黄莺 《传承》 2002年第3期23-25,共3页
关键词 邓子恢 包产到户 农业生产责任制 南江区 集体经济 农垦工作会议 毛泽东 中央农村工作部 党委领导 包产到组
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Red Soil Resource Information System and Its Preliminary Application 被引量:4
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作者 WANGRENCHAO SHIZHOU 《Pedosphere》 SCIE CAS CSCD 1998年第1期9-14,共6页
Red soil is a very important soil resource in southern China. However, due to being simultaneously of high productive potentialities and severely degraded, it needs harnessing urgently. Red Soil Resource Information S... Red soil is a very important soil resource in southern China. However, due to being simultaneously of high productive potentialities and severely degraded, it needs harnessing urgently. Red Soil Resource Information System (RSRIS) based on remote sensing and geographic information system (GIS) plays an important role in survey, evaluation, utilization and management of red soil resource. RSRIS of Quzhou City) Zhejiang Province (1:250000) and RSRIS of Longyou County, Zhejiang Province (1:50000) have been made respectively on SUN SPARC station and using ARC/INFO. This paper introduces the system design,database creation and system functions, and it particularly focuses on developing applied models, such as red soil resource division and mapping, suitability evaluation, erosion risk evaluation, plant utilization zone etc. The problems on study of RSRIS and its developing strategy are also discussed. 展开更多
关键词 applied model geographic information system red soil resource
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Complementary Zoning Frameworks for Sustainable Management of Eco-economic Capital:a Case Study of Lijiang,China 被引量:1
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作者 YANG Dewei QIU Quanyi LIU Wenjuan 《Journal of Mountain Science》 SCIE CSCD 2012年第6期760-769,共10页
We propose two zoning frameworks for regional decision-makers to regulate eco-economic capital in Lijiang,southwest China,using an index system,layer overlay,and GIS spatial analysis.The frameworks include eco-economi... We propose two zoning frameworks for regional decision-makers to regulate eco-economic capital in Lijiang,southwest China,using an index system,layer overlay,and GIS spatial analysis.The frameworks include eco-economic zoning and major function-oriented zoning,with an emphasis on ecoeconomic capital and human activities.The two frameworks share common advantages in top-down resource regulation by a certain function and the pursuit of competitiveness,sustainability and welfare fairness.Their differences in development orientation,functional links and scale suitability provide a complementary approach for regional decisionmakers.The frameworks will help to understand complex eco-economic resource patterns and foster appropriate regional regulation strategies. 展开更多
关键词 CAPITAL Eco-economic zoning GIS Function-oriented zoning
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Trends of Extreme Flood Events in the Pearl River Basin during 1951-2010 被引量:5
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作者 WU Zhi-Yong LU Gui-Hua +2 位作者 LIU Zhi-Yu WANG Jin-Xing XIAO Heng 《Advances in Climate Change Research》 SCIE 2013年第2期110-116,共7页
The study investigated the trend of extreme flood events in the Pearl River basin during 1951-2010. Stream flow data at 23 gauging stations were used for the study. The Pearson type III distribution was selected for t... The study investigated the trend of extreme flood events in the Pearl River basin during 1951-2010. Stream flow data at 23 gauging stations were used for the study. The Pearson type III distribution was selected for the flood frequency analysis. Results indicate that extreme flood events increase significantly in the Pearl River Basin since 1980. At the 23 gauging stations, there are 16 (70%) stations show positive (increasing) trends in 1981-2010. Most of the 16 stations are located along the West River and North River. While 7 (30%) stations show negative (decreasing) trends, and are found in the East River and the southeast region of the West River Basin. 展开更多
关键词 FLOOD TREND climate change Pearl River Basin
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Assessment of heavy metals in sediment cores from Xiangjiang River,Chang-Zhu-Tan region,Hunan Province,China 被引量:2
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作者 龙永珍 戴塔根 +1 位作者 池国祥 杨柳 《Journal of Central South University》 SCIE EI CAS 2012年第9期2634-2642,共9页
Samples were collected from two core sediments(C1 and C2) of Xiangjiang River,Chang-Zhu-Tan region,Hunan Province,China.The heavy metal contents are relatively higher,especially for the surface or near the surface lay... Samples were collected from two core sediments(C1 and C2) of Xiangjiang River,Chang-Zhu-Tan region,Hunan Province,China.The heavy metal contents are relatively higher,especially for the surface or near the surface layers.The calculated anthropogenic factor values indicate that all the heavy metals except for Cr in the core samples are enriched,especially for Cd,with the maximum enriching coefficients of 119.44,and 84.67 in C1 and C2,respectively.The correlation of heavy metals with sulphur indicates that they are precipitated as metal sulphides.Correlation matrix shows significant association between heavy metals and mud.Factor analysis identifies that signified anthropogenic activities affect the region of Xiangjiang River. 展开更多
关键词 heavy metals core sediment POLLUTION Xiangjiang River Chang-Zhu-Tan region
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Road Impacts on Spatial Patterns of Land Use and Landscape Fragmentation in Three Parallel Rivers Region,Yunnan Province,China 被引量:8
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作者 LIANG Jun LIU Ye +3 位作者 YING Lingxiao LI Peng XU Yue SHEN Zehao 《Chinese Geographical Science》 SCIE CSCD 2014年第1期15-27,共13页
The structure and function of network is a central issue in landscape ecology.Road networks with hierarchical structure are crucial for understanding landscape dynamics.In this study,we compared the distribution of na... The structure and function of network is a central issue in landscape ecology.Road networks with hierarchical structure are crucial for understanding landscape dynamics.In this study,we compared the distribution of national road,provincial road,county road and rural road in the Three Parallel Rivers Region(TPRR)in Yunnan Province of China,and estimated the effect of roads(and other factors)on the spatial patterns of land use and land cover with logistic regression.In addition,we analyzed the land use and land cover change(LUCC)and landscape fragmentation in 1989–2005 along a buffer zone of the primary traffic corridor,national road G214.The results showed that,county and rural roads had much higher percentage of length extending into more natural habitats at higher elevation and steeper slope,compared with the higher level roads in this region.While the distributions of natural land cover types were dominated by environmental factors,human land use types i.e.,building land and farmland types were significantly related with roads,linking more closely with lower level roads.The LUCC dynamics(1989–2005)of the G214 buffer zone showed a general trend of land transformation from conifer forests and valley arid shrubs to building land and farmland,and from ice and snow to alpine shrubs and forests.With the length of G214 unchanged during the time,the overall landscape pattern changed little in the buffer zone,but habitat fragmentation and area decrease had occurred for the natural vegetation types,in contrast to patch mergence and expansion of human land use types,and landscape fragmentation was intensified above 2500 m a.s.l.but declined below the elevation.The results indicated the dynamics of landscape composition and patch type level distribution in spite of the stability of the overall landscape pattern,and implied the potential role of roads,especially the low level roads on landscape changes. 展开更多
关键词 road network road level ecological impacts land use and land cover change(LUCC) landscape fragmentation the Three Parallel Rivers Region
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Drought over China in the 21st Century: Results of RegCM3 被引量:5
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作者 LIU Ke JIANG Da-Bang MA Jian-Yong 《Atmospheric and Oceanic Science Letters》 2012年第6期509-513,共5页
Based on 150-year simulations of a regional climate model, RegCM3, under the Special Report on Emissions Scenarios (SRES) A1B scenario, the effective drought index (EDI) is used to project the future drought change in... Based on 150-year simulations of a regional climate model, RegCM3, under the Special Report on Emissions Scenarios (SRES) A1B scenario, the effective drought index (EDI) is used to project the future drought change in China. During the baseline period 1986-2005, RegCM3 was found to reliably simulate the spatial pattern of drought over the country. Over the 21st century, the regionally averaged EDI should increase, corresponding to a decrease of drought, while the probability of extreme drought events should increase. Geographically, drought should clearly increase in Northeast China, the middle and lower reaches of the Yangtze River valley, Southwest China, and southern Tibet but decrease in most parts of the rest of the country. 展开更多
关键词 China DROUGHT EDI REGCM3
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The Jinsha River Groundwater Observation Network and Discussion about Its Earthquake Precursor Monitoring Capability
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作者 Li Wanming Che Yongtai +2 位作者 Liu Chenglong Yu Jinzi He Anhua 《Earthquake Research in China》 2012年第2期181-200,共20页
A groundwater observational network for monitoring seismic precursors has been established at the reservoirs on the lower reaches of the Jinsha River in southwestern China, where a series of hydropower stations are un... A groundwater observational network for monitoring seismic precursors has been established at the reservoirs on the lower reaches of the Jinsha River in southwestern China, where a series of hydropower stations are under construction. It is the second network in China that is operated by enterprises with the purpose to observe and study earthquake precursors in reservoir areas. This paper presents the layout and technical constitution of the network, features of its observational wells and aquifers and the preliminary result of its experimental operation. Its capability to monitor seismic precursor is evaluated based on an analysis of the well-aquifer system as well as the multiple-monthly, monthly, daily and hourly variations of water levels and water temperatures observed by this network. 展开更多
关键词 Groundwater observational network Reservoirs in lower reaches of JinshaRiver Earthquake precursor monitoring
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Study on Transmission Planning of Cascade Hydropower Stations along Lancang River Basin
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作者 Cui Wenjia Du Zhongming Dai Jianfeng 《Electricity》 2012年第1期26-31,共6页
Most of the hydropower projects in Southwest China and the adjacent foreign regions will be put into operation between 2015 and 2020, which will bring some difficulties for reasonable accommodation and delivery of ele... Most of the hydropower projects in Southwest China and the adjacent foreign regions will be put into operation between 2015 and 2020, which will bring some difficulties for reasonable accommodation and delivery of electric energy. In this paper the author studies the development scale, development schedule, accommodation and transmission schemes of the cascade hydropower stations along the Lancang River basin, one of the five large basins in China, based on the load characteristics of grids at both the sending end and the receiving end, the strategy of complementary utilization of thermal power and hydropower, the advanced transmission technologies, and the optimal economic performance. The study results show that, the cascade hydropower stations on the upper reaches of the Lancang River in Yunnan should mainly serve Guangdong Province, with proper planning of partly serving Yunnan Province during dry seasons. The transmission schemes should adopt UHVDC, UHVAC, and single-tower double-circuited HVDC transmission scheme according to the transmission capacity and distance. 展开更多
关键词 hydropower station transmission scheme electric energy accommodation
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Proximal development,systematic taxonomy,and dispersal pattern of the Early-Middle Ordovician graptolite Acrograptus from South China 被引量:4
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作者 LI LiXia FENG HongZhen +1 位作者 WANG WenHui CHEN WenJian 《Science China Earth Sciences》 SCIE EI CAS 2012年第7期1110-1122,共13页
Based on the well-preserved specimens from the Nanba section in Yiyang, Hunan Province, the definition of the graptolite ge- nus Acrograptus is revised here. The revised Acrograptus is a dichograptid form with stipes ... Based on the well-preserved specimens from the Nanba section in Yiyang, Hunan Province, the definition of the graptolite ge- nus Acrograptus is revised here. The revised Acrograptus is a dichograptid form with stipes subborizontal to deeply declined, sicula long and slender; th 11 budding from the top of the metasicula, proximal development of isograptid type with th 12 as the dicalycal theca; asymmetric proximal end resulting from the divergence of thl1 and thl2 from the sicula at different levels; slender crossing canals composed of extremely slender Acrograptus is assigned to the subfamily Sigmagraptinae prothecae of thlt and thl2. According to the revised definition, of the family Dichograptidae, including six species, i.e., A. affinis (Nicholson), A. filiformis (Tullberg), A. gracilis (Tornquist), A. nicholsoni (Lapworth), A. pusillus (Tullberg), and A. saukros (Ni). During the Early-Middle Ordovician, these six species were widely distributed in South China, especially in the Upper Yangtze Region as well as the central and eastern Jiangnan Region. This study further indicates that Acrograptus first appeared in a deep-water setting on the Jiangnan Slope in South China during early Floian (Tetragraptus approximatus Biozone), and subsequently expanded into the shallow-water region on the Yangtze Platform due to a remarkable dispersion event in middle Floian (Pendeograptus fruticosus Biozone). It is here indicated that the dispersal of Acrograptus may be directly controlled by the large-scale transgression event occurring in middle Floian. 展开更多
关键词 proximal development systematic taxonomy dispersal pattern Acrograptus Ordovician South China
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A comparison study of tungsten-bearing granite and related mineralization in the northern Jiangxi-southern Anhui provinces and southern Jiangxi Province in South China 被引量:19
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作者 SU HuiMin JIANG ShaoYong 《Science China Earth Sciences》 SCIE EI CAS CSCD 2017年第11期1942-1958,共17页
The southern Jiangxi Province(SJP) and northern Jiangxi-southern Anhui provinces(NJSAP) are the two most important tungsten metallogenic districts in South China. The SJP district is a well-known tungsten producer in ... The southern Jiangxi Province(SJP) and northern Jiangxi-southern Anhui provinces(NJSAP) are the two most important tungsten metallogenic districts in South China. The SJP district is a well-known tungsten producer in South China where distributes several ore concentrated areas such as the "Chongyi-Dayu-Shangyou", "Yudu" and "Longnan-Quanan-Dingnan"areas, with many large and super large tungsten deposits including the famous Xihuashan, Piaotang, Pangushan and Dajishan deposits. In recent years, major prospecting breakthrough for W-polymetallic resources has been made in the NJSAP district.Several large and super large W-Cu(Mo) deposits, such as the Dahutang, Zhuxi, Dongyuan and Baizhangyan deposits, are discovered. These deposits are all genetically associated with the Yanshanian(Mesozoic) granitic magmatism. In this study, a systematic comparison of the temporal and spatial distribution, petrology, geochronology, and geochemical characteristics of the tungsten-bearing granites between the SJP and NJSAP districts has been made, with an aim to improving the understanding of the petrogenesis of the granites and associated metal enrichment mechanisms in the two tungsten ore districts in South China. The following conclusions can be drawn:(1) The ages of the tungsten-bearing granites and associated mineralization are different in the two districts, in the SJP district the ages are mainly concentrated in 165–150 Ma, whereas in the NJSAP district it displays two age periods, one is 150–140 Ma(Late Jurassic-Early Cretaceous), and the other is 135–120 Ma(Early Cretaceous).(2) The tungsten-bearing granites from both the NJSAP and SJP districts are highly fractionated granitic rocks, but the SJP granites have experienced higher degree of fractional crystallization and more extensive fluid metasomatism than the NJSAP granites.(3) The petrogeneses of the tungsten-bearing granites from the two districts are different, those from the NJSAP district originated from partial melting of less mature sandstone-mudstone intercalated with meta-volcanic rocks of the Neoproterozoic Shuangqiaoshan Group which are both W and Cu enriched, in contrast those from the SJP district were likely derived from the highly mature,clay-rich mudstones of the Mesoproterozoic age which are only W enriched. In summary, the different source rocks with different metal enrichment features and different magmatic evolution and fractional degrees for the granites in the two districts might be the key factors that controlled the different matallogenic characteristics of tungsten ore deposits in the two districts in South China. 展开更多
关键词 Tungsten-bearing granites Material sources Metallogenic characteristics Northern Jiangxi-southern Anhui provinces Southern Jiangxi Province
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Zircon SHRIMP U-Pb geochronology of the Neoproterozoic Chengjiang Formation in central Yunnan Province(SW China) and its geological significance 被引量:27
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作者 JIANG XinSheng WANG Jian +4 位作者 CUI XiaoZhuang ZHUO JieWen XIONG GuoQing LU JunZe LIU JianHui 《Science China Earth Sciences》 SCIE EI CAS 2012年第11期1815-1826,共12页
The Chengjiang Formation is the earliest continental clastic deposit after the Jinning Orogeny in central Yunnan Province,and therefore its accurate depositional age is significant for understanding the formation and ... The Chengjiang Formation is the earliest continental clastic deposit after the Jinning Orogeny in central Yunnan Province,and therefore its accurate depositional age is significant for understanding the formation and evolution of the Neoproterozoic rift basins in southern China.However,hampered by accuracy of the dating technique,the existing age data for the Chengjiang Formation are not very reliable.A large number of magmatic zircons were obtained from the tuff interbed in the lower part of the Chengjiang Formation in Jinyang area and the bottom part of the Chengjiang Formation in Dongchuan area,central Yunnan Province,and high-precision SHRIMP U-Pb dating was carried out on these zircons.The results show that the weighted mean 206 Pb/238 U ages are 797.8±8.2 and 803.1±8.7 Ma respectively.In combination with related geological evidence,it has been demonstrated that the bottom boundary age of the Chengjiang Formation should be 800±5 Ma,whereas the top boundary age could be ca 725 Ma.By synthetically analyzing the latest age data for the relevant strata,it has been confirmed that the Chengjiang Formation should be correlated with the Suxiong Formation and the Kaijianqiao Formation in western Sichuan Province,the Liantuo Formation in the middle and lower Yangtze,the Hongchicun Formation and the Shangshu Formation in northern Zhejiang Province,the Puling Formation in southern Anhui Province,the Luokedong Formation and the Majianqiao Formation in northwestern Jiangxi Province,the Wuqiangxi Formation in northwestern Hunan Province,the Fanzhao Formation and the Qingshuijiang Formation in southeastern Guizhou Province,and the Sanmenjie Formation and the Gongdong Formation in northern Guangxi Province.Sedimentary cycle analysis shows that the sedimentary filling sequence of the Neoproterozoic rift basins in southern China can be divided into four cycles.Among them,Cycle II began at ca.800 Ma,accompanied by intensive tectonic-thermal events.The zircon U-Pb ages from the bottom of the Chengjiang Formation reported in this paper indicate that the Neoproterozoic Kangdian rift subbasin probably started to develop at ca.800 Ma and therefore missed Cycle I of the Neoproterozoic sedimentary filling sequence in southern China. 展开更多
关键词 NEOPROTEROZOIC Chengjiang Formation zircon SHRIMP U-Pb age rift basin sedimentary cycle southern China
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Tracking shallow marine red beds through geological time as exemplified by the lower Telychian (Silurian) in the Upper Yangtze Region,South China 被引量:28
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作者 RONG JiaYu WANG Yi ZHANG XiaoLe 《Science China Earth Sciences》 SCIE EI CAS 2012年第5期699-713,共15页
Marine red beds occur frequently in China through geological time.Despite their complex environments,the red beds are found in three depositional settings:1) oceanic,deep water,as in the Upper Cretaceous of southern T... Marine red beds occur frequently in China through geological time.Despite their complex environments,the red beds are found in three depositional settings:1) oceanic,deep water,as in the Upper Cretaceous of southern Tibet;2) outer shelf,deeper water,as in the Lower-Middle Ordovician of South China;and 3) inner shelf,shallow water,as in the Silurian and Triassic in South China.The Silurian marine red beds are recurrent in the lower Telychian,upper Telychian,and upper Ludlow.This paper is to document the marine nature of the lower Telychian red beds (LRBs) in the Upper Yangtze Region and to discuss the spatial and temporal distribution of the LRBs and their depositional environments.The LRBs are best developed on the north side of the Cathaysian Oldland,which can be interpreted as the source area.It is inferred that they were deposited during a marine regression,characterized by the lack of upwelling,low nutrition and organic productivity with a decrease of biodiversity and a high rate of sedimentation.The iron-rich sediments may have been transported by rivers on the oldland into the Upper Yangtze Sea,as rates of deposition were rapid enough to counteract normal reducing effect around sediment-water interface.The LRBs are different from the off-shore,deeper water red beds of lower Telychian in Avalonia and Baltica and further from the oceanic,deep water red beds of Upper Cretaceous in southern Tibet chiefly in palaeogeographic settings,biotic assemblages and marine environments. 展开更多
关键词 shallow marine red beds lower Telychian of Lower Silurian South China DISTRIBUTION environments
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Holocene delta evolution and sequence stratigraphy of the Pearl River Delta in South China 被引量:13
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作者 WEI Xing WU ChaoYu 《Science China Earth Sciences》 SCIE EI CAS 2011年第10期1523-1541,共19页
We analyzed the sedimentary characteristics and chronostratigraphy of the Pearl River Delta in South China, and discussed the Holocene stratigraphic characteristics and the filling process since the Holocene, based on... We analyzed the sedimentary characteristics and chronostratigraphy of the Pearl River Delta in South China, and discussed the Holocene stratigraphic characteristics and the filling process since the Holocene, based on 90 boreholes. Our results showed that the maximum transgressive surface of the Pearl River Delta was located in the soft marine silt horizons, whereas it was shown as an erosion surface in areas with tidal scour. From bottom to top, Holocene sedimentary sequences were fluvial facies, floodplain-estuary facies, and estuary-delta facies in the paleo-valley, while the paleo-interfluve sequences were described as littoral facies, estuary facies, and delta facies. Vertical accumulation sequences of Holocene sediments were shown primarily as positive tapering-shaped sequences with no typical foreset, topset, or other sedimentary sequences of the Gilbert Delta. The paleo-Pearl River estuary had different evolution models in the highstand systems tract (HST) compared with other large deltas worldwide, in that it is dominated by a unique and complex geomorphologic boundary, and that it is a multi-sourced delta compounded by the independent and parallel development of fluvial sedimentary bodies with different scales. A huge estuary was formed in the present Pearl River Delta area when the post-glacial transgression reached maximum at about 6 ka BP. The estuary was divided into two parts by obstruction of a series of islands, an upper part composed of the semi-enclosed inner paleo-bay connected to rivers and a lower part consisting of the outer paleo-bay connected to the ocean. Both of these areas were interlinked by only a few narrows, in which the fluvial sediments are accumulated primarily in the inner paleo-bay. During 6-2 ka BP, the sedimentation in various regions of the inner paleo-bay occurred simultaneously with independent development under the remodeling and transformation effect of complex boundaries on river and ocean dynamics. After 2 ka BP, the evolution of the delta is no longer a simple natural process, but rather a common remodeling process accomplished by nature and humans. 展开更多
关键词 Pearl River Delta HOLOCENE stratigraphic framework delta evolution
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New observations on Vetulicola longbaoshanensis from the Lower Cambrian Guanshan Biota(Series 2, Stage 4), South China 被引量:2
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作者 LI JinShu LIU JianNi OU Qiang 《Science China Earth Sciences》 SCIE EI CAS CSCD 2017年第10期1795-1804,共10页
Cambrian vetulicolians are enigmatic metazoans which play an important role in understanding the early animal evolution. Vetulicola longbaoshanensis Yang et al., 2010 is a unique species reported from the Guanshan Bio... Cambrian vetulicolians are enigmatic metazoans which play an important role in understanding the early animal evolution. Vetulicola longbaoshanensis Yang et al., 2010 is a unique species reported from the Guanshan Biota, Cambrian Series2, Stage 4 at eastern Yunnan, South China, which expands our understanding of vetulicolians. Here, new exceptionally preserved materials of V. longbaoshanensis from the Lower Cambrian Wulongqing Formation(which yields the so-called Guanshan Biota)in both Wuding and Kunming areas are described, in which the gill structures of V. longbaoshanensis are well preserved. The gill structures of our fossils are more complicated than those in the type species: the gill sac is gourd-shaped and can be divided into a smaller anterior part and a larger posterior part, prominent gill silt and dense gill filaments present in the joint of the two parts. Comparative analyses indicate that vetulicolians from the Guanshan Biota are similar to the Vetulicola rectangulata Luo et Hu, 1999 from the Chengjiang Biota in gross morphology. However, compared with the V. rectangulata, the Guanshan forms possess a larger body size, a higher length/height ratio of anterior body, and a higher ratio of gill sac width to anterior body height, probably typifying the derive characters anticipated of vetulicolians. These new materials, therefore, shed new light on our understanding of vetulicolians morphology and the early evolution of the gill structures. 展开更多
关键词 Vetulicola longbaoshanensis Guanshan Biota Chengjiang Biota Lower Cambrian
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Distribution and enrichment patterns of selenium in the Ediacaran and early Cambrian strata in the Yangtze Gorges area, South China
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作者 TIAN XingLei LUO KunLi 《Science China Earth Sciences》 SCIE EI CAS CSCD 2017年第7期1268-1282,共15页
The distribution and enrichment patterns of selenium(Se) in the E-?1 strata in the Yangtze Gorges area of South China were obtained. The geochemical characteristics of the significantly and non-significantly enriched ... The distribution and enrichment patterns of selenium(Se) in the E-?1 strata in the Yangtze Gorges area of South China were obtained. The geochemical characteristics of the significantly and non-significantly enriched strata of Se were analyzed.The observed enrichment factor(EF, relative to the upper continental crust) and concentration coefficient(CC, relative to the similar lithology in Eastern China) both suggest that Se is the most enriched/concentrated(SeEF=26.97, SeCC=48.04) among the analyzed23 trace elements the E-?1 strata. The normalized enrichment factor(EF′, EF after Al or Th normalized) shows Se is secondly enriched(SeEF′=218.73), which is slightly lower than cadmium(CdEF′=288.46) but significantly higher than the third enriched trace element arsenic(AsEF′=97.49). Se concentrations in the E-?1 strata vary from <10.5 to 30.08 ppm with an arithmetic mean value of 1.35 ppm. Compared to the Nantuo Formation, Se increased 11.78 times in the whole E-?1 strata and the average EF values are displayed as Shuijingtuo(92.58)>Yanjiahe(54.45)>Doushantuo(24.72)>Dengying(2.48)>Shipai(1.95)>lower Tianheban(1.24)Formations. Se concentrations in the E-?1 strata are best displayed on natural logarithm normal quantile-quantile(Q-Q) plots and shown as a positive-skewed distribution pattern. The Se significantly enriched(EF>10) strata sequences mainly include the lower and upper Doushantuo member II(DST-II), top DST-III, DST-IV, the basal and upper Yanjiahe Formation, and lower and upper Shuijingtuo Formation. Geochemical characteristics indicate that Se concentrations in the significantly enriched strata were generally influenced by terrigenous detrital as well as the combined action of single or multiple factors, such as hydrotherm,volcanic debris and deep source. Moreover, pyrite and organic matter promoted the enrichment of Se in the upper DST-II, DST-IV,upper Shuijingtuo Formation and lower DST-II, upper Shuijingtuo Formation, respectively. The Se concentrations in the not significantly enriched strata(except for DST-I, middle Shuijingtuo Formation, Shipai Formation and lower Tianheban Formation)were also influenced by terrigenous detrital, but other enrichment activities(e.g., hydrothermal, volcanic debris, and deep source)were generally insignificant. 展开更多
关键词 Ediacaran-early Cambrian SELENIUM Distribution and enrichment patterns Elemental geochemistry
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