三江多才玛超大型铅锌矿床同位素地球化学及矿源研究

多才玛超大型铅锌矿床是三江北段铅锌铜银多金属成矿带中的典型矿床,其主要硫化物的δ34S值变化范围大,主要集中于-26.72‰~-4.1‰之间,具塔式分布特征;其中,方铅矿的δ34S最高值大于黄铁矿的相应值。这表明成矿过程中硫同位素未达到平衡,硫主要是细菌还原硫酸盐的产物。矿区208Pb/204Pb=38.985~39.253,206Pb/204Pb=18.825~18.918;铅同位素构造环境演化图解和Δβ-Δγ成因分类图解显示铅的来源复杂多样,不仅来自上地壳和造山带,还来自壳幔混合的俯冲带。δ13CV-PDB=1.2‰~6.7‰,而δ18OV-SMOW=16.4‰~23.4‰,碳氧同位素明显来源于海相碳酸盐岩,成矿过程中应伴随有碳酸盐岩的溶解作用。综上,多才玛大型铅锌矿成矿物质来源复杂,碳酸岩围岩和深部物质都有可能提供成矿物质来源,生物作用参与成矿的痕迹明显。     

胶东大庄子金矿微量元素及Pb-S同位素地球化学研究

报道了大庄子金矿Pb、S同位素 ,稀土和微量元素等地球化学特征 ,并讨论了其地质意义 .大庄子金矿Pb同位素组成与胶东群和荆山群相似 ,而S同位素组成 (δ34Scdt=1 1 .9‰±0 .4‰ )与荆山群更为相近 ,Pb、S同位素组成与胶东主要金矿基本一致 ,研究显示其成矿物质可能主要来源于胶东群和荆山群 .对蚀变岩和较新鲜原岩的稀土 (REE)和微量元素含量研究发现 ,钾化蚀变过程中两者都从流体中带入围岩 ;而绢英岩化蚀变过程中 ,REE从围岩中带出 ,微量元素既有带入也有带出 ;Cu、Pb、Zn等主要金属元素在两蚀变过程中主要是带入 .围岩及黄铁矿的稀土元素分配曲线特征 ,揭示了成矿物质的沉淀明显受微观环境的制约 ,浸染状黄铁矿的沉淀伴随着成矿流体与围岩之间的蚀变作用而发生 ,此时水 /岩反应进程导致的成矿流体PH值和Eh值等因素的变化 ,可能是成矿物质沉淀的主导因素 ;而脉状黄铁矿则直接从成矿流体中沉淀而出 ,围岩的影响不明显 ,成矿流体演化过程中温度、压力的变化 ,可能是成矿物质沉淀的主导因素     

A carbon- and oxygen-isotope record of recent environ- mental change from Qinghai Lake, NE Tibetan Plateau

An understanding of natural climatic variability is essential for evaluating anthropogenic impacts on recent and future climate[1—3]. Due to the lack of lengthy instrumental records, such an understanding must be gained from natural archives of climate change. Palaeolimnological indicators of past lake levels may provide a sensitive record of changes in effective precipitation in closed basins. This approach is particularly relevant on the Tibetan Plateau, where instrumental records are very…     

试论"环青海湖国际公路自行车赛"对高原旅游业发展的影响

本文就“环青海湖国际自行车公路赛”对青海高原旅游业发展的意义、作用以及对沿途周边地区体育旅游资源的影响进行了讨论.     

青海湖环湖区蝗虫与地貌类型关系的研究

蝗虫对青海湖环湖区的草地有相当严重的危害．摸清蝗虫发生与其生态条件之间的关系,是进行蝗虫有效防治的前提．不同类型的地貌通过其对水热条件的重新分配对蝗虫的发生有不同的影响．作者根据野外实地调查资料,就环湖区蝗虫发生与湖滨阶地、构造台地及山坡地等该区主要地貌类型与蝗虫密度的关系进行了初步研究．     

Quantitative reconstruction of the paleosalinity at Qinghai Lake in the past 900 years

Based on the function relationship between the shell length of Limnocythere inopinata and the salinity of its living water in Tibetan Plateau lakes, the paleosalinty of Qinghai Lake in the past 900 years was reconstructed through the measurement of the adult body length of Limnocythere inopinata. Meanwhile, the paleosalinity sequence of Qinghai Lake during the same period was rebuilt by the St/Ca ratio of the shell of Eucypris inflata combined with the St/Ca ratio of living ostracod valves from the species of genus Eucypris inflata and the host water. The paleosalinity results obtained by two different methods were compared and assessed in this paper. To check the result, it was also contrasted with other historical climatic sequences of this area including tree ring and ice core. It was shown that the paleosalinity sequence rebuilt by adult ostracod body length had high reliability, and the paleosalinity reconstruction method by trace elements of ostracod shells was not suitable for Qinghai Lake. From the reconstructed paleosalinty sequence of Qinghai Lake, it can be found that low salinity during 1160-1290 AD showed the humid climate condition on the Mediaeval Warm Period in this area, while the high salinity during 1410-1540 AD, 1610-1670 AD and 1770-1850 AD which was corresponding to the three cold pulses of the Little Ice Age with a dry climate condition. And the high salinity in the latest several decades was consistent with recent warm and dry trends of the climate in this area. The good consistency of the reconstructed palaeosalinity sequence and the precipitation sequence in this area rebuilt by tree ring proves the reconstruction of past lake salinity is reliable.     

青海省吸血蚋类区系调查研究初报(双翅目:蚋科)

对青海省蚋类进行初步分类区系调查,摸清该省代表性地区的蚋类区系分布。方法:选择青海省6个不同生境的代表性地区,采用常规方法采集幼蚋,经隔离培养育出成虫,制片、鉴定、编制名表并进行相关讨论。结果:记载青海省蚋科3属(畦克蚋属、后克蚋属、蚋属)共20种,其中含9个新种。结论:青海省具有蚋类多样性及明显地方性,反映了古北界区系特征并具有东洋界和古北界过渡性的区系特征。     

青海湖沉积物中微量元素纵向分布反映的古环境意义

通过对青海湖QH1岩心沉积物中微量元素Li,V,Cs,Co,REE(La,Ce,Pr,Nd,Sm,Eu,Gd,Tb,Dy,Er,Yb)及wCs/wRb的高分辨率分析,结果表明:微量元素在沉积物中的质量分数变化与沉积环境密切相关,在温暖湿润的气候环境下,沉积物中w∑REE,wLi,wV,wCs,wC.较高、wCs/wRb较大;而在冷干的气候环境条件下,元素质量分数相对较低.∑REE(稀土总量)与wCs/wRb之间呈良好的正相关性,∑REE可以作为反映青海湖环境的一个有效指标.近8500年来湖区气候环境变化特征表现为冷干与暖湿的交替,气候的突变在沉积物上表现为元素质量分数的突变.     

青海湖面积动态监测系统的设计与实现

文中以遥感影像为依托,根据历史及现有的遥感影像数据生成各时期青海湖范围水涯线,结合其他矢量数据以及统计数据,设计并实现了“青海湖面积动态监测系统”.系统能够将青海湖面积变化以多种方式客观、科学的展现出来,为青海湖流域生态环境保护和综合治理提供了数据参考.     

A carbon－and oxygen－isotoperecord of recent environ－mental change from Qinghai Lake, NE Tibetan Plateau

A c. 300-year oxygen and carbon isotope record derived from fine-grained and ostracod carbonate from Qinghai Lake testifies to dramatic interannual to illterde-cadal linmologicai change. Fine-grained carbonates, whichare mainly authigenic, are likely to have formed in the epillmnion of the lake and their isotopic composition reflects the summer temperature and, more importantly, the isotopic composition of the near-surface waters, which is mainly afunction of evapor ative concentration. Ostracod shells aresecreted in the benthos of the lake, and their isotopic compo-sition reflects summer bottom-water conditions, together with fractionation effects, which may differ between species.Differences between contemporaneous values from authi-genic carbonates and ostracod shells may provide an indica-tion of stratification within the lake and variations in effec-tive precip itation over the northeast part of the Tibetan Pla-tcau over the past 300 years. A period of moderate evapora-tive concentration, from about 300 to 100 yr BP, was inter-rupted by a marked wet phase from-100 to 40 vr BP. which was in turn followed by a return to drier conditions in the most recent part of the record. The increase in δ^18O values in the latter part of the record accords well with instrumental records of lake-level lowering and salinity increase since about 1955 AD.     

青海早熟禾属植物系统修订

本文通过对青海省早熟禾属植物的研究,提出了一个青海省早熟禾属分类系统排列,首次确认青海省产10组45种,其中8种为青海新记录种类,2种青海特有种．     

青海湖水位下降的生态环境效应

本文主要分析了青海湖水位下降所导致的湖区生态环境变化,指出青海湖流域的生态环境保护与综合治理任重道远.     

A 16000-year pollen record of Qinghai Lake and its paleo-climate and paleoenvironment

The paleoclimate and paleoenvironment of Qinghai Lake indicated by a 16000-year pollen record are as follows. It was very cold and dry before 15200 years. During the Late Glacial, the climate varied from colder and semiarid to cool and semi-humid and fluctuated frequently but with little amplitude. Three cold events in the periods of 13400–13000, 11600–12000, and 11000–10400 aBP respectively correspond to the Oldest Dryas, Older Dryas and Younger Dryas events, whereas the two warm periods between them, 12000–13000 and 11600–11000 aBP, respectively correspond to Bölling and Alleröd periods. The temperature increased abruptly after the Younger Dryas event, and then the climate gradually turned to be warm and wet from warm and semiarid. In the Holocene, the largest amplitude of cold event that occurred at ca. 8200 aBP is quite prominent. The Holocene climatic optimum culminated at 6700 aBP. After 2100 aBP, the climate tended to be cold and dry, keeping on up to now. Palaeoclimatic evolution and events of Qinghai Lake based on pollen assemblage and concentrations can be well parallel with the global climatic events.     

青藏高原西部燕山晚期花岗岩地球化学特征及其大地构造意义

对青藏高原西部燕山晚期花岗岩进行了地质、地球化学综合研究。结果表明 ,燕山晚期早白垩世花岗岩为 I型 ,形成于火山弧环境 ,岩石组合为石英二长闪长岩 -花岗闪长岩 -二长花岗岩 ,岩石系列为高钾钙碱性系列 ,A/ CNK<1,稀土元素含量中等 ,并且属轻稀土富集型 ,铕亏损不明显 ,L IL E有选择地得到富集 ,HFSE相对亏损 ;晚白垩世花岗岩为 S型 ,形成于同碰撞环境 ,岩石组合为二云母二长花岗岩 -二云母花岗岩 ,岩石系列为高钾钙碱性系列 ,但 A/CNK>1.1,稀土元素含量较低 ,铕亏损明显 ,微量元素中以 Rb和 F含量高为显著特征。为研究喀喇昆仑山构造演化提供了限定条件     

WDC-D地球化学数据分类与编码的初步研究

首先以地球化学实体为基本分类对象,运用线分类法进行数据分类.作者共把地球化学数据分为四个层次,从第一到第四层次的数据量分别为9、40、192和604.然后作者采用层次码编码方法对数据进行编码.码长共有9位,第1位用“J”表示地球化学数据分类在WDC-D中的顺序;第2位用“1~9”表示第一层次数据;第3、4位,第5、6位,第7、8位均用“00~99”分别表示第二、三、四层次数据,第9位用“1~3”表示数据的共享级别.     

基于RS和GIS的青海湖流域湿地景观格局变化分析

在RS和GIS技术支持下,以1987年、2000年以及2010年的TM遥感影像为数据源,利用人机交互目视解译方法获取青海湖流域湿地景观数据,运用景观生态学原理,选取景观破碎度和景观分维数,对青海湖流域的湿地景观格局变化进行定量的分析.结果显示,(1)青海湖流域的主体湿地景观是高寒沼泽.(2)青海湖流域湿地景观的面积波动明显,景观结构发生了一定变化.(3)1987~2000年湿地景观面积逐渐迅速减少,景观破碎度以及景观分维度明显增加.(4)2000~2010年湿地景观面积增加迅速,景观的破碎度显著减少,景观聚合程度增强.