柴达木盆地南北推覆构造概论

柴达木盆地南北地区,可以划分出两个巨型推覆构造带,分别称为柴北缘推覆构造带和东昆仑推覆构造带。其间的柴达木盆地形成一个相对的应变减弱区(低应变带)。两大推覆构造带在相同力源作用下统一构成了青海省北部的基本构造格局,成为华北板块的南部边缘带,是华北板块与南华板块碰撞拼合形成的浅部构造变形的产物,也是南北板块拼合的证据。     

Precise timing of the Early Paleozoic metamorphism and thrust deformation in the Eastern Kunlun Orogen

In Dulan County, Qinghai Province NW China, the arc volcanic sequences in the northern side of the Central Fault of the East Kunlun were metamorphosed progressively from upper greenschist facies in the south to epidote-amphibolite facies in the north. High-angle thrust deformation was developed synchronously with the peak metamor-phim and superimposed with later low-angle striking-slip deformation. Zircon U-Pb dating yields a concordant age of(448 ± 4) Ma for the metavolcanics. Syn-kinematic horn-blende and muscovite separated from the high-angle thrusting belt give ⁴⁰Ar-³⁹Ar plateau age of (427 ± 4) Ma and 408 Ma, respectively. These results precisely constrain the timing of the closure of early Paleozoic volcanic basin (Proto-Tethys) over the eastern portion of the East Kunlun Orogen, and the thrust tectonic slice had a cool rate of ca. 9℃/Ma. Keywords: East Kunlun Mountains, metamorphic and deformation event, geochronology.     

东昆仑造山带下中三叠统沉积岩地球化学特征

东昆仑造山带具有软磁撞、多旋回的特点，造山带内的沉积盆地具有多物源和不同的大地构造背景，东昆仑造山带东段下、中三叠统沉积岩的常量元素组成特征表明，母岩大多数为杂砂岩，部分为长石砂岩和岩屑砂岩，表明该沉积盆地是一个多物源的浊积岩复理石盆地，陆源碎屑来自与其吡邻的活动大陆边缘、被动大陆边缘和火山岛弧，稀土元素的配分模式和特征值表明该沉积盆地的大地构造背景具有活动大陆边缘和大陆岛弧的特征，更接近于活动大陆边缘，说明该盆地是一个发育于大陆壳这上的复理石前陆盆地。     

青藏高原日土地区构造单元划分,特征及演化

西藏高原的构造单元及深断裂基本上汇聚在日土地区,是揭开青藏高原成因奥秘关键之地。笔者将该地区划分为6个亚一级和若干次级构造单元:昆仑海西、冈底斯早燕山两褶皱系和巴颜喀拉印支褶皱带具典型地槽性质,喀喇昆仑晚海西、喜马拉雅晚燕山两褶皱系和羌塘地块趋于准地台性质。各单元由活动转稳定过程、深断裂形成与封闭、岩浆活动等均具北老南新逐渐阶段性迁移特征;岩石圈固结有自北而南逐渐推移扩大趋势。巨大蛇绿岩带显示新生地槽的发展演化。     

Genetic consequences of postglacial colonization by the endemic Yarkand hare （Lepus yarkandensis） of the arid Tarim Basin

Orogenesis of the Qinghai-Tibetan Plateau,which occurred in a stepwise manner,contributed to the extreme aridity of the Tarim Basin,resulting in vulnerable and unstable ecosystems.Quaternary climatic oscillations may have affected the ecosystems and,consequently,the distributions and genetic structuring of the Tarim Basin’s biota.We used nucleotide sequence data from 2 mitochondrial (mt) DNA genes (Cyt b and the D-loop) to test hypotheses associated with the matrilineal and demographical histories of the Tarim Basin’s endemic Yarkand hare (Lepus yarkandensis).Range-wide sampling involving 20 populations and 224 individuals detected 126 haplotypes that clustered into 5 major lineages in both the phylogenetic tree and median-joining network.Populations from the northern and eastern Tarim Basin shared a similar history,as did those from the western and southern regions.Demographical analysis and genetic diversity estimations suggested that the western and southern regions might have served as glacial refugia for the Yarkand hare during Quaternary climatic oscillations.The distribution of the Yarkand hare,especially in the northern and eastern parts,probably represented 3 postglacial colonization events,dated to 0.21,0.090 and 0.054 MYA,which corresponded to known interglacial periods.Given the relatively complete geographic isolation between the eastern and southern populations,the Yarkand hare likely dispersed during postglacial periods from the southwest to the north,and then onward to the east.The absence of water likely forced the species into refugia,and this differed from other Pleistocene biogeographical drivers.The demographical and historical patterns have important implications for conservation.     

基于遥感解译的西昆仑盆山耦合带构造地质特征

通过ETM图像解译,结合区域地质调查资料,对西昆仑造山带及其前陆盆地的大地构造归属问题进行分析研究。西昆仑归属于青藏大陆边缘造山带,构造运动学机制为由南向北剪切逆冲,形成强劲的剪切推覆带,塔里木南缘表现为由北向南俯冲,认为盖孜-库斯拉甫断裂是青藏大陆与塔里木大陆的控制性断裂。     

巴彦浩特盆地沉降史分析

运用回剥分析技术对巴彦浩特盆地的沉降史作了定量方面的研究，认为巴彦浩特盆地是在早古生代的古隆起基础上发育起来的，共经历了两个隆升期和三个沉降期，两个隆升期是：三叠纪—早侏罗世、晚白垩世；三个沉降期是：志留纪—二叠纪、中侏罗世—早白垩世及第三纪—第四纪．相应地形成了四种类型的盆地，即志留纪—二叠纪前陆盆地（南部坳陷带）、石炭纪—二叠纪裂陷槽（东部坳陷带及其以东地区，为贺兰裂陷槽的一部分）、中侏罗世—早白垩世断陷盆地及新生代的坳陷盆地．晚古生代时，沉降主要发生在盆地的南部坳陷带及东部坳陷带内，侏罗纪时，南部坳陷带隆起，西部坳陷带及东部坳陷带为主要沉降区，受断陷活动控制，其间为中央隆起带分隔．早白垩世盆地全面下沉，成为统一盆地     

塔里木盆地周缘洋盆开合在盆地内部的构造沉积响应

依据塔里木盆地周缘蛇绿岩年龄及盆内钻井岩性、古生物、地球物理等资料,以古天山洋和古昆仑洋的开合演化为线索,将盆地构造沉积响应划分为五个期次。南华纪-震旦纪早世Rodinia泛大陆开始裂解,塔里木陆块北部发育南天山海槽、南部发育库地小洋盆,同期塔里木盆地只有中北部地区沉积碎屑物,塘古孜巴斯至古城墟地区为古隆起无沉积;震旦纪晚世-奥陶纪中世南天山洋和北昆仑洋(原库地小洋盆)进入成年期,塔里木陆块西部高地发育快速生长的碳酸盐岩台地,东部低地(满加尔)发育饥饿盆地,塔里木陆块形成了西台东盆的沉积格局;奥陶纪晚世-泥盆纪北昆仑洋和南天山洋分别向中昆仑和中天山微陆块俯冲(最终与塔里木陆块拼贴),塔里木陆块边缘逐渐出现不同规模的陆源剥蚀区,陆块内碳酸盐台地逐渐消亡;石炭纪-二叠纪中世北天山洋和南昆仑洋-阿尼玛卿洋关闭造山,塔里木陆块内部实际处于广义的弧后扩张状态,期间接受了海陆交互相碎屑岩沉积及海相碳酸盐岩沉积;二叠纪晚世至今金沙江洋、澜沧江洋、班公-怒江洋和雅鲁藏布江洋等先后关闭,受此影响天山、昆仑造山带强烈抬升,塔里木盆地发育库车和塔西南2个前陆盆地。     

Modeling impacts of East Asian Ocean-Land thermal contrast on spring southwesterly winds and rainfall in eastern China

Using the National Centers for Environmental Prediction–National Center for Atmospheric Research （NCEP–NCAR） reanalysis dataset, the NOAA’s Climate Prediction Center’s merged analysis of precipitation, and the MM5v3 Meso-scale Model, the impacts of surface temperature differences between the East Asian land and its adjacent oceans on spring southwesterly winds and rainfall over eastern China are studied. The modeling results show that the temperature differences exert strong influence on the occurrence of the southwesterly winds and rainfall over southern China and their northward advances. When surface temperature increases over the land and decreases over the oceans, the temperature gradient with a winter feature earlier changes toward the gradient with a summer feature. Both the low-pressure system east of the Tibetan Plateau and the subtropical high-pressure system over the western Pacific strengthen, accompanying with the strengthening of the lower-tropospheric southwesterly winds over eastern China. Accordingly, the upward motion increases over the Yangtze-Huaihe River （YHR） valleys and decreases over southern China, leading to an increase of spring rainfall over the YHR valleys and a decrease over southern China. Thus, the rain belt over eastern China appears over the YHR valleys but not over southern China. Under a weaker condition of the spring thermal contrast, the rain belt does not occur over eastern China. When the spring thermal contrast pronouncedly strengthens, the rain belt over southern China may advance northward into the YHR valleys during spring, though there is no onset of the tropical monsoon over the South China Sea. This forms a rain belt similar to that of the YHR valleys during the summer Meiyu period.     

柴达木盆地中新世中期以来构造的运动学模型

柴达木盆地是位于青藏高原内部的山间盆地,盆地新生代的变形受到两侧山体隆升的主导.通过贯穿盆地地震剖面的精细构造解释和分析,依据生长地层的结构,我们认为自中新世中期以来昆仑山前冲断楔体以平均4.7 mm/a的速度向盆地逆冲,导致盆地南斜坡向昆仑山方向仰冲;这为东昆仑山北麓出露的倾向北向南逆冲的多条断层和盆地南部向南逆冲的断层控制的断层相关褶皱作用所证实.盆地北部祁连山前冲断楔体向盆地方向逆冲,导致盆地北部向北逆冲的断层在地表形成北翼陡、南翼缓的断层相关褶皱背斜,向北逆冲的断层在盆地东部局部位置出露地表.昆仑山前冲断楔体和祁连山前冲断楔体的楔顶已经相向冲断至盆地中部,并造成第四系的变形.     

滇东南木利锑矿坡脚期生物礁及其控矿意义

产于下泥盆统坡脚组的滇东南木利生物礁是华南泥盆系众多生物礁中层位最低的。礁类型特殊,属发育在砂泥质陆棚坡折带的堤礁。该礁长约8km,宽150-200m,高70-80m,由间隔黑色页岩的三层礁体组成,每个礁体可划分出6个亚相和5个生长演化阶段。通过锑矿定位机制和矿床成因研究,该礁对锑矿有极重要的层、相、位控制作用,控矿机理为礁型古“油气捕”转化为“矿捕”的作用。     

Reservoir-forming age and its exploration sisnificance to stratisraphic reservoirs in southern Songliao Basin

Despite many studies concerning the forming age, evolution characteristics and the age of petroleum charging in the Fuxin upheaval of southern Songliao Basin, no consensus has been reached so far. This paper presents the first K-Ar dating of autogenetic illite from stratigraphic petroleum reservoirs in the Fuyu oil layer of the Fuxin upheaval belt. Isotopic test and age calculation were carried out based on the separation and purification of illite mineral, X-diffraction analysis and the detection of scanning electron microscopy. The evolution characteristics of structure, sedimentation, reservoir-forming about the Fuxin upheaval belt were interpreted in terms of the synthetical analysis of ＂six-type geological history＂ evolution in southern Songliao Basin. The geologic background of petroleum evolution and reservoir formation are similar in the entire central depression region of southern Songliao Basin. The Changling sag and the Fuxin upheaval belt brought about obvious upheaval-sag separation after the hydrocarbon-generation peak of K2qn^1 and the main reservoir-forming period of the Fuyu oil layer, namely reservoir-forming happened before the Fuxin upheaval belt extensively raised. The reservoirs have three characteristics： the hydrocarbon source rock above the reservoir, the oil source in the locality, and the vertical migration. The geological cognition is corrected, that is, oil source came from the Changling sag and migrated from the side direction. The bulk process of petroleum charging in the stratigraphic hydrocarbon reservoirs in the Fuxin upheaval belt of southern Songliao Basin is determined according to the isotopic age of autogenetic illite in combination with the method of fluid inclusions. The cognition is helpful to exactly evaluate the resource potential and exploration direction in the Fuxin upheaval belt, Changling sag and their peripheral areas. The present results indicate that the combination of the two methods （the K-Ar dating of autogenetic illite and fluid inclusions） is an effective way to lay bare petroleum charging history and ascertain reservoir age.     

台中-晋江横向构造带对福建现代地壳变形和地震的影响

台中-晋江横向构造带是一条重要的断裂带,控制了福建地区新生代地壳变形和现今地壳运动的南北差异。研究表明,受该断裂带控制,形成福建现代地壳运动南北分区,地壳活动南强北弱、南升北降的特点;历史中强地震基本分布在断裂以南的东部和邻近海域地区,形成南部地震集中区;1999--2006年环境剪应力值高值区集中分布在台中-晋江横向构造带以南,也反映了南强北弱、南北分区的特点。     

柴达木盆地东部"走廊域"中新生代构造特征及构造演化

通过横穿柴达木盆地东部的“走廊域”剖面地表地质、航磁、重力、大地电磁测深和地震资料的综合分析，认为在东昆仑构造带与南祁连构造带之间，包括巴颜喀拉地块北缘，柴达木地块和祁连地块南缘等3个一级构造单元，柴达木地块内则包括了昆中构造带、昆北构造带和柴达木盆地3个二级构造单元。受东昆仑构造带和南祁连构造带相向挤压作用，柴达木盆地东部持续沉降，但由于具有稳定的花岗质基底，盆地坳陷幅度较小，且断裂及褶皱构造不发育。由此造就了柴达木盆地东部中新生代地层厚度小，烃源岩不发育，构造圈闭缺乏，除第四系天然气外，中生界、古近系和新近系油气资源前景受到极大限制。     

The large-scale ductile shear zone in Kuda, western Kunlun

A set of metamorphic suites, previously known as the Precambrian metamorphic basement in Kuda, western Kunlun has been determined as a large nappe ductile shear zone which develops penetrative foliation, oriented stretching lineation, various but consistent kinematic indicators of thrusting from north to south. The microstructure and the supermicrostructure also display the ductile deformation characteristics, and the paleotectonic differential stress is obtained. The metamorphic age is 426–451 Ma dated by⁴⁰Ar/³⁹Ar method. According to tectonic background, it is a product of early Paleozoic accretionary wedge orogenesis in western Kunlun.     

Coral reef ecosystems in the South China Sea as a source of atmospheric CO<Subscript>2</Subscript> in summer

Field measurements of air-sea CO2 exchange in three coral reef areas of the South China Sea (i.e. the Yongshu Reef atoll of the Nansha Islands, southern South China Sea (SCS); Yongxing Island of Xisha Islands, north-central SCS; and Luhuitou Fringing Reef in Sanya of Hainan Island, northern SCS) during the summers of 2008 and 2009 revealed that both air and surface seawater partial pressures of CO2 (pCO2) showed regular diurnal cycles. Minimum values occurred in the evening and maximum values in the morning. Air pCO2 in each of the three study areas showed small diurnal variations, while large diurnal variations were ob-served in seawater pCO2. The diurnal variation amplitude of seawater pCO2 was ~70 μmol mol–1 at the Yongshu Reef lagoon, 420–619 μmol mol–1 on the Yongxing Island reef flat, and 264–579 μmol mol–1 on the reef flat of the Luhuitou Fringing Reef, and 324–492 μmol mol–1 in an adjacent area just outside of this fringing reef. With respect to spatial relations, there were large differences in air-sea CO2 flux across the South China Sea (e.g. ~0.4 mmol CO2 m–2 d–1 at Yongshu Reef, ~4.7 mmol CO2 m–2 d–1 at Yongxing Island, and ~9.8 mmol CO2 m–2 d–1 at Luhuitou Fringing Reef). However, these positive values suggest that coral reef ecosystems of the SCS may be a net source of CO2 to the atmosphere. Additional analyses indicated that diurnal variations of surface seawater pCO2 in the shallow water reef flat are controlled mainly by biological metabolic processes, while those of deeper water lagoons and outer reef areas are regulated by both biological metabolism and hydrodynamic factors. Unlike the open ocean, inorganic metabolism plays a significant role in influencing seawater pCO2 variations in coral reef ecosystems.     

西昆仑上新世隆升的砂岩重矿物特征及金红石地球化学记录

对西昆仑造山带山前叶城地区柯克亚剖面新生代砂岩样品中重矿物及碎屑金红石的微量元素进行分析, 结果表明重矿物含量及其组合特征具有明显分段性, 上新世阿图什组(N2a)底部以下为较稳定重矿物阶段, 以上为不稳定重矿物阶段, 反映西昆仑在上新世经历过一期快速隆升过程。碎屑金红石微量元素特征表明, 剖面从下至上, 源岩为泥质变质岩的比例逐渐降低, 基性变质岩的比例逐渐增高, 反映西昆仑快速隆升导致基底被抬升剥蚀, 基底岩石对物源的贡献增大。金红石母岩类型主要为角闪岩/榴辉岩相和麻粒岩相变质岩, 可能由于西昆仑西部快速隆升, 形成西高东低的地貌格局, 西昆仑西部成为该区的优势物源区。     

Discovery of a large area of ice-wedge networks in Ordos： Implications for the southern boundary of permafrost in the north of China as well as for the environment in the latest 20 kaBP

Deep sea deposits, ice cores and loess deposits have been used extensively and successfully, to study global climatic changes. Since permafrost is a consequence of cold climates, indicators of permafrost can also be used to reconstruct ancient climates in certain areas during certain periods. The recent discovery of large areas of ice wedge networks, and determination of their ages, have enabled us to locate the southern boundary of the permafrost that ex-isted in China about 20 thousand years…     

苏丹Fula坳陷同裂谷期构造格局和沉积体系分布

Muglad盆地Fula坳陷是一个发育于晚侏罗世—早白垩世的裂谷盆地,发育着3条较大的同沉积断裂和东、西两侧的控盆边界断层,这些断裂将盆地分割成"两凹一隆两斜坡"的构造格局.Fu-la坳陷内部次级构造单元包括南部断阶带、南部凹陷、中部构造带、北部凹陷和北部断阶带"三正两负"5个二级构造带.盆地断裂的差异活动控制着沉积地层厚度、水体深浅和沉积格局的变化.同裂谷早中期,Fula坳陷发育河流、三角洲和近岸水下扇沉积,主要物源来自盆地北部;同裂谷中晚期,Fula坳陷发育扇三角洲、三角洲和近岸水下扇沉积,但主要物源来自盆地南部.最后,明确了生储盖组合特征,预测了有利储层分布地区.     

青藏高原隆升对中国疆域自然环境的影响：破解“胡焕庸线”的思考

我国疆域广大,人口、土地、耕地和发展程度很不均衡。1933年,知名学者胡焕庸据此提出了著名“胡焕庸线”。利用这条北东南西走向直线,将中国大陆划分为东西两个部分。该线的东、西两侧差异悬殊。究其原由,制约因素的多元的,而近地表的自然环境和地球内部物质与能量的交换起着重要作用。研究与探索表明:(1)印度次大陆与欧亚大陆两陆—陆板块的碰撞—挤压驱使高原南缘喜马拉雅造山带的突起是根本原因。(2)喜马拉雅造山带的突起阻隔了印度洋南来温湿气候的北进,并形成了西风带造成了我国西北地域的干旱和荒漠化。(3)在力系作用下,壳、幔物质重新分异、调整,地壳短缩增厚、高原整体台升不仅导致东、西两部降水量、气温、人口、耕地与生态环境的显著改变,且地球物理场发生了强烈变异与分布不均。(4)西部发展的关键在于水,水进则人进,人进则文化进,文化进则科技进,科技进则发展快,西部人民生活与生存环境不断优化,社会则更安宁。(5)东部不断强化开辟地下空间与利用,西部期盼“红旗河”工程实施,维护生态环境,兴建亿亩现代化耕地、牧场与绿洲。我国东部与西部共同发展与建设十分重要,饭碗要永远端在自己手中。