AMT法勘查额济纳盆地与巴丹吉林沙漠接触关系

 查明额济纳盆地东部与巴丹吉林沙漠之间的接触关系,有助于分析额济纳盆地地下水水位下降、生态环境恶化的原因。通过当地地质资料和物探方法的对比分析,选择合理有效的音频大地电磁法（AMT）物探手段,在该区域进行了原始创新性的勘查工作。勘查结果认为额济纳盆地上升、巴丹吉林沙漠下降,两侧地层岩性厚度变化较大,推断额济纳盆地与巴丹吉林沙漠为张性断层接触。研究可为分析两者之间地下水转化关系和额济纳盆地地下水水位下降原因、探讨盆地与沙漠区地下水形成机制提供依据,对恢复治理额济纳盆地生态环境具有一定帮助。     

太原盆地QK1钻孔60ka.B.P以来气候环境演化的沉积记录

通过对太原盆地QK1钻孔60 ka.B.P.以来的沉积物进行粒度、磁化率分析,探讨了太原盆地60 ka.B.P.以来的气候环境演化过程。太原盆地60 ka.B.P.以来主要经历了以下演化阶段:59.6～40 ka.B.P.属滨湖相沉积;40～31.5 ka.B.P.属以河流相漫滩沉积;31.5～14.58 ka.B.P.属河流相边滩沉积;14.58～12.5 ka.B.P.河流相漫滩沉积;12.5～9 ka.B.P.河漫湖泊沉积;9 ka.B.P.至今属河流相边滩沉积。60 ka.B.P.以来太原盆地的气候由温暖偏湿转为温暖湿润,在末次冰期表现为寒冷干燥,进入全新世大暖期以后,气候具有全球性特征的同时也兼具区域性特点。各指标分析表明太原盆地的气候环境演化主要受全球性气候变化及区域气候的影响,由于盆地沉降中心与边缘沉积速率的差异,在一定程度上受到地区构造活动的影响。     

Quaternary glacier development and the relationship between the climate change and tectonic uplift in the Helan Mountain

Isolated NE-SW stretching the Helan Mountain massif, separating the temperate grassland of the Ordos plateau from the Tenggeli Desert, is a key position of studying the glacier development in west China as well as the coupling conditions of climate change with tectonic uplift. The glacial landforms and deposits including cirques, peaks, knife-edge ridges, lateral moraines, and terminal moraines distribute above 2800 m a.s.l. in the middle part of the Helan Mountain. This distribution indicates that here was once glaciated during the late Quaternary. Morphology features show a clear sequence of landscape forming events took place throughout the Helan Mountain. Laboratory optically stimulated luminescence (OSL) and accelerator mass spectrometry radio-carbon dating (AMS 14 C) results indicate a late history of glacial advance. Late Pleistocene glaciers in the middle part of the Helan Mountain advanced to near their positions at least four times, and the glacial sequences can be assigned as the middle stage of last glacial cycle (MIS3b, 43.2±4.0 ka), last glacial maximum (LGM, ~18 ka), late glacial (12.0±1.1 ka) and neo-glacial (3.4± 0.3 ka) respectively. Adopting equilibrium line altitude ~2980 m of last glacial maximum and the modern theoretical snowline altitude ~4724 m as the maximum amplitudes, and the standard marine isotope curve (MIS) as the glacial equilibrium line change since the Gonghe Movement (150 ka), the relationship between the mountain altitude and glacier development is discussed herein. Compared with other environmental indexes such as the loesspaleosol and ice core, conclusions are made that glacier advances in the Helan Mountain during the late Quaternary obviously depended on the coupled control of tectonic uplift of mountain with the climate condition. It is at last glaciation that the mountain reached the altitude above snowline and coupled with the glacial climate. The glacial advances occurred in the early and middle stages of last glacial cycle after the Gonghe Movement.     

鄂尔多斯盆地侏罗系层序地层与盆地充填演化耦合关系

应用沉积相分析和层序地层研究方法,系统研究了鄂尔多斯盆地侏罗系沉积特征和层序界面的综合识别,总结出了7种层序界面的物质表现形式,将盆地侏罗系划分出2个超长期、9个长期和19个中期基准面旋回.进一步探讨了盆地侏罗系"层序-沉积-构造"之间的耦合关系,认为富县期-延安期整个盆地经历了4次较大的构造沉降旋回,对应于4个长期基准面旋回;直罗期-芬芳河期,盆地再一次经历了较完整的由抬升、充填再到强烈抬升的演化过程,共发育有5次大的旋回,分别对应于5个长期基准面旋回.     

Landscape evolution and palaeoclimate in the deserts of northwestern China, with a special reference to Badain Jaran and Taklamakan

A comparative study of geomorphologic landscapes in the Badain Jaran Desert and Taklamakan Desert was made on the basis of field investigations, thermolumi-niscence and radiocarbon dating as well as analysis of sand grain texture. The sand seas of the Badain Jaran Desert differ greatly from that of the Taklamakan Desert in terms of dune morphology, interdune relief, dune stratigraphy and sand sources. The thermoluminiscence ages of the dunes suggest that the basic configuration of the megadunes in the Badain Jaran Desert has not changed at least since Middle Holocene. There were periods of more humid environment during the last glaciation and Holocene in both deserts, but events of higher precipitation in the Badain Jaran Desert were more frequent than in the Taklamakan. In both desert areas, aeolian processes have been intensified during the last 2000 a.     

Water cycle evolution in the Haihe River Basin in the past 10000 years

The water shortage problem in the Haihe River Basin is the most severe in China, and has restricted its economic development. Over-extraction of groundwater has been very severe in the past 30 years. To solve this problem, scientific decisions should be made from a historical perspective. It is important to describe water cycle evolution in the Haihe River basin over the past 10000 years. Datasets of paleoclimate, paleogeography, palynoflora, historical record, isotopic abundance ratio and content were collected for research on different time scales. Some interesting conclusions were drawn by a comprehensive analysis method. First, radiation was the intrinsic force driving the evolution of water cycle. Generally, precipitation increased with temperature. Second, precipitation was high during 8 ka-5 ka B.P., the so-called Yangshao warm period of the Middle Holocene, which recharged the major part of the Quaternary groundwater. Third, heavy floods during this period transported sediment to the seaside, forming the Coastal Plain where cities such as Tianjin, Huanghua, Cangzhou are now located. In the last 3000 years, intermittent moderate floods did not have enough energy to transport sediment to the sea. Rivers usually overflowed in the piedmont region of the Taihang Mountains, and sediment deposited there formed the Piedmont Plain, where locate Shijiazhuang, Xingtai, Handan, Baoding and other cities. Precipitation had a high correlation with temperature in Haihe River Basin in the past 10000 years: the high temperature usually coupled with high precipitation. Today precipitation in the Haihe River Basin is relatively low, owing to low temperature. This study reveals the relationship between temperature, precipitation and river networks in the past 10000 years in Haihe River Basin, which has great scientific and practical importance in understanding the current water circulation and water shortage.     

太原盆地边缘地貌与新构造运动及其意义

应用构造地貌的观战把太原盆地及其边缘地貌分为：外围断块抬升山地,抬升轻微的丘陵台地,山前堆积的洪积倾斜平原和沉降堆积的冲积平原４种地貌单元。     

江汉盆地白垩系沉积相与沉积演化

在对江汉盆地露头剖面野外实测、钻井及分析化验资料综合研究的基础上,运用层序地层学、沉积学和测井地质学原理,识别了白垩系层序及沉积相类型、沉积特征。研究表明, 受燕山期幕式构造运动的影响,白垩系可划分为两个构造层序,主要发育冲积扇、辫状河、辫状河三角洲和氧化型湖泊四种主要沉积相类型;早白垩世,由于拉张断陷强度较弱,仅在盆地边缘断裂前缘的局部地区发育一套粒度较粗的冲积扇-辫状河砂砾岩沉积;至晚白垩世,在区域引张力的作用下盆地整体拉伸断陷,从盆缘往盆内方向依次发育冲积扇—辫状河—三角洲—氧化型湖泊沉积,构成一个自下而上粒度由粗变细的沉积序列。     

早泥盆世古亚洲洋构造作用:来自可可托海和额济纳旗花岗岩年代学研究

古亚洲构造域内发育有大量的古生代酸性侵入岩。对阿尔泰造山带可可托海近3号脉的酸性侵入岩体进行LA-ICP-MS锆石U-Pb定年分析,以确定其岩浆作用时代及其岩浆活动的构造意义。研究区内的花岗岩包含的锆石大部分为自形-半自形晶,显示为典型的岩浆成因;测年结果发现,该岩体形成于404.4±3.2 Ma,为早泥盆世岩浆活动的产物。通过对额济纳辉森乌拉西糜棱岩化二长花岗岩中白云母⁴⁰Ar/³⁹Ar同位素年代学分析,获得白云母的坪年龄和等时线年龄分别为407.69±3.09 Ma和407.65±3.99 Ma,这暗示了拐子湖-呼和音乌苏弧形挤压带在早泥盆世活动的冷却年龄。以上事件与早泥盆世古亚洲洋的俯冲、碰撞的构造环境关系密切。     

A high-resolution environmental change record since 19 cal ka BP in Pumoyum Co,southern Tibet

A 380-cm-long sediment core was acquired from the deep water area of Pumoyum Co, southern Tibet. Twenty-five plant residue samples were selected, and organic carbon stable isotopes were obtained using the AMS ¹⁴C chronological method. The ¹⁴C age and carbon reservoir effect were calibrated with surface sedimentation rate measurements using ²¹⁰Pb dating. Results showed that the core sediment deposited over 19 cal ka BP. Based on a multi-proxy analysis of TOC and IC contents, grain size and pollen assemblage data, the palaeoclimatic evolution of Pumoyum Co was reconstructed since the last glacial. Pumoyum Co was a shallow lake prior to 16.2 cal ka BP; although the glacier around the lake began to melt due to increasing temperatures, climate was still cold and dry. In the interval of 16.2–11.8 cal ka BP, the sedimentary environment fluctuated drastically and frequently. Two cold-events occurred at 14.2 and 11.8 cal ka BP, and these may correspond to the Older Dryas and the Younger Dryas events, respectively. After 11.8 cal ka BP, Pumoyun Co developed into the deep lake as it is now. The lake water temperature was relatively lower at that time because of influx of cold water from glacial meltwater entering the lake. As a result, the multi-proxy indicators showed no sign of warm conditions. Comparisons between the sedimentary record of Pumoyum Co with that of other lakes of the same age in southern Tibet indicate a warmer climate following the last deglaciation influenced the southeastern Tibetan Plateau. These results imply that the southwest Asian monsoon gradually became stronger since the deglaciation during its expansion to the inner plateau. The glacial-supplied water of the lake responded sensitively to cold-events. The entire southern Tibet region was dominantly influenced climatically by the southwest Asian monsoon during the Holocene.     

高邮凹陷始新统统戴南组古环境演化及沉积特征

苏北盆地高邮凹陷始新统戴南组(E2d)地层中发育丰富的岩性地层油气藏.通过钻井岩心、古生物、微量元素、测井等资料,对E2d地层沉积环境演化及展布规律进行了详细研究.研究结果表明:E2d地层沉积期气候属于温热而湿润的亚热带型气候;戴一段(E2d1)沉积期在吴堡构造运动活动较强背景下,凹陷水体处于半咸水-淡水过渡湖相与扇三角洲和近岸水下冲积扇的环境,在凹陷南部断阶带发育了近岸水下冲积扇,北斜坡发育扇三角洲沉积以及湖泊沉积;戴二段(E2d2)沉积期构造活动减弱,凹陷湖泊属于淡水-微咸水水体环境,在凹陷南部断阶带发育扇三角洲,北斜坡发育三角洲及湖泊相沉积.在上述沉积相背景下发育与展布的砂体成为油气聚集的重要储集单元.     

柴达木盆地北缘第三系沉积体系演化模式

基于柴达木盆地北缘第三系的地质背景和构造演化,结合野外露头、岩心、测井解释和地震相特征,研究了沉积相的纵横分布特征并建立了柴北缘第三系沉积体系演化模式。结果表明:盆地边缘的马北、马西和平台地区一带主要以冲积扇和辫状河沉积为主,靠近湖盆中心的南八仙、冷湖Ⅵ号和Ⅶ号、鄂博梁等地区主要发育辫状河三角洲平原或前缘相带。路乐河组(E1+2)冲积扇较为发育,辫状河相对发育;下干柴沟组(E3)主要发育辫状河和辫状河三角洲沉积,下干柴沟组下段(E13)到下干柴沟组上段(E23)是一个辫状河向辫状河三角洲演化的水进沉积序列;上干柴沟组(N1)和油砂山组(N2)发生进一步湖侵,湖盆扩张,为辫状河三角洲前缘与滨浅湖的交互沉积。在此基础上,建立了柴北缘古近纪—新近纪从物源区向盆地中心发育的冲积扇—辫状河—辫状河三角洲—湖泊沉积体系模式,并探讨了沉积体系演化过程及其油气意义。     

Distribution feature of terrestrial heat flow densities in the Bohai Basin,East China

Temperature logging curves at 8 boreholes and well-testing temperature data at 142 boreholes are used to determine geotemperature gradients in the Bohai Basin. The thermal conductivities of 86 rock samples are measured at laboratory and the effects of porosity and temperature are corrected to obtain conductivities in situ. Terrestrial heat flow densities at 76 wells are determined based on these data. The distribution of the heat flow indicates that the terrestrial heat flow in the Bohai Basin is relatively high with an average value of 65.8 mW/m². This characteristic is caused by the tectonic evolution of the basin. During Cenozoic, the lithosphere stretched intermittently and the crust thinned so that heat conducted from the mantle increased and formed thermal abnormity at depth beneath the basin.     

Speculation on the timing and nature of Late Pleistocene hunter－gatherer colonization of the Tibetan Plateau

1 Human biogeography on the edge The Qinghai-Tibetan Plateau occupies nearly 1.25 million km2 of the Asian continent and reaches an average elevation of more than 4000 m a.s.l. (Fig. 1). In addition to playing a critical role in global climate systems[1,2], the plateau is distinguished as the largest continuous high elevation ecosystem on the planet. This harsh, barren Fig. 1. Map of the Qinghai-Tibetan Plateau (left) and an elevation cross-section from the Badanjaran Desert in the n…     

柴北缘马海东地区路乐河组冲积扇特征

柴达木盆地北缘马海东地区新揭示了路乐河组。为明确其沉积相类型及有利的储集相带,通过野外和岩心沉积构造的观察、粒度分析、测井相分析等方法系统研究了路乐河组的沉积特征,分析了沉积充填规律,建立了沉积相模式。研究表明,柴达木盆地北缘路乐河组广泛发育冲积扇相沉积,自盆缘向盆内依次发育扇根-扇中-扇缘沉积。路乐河组填平补齐,以北东方向的祁连山为物源区的冲积扇向盆内的马北古凸起超覆,控制了柴北缘中段的地层展布和沉积演化规律。马海东地区发育3个砂层组,处于冲积扇的扇中-扇缘亚相,发育河道充填和漫流沉积微相。扇中河道充填、漫流沉积以及扇缘河道充填沉积是较为有利的储集相带。     

Validating a dust production model by field experiment in Mu Us Desert, China

It is essential for validation and improvement of a dust production model to perform field observations on dust emissions. The dust production model (DPM model) consists of two physically explicit sub-models, namely saltation model [1, 2] (eq. (1)) and sandblasting model [3] (eqs. (2) and (3)). Fh is saltation flux, E is fraction of erodible surface, C is a dimensional constant, ρa is air density, g is gravitational acceleration, U* is the wind friction velocity, Ut*(Dp) is threshold frict…     

安哥拉宽扎盆地白垩系油气成藏条件及勘探潜力

以安哥拉宽扎盆地的构造演化、沉积充填特征研究为基础,重点开展了宽扎盆地的盐上和盐下构造单元划分及盆地油气成藏基本条件研究,系统总结了宽扎盆地的白垩系油气成藏模式,指出了有利勘探区。宽扎盆地经历了裂谷阶段、过渡阶段和被动陆缘阶段的构造沉积演化阶段,不同的构造演化控制着宽扎盆地的盐上、盐下构造单元变化及生储盖条件的变化,形成了盐下自生自储运聚成藏模式和盐上下生上储跨越式运聚成藏模式。宽扎盆地临近大西洋枢纽带以西及附近深海的盐下地垒（高地）与盐岩分布厚盐区的叠置区域是盐下油气聚集的有利区带,其勘探潜力大。宽扎盆地盐上Albian阶碳酸盐岩及砂岩发育的盆地近海区域是盐上有利勘探区。     

Formation mechanisms of megadunes and lakes in the Badain Jaran Desert, Inner Mongolia

Field observations demonstrate that calc-sinters occurred in the lakes of Badain Jaran Desert. 87Sr/86Sr ratios,14C,δ 13C and mineral com-positions of calc-sinters,and 3He/4He,4He/20Ne,δ 18O,δ D,pH and TDS of water from springs and lakes are analyzed in detail. The results indicate that the lake water is supplied through deep fault zone. The “ker-nel” of stabilized dunes in the Badain Jaran Desert perhaps consists of calc-sinters and calcareous ce-mentation layers. Deep-seated groundwater effuses from this “kernel” and recharges to lakes in desert. Precipitation and snowmelt water from the Qing-hai-Tibet Plateau is fed into the Badain Jaran Desert,Gurinai,Wentougaole and Ejinqi areas through the Xigaze-Langshan Fault zone. The isotopic composi-tions of groundwater in the Alax Plateau are abnor-mal due to the strong evaporation of the Gyaring and Ngoring lake water in the headstream of the Yellow River. Groundwater dissolves dissoluble fractions of rocks during its transportation through the fault zone and flows out of the mouth of spring in the Badan Jaran Desert. The dissoluble fractions are finally de-veloped into calc-sinters and calcareous cementation layers around the spring. Calci-sinters are gradually largened and eventually emerge on the surface of lake water. Eolian sands accumulate on the surfaces of calc-sinters and calcareous cementation layers,and eventually develop into dunes. Invasion of magma causes an increase in the temperature of groundwater within the faults. Groundwater evapora-tion provides water vapor for the formation of humid stabilized dunes during its upwelling. Rhizoconcre-tions found in Yihejigede indicate that the dune was formed and remained immovable 4700 years ago. The height of the megadunes is proportional to thermal quantity carried by the groundwater.     

The long-term denudation rate of granitic regolith in Qinhuangdao,North China determined from the in situ depth profile of the cosmogenic nuclides 26Al and 10Be

This study quantifies the surface denudation rate of granitic regolith via the application of the in situ cosmogenic ^26Al and ^10Be depth profile in China. The concentration ranges of ^26Al and ^10Be in the quartz along the -3-m granitic regolith profile in Qinhuangdao are （4.9-23.1） × 10^5 and （2.3-36.6）×10^4 atoms/g, respectively. With the exception of the surface sample, both ^26Al and ^10Be concentrations decrease exponentially with sample depth. The Chi-square best-fitting results revealed a total denudation rate of -9 m/Ma averaged over a 103-105 a timescale, which is lower than the values observed in global granitic outcrops. Compared with global datasets, the flat terrain due to the lack of tectonic activities is most likely the dominant factor that controls the local denudation process. The surface sample offsets from the theoretical cosmogenic nuclide distribution implies that the denudation rate from river basin sediment could be overestimated because of the bioturbation in the surficial soil layer.     

柴达木盆地西部地区隐蔽油气藏形成与分布

柴达木盆地西部地区沉积以近物源、多物源的冲积扇—河流—三角洲—湖泊沉积体系为特征,岩性横向变化大,各种砂体岩性圈闭十分发育;构造活动强烈且具多期性,形成多种地层、裂缝、复合型隐蔽圈闭以及隐伏的构造圈闭.充足的油源为该区隐蔽油气藏的形成提供了丰厚的物质基础;晚期生烃保证了后期形成的裂缝型隐蔽圈闭也可成藏.分析柴西地区隐蔽油气藏的形成条件,认为柴西地区隐蔽油气藏类型多,分布广,蕴藏储量大,具有相当大的勘探潜力.