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1.
临夏盆地早更新世东山古湖沉积的高分辨率气候记录 总被引：3，自引：0，他引：3
临夏盆地东山古湖（２．３５～１．６５ＭａＢ．Ｐ．）沉积厚达８４ｍ,是六盘山以西早更新世湖相沉积的典型代表。以２．５ｍ的间隔对其进行系统采样,以ＣａＣＯ３含量变化为指标建立高分辨率的气候变化曲线,对曲线进行周期分析表明,东山古湖所反映的气候波动具有明显的４１０００ａ主导周期;其中２．２８ＭａＢ．Ｐ．和１．７５～１．８０ＭａＢ．Ｐ．时段为两个明显的冷湿时期,表明东亚季风在建立初期具有不稳定性。 相似文献
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云南大理点苍山地区更新世晚期沉积地层的ESR测所研究 总被引：1，自引：0，他引：1
本文采用电子自旋共振（ＥＳＲ）方法测定了云南点苍山地区更新世晚期沉积地层的形成年代。测年结果显示：（１）点苍山地区冰川沉积物的ＥＳＲ年龄均小于１４０．３５ＫａＢＰ．，说明该地区的第四纪冰川作用最早出现于中更新世晚期，主要发生于晚更新世；（２）点苍山西麓平坡附近最高一级基座阶地的堆积时代为１８４．３ＫａＢＰ．，证明西洱河阶地系列为中更新世以来的产物；（３）点苍山东侧白雀寺地区深３．７ｍ处的褐红色地层 相似文献
3.
内蒙古岱海气候环境演变的沉积记录 总被引：4，自引：0，他引：4
根据对岱海湖泊岩芯沉积物的有机碳同位素,碳酸盐和磁化率等指标的综合分析,讨论岱海近１０００年的气候环境演化过程,结果表明：９８０ａＢ．Ｐ－７３０ａＢ．Ｐ．,气候以暖湿为主,岱海为高湖而期;７３０ａＢ．Ｐ．－４８０ａＢ．Ｐ．,以冷偏干气候为主;４８０ａＢ．Ｐ．－２７０Ｂ．Ｐ．,湖而急剧下降,气候冷偏湿转冷干气候;２７０ａＢ．Ｐ．－１１０ａＢ．ｐ．,湖泊收缩,以温干气候为主;１１０ａＢ．Ｐ．以来,有效 相似文献
4.
对南极普里兹湾ＮＰ９５１柱样的元素地球化学特征及其古环境意义进行了研究。结果表明，本区沉积物在沉积过程中受冰盖消融、淡水涌入和陆源物质的影响较大；沉积物中ＳｉＯ２、Ａｌ２Ｏ３、Ｆｅ２Ｏ３、ＣａＯ、ＭｇＯ、Ｐ、Ｓ、Ｃｏｒｇ等元素组分较好地记录了由古气候变化而引起的物源改变，这些元素组分在地层中的分布规律与古海洋沉积环境及古气候变迁相一致；自晚更新世末期以来的气候大致可分为温暖期、寒冷期、高温期、转冷期和转暖期五个区段；在柱样的１４５ｃｍ（１４．４ｋａＢ．Ｐ．）、８５ｃｍ（１０．３ｋａＢ．Ｐ．）和２５ｃｍ（６．３ｋａＢ．Ｐ．）处出现了古气温的高值点，指示了气候的变化；８５ｃｍ处元素含量的突变指示了异常事件的发生，该层位正好对应于哥德堡地球磁场漂移，全球气温突然变暖，标志着１０．３ｋａＢ．Ｐ．以后南极地区进入了全新世。 相似文献
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在南极中山站地区的土壤和湖泊沉积物中都有高岭石存在，本文分析了这些土壤样品的水溶态镁离子和ｐＨ值。结果表明，中山站地区土壤中的高岭石含量存在明显的空间分异，含量范围为２６％～５７％；而中山站地区奈拉湖不同时间的湖泊沉积物中高岭石含量范围则为５．８％～２３．２％。通过研究土壤中高岭石含量和土壤溶液性质的关系，发现土壤中高岭石含量与土壤溶液的ｐＨ和水溶态镁离子有一定联系。奈拉湖沉积物中高岭石的时间变化表明土壤中的高岭石含量在百年尺度上即可发生明显改变，这和土壤溶液性质发生改变的时间尺度是一致的。 相似文献
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干旱区内陆河流域中游地区全新世沉积相变与环境变化——以石羊河流域为例 总被引：1，自引：0，他引：1
中国干旱区内陆河流域中游地区分布了大量晚第四纪河、湖相交替的沉积地层,这些沉积物被广泛用于古气候和古环境重建。然而,以往的研究较多关注沉积物的理、化、生指标,而忽略了沉积相变的古环境意义,这可能使古环境重建结果产生偏差。针对这一问题,选取干旱区典型内陆河——石羊河中游地区的JDT全新世沉积剖面,进行年代学、沉积相、岩性和粒度的研究,并与该区域已有的HSH全新世剖面的地球化学和古生物指标进行对比,在分析沉积相的基础上讨论二者的环境代用指标,重建石羊河中游地区全新世的古环境。两个剖面在年代和岩性上具有很好的一致性,指示了石羊河中游地区约8500 cal yr BP-3000 cal yr BP以来的沉积过程。两剖面从底部到上部可分为六层:河流相沉积(F层)——河湖相沉积(E层)——湖相沉积(D层)——浅湖—风成沉积(C层)——风成沉积(B层)——风成沉积(A层),代表了不同沉积相及其转换过程。综合讨论沉积物岩性、沉积相和各种古环境代用指标认为:石羊河中游地区的沉积相体现了从河流相到湖相再到风成沉积物的变化过程,指示了全新世的干旱化过程。这与以往研究中认为石羊河流域全新世气候变化具有波动性的观点存在一定差异。因此,在研究沉积相变化的基础之上讨论沉积物的物理、化学和生物指标的含义,而非简单地研究这些指标的数值,是干旱区流域性气候变化对比研究的新视角。 相似文献
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中国干旱区内陆河流域中游地区分布了大量晚第四纪河、湖相交替的沉积地层,这些沉积物被广泛用于古气候和古环境重建。然而,以往的研究较多关注沉积物的理、化、生指标,而忽略了沉积相变的古环境意义,这可能使古环境重建结果产生偏差。针对这一问题,选取干旱区典型内陆河——石羊河中游地区的JDT全新世沉积剖面,进行年代学、沉积相、岩性和粒度的研究,并与该区域已有的HSH全新世剖面的地球化学和古生物指标进行对比,在分析沉积相的基础上讨论二者的环境代用指标,重建石羊河中游地区全新世的古环境。两个剖面在年代和岩性上具有很好的一致性,指示了石羊河中游地区约8500 cal yr BP-3000 cal yr BP以来的沉积过程。两剖面从底部到上部可分为六层：河流相沉积（F层）——河湖相沉积（E层）——湖相沉积（D层）——浅湖—风成沉积（C层）——风成沉积（B层）——风成沉积（A层）,代表了不同沉积相及其转换过程。综合讨论沉积物岩性、沉积相和各种古环境代用指标认为：石羊河中游地区的沉积相体现了从河流相到湖相再到风成沉积物的变化过程,指示了全新世的干旱化过程。这与以往研究中认为石羊河流域全新世气候变化具有波动性的观点存在一定差异。因此,在研究沉积相变化的基础之上讨论沉积物的物理、化学和生物指标的含义,而非简单地研究这些指标的数值,是干旱区流域性气候变化对比研究的新视角。 相似文献
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通过柴达木盆地察尔汗地区湖相沉积物的L*、a*和b*值与有关地球化学指标的相关关系分析,对湖相沉积物颜色指标在古气候研究中的意义进行了探讨,并据此分析了130 ka B.P.以来该区的古气候演变过程。结果表明,L*值与沉积物碳酸盐含量正相关,L*值高时,气候冷干,碳酸盐含量较高;反之,气温上升,湿度增加。b*值和a*值与沉积物中Fe、Mg含量相关,高a*值反映气温较高,b*值可用于反映湖水深度变化和有效湿度的变化,b*值高,湖水浅,氧化作用增强。察尔汗地区色度曲线反映的气候变化特征与其他的气候指标曲线相吻合。 相似文献
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浑善达克沙地全新世沉积特征与环境演变 总被引：44，自引：9，他引：44
浑善达克沙地全新世沉积主要有风成砂－古土壤和河湖相－古土壤－风成砂沉积序列，其中保存了大量粒度，化学元素，孢粉及披毛犀化石等环境变化证据。据此可把全新世气候划分为８个旋迥，经历了升温波动期（１０～７．１ｋａＢ．Ｐ．）、温暖期（７．１～３．２ｋａＢ．Ｐ．）和温干冷干频繁波动期（３．２ｋａＢ．Ｐ．至今）三个演变阶段。 相似文献
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塔克拉玛干沙漠腹地晚冰期以来的环境与气候变化 总被引：6，自引：1，他引：6
通过对塔克拉玛干沙漠腹地地层剖面的沉积类型、孢粉、ｐＨ值、有机质、ＣａＣＯ＿３和地球化学气候指标Ｃ等分析，认为本区晚冰期以来一直处于荒漠环境，气候变化可划出四个阶段：１３－１０ｋａＢ．Ｐ．气候寒冷。温凉，干旱，湿度相对后期较大；１０－８ｋａＢ．Ｐ．气候温暖干旱，湿度相对减小；８－３ｋａＢ．Ｐ．气候炎热干旱，湿度最小；３ｋａＢ．Ｐ．至今气候温暖干旱，湿度较前增大，气候及环境与今相似。 相似文献
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从１９９２年４月至１２月对东南极中山站近岸当年冰生物量及其环境因子进行了观测。冰底有色层出现在４月下旬和１１月下旬，集中于冰底２～３ｃｍ，叶绿素ａ最高含量分别为８８．３ｍｇ／ｍ３和２８１０ｍｇ／ｍ３，相应的冰藻数量分别为３．５×１０６和１．２１×１０８个／升。柱总叶绿素ａ含量的季节性变化极为显著，尤其是以春季的大幅度快速增值为特征，变化范围为１．１７～５９．７ｍｇ／ｍ２，冰藻生物量主要分布在冰底，冬季期间则集中在冰底或冰的中上层。藻类优势种较为单一，秋季优势种为Ｎｉｔｚｓｃｈｉａｌｅｃｏｉｎｔｅｉ、Ｎ．ｂａｒｋｌｅｙｉ和Ｎ．ｃｙｌｉｎｄｒｕｓ；春季优势种为Ａｍｐｈｉｐｒｏｒａｋｊｅｌｍａｎｉ，Ｂｅｒｋｅｌｅｙａｒｕｔｉｌａｎｓ和Ｎ．ｌｅｃｏｉｎｔｅｉ。中山站近岸冰藻生物量的垂直分布和季节变化以及春季优势种的组成与东南极其它固冰区具有较强的相似性，与亚南极固冰区差异较大。 相似文献
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CONCENTRATIONS AND DISTRIBUTIONS OF FREE AMINO ACIDS IN SEA AND LAKE ICE CORE OF ANTARCTICA 
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下载免费PDF全文 The sea ice core (1.6m) and lake ice core (1.5m) were taken respectively from sea sampling site and Ace Lake near Davis Station, Vestfold Hills, Antarctica in November and October, 1988. The concentrations of amino acids in each 10cm of ice cores were determined by High Pressure Liquid Chromatography (HPLC). The results showed that the concentrations of amino acids revealed seasonal variation during the year. The highest concentration of amino acids, which was 30. 92μmol/ml, were found in the bottom of sea ice core, and it was approximately 45 μmol/ml in the lake ice core. The lowest concentration was approximately 8.0μmol/ml which is presented in surface of the sea ice core, but it was 14.0μmol/ml which was found in 60cm section of lake ice core. The seasonal variation process of concentration of amino acids were much similar to that of phytoplankton cells number in sea ice core, and the distribution and seasonal variation rate of individual amino acids were also much similar in each ice core secti 相似文献
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本文着重描述了SGR钻孔处冰盖上的积雪在密实化过程中的特征变化,并对该过程进行了分段的和全面的回归分析.结果表明,冰盖密度随深度增大,但增长幅度随深度减小.作者提出密度变化减小度的概念.计算得出的所研究冰芯钻取点的密度变化减小度为-0.15kg/m~3·m~2,粒雪成冰前的密实速率平均值为4.08kg/m~3·a.本文得到的冰盖密度变化“临界点”与以往报道的有所不同.分析这一现象时,作者强调当积雪还在活动层时冰盖温度的影响,并以此解释密度剖面的异常变化以及离差的回升.特别指出,积雪的密度变化具有气候学意义,它在一定程度上能够反映出积雪形成及变化过程中气候变化的某些信息.本文由密度变化确定的钻孔点雪冰转化深度为50米. 相似文献
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LIU Shiyin WANG Ninglian DUAN Keqin XIAO Cunde DING Yongjian HAN Haidong 《地理学报(英文版)》2004,14(4):401-410
1IntroductionIn the early 1960s, glaciers in western China were classified into maritime- and continental-types by different glacial environment and physical characteristics (Shi and Xie, 1964). With extensive glaciological investigations in the western regions (Lanzhou Institute of Glaciology and Geocryology of CAS, 1988), Lai and Huang (1990) suggested a new classification of temperate, subpolar and quasipolar glaciers, corresponding to the maritime-, subcontinental- and extremely contin… 相似文献
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Glacier inventory compilation during the past 20 years and modifications of that for the Eastern Pamir and Banggong Lake indicate that there are 46,342 modern glaciers with a total area and volume of 59415 km2 and 5601 km3 respectively in China. These glaciers can be classified into maritime and continental (including sub-continental and extremely continental) types. Researches show that glaciers in China have been retreating since the Little Ice Age and the mass wastage was accelerated during the past 30 to 40 years. Being an important part of glaciological studies in China, ice core climatic and environmental studies on Tibetan Plateau and in the Antarctica have provided abundant, high resolution information about past climatic and environmental evolution over the Tibetan Plateau and Antarctica. Except for different parameters recorded in ice cores relating to climate and environment changes on Tibetan Plateau, records from ice cores extracted from different glaciers show that the discrepancies in climatic and environmental changes on the north and south parts of the plateau may be the consequence of different influencing effects from terrestrial and solar sources. Glaciological and meteorological phenomena imply that Lambert Glacier valley is an important boundary of climate in the east Antarctica, which is thought to be connected with cyclonic activities and Circum-polar Waves over the Antarctica. 相似文献
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Glacier inventory compilation during the past 20 years and modifications of that for the Eastern Pamir and Banggong Lake indicate that there are 46,342 modern glaciers with a total area and volume of 59415 km^2 and 5601 km^3 respectively in China. These glaciers can be classified into maritime and continental (including sub-continental and extremely continental) types. Researches show that glaciers in China have been retreating since the Little Ice Age and the mass wastage was accelerated during the past 30 to 40 years. Being an important part of glaciological studies in China,ice core climatic and environmental studies on Tibetan Plateau and in the Antarctica have provided abundant, high resolution information about past climatic and environmental evolution over the Tibetan Plateau and Antarctica. Except for different parameters recorded in ice cores relating to climate and environment changes on Tibetan Plateau, records from ice cores extracted from different glaciers show that the discrepancies in climatic and environmental changes on the north and south parts of the plateau may be the consequence of different influencing effects from terrestrial and solar sources.Glaciological and meteorological phenomena imply that Lambert Glacier valley is an important boundary of climate in the east Antarctica, which is thought to be connected with cyclonic activities and Circum-polar Waves over the Antarctica. 相似文献
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自１９９２年４月１２日至１２月３０日对中山站以西内拉峡湾海冰和冰下水柱中藻类优势种组成和丰度进行了测定。４月份和１１月中旬至１２月中旬冰柱和水柱（０～５０ｍ）藻类丰度高达１０８～１０９ｃｅｌｓ／ｍ２。冰藻的普遍或季节性优势种主要包括Ａｍｐｈｉｐｒｏｒａｋｊｅｌｍａｎｉ、Ｂｅｒｋｅｌｅｙａｒｕｔｉｌａｎｓ、Ｎａｖｉｃｕｌａｇｌａｃｉｅｉ、Ｎｉｔｚｓｃｈｉａｂａｒｋｌｅｙｉ、Ｎ．ｃｙｌｉｎｄｒｕｓ、Ｎ．ｌｅｃｏｉｎｔｅｉ和Ｎｉｔｚｓｃｈｉａｓｐ．。由于藻类结合入冰后自身的演替，春－夏季海冰剖面中所记录的优势种组成并不能准确反映冰底优势种的季节演替过程。从冰底和水表藻种组成的对比表明，两者仅在春末冰底冰藻水华期间具有较强的相似性。秋、春季冰底冰藻水华的形成以现场生长为主，夏初冰藻释放入水后对冰下浮游植物的播种作用不明显。 相似文献
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Studies of the past climate variation on the Tibetan Plateau(TP) are currently limited in number and low in density and temporal resolution. We investigated the climate condition from about 400 years before present(B.P.) in the central TP at the shore of Co(means "lake") Nag using aeolian sediments. A 2.7-m sand profile with 57 sediment samples and six optically stimulated luminescence(OSL) samples were studied through grain-size analysis, geochemical elements and parameters, and depositional rate estimation. A previous assumption was verified that sand deposition at the shore of Lake Co Nag originated from hills to the east. Two significant wet periods between 90–140 and about 380 years B.P. were indicated by the variation of element profiles and sediment depositional rates. Aeolian activity is sensitive to variations from different seasonal changing patterns of climate factors in the study area, and aeolian sediments respond differently to climate conditions during the cold little ice age(LIA) and the warm 20 th century. Present day dry seasons of winter and spring might be much warmer and drier compared to seasons of 400 years ago although summer precipitation has increased, resulting in significantly more aeolian activity and higher depositional rate(about 6 times compared to 380–240 years ago) of sandy sediments. Aeolian problems like blown-sand deposition and desertification may be worse in a projected warming future in the central TP as well as other cold and high altitude regions. Our results suggest an agreement with environmental evolution during the little ice age and the 20 th century in a broader scale on the TP. 相似文献