干旱区地下水咸化机制的区域氘盈余解析

定量研究干旱区地下水的咸化机制对于水资源管理具有重要意义。针对已有研究需要考虑补给源水δ18O和δ2H值的局限,提出了一种利用区域氘盈余计算初始水、蒸发和溶滤对地下水咸化贡献的方法,并以罗山地区第四系地下水为例进行了分析。结果表明:该方法计算误差较小,可以有效区分蒸发和溶滤的贡献。地下水先溶滤后蒸发的自然咸化过程决定了溶滤作用的主导地位,咸化规模主要取决于溶滤作用程度。     

Variability and stability of water resource in the arid regions of China: a case study of the Tarim River basin

In this study, we analyzed two long term streamflow records of the Aksu River basin, the main water source of the Tarim River basin, using multiscale t-test and F-test with the aim to understand the changing characteristics of hydrological regimes in terms of the first moment (mean or average) and the second moment (variance). The results indicate the following: 1) In general, increasing streamflow was observed in two periods: 1965–1970 and 1980–1985. Since 1986, the streamflow of the Aksu River has been persistently increasing. 2) Synchronous variations can be found between the subseries variance and the subseries mean, i.e., an increase in the subseries mean is usually consistent with an increase in the subseries variance, and vice versa. Therefore, streamflow changes of the Aksu River tend to be unsteady, although streamflow is persistently increasing since 1986. 3) The streamflow changes of the Aksu River are heavily dependent on precipitation and ice melting. Increase of precipitation and more ice melting in recent decades, particularly after the 1980s, are the major causes of streamflow changes of the Aksu River basin.     

塔里木盆地西北缘皮羌辉长岩体的时代讨论

皮羌辉长岩体位于塔里木盆地柯坪断隆西部,皮羌村北约15 km处。该岩体的围岩包括志留系、泥盆系和石炭系—二叠系,新近系不整合覆盖其上。采集该辉长岩样品进行单矿物分离,取分离出的斜长石进行Ar-Ar定年。700～1400℃的8个加热阶段析出的~(39)Ar为总量的95.89%,在坪谱图上得到一个较稳定的坪,坪年龄为265.5±1.2 Ma;与之相对应的等时线年龄为267.29±5.62 Ma。结合区域地质分析,皮羌辉长岩体的侵入时代为中二叠世早期;是塔里木二叠纪岩浆活动的一部分。其侵入后基本未受后期构造热事件影响。     

塔里木盆地西北缘皮羌辉长岩体的时代讨论

皮羌辉长岩体位于塔里木盆地柯坪断隆西部,皮羌村北约15 km处。该岩体的围岩包括志留系、泥盆系和石炭系—二叠系,新近系不整合覆盖其上。采集该辉长岩样品进行单矿物分离,取分离出的斜长石进行Ar-Ar定年。700～1 400 ℃的8个加热阶段析出的39Ar为总量的95.89％,在坪谱图上得到一个较稳定的坪,坪年龄为265.5±1.2 Ma; 与之相对应的等时线年龄为267.29±5.62 Ma。结合区域地质分析,皮羌辉长岩体的侵入时代为中二叠世早期; 是塔里木二叠纪岩浆活动的一部分。其侵入后基本未受后期构造热事件影响。     

塔里木盆地西部的新生代断裂活动

研究区以塔里木盆地西部的巴楚隆起为核心,包括其南侧的麦盖提斜坡和北侧的北部坳陷(阿瓦提凹陷)。这里新生代断裂异常发育。以鸟山-古董山地区为重点,通过精细的地震剖面解释,在塔里木盆地西部识别出5期新生代断裂活动,分别发生于:白垩纪末-古近纪初(ca.65Ma)、中新世末-上新世初(ca.5Ma)、上新世末-更新世中期(ca.3~1.5Ma)、更新世中-晚期(ca.1~0.1Ma)和全新世(ca.0.01Ma)。中寒武统和古近系膏盐层构成了研究区的2个主滑脱面。ca.65Ma的冲断受控于基墨里中间大陆与亚洲大陆碰撞的远程效应;ca.5Ma、ca.3~1.5Ma、ca.1~0.1Ma和ca.0.01Ma的断裂活动(包括滑脱断层、冲断层、走滑断层和正断层)均受控于印度-亚洲碰撞的远程效应。晚新生代(中新世以来)的断裂活动以脉动式冲断为特征,两次相邻脉动式冲断之间为时间不等的短暂的构造间歇期;间歇期构造平静,甚至可以形成正断层。     

塔里木盆地西部奥陶系内部不整合

塔里木盆地西部柯坪地区奥陶系内部存在两期主要不整合。其一,位于下奥陶统蓬莱坝组与鹰山组之间,为平行不整合。该不整合在柯坪县北水泥厂剖面上缺失牙形石Glyptoconus floweri带和Tripodus proteus—Paltodus deltifer带,有大至相当于5.5Ma的地层缺失量;在乌什县鹰山北坡剖面上缺失了牙形石Glyptoconus quadraplicatus带、Glyptoconus floweri带和Tripodus proteus/Paltodus deltifer带,有相当于约7.2Ma的地层缺失量。其二,存在于上奥陶统铁热克阿瓦提组与下伏地层之间,主要为平行不整合,局部为角度不整合。古生物研究表明其间的地层缺失量变化相当大,在柯坪大湾沟、大湾沟东以及羊吉坎剖面上,不整合之下地层为印干组,地层缺失量比较少,时间间隔为1~2Ma;在阿克苏四石厂剖面和柯坪铁热克阿瓦提剖面,其下伏地层为其浪组,缺失了印干组和其浪组的上部,其时间间隔相当于约5Ma;在伽师三间房剖面,下伏地层为吐木休克组或一间房组,缺失地层的时间间隔约为15Ma;西克尔地区地层缺失量最大,铁热克阿瓦提组直接覆于中奥陶统鹰山组之上,缺失地层的时间间隔超过了20Ma。     

哈得逊油田成藏研究

对哈得逊油田的原油成分、原油和储层沥青族组分碳同位素、储层自生伊利石年龄和包裹体研究,以及该地区沉积和构造历史的研究表明,哈得逊油田发生过两次油气充注,第一次油气充注发生在晚二叠纪,早期原油在油田范围内只是经过,并没有聚集成藏。由于当时储层埋藏较浅,储层成岩作用弱,没有包裹体的形成。晚海西期由于构造抬升,储层中残留的早期原油发生了降解,只保留了一些重质组分。目前油藏中保存下来的原油为喜马拉雅期注入的、由O2 O3源岩形成的原油。     

Meso-Cenozoic extensional structures in the Northern Tarim Basin, NW China

Meso-Cenozoic extensional structures are important for understanding the tectonics of the Chinese Central Asia. This paper presents a systematic investigation on the Meso-Cenozoic extensional structures in the Northern Tarim Basin. Close interpretations of seismic data reveal that the Meso-Cenozoic extensional structures were widely developed in the Northern Tarim Basin. These extensional structures are regionally composed of many small normal faults, which usually group into left- or right-step en echelon and form several transtensional fault zones. Combinations of normal faults in profile become small graben-horst or staircase-like cross-sections. Based on the areal distribution, structural style, combination relationship, formation and evolution time, and formation mechanism of the extensional structures, we found that the Meso-Cenozoic extensional structures in Northern Tarim Basin can be classified into two conjugate normal fault systems, which were formed separately in Jurassic-Early Cretaceous and Late Cretaceous-Neogene. The former is likely associated with the stress relaxation after a collisional orogeny accompanied with a certain degree of anticlockwise rotation of the Tarim block relative to the South Tianshan; the latter is possibly induced by the east by south tectonic escape of the Tarim block with a certain degree of clockwise rotation relative to the South Tianshan triggered by the far-field effect of the Himalayan orogeny.     

Open tensile fractures at depth in anticlines: A case study in the Tarim basin,NW China

Understanding fracture openness in the Earth's crust is crucial for understanding fracture properties and their impact on fluid flow and potentially also in reservoir modelling. Here, we present cases showing the presence of open tensile fractures at depth in anticlines by integrating borehole imaging logs, core observations, casting sections, physical modelling, in‐situ stress analysis and production data in petroleum wells, and analysing the time of fracturing by fluid inclusion analysis. The data come from the Cretaceous Bashejiqike Formation in the Kuqa Depression, Tarim basin; its current depth varies between 6,000 and 8,100 m. The results show that tensile fractures are the main fracture type in the studied formation and that their hydraulic conductivity is poorly affected by the current maximum horizontal stress direction. Furthermore, we find that fracture development is uninterrupted during continued anticline folding, although there is a dominant time of fracturing.     

塔里木盆地孔雀河地区寒武系-下奥陶统沉积特征

应用地震、测井和野外剖面对孔雀河地区寒武系—下奥陶统的沉积相进行了研究,识别出次深海相、浅海陆棚相、台地前缘斜坡相、生物礁、开阔台地相、局限台地相和台地蒸发岩相7种沉积相。这些沉积相可以划分为3个沉积区,分别是盆地沉积区、台地边缘沉积区和台地沉积区。在草湖、尉犁和铁干里克3个地区发育前台地边缘沉积区和台地沉积区的沉积相,3个地区之间发育有盆地沉积区的沉积相。台地蒸发岩相只发育于草湖地区的北部。生物礁在3个地区开阔台地向海和背海一侧都广泛发育,这些生物礁是油气聚集的有利场所。     

塔里木盆地轮南古隆起形成时间的判定

轮南古隆起位于塔里木盆地北部,是一个大型基底卷入型鼻状背斜。卷入背斜构造变形的地层包括下古生界及其以下地层。它的形式演化控制着轮南复式油气聚集区的形成与分布。过轮南古隆起的地震剖面上显示,这里发育上泥盆统东河砂岩底、志留系底和上奥陶统底3个与古隆起形成密切相关的不整合面。上奥陶统底是一个低角度不整合面至平行不整合面,地层间断很小。志留系与下伏地层之间是一个低角度不整合接触,存在一定规模的地层间断。东河砂岩与下伏地层之间是一个明显的角度不整合接触,是一个较大的地层间断。东河砂岩直接不整合覆盖在下志留统甚至更老地层之上。上奥陶统至下志留统（中-上志留统缺失）为生长地层;上奥陶统之下的地层是前生长地层;东河砂岩及其上覆的石炭系是生长后地层。根据已有构造分析成果,塔里木盆地中志留世—中泥盆世处于造山后区域性伸展构造背景。据此分析,轮南古隆起（背斜）的构造变形起始于中奥陶世末—晚奥陶世初,持续至早志留世。此后进入风化夷平阶段,古隆起依然存在,但是背斜构造变形已经结束。至东河砂岩沉积时,轮南古隆起基本被夷平,并逐渐被埋于地下。     

Analysis of snowmelt model for flood forecast for water in arid zone: case of Tarim River in Northwest China

Field studies were carried out in Tarim River Basin, Northwest China for analysis of snowmelt model for flood forecast for a river in arid zone. Snow is a major source for water availability in arid zone of Northwest China where 50% of snow cover withdrew by sublimation during dry and cold climatic condition. The analysis of weekly forecast of daily discharges was helped by the temperature index model, ARIMA model for temperature and flow, D-IUH runoff model and D-IUH model estimation where the temperature forecast was used as driving variable; the numerical simulations were carried out using SUSA^® software for testing the sensitivity of the D-IUH to the input values of the parameter and an analysis of the forecast results against the set of input parameters resulted in a determination coefficient R ² = 0.5. The standard deviation was 3.28 and the mean for the Tarim River was 5.37 (mm d^?1) implying that the forecasted data is in strong agreement with the observed data. The combination of methods is better useful for calculation in order to avoid errors of appreciation.     

DRAV model and its application in assessing groundwater vulnerability in arid area: a case study of pore phreatic water in Tarim Basin,Xinjiang, Northwest China

According to the characteristics of groundwater in arid area, this paper proposes DRAV model for groundwater vulnerability assessment, where D is groundwater depth, R is the net recharge of aquifer, A is the aquifer characteristics, and V is the lithology of vadose zone. As a case study, the paper assesses the vulnerability of pore phreatic water in Tarim Basin of Xinjiang, China by using the DRAV model. The results indicate that the areas of phreatic water with vulnerability index ranges of 2–4, 4–6, 6–8 and >8 accounting for 10.1, 80.4, 9.2 and 0.2% of the total plain area of the Tarim Basin respectively, and the areas with the latter two vulnerability ranges (6–8 and >8) are mainly located in the irrigation districts with thin soil layer (20–30 cm thick surface soil of vadose zone, mainly with underlying sandy gravel) and with silty and fine sand layer. Such vadose zone generally lacks sandy loam and clayey soil and has larger recharge by infiltration of irrigation water.     

塔里木盆地西北缘沙井子构造带断裂构造分析

沙井子构造带位于塔里木盆地西北缘,是分隔阿瓦提凹陷和温宿凸起的边界断裂。它是塔里木盆地研究最薄弱的大型断裂构造带之一。根据系统、精细的地震资料解释,沙井子构造带存在3套断裂体系:深部楔状冲断构造、狭义沙井子断裂和浅部的伸张构造。深部楔状冲断构造形成于志留纪—泥盆纪,由北西倾向的主冲断层和南东倾向的反冲断层形成构造楔; 构造楔主要由前寒武纪变质岩组成,冲断前锋楔入于寒武系中部,造成上覆地层向温宿凸起方向的急剧抬升。狭义的沙井子断裂,即通常所说的沙井子断裂,为一条高角度基底卷入型挤压走滑断裂,形成于二叠纪末—三叠纪初,错断了早期的深部冲断楔。浅部的伸展构造形成于第四纪早-中期,为一系列较小规模的正断层,沿狭义沙井子断裂呈右步雁列状排列,构成左行剪切张扭性断裂带。深部的楔状冲断构造和浅部的伸展构造是本次研究的新发现。     

Geochemistry of Altungol cap dolostones from the Tarim Basin,NW China

The Snowball Earth hypothesis postulates that the whole earth was covered by ice sheets for millions of years in the Neoproterozoic. In Tarim Basin, there are four intervals of glacial deposits recorded in the Quruqtagh area during the Neoproterozoic. In chronological order, they are Bayisi, Altungol, Tereeken, and Hankalchough glaciations. In this study, we analyzed carbon, oxygen, and strontium isotopes; whole-rock geochemistry; and acid-insoluble residua of the ～5-m-thick Altungol cap dolostone (ten samples) in Quruqtagh unit of the Tarim basin. The geochemical data of whole rock are used to explain the ocean environmental changes, while the geochemical data of acid-insoluble residua reflect the changes of the continental environment. The δ¹³C_PDB of cap dolostone varies from ?2.5 to ?1 ‰, which is likely due to the influence of organics. From the bottom to the top of the Altungol cap dolostones, the chemical index of alteration of acid-insoluble residua rises from 72 to 77, but the index of chemical variation drops from ～3 to ～1. Ni, Zn, Cu, and Y contents of acid-insoluble residua are enriched in 2.5 m. The values of iron maintain at a high level in all of the whole-rock samples (>5.15 %), but in the samples of acid-insoluble residua, the values of iron are higher than in the whole rock (19～60 %) below 1.5 m. The variations in chemical composition were probably associated with the changes of continental weathering. The geochemistry suggests that ocean and continent environmental variations had taken place after the Altungol glaciation, including the destruction of ocean stratification and the changes of chemical weathering. During this period, the source of this area had changed. At first, the weathering residues of the parent rocks were exhausted by meltwater. Then, the vigorous weathering of freshly exposed continental crust provided a new source.     

塔里木盆地瓦吉里塔格超镁铁岩地球化学反演

二叠纪是塔里木盆地热-构造演化史上最重要的时期,这一时期在塔里木盆地中部和西北部发生了大规模的基性-中酸性岩浆活动.对塔里木盆地西北部瓦吉里塔格超镁铁岩的地球化学反演表明:瓦吉里塔格超镁铁岩(包括角砾和胶结物)是由残余岩浆和橄榄石、单斜辉石不同比例混合的产物,其中角砾主要由橄榄石和残余岩浆组成,其比例达到了72∶28.与角砾中橄榄石(平均Fo=0.82)平衡的熔体的w(MgO)为9.06%、w(FeOt)为11.77%,是由w(MgO)为11.46%、w(FeOt)为12.12%的原始岩浆经7.3%的橄榄石(Fo=0.82)分异而成的.其原始岩浆并不属于高镁岩浆,而是地幔石榴子石橄榄岩低程度(<5%)部分熔融的产物,初始熔融温度约1 150～1 250 ℃,压力约2.2 GPa,深度约70 km.结合前人研究成果认为,塔里木盆地二叠纪岩浆活动的形成可能与软流圈上涌导致的软流圈-岩石圈的相互作用有关,目前尚没有直接的岩石地球化学证据表明有地幔柱活动的参与.     

Structural evolution of the Piqiang Fault Zone,NW Tarim Basin,China

The Piqiang Fault is a prominent strike-slip (tear) fault that laterally partitions the Keping Shan Thrust Belt in the NW Tarim Basin, China. In satellite images, the Piqiang Fault appears as a sharp, NW-trending lineament that can be traced for more than 70 km. It is oblique to the general structural trend of the thrust belt and subparallel to the thrust transport direction. This paper presents a structural analysis of the Piqiang Fault, based on satellite image interpretation and field data. A net loss of Late Paleozoic sediment across the fault zone implies that it was initiated as a major normal fault during the Early Permian, and corresponds to widespread extension and magmatism during this period. Differential erosion across the fault resulted in the subsequent removal of sediment from the east relative to the west. During the Middle to Late Cenozoic, contraction of the NW Tarim Basin and the formation of the Keping Shan Thrust Belt resulted in reactivation of the Piqiang Fault as a strike-slip (tear) fault. The fault has accommodated lateral differences in thrust density and spacing which have arisen due to the abrupt, pre-existing change in stratigraphic thickness across it. The Piqiang Fault provides an insight into the formation of oblique, strike-slip (tear) faults in contractional belts and demonstrates the importance of inherited basement structures in such settings.     

Tectonic Units Division of Crystalline Basement in the Tarim Basin, NW China

<正>By the geological investigation for crystalline basement outcrops in Northeast and northwest margins of Tarim Basin,we provide essential constrains interpreting the structure,petrology and age of the pre-Sinian basement.On the basis of interpretation for aeromagnetic anomalies,     

水洗作用对油藏中烃类组成的影响

通过塔木盆地塔中１０井油层和水层石炭系储集岩烃类宏观组成和分子地球化学特征研究,认识到油层和水层中储集岩含油率和烃类族组成存在着明显的差异。水洗作用对饱和烃生物标志化合物尤其是二环倍半萜影响较大,水层中倍半萜烷化合物已被消耗殆尽,三环萜烷含量降低, 伽玛蜡烷含量则相对增加;孕甾烷、升孕甾烷和重排甾烷的含量亦相对降低。水洗作用导致储集岩烃类芳烃组成中二苯并噻吩系列化合物的含量显著下降,二环和三环多环     

塔里木盆地显生宙古隆起的分布及迁移

塔里木盆地属于多期叠合盆地,存在多期不整合与古隆起构造,二者的形成及发育密切相关。利用钻井、地震、野外露头等综合资料,开展了盆地尺度的构造层、不整合结构构造、累积最小生长指数分析,进一步了解盆地内多个古隆起的分布、成因及隆升过程,特别是和田、塔中、塔北、巴楚、塔东古隆起及其内部的形成演化。发现盆地内不同时期古隆起构造变形和展布与盆地周缘造山带构造作用相响应。早古生代以来盆地内古隆起经历了6次大的迁移,每次迁移的动力来源于该时期盆地周缘的板块边缘或造山带的构造活动。根据隆起形成的主控因素,塔里木盆地古隆起主要可分为4种成因类型,包括断控隆起、继承性隆起、前陆盆地前缘隆起和构造古地理隆起等。古隆起隆升的差异还体现在隆起区内不同部位上,对油气成藏有重要意义。