长山群岛水环境基本特征与水资源开发研究     

邓伟 《地理科学》1997,17(3):278-284

长山群岛特有的地质，地理环境肽其气候条件决定其水环境容量水，水资源有限。海岛区域开发协调发展的道路，水资源开发不应以损害水环境炒代价，必须走水资源持续利用的开发模式  相似文献   

印尼多岛海沉积记录基本特征与云南古特提斯研究     

方念乔 《地学前缘》2002,9(3):173-181

以新生代印度尼西亚多岛海沉积记录作为典型分析对象 ,对陆 (岛 )海相间结构背景下的沉积作用的主要特征及其构造地理意义进行讨论。各种类型的深水沉积作用在多岛海槛式盆地中多有反映 ,但以浊积和半远洋沉积最为突出 ,典型的远洋沉积仅发育于多岛海外围的开放大洋地区。连续而持久的远洋沉积记录是判别古代洋盆规模的最有效的依据之一。云南昌宁—孟连造山带作为古特提斯多岛洋主洋盆 ,包含的以放射虫硅质岩为代表的远洋记录覆盖的地质历史至少达 130Ma。结合明显的等深流记录、可能的巨大火成区记录、巨量陆屑输入记录等多方面的证据 ,笔者认为 ,云南地区所揭示的东古特提斯的规模远非当代的印尼多岛海可比。对多岛海背景下的若干古海洋学问题也进行了讨论  相似文献   

崎岖列岛海区现代沉积环境   总被引：1，自引：0，他引：1  

李玉中  陈沈良  谷国传 《上海国土资源》2002,(2):11-16

长江入海扩散悬沙和当地岛屿风化物是崎岖列岛海区现代沉积主要物质来源。崎岖列岛的地形、潮流、长江冲淡水和风浪是影响列岛海区现代沉积环境的主要因素。根据沉积环境的差异可将列岛海区划分为4大沉积区：列岛区外沉积区、列岛周边沉积区、列岛峡道沉积区和峡侧向潮汐通道沉积区。列岛区外沉积区主要受外海潮流、风浪和长江冲淡水的影响，主要沉积物为粘土。列岛峡道沉积区受峡道内强劲的往复流影响，峡道西部以粗颗粒沉积物为主，峡道东部深槽区的粘土和亚粘土沉积物应属冲刷出露出的早期沉积地层。  相似文献   

Absolute palaeointensity of Oligocene (28–30 Ma) lava flows from the Kerguelen Archipelago (southern Indian Ocean)     

G. Plenier  P. Camps  R. S. Coe  M. Perrin 《Geophysical Journal International》2003,154(3):877-890

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CLIMATE OSCILLATIONS AS RECORDED IN SVALBARD ICE CORE ω¹⁸O RECORDS BETWEEN AD 1200 AND 1997     

ELISABETH ISAKSSON  DMITRY DIVINE  JACK KOHLER  TONU MARTMA  VEIJO POHJOLA  HIDEAKI MOTOYAMA  OKITSUGU WATANABE 《Geografiska Annaler: Series A, Physical Geography》2005,87(1):203-214

ABSTRACT. We apply two different time series analytical tools to ω¹⁸O records from two Svalbard ice cores. One ice core is from Lomonosovfonna at 1250 ma.s.l. and the other from Austfonna at 750 m a.s.l. These cores are estimated to cover at least the past 800 years and have been dated using a combination of known reference horizons and glacial modelling. Wavelet analysis reveals low frequency oscillations on the 60–120–year scale on the lower elevation site Austfonna while the higher altitude site on Lomonosovfonna does not reveal such variability throughout the record. The second method, Significant Zero Crossing of Derivates (SiZer) does not resolve the low-frequency periodicity seen in the wavelet analysis. The low-frequency variability resolved by the wavelet analysis is similar to what has been found in various climate records including instrumental temperatures and tree-rings, and has been proposed as the most important oscillation for the observed trends in Arctic air temperatures.  相似文献   

The felsic complex of the Vallehermoso Caldera: interior of an ancient volcanic system (La Gomera, Canary Islands)     

J.A. Rodriguez-Losada  J. Martinez-Frias 《Journal of Volcanology and Geothermal Research》2004,137(4):261-284

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Recent Environmental Change and Atmospheric Contamination on Svalbard as Recorded in Lake Sediments – Synthesis and General Conclusions   总被引：3，自引：2，他引：3  

H.J.B. Birks  Vivienne J. Jones  N.L. Rose 《Journal of Paleolimnology》2004,31(4):531-546

The major patterns of biostratigraphical and geochemical change detected in a multidisciplinary study on recent environmental change and atmospheric contamination on Svalbard are summarised and synthesised. The patterns discussed are changes in sediment accumulation rates, organic matter accumulation rates, atmospheric contaminants, and biological assemblages (diatoms, chrysophyte cysts, chironomids). Possible environmental factors that may have influenced these patterns are discussed, in particular, the role of atmospheric contamination (including the deposition of nitrogen-compounds), local human impact, and recent climatic change. The major conclusions are (1) sediment accumulation rates show consistent temporal and geographical patterns with rates increasing towards the present-day and highest in the south, (2) sediment organic-matter accumulation rates increase markedly in the last 50–100 years, (3) atmospheric contamination is a combination of local and regional sources, (4) sediment inorganic geochemistry suggests catchment and lake responses to climate change in the last 30–50 years, (5) all lakes show a marked increase in the rate of biotic compositional changes in the last 50–100 years, and (6) Svalbard lakes appear to be highly dynamic and show considerable biotic and sedimentary changes in recent decades. The most likely cause of many of the observed changes is recent climatic change, with some local human activity at one site. Detailed interpretation of the observed changes is problematic given current limited knowledge about high Arctic limnology, biology, and catchment processes.  相似文献   

Distribution and Autecology of Chrysophyte Cysts from High Arctic Svalbard Lakes: Preliminary Evidence of Recent Environmental Change   总被引：1，自引：1，他引：1  

Alexandra M. Betts-Piper  Barbara A. Zeeb  John P. Smol 《Journal of Paleolimnology》2004,31(4):467-481

Chrysophycean stomatocyst assemblages were analysed from the sediments of 17 lakes and ponds from Svalbard as one component of a multi-proxy investigation of recent environmental change in the high Arctic. Sediment cores and water chemistry were collected from each of the study lakes, and chrysophyte stomatocysts were investigated from the top 0.25 cm of sediment (present-day) and bottom (i.e., bottom of short sediment core, pre-industrial) sediment samples. This study represents the first undertaking of chrysophyte cyst morphology and distribution on Svalbard. A total of 153 cyst morphotypes were described with light microscopy and/or scanning electron microscopy, of which 21 are new forms. Canonical correspondence analysis indicates that the present-day distribution of cysts is significantly related to pH (p= 0.02), altitude (p= 0.02), and Na⁺ (p= 0.04). Marked shifts in chrysophyte cyst assemblages were recorded between the top and bottom sediment samples of most lakes. A recent study has demonstrated that Svalbard lakes receive atmospheric contaminants from both local and remote sources. The observed assemblage shifts may be the result of the combined effects of these point sources and long-range pollutants, or the effects of recent climate change, or both.  相似文献   

舟山群岛地区的地质构造背景   总被引：3，自引：0，他引：3  

汪豫忠 《华南地震》1995,15(1):55-61

从大地构造、磁场和新构造分区特点等方面，对舟山群岛地区的地质构造背景作了较为详细的论述，指出该区处于基底构造交汇，新构造和地震活动强弱分区的过渡地带，新构造运动在中更新世之后趋于平稳；全新世为间歇性活动，强度较弱，基底由若干微块体组成，块体间为不稳定边界，舟山群岛及其海域深部以东西向、浅表部以北东和北东向构造为主，具有孕震和发震的地质构造背景。  相似文献   

Molluscs in Kongsfjorden (Spitsbergen, Svalbard): a species list and patterns of distribution and diversity     

Maria W&#;odarska-Kowalczuk 《Polar research》2007,26(1):48-63

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