末次盛冰期以来全球湿润状况的地质证据──全球古湖泊数据库及其湖水位变化的大尺度时空分析     

秦伯强  S.P.Harrison  于革  P.E.Tarasov  B.Damnati 《湖泊科学》1997,(3)

介绍了正在建设中的全球湖泊数据库的情况，以及该数据库的水位资料所反映的晚更新世末期以来全球湿润状况的变化。通过大尺度湖水位变化的时空分析，结果显示当今湖泊水位状态较历史时期而言，位于低纬干旱或半干旱地区的湖泊水位较低，而中纬及高纬湿润地区的湖泊水位较高。自末次冰盛期以来，北美大陆中南部地区湖泊水位自高至低，反映出该地区气候条件由湿变干，至早、中全新世达最干旱。而在非洲及南亚季风地区，冷期偏干，暖期偏湿。特别是在早、中全新世的温暖时期，为历史上最湿润时期。北半球中纬度地带的气候干湿变化与北半球冰盖的存在及其消融导致的西风带的南北摆动有关；而北半球季风区在早、中全新世出现的高潮面与北半球夏季辐射的增加有密切联系。  相似文献   

数字磁变仪的设计与实现     

张平  刘春节 《地球物理学进展》1997,12(1):113-119

本文介绍了石英光电磁变仪及其数字化采集，记录的设计和实现，并讨论了数字磁变仪系统在地磁台站的应用结果。  相似文献   

用光盘转录航空物探数据     

戚巧俊  雍卫华 《物探与化探》1997,21(3):225-227

航空物探数据具有较高的保存开发价值,由于磁带保存的有效年限较短,航空物探勘查所获资料存在着丢失的危险。航空物探数据光盘转录将解决这些难题,为航空物探资料的二次开发和利用创造条件。本光盘数据从任一与RICOHRS-5060E型光盘机兼容的光盘机上均可读出。  相似文献   

Reconstruction of atmospheric CO2 from ice-core data and the deep-sea record of ontong Java plateau: the Milankovitch chron     

Wolfgang H. Berger  Memorie K. Yasuda  Torsten Bickert  Gerold Wefer 《International Journal of Earth Sciences》1996,85(3):466-495

We provide a reconstruction of atmospheric CO₂ from deep-sea sediments, for the past 625000 years (Milankovitch chron). Our database consists of a Milankovitch template of sea-level variation in combination with a unique data set for the deep-sea record for Ontong Java plateau in the western equatorial Pacific. We redate the Vostok ice-core data of Barnola et al. (1987). To make the reconstructions we employ multiple regression between deep-sea data, on one hand, and ice-core CO₂ data in Antarctica, on the other. The patterns of correlation suggest that the main factors controlling atmospheric CO₂ can be described as a combination of sea-level state and sea-level change. For best results squared values of state and change are used. The square-of-sea-level rule agrees with the concept that shelf processes are important modulators of atmospheric CO₂ (e.g., budgets of shelf organic carbon and shelf carbonate, nitrate reduction). The square-of-change rule implies that, on short timescales, any major disturbance of the system results in a temporary rise in atmospheric CO₂.  相似文献   

西昆仑山南侧甜水海湖岩芯铁变化的环境记录   总被引：11，自引：0，他引：11  

余素华  李世杰 《地球化学》1997,26(6):88-98

阐述了青藏高原西昆仑山南侧甜水海湖岩芯沉积物中氧化铁的丰度、频率分布和富集系数的变化规律。其丰度值范围FeO0．39％-3.95％，平均值为1．25％；Fe2O30．44％－8．09％，平均值为2．60％；Fe2O3／FeO0．21－3．60，平均比值1．12。说明该彻岩芯沉积物中铁平均丰度值较低，但其变化幅度较宽且清楚，在一定程度上反映了古气候环境具有较大幅度的波动。变异系数值表明，该湖岩芯沉积物中FeO的离散程度较Fe2O3大。大约距今23万年来氧化铁的沉积地球化学特征可划分出7个环境演化阶段，并基本上可与深海氧同位索阶段对比。揭示了甜水海湖演化与青藏高原强烈隆升引起的气候环境改变的密切关系。在距今23一15万年，沉积以河流相或冲积、洪积相为主，沉积环境以氧化环境为主导，气候以温干型波动；在距今15－7．4万年，沉积以湖相为主，沉积环境以还原环境为主导，气候以温湿型为主；在距今74万年以来，湖盆沉积环境多样化，沉积物以湖相和近源冲积、洪积相交替出现。气候出现冷湿、冷干、温湿和温干多种波动模式。这些资料分析初步认为甜水海古湖大约形成于距今15万年，即青藏高原第三成湖期，这也与青藏高原在距今15万年左右的再次构造隆升有关。  相似文献   

黑龙江省及其邻区非构造性地震振动研究     

孟宪森  郑辉  关玉辉  王晓峰  姜锦华 《中国地震》2004,20(2):197-203

应用周期-频度谱方法对黑龙江省数字地震台网资料进行处理，给出了矿震、电缆应力释放、震源车作业、火山地震等振动的周期-频度谱和链波指数，并对构造地震和爆破的链波指数进行了讨论。针对港震公司的数字地震记录格式编写了专门的处理程序，为数字地震台站开展周期-频度谱分析提供了有力的工具。  相似文献   

中国兴凯湖北岸平原晚全新世花粉记录及泥炭沼泽形成   总被引：7，自引：1，他引：7  

张淑芹  邓伟  阎敏华  李小强  王升忠 《湿地科学》2004,2(2):110-115

通过兴凯湖北岸平原泥炭剖面高分辩率花粉分析研究，对晚全新世花粉划分4个组合带。XKH-4组合时期(1857～1746aB．P．)为沼泽发育前期，这一时期花粉浓度小，陆生草本植物占优势，气候干冷。XKH-3组合时期(1746～1287aB．P．)为沼泽发育早期，这一时期花粉浓度较大，且水生植物花粉含量为剖面最高，喜温落叶阔叶植物大发展时期，气候温和湿润。XKH-2组合时期(1287～602aB．P．)为沼泽发育中期，这一时期花粉浓度最小，但以陆生草本植物为主，木本植物为辅，水生植物急剧减少，针叶植物出现两次高峰，气候向冷干方向发展。XKH-1组合时期(602aB．P．至今)为沼泽发育盛期，这一时期花粉浓度最大，陆生草本植物大发展时期，气候波动较大。  相似文献   

Real-time simulation of ground displacement by digital accelerograph record   总被引：1，自引：0，他引：1  

金星  马强  李山有 《地震学报(英文版)》2005,18(1):82-88

Introduction The observation records of strong ground motion previously, on the one hand, supplied basicdata both to research on earthquake engineering and to constitute the criterion of aseismatic de-signing of all project structures; on the other hand, it provided important information for the re-search on the process of epicenter burst in seismology. With the development of research on strongground motion observation, especially the development of the new generation accelerograph,which…  相似文献   

Mesozoic-Cenozoic tectonic transition in Kuqa Depression-Tianshan, Northwest China: Evidence from sandstone detrital and geochemical records   总被引：2，自引：0，他引：2  

LI Zhong  GUO Hong  WANG Daoxuan & LIN Wei . Institute of Geology  Geophysics  Chinese Academy of Sciences  Beijing  China . Tarim Oilfield Branch  CNPC  Korla  China  . Hefei University of Industry  Tunxilu  Hefei  China 《中国科学D辑(英文版)》2005,48(9):1387-1402

Succeeding to multiply collisions of different blocks in Late Paleozoic[1―5], complex intracontinental structural deformation occurred in the Tianshan area during Mesozoic-Cenozoic[6―16], which controlled coeval basin-range evolution and resulted in intensive modi- fication and adjustment of the Paleozoic oil-gas reser- voirs[17―19]. The Kuqa Depression is a secendary struc- tural unit of the Tarim basin, in which Mesozoic- Ce- nozoic deposits occur in thickness of 6000―7000 m. The Kuq…  相似文献   

A Holocene high-resolution record of aquatic productivity,seasonal anoxia and meromixis from varved sediments of Lake Łazduny,North-Eastern Poland: insight from a novel multi-proxy approach     

Andrea Sanchini  Sönke Szidat  Wojciech Tylmann  Hendrik Vogel  Agnieszka Wacnik  Martin Grosjean 《第四纪科学杂志》2020,35(8):1070-1080

Anthropogenic eutrophication and spreading anoxia in freshwater systems is a global concern. Little is known about anoxia in earlier historic times under weaker human impact, or under prehistoric natural conditions with different trophic, land cover and climatic regimes. We use a novel approach that combines high-resolution hyperspectral imaging with µ-XRF and HPLC-pigment data, which allows us to assess chloropigments (productivity) and bacteriopigments (anoxia) at seasonal subvarve-scale resolution. Our ~9700 cal a bp varved sediment record from NE Poland suggests that productivity increased stepwise from oligotrophic Early Holocene conditions (until ~9200 cal a bp ) to mesotrophic conditions in the Mid- and Late Holocene. Natural eutrophication was mainly a function of progressing landscape evolution with intense weathering under dense forest and warm-moist climatic conditions. Generally, anoxia increased with increasing productivity. Seasonal anoxia and some multi-decadal periods of meromixis were the common mixing patterns throughout the Holocene except for a period of persisting meromixis between ~5200 and 2000 cal a bp. Anthropogenic deforestation around 400 cal a bp resulted in substantially better lake oxygenation despite high productivity. In this small lake, aquatic productivity and lakeshore forest cover (wind shield) were more important factors controlling oxic/anoxic conditions than Holocene temperature variability.  相似文献