柴达木盆地南缘和北缘金属矿产资源地球物理勘查进展

柴达木盆地南缘和北缘地处秦祁昆成矿域西段,成矿条件优越,地质构造复杂.总结分析柴达木盆地南缘和北缘找矿模型和地球物理勘探现状,对深部找矿突破具有重大指导意义.柴达木盆地南缘和北缘矿床成因以喷流沉积型多金属矿、岩浆熔离型镍铜钴矿、沉积型铁矿、层控型铅锌矿及热液型多金属矿为主.矿床形成时代分为前寒武纪、早古生代早中期、晚古...     

柴达木盆地侏罗系油气成藏模式与油气聚集规律

针对柴达木盆地侏罗系油气勘探目标选择的难点,从烃源岩与圈闭时空配置的角度,建立侏罗系油气早期聚集早期成藏、早期聚集晚期成藏、晚期聚集晚期成藏3种模式。盆地油气来源、充注时期、油藏调整及破坏等方面存在规律性,这决定了油气分布的有序性,呈现出“断褶区聚气,山前、潜伏区聚油,凸起顶、凸起斜坡区油气并存”的基本格局和油气富集程度依次变好的序列。据此预测油气富集范围,从中优选冷湖4号东斜坡、乌南—巴依凸起斜坡、怀头他拉—德北斜坡、潜伏Ⅰ号等新靶区。     

Silicon and oxygen isotopic composition of igneous rocks from the eastern Manus Basin

This paper reports silicon and oxygen isotopes of 20 kinds of igneous rocks and their major elements from the eastern Manus Basin. Combining silicon and oxygen isotopic data from other studies, we suppose that both δ30Si and δ18O values increase with the increasing of SiO2 content. It means that the fractionation of silicon and oxygen isotopes are affected by the silica content. The positive correlation between CaO/Al2O3 ratios and MgO and that between Si/Al and SiO2 content indicate that clinopyroxene is the predominant mineral phase in our samples. We suppose that the fractionation of silicon and oxygen isotopes are influenced by mineral fractional crystallization. Probably, it is due to their different silicon and oxygen bridges. In this study, the δ30Simean value=-0.17‰±0.17‰ and δ18Omean value= +6.07‰±0.57‰ are higher than normal δ30Si and δ18O values of mantle, and we propose that these igneous rocks in the eastern Manus Basin are affected by hydrothermal alteration.     

柴北缘沙柳河榴辉岩岩石化学及变质条件研究

柴达木盆地北缘东端沙柳河一带榴辉岩呈布丁构造赋存在新元古代末期花岗质片麻岩中，榴辉岩主要由石榴子石、绿辉石和金红石等矿物组成。通过对该地榴辉岩的岩石化学和变质条件研究，发现其峰期变质条件为492．12℃～653．48℃和1．008～1．625GPa。未达到超高压的环境，在岩石中也未发现明显的超高压证据，与柴达木盆地北缘其他地区(鱼卡河、锡铁山、野马滩)榴辉岩有所区别。     

Geochemistry and genesis on saturated hydrocarbon of crude oils in Gas Hure Oilfield in Qaidam Basin

Gas Hure Oilfield is the biggest one in the Qaidam Basin.Through intensive sampling and GC-MS analysis,the authors analyzed the geochemical characteristics of the crude oils in the Gas Hure Oilfield.The results show that the crude oils have even-odd carbon predominance for n-alkanes.In shallow reservoir,part of crude oils suffered biogenic degradation.As for normal oils,they have low Pr/Ph ratios with abundant gammacerane and C35 homohopane,which indicate that the crude oils are formed in strong reducing salt water environment.Compared deep(E13) reservoir with shallow(N1-N12) reservoir,the ancient salinity of sedimentary environment of N1--N12 crude oils is slightly higher than that of E13 crude oils;the C-21/C+22 ratios of crude oils are 1.02-1.71 with a higher abundance of C27 sterane,which shows that their mainly origin matrix are bacteria and algae;the C29 sterane 20S/(20S+20R)is generally low,the ratio in deep E13 reservoir distributes between 0.31 and 0.40,but in shallow reservoir is relatively low with 0.29-0.36.At the same time,C29 sterane αββ/(αββ+ααα)and Ts/Tm both are extremely lower.All the above show that the crude oils in Gas Hure are mainly low mature oils,although the maturity of deep reservoir crude oils is slightly higher than shallow one.     

柴达木盆地及其邻区早—中二叠世构造岩相古地理格局

通过大量野外观察、分析测试和综合研究,结合覆盖全区不同比例尺的区域地质调查资料,对柴达木盆地及其邻区早—中二叠世构造岩相古地理格局进行了研究,并探讨了其形成机制.结果表明:柴达木盆地及其邻区中、北部早—中二叠世为陆内盆山裂谷系统,主体处于伸展构造背景,总体表现为堑垒相间的构造古地理格局;南部为巴颜喀拉洋盆,早—中二叠世是巴颜喀拉洋盆扩张最为剧烈且规模最大的时期,巴颜喀拉洋盆中洋岛、海山遍布;早—中二叠世晚期强烈的华力西构造运动使古板块间的相对运动加剧,巴颜喀拉洋盆大洋岩石圈板块向北强烈俯冲,形成东昆仑陆缘岩浆弧及其南部增生带,东昆仑陆缘岩浆弧岩浆活动十分强烈,宗务隆山—西秦岭陆源裂谷盆地进一步发育,形成十分复杂的构造岩相古地理格局.早—中二叠世是研究区地球动力学机制从强烈扩张到强烈汇聚的转折时期,加强其构造岩相古地理研究对建立该区地层序列、探讨其地质演化历史以及指导找矿等均具有重要意义.     

柴达木盆地矿产开发中环境地质问题及防治对策

在柴达木盆地环境现状实际调查基础上，根据调查资料论述了柴达木盆地地区矿产开发引起的主要环境地质问题及其危害。分析了引起土地沙化．土壤盐渍化，水土污染，崩塌地面塌陷，生态环境恶化产生原因，并在地质环境保护方面提出合理化建议，以期为西部开发过程环境保护提供依据。     

柴北缘鱼卡河超高压变质金红石中Si含量及其地质意义

利用LA-ICP-MS方法对柴达木盆地北缘鱼卡河超高压变质的多硅白云母榴辉岩及共生的石榴角闪钠长岩中的金红石进行了详细的矿物学和LA-ICP-MS原位微量元素研究。结果表明:多硅白云母榴辉岩中金红石显示Si成分环带,且Si含量(质量分数,下同)随变质压力而发生规律性的变化;从进变质到峰期变质阶段,金红石中Si含量从核部向边部呈升高趋势,峰期金红石的边部Si含量达到最高,退变质阶段金红石中Si含量从核部向边部呈降低趋势;石榴角闪钠长岩中的金红石主要呈包体产于多硅白云母、石榴子石、角闪石和钠长石中;在相同的超高压变质条件下,石榴角闪钠长岩中多硅白云母包体金红石的Si含量((1018~2741)×10^-6,平均为1924×10^-6)明显高于多硅白云母榴辉岩中的峰期金红石((450~2397)×10^-6,平均为952×10^-6)。综合多硅白云母榴辉岩和石榴角闪钠长岩的产状、变质演化和全岩成分以及前人对大别—苏鲁超高压榴辉岩中富硅金红石的研究结果提出,超高压变质岩石中金红石的Si含量与变质压力成正相关关系,金红石中Si含量大于500×10^-6可以作为榴辉岩经历超高压变质作用的指示标志。超高压金红石中Si含量与全岩成分中SiO2和TiO2含量有关,随SiO2含量的升高和TiO2含量的降低而升高。     

THE IMPACT OF HUMAN ACTIVITIES ON GROUNDWATER RESOURCES IN THE SOUTH EDGE OF TARIM BASIN，XINJIANG

In the modern times ,the population growth,development of industrial and agricultural production and the petroleum exploitation,brought about the unceasing expansion of artificial oasis and abrupt increase of water demand .The artificial hydraulic irrigation engineering took the place of the natural river systerm,the reservoirs took the placeof natural lakds,which in turn enhanced the space-time redistribution of surface water based on the natural evolution,and so did groundwater.The groundwater recharge reduced 26.2% in 46 years from 1950 to 1995 in the southern piedmont fold plain of Tarim Basin due to mean yearly population increase rate of 27.7‰ and associated with the water use rate increasing from 24.6% to 58.4%.At the same time the artificial water system seepage give primary play to groundwater recharge,which is up to 57.6% whilst that of the natural system reduce to 33.7%.As a result,groundwater level drop 3-5m widespread except some irrigation area and surrounding of plain reservoir.Sping water discharge also reduce about 37.6% and discharge some continuously move away to the north with the value of 0.5-1.2km in the past 40 years.     

Geochemistry and genesis on saturated hydrocarbon of crude oils in Gas Hure Oilfield in Qaidam Basin

Gas Hure Oilfield is the biggest one in the Qaidam Basin.Through intensive sampling and GC-MS analysis,the authors analyzed the geochemical characteristics of the crude oils in the Gas Hure Oilfield.The results show that the crude oils have even-odd carbon predominance for n-alkanes.In shallow reservoir,part of crude oils suffered biogenic degradation.As for normal oils,they have low Pr/Ph ratios with abundant gammacerane and C35 homohopane,which indicate that the crude oils are formed in strong reducing sa...     

地下水循环结构的动力学研究进展

由地下水补给、径流和排泄过程构成的地下水循环运动,是水文循环的重要组成部分,也是水文地质学的基本研究对象。地下水循环在空间上表现为不同结构单元的组合,存在以含水层特性为依据的介质结构和以渗流场为依据的动力结构2种划分方法。地下水流系统是动力结构意义上的地下水循环单元。近10年来,区域地下水流系统理论取得了显著进展,更加全面深入地揭示了地下水循环结构的动力学特性。通过对河间地块地下水流系统的研究,发现潜水面最高点并非地下水分水岭的准确位置。在盆地尺度上,系统研究了沟谷地貌、降水入渗强度、渗透性随埋深变化和盆地厚度等因素对潜水面波形与地下水循环动力结构的影响,初步发现了动力结构的周期性或趋势性演化特征。通过大规模流线路径的精细识别或驻留时间的统计分析,提出了三维地下水循环单元的划分方法。在水文地质效应方面,发现地下水循环的动力结构对地下水年龄的分布有重要影响。地下水循环的动力结构反映了不同补给区和排泄区之间的水力联系,在盆地尺度地球化学过程、流域尺度生态水文过程中发挥着关键作用,未来的研究重点是三维地下水循环的动力特性和演变规律。     

THE GROUNDWATER RESOURCES AND ITSSUSTAINABLE DEVELOPMENTIN THE SOUTH EDGE OF TARIM BASIN

1 INTRODUCTIONSustainability as present understand comes fromword protection strategy commission, which firstly putforward some wide excepted environmental sustainability principles and three important identifications forlife support system: soil, air and water. Then, in thereport of Our Common Future (WCED, 1987), theconcept of sustainable development is put to an outstanding level. Sustainable groundwater resources development is then a great issue in the recent years andthe future (…     

VARIATIONS IN ISOTOPIC COMPOSITIONS OF CHLORINE IN EVAPORATION-CONTROLLED SALT LAKE BRINES OF QAIDAM BASIN，CHINA

ＩＮＴＲＯＤＵＣＴＩＯＮＣｈｌｏｒｉｎｅｈａｓｔｗｏｎａｔｕｒａｌｌｙｏｃｃｕｒｉｎｇｓｔａｂｌｅｉｓｏｔｏｐｅｓ,　35Ｃｌａｎｄ　37Ｃｌ.Ｓｅｖｅｒａｌｓｔｕｄｉｅｓｒｅｐｏｒｔｅｄｔｈｅｖａｒｉａｔｉｏｎｓｉｎｔｈｅｉｓｏｔｏｐｉｃｃｏｍｐｏｓｉｔｉｏｎｏｆｃｈｌｏｒｉｎｅｉｎｎａｔｕｒｅ.Ｈｏｗｅｖｅｒ,ｉｎｔｈｅｅａｒｌｙｙｅａｒｓＯｗｅｎａｎｄＳｃｈａｅｆｆｅｒ(1955)ｒｅｐｏｒｔｅｄｎｏｏｂｓｅｒｖａｂｌｅｄｉｆｆｅｒｅｎｃｅｉｎｔｈｅ　37Ｃｌ35Ｃｌｒａｔｉｏｓｉｎｔｅｎｓａｍｐｌｅｓｅｘ…     

New paleomagnetic evidences of paleogene tectonic rotation of the Qaidam Basin and adjacent region： mechanism and its tectonic implication

In order to better understand the tectonic evolution of the Qaidam Basin. The authors carried out a paleomagnetic study on 39 samples of 7 sites from Hongsanhan section, northwest Qaidam Basin. Stepwise thermo-demagnefizafion isolated a high-temperature component （HTC）, which passes the fold and reversal tests at 95 % confidence level. It suggests that the HTC should be primary. Unblocking temperature （about 685℃ ） and the experiment of isothermal remanence indicate that hematite is the mainly carrier of the remanence. A tilt-corrected mean direction is： Ds= 7.1°, Is= 38.5°, α95 = 7.4°. Corresponding to a palaeopole at, φ= 250. 1°E, λ= 72.0°N, A95 = 6.8°, Compared with the reference APWP of Eurasia, the sampling area occurred a non-significant rotation （3.4° ± 5.5°） relative to Eurasia since Eocene due to the affect of left-lateral Altyn fault, Based on the paleomagnetic results of early Cretaceous and Teritary within the Qaidam block, we can obtained the mean clockwise rotations from the samples deposited from 160 Ma to 45 Ma is 24.5° ± 9.0°, and from 38 Ma to present is - 0.5° ± 7.5° relative to present geomagnetism respectively. During the Mid Eocene （45 -38 Ma） rotation phase, there should existing an important early tectonic event in northern part of the present-day Tibetan Plateau, which probably represents one of large-scale strike-slip events of the Altyn strike-slip fault.     

New paleomagnetic evidences of paleogene tectonic rotation of the Qaidam Basin and adjacent region: mechanism and its tectonic implication

In order to better understand the tectonic evolution of the Qaidam Basin. The authors carried out a paleomagnetic study on 39 samples of 7 sites from Hongsanhan section, northwest Qaidam Basin. Stepwise thermo-demagnetization isolated a high-temperature component (HTC), which passes the fold and reversal tests at 95% confidence level. It suggests that the HTC should be primary. Unblocking temperature (about 685℃) and the experiment of isothermal remanence indicate that hematite is the mainly carrier of the remanence. A tilt-corrected mean direction is: Ds=7.1°, Is=38.5°, α95=7.4°. Corresponding to a palaeopole at, φ＝250.1°E, λ＝72.0°N, A95=6.8°, Compared with the reference APWP of Eurasia, the sampling area occurred a non-significant rotation (3.4°±5.5°) relative to Eurasia since Eocene due to the affect of left-lateral Altyn fault, Based on the paleomagnetic results of early Cretaceous and Teritary within the Qaidam block, we can obtained the mean clockwise rotations from the samples deposited from 160 Ma to 45 Ma is 24.5°±9.0°, and from 38 Ma to present is -0.5°±7.5° relative to present geomagnetism respectively. During the Mid Eocene (45～38 Ma) rotation phase, there should existing an important early tectonic event in northern part of the present-day Tibetan Plateau, which probably represents one of large-scale strike-slip events of the Altyn strike-slip fault.     

柴达木盆地北部滩间山群碳沥青地球化学特征与成因

固体沥青研究由于其组成的复杂性、形成机制与影响因素的多变性而面临很多难题。在柴达木盆地北部联合沟地区滩间山群发现大量厚层碳沥青,对盆地内的资源勘探具有重要价值。通过野外地质填图以及有机地球化学分析与盆地模拟,对碳沥青的空间分布特征、地球化学特征与成因进行了探讨。结果表明:碳沥青呈NW—SE向分布在滩间山群a段的砂岩与灰岩中;碳沥青中氯仿沥青"A"含量低,族组分中饱和烃与芳烃含量低,而非烃与沥青质含量高;饱和烃与芳烃碳同位素组成偏轻,碳沥青等效镜质体反射率在3.74%~4.72%之间,达到过成熟阶段;饱和烃气相色谱呈后峰形单峰态;油岩对比发现碳沥青与石炭系、侏罗系烃源岩不具有对比性,与滩间山群a段泥岩具有可对比性;碳沥青成因与晚泥盆世、早二叠世岩浆侵入有关,两期热事件使烃源岩生成的原油热变质成重油、沥青,甚至碳沥青。     

鄂尔多斯盆地多级次地下水流系统中硝酸盐分布特征及其成因

水资源短缺的鄂尔多斯盆地内地下水遭受硝酸盐(NO^-₃)污染等问题日益突出,识别盆地不同地下水流系统的NO^-₃分布规律及其成因,对地下水资源的合理利用与保护具有重要意义。选取鄂尔多斯盆地北部湖泊集中区白垩系地下水系统为研究对象,基于水化学和聚类-主成分分析划分地下水流系统级次,在此基础上对比分析不同级次地下水流系统中NO^-₃分布特征,综合水化学和环境同位素分析识别多级次地下水流系统中NO^-₃来源及其潜在过程。研究表明：研究区ρ(NO^-₃)超出地下水质量标准(GB/T 14848-2017)Ⅲ类水标准的地下水样品集中在局部-中间地下水流系统,其超标率达到28%;区域地下水流系统中ρ(NO^-₃)均值约为1 mg/L。研究区不同级次地下水流系统中ρ(NO^-₃)分布特征主要与人类活动影响程度有...     

Stable isotopes distribution in core Ck6 and variations of paleoclimate over Qarhan Lake region in Qaidam Basin, China

Depositing ages of sediment in Core Ck6 of Qarhan Lake were dertermined by¹⁴C,²³⁰Th and geomagnetic polarity methods. Results of analyses of stable isotopes composition in carbonate and organic matter were used to set up a model of fluctuating paleoclimate (since 750 ka B. P.) consisting of 11 warm and humid stages and 10 dry and cold stages.     

Analysis of groundwater recoverable resource by numerical method in Linfen Basin of Shanxi, North China

Calculation of the groundwater recoverable resource is the main part of groundwater resource evaluation. The three-dimensional groundwater flow model in Linfen Basin was established by GMS software. Then the numerical model was calibrated by observed groundwater level from February to December in 2 000. Based on the calibrated model, the groundwater recoverable resource is calculated. The simulation result shows that under the given value of the groundwater recoverable resource, the groundwater level would decrease significantly in the first 1 000 days, while the water level would drop slowly in 1 000 to 2 000 days, and the water level change tend to be stable after 2000 days.     

Analysis of groundwater recoverable resource by numerical method in Linfen Basin of Shanxi, North China

Calculation of the groundwater recoverable resource is the main part of groundwater resource evaluation. The three-dimensional groundwater flow model in Linfen Basin was established by GMS software. Then the numerical model was calibrated by observed groundwater level from February to December in 2 000. Based on the calibrated model, the groundwater recoverable resource is calculated. The simulation result shows that under the given value of the groundwater recoverable resource, the groundwater level would decrease significantly in the first 1 000 days, while the water level would drop slowly in 1 000 to 2 000 days, and the water level change tend to be stable after 2000 days.