有孔虫初房特征变化在珠江三角洲晚全新世东亚夏季风降雨研究中的应用

研究中国降雨格局变化对理解东亚夏季风演化意义重大。本文分析了珠江三角洲柱状样ZJK03-Z中浅水底栖有孔虫常见种Rotalidium annectens的平均初房大小、微球型/显球型比值和壳体δ18O值,以及底栖有孔虫组合中瓷质壳的百分含量,探讨它们对由夏季风降雨引起的河口水体盐度变化的响应,得到了珠江三角洲3114—1260a BP季风降雨的强度变化,识别出了这期间14次季风降雨减少的偏干期。与南美洲Cariaco海盆的钛含量记录对比,二者一致的结果表明,珠江三角洲晚全新世的东亚夏季风降雨与热带辐合带(ITCZ)的南北移动密切相关:夏季风降雨减少,对应于ITCZ纬度位置的南移。     

Distributional characteristics of grain sizes of surface sediments in the Zhujiang River Estuary

Distributions of the parameters of sedimentary grain sizes and their correlations were studied to trace the sources of silts and their movement trends in the Zhujiang River Estuary based on the analyses of grain sizes from more than 1080 sedimentary samples. The distributions of the median diameter, public value, quartile deviation, and skewness of sediments were complex in the Zhuiiang River Estuary mainly because of the impact of the matter source regions, distances from the source regions, and hydrodynamic conditions, such as waves, tidal currents, and coastal currents. Analyses of the parameters of the grain sizes for the various types of sediments showed that the distributions of the surface sediments in the Zhujiang River Estuary were controlled by many factors. Their matter sources were mainly the sediments discharged from the runoffs and ebb tidal currents, and from the open sea. The sediments mainly moved by suspension movement. The silts formed a large area of sediments with suspended fine silts in the Zhujiang River Estuary by internal adjustment transportation in the area, and moved toward the western coast of the Zhujiang River Estuary under the effect of Coriolis forces and coastal currents.     

Sequence stratigraphic modelling and reservoir architecture of the shallow marine successions of Baram field,West Baram Delta,offshore Sarawak,East Malaysia

The Baram Delta Province is located in the northern part of Sarawak (West Baram Delta) and extends north-eastward into Brunei and further into the south-western part of Sabah (East Baram Delta). The delta is a Neogene basin which developed over an accretionary wedge implying Cretaceous to Eocene sediments during the Late Eocene to Late Miocene times (Tongkul, 1991; Hutchison et al., 2000; Morley et al., 2003; Sapin et al., 2011).Facies and well log analyses were carried out on core and well data for the Late Miocene successions of Baram field, a medium-sized oilfield located in the north-eastern flank of the Baram Delta Oil Province, offshore Sarawak. A numerical model of sea-level fluctuations and progradational basin-fill was generated using the Clastic Modeling Program (Hardy and Waltham, 1992a and 1992b; Waltham, 1992) software to evaluate the possible controls of sea-level changes in the development of the siliciclastic successions and their bounding surfaces. This model was based on four lines of evidence, namely core data, fieldwide wireline logs correlation, seismic sections and average thickness variations across the field.Cored intervals of the Upper Cycle V (Late Miocene) display reservoir successions dominated by thick swaley cross-stratified (SCS) sandstones, thin hummocky cross-stratified sandstones and other shallow marine, wave and storm-dominated facies, interbedded with laminated shelfal mudstones. The vertical facies organisation suggests deposition during shoreface progradation associated with a fall of relative sea level.Analysis and correlation of well logs reveal stacking patterns comprising three scales of depositional cyclicity: the parasequences (∼10–∼30 m thick), the parasequence sets (∼45–∼130 m thick) and the major cycles (∼600–800 m thick).Field-wide, dip-oriented seismic sections show very well-developed horizontal to slightly upward convex layers traceable over great distances, which suggests a ramp-type margin, in which the basin floor dipped gradually seaward and lacked a distinct shelf-slope margin.The evidences gathered demonstrate that the deposition and build-up stratigraphy of the Late Miocene sedimentary successions could have been strongly controlled by superimposed short-term, medium-term and long-term sea-level changes.The simulated sea level and sedimentary basin-fill model, generated by the Clastic Modelling Program, match to the well log correlation. This model illustrates that high frequency sea-level fluctuations enable sands to be distributed over large areas within a shallow, low gradient shelf. Our study shows that integrated studies incorporating cores, well logs, seismic sections and simulated models can be employed as important tools for correlation and reservoir modelling.     

Three-dimensional facies architecture analysis using sequence stratigraphy and seismic sedimentology: Example from the Paleogene Dongying Formation in the BZ3-1 block of the Bozhong Sag,Bohai Bay Basin,China

The Bohai Bay Basin is a classic non-marine rift basin in eastern China. The Paleogene Dongying sequences are the main hydrocarbon-bearing stratigraphic unit in the basin. Using three-dimensional (3-D) seismic data and one well control in the BZ3-1 Block in the western slope of the Bozhong Sag, we analyzed 3-D facies architectures of the Dongying sequences. The Dongying Formation, a second-order sequence, can be subdivided into four third-order sequences (from base to top: SQ1, SQ2, SQ3, and SQ4). The facies architecture was analyzed by using the seismic sedimentology approach based on 3-D seismic data. Sediment of the Dongying sequences was derived from the northern Shijiutuo Uplift via four major configurations of incised valleys, namely “V”, “U”, “W”, and composite shaped incised valleys. Seismic stratal slices reveal branching and converging characteristics of the channels from upstream to downstream. On the basis of an integrated analysis of well log, core data, seismic facies based on multi-seismic attributes, three sedimentary facies (e.g., “delta”, “fan-delta”, and “shore” or “shallow lacustrine” facies) have been recognized. The four types of incised valleys and their evolution control the sedimentary systems in the sedimentation area. The numbers and sizes of the fans are controlled by the sedimentary systems at various scales. Incised valley-fill and deltaic sand bodies are excellent hydrocarbon reservoirs and potentially good exploration targets for the study area. The reservoir quality of sequences SQ1, SQ2, and SQ3 become better gradually from base to top. The proposed sediment dispersal patterns may aid in the prediction of potential reservoir distribution. This study also demonstrates that facies architecture analysis using sequence stratigraphy and seismic sedimentology may serve as an effective approach for constructing 3D facies models for petroleum exploration in areas lacking of well or outcrop data.     

Dispersal of the Zhujiang River (Pearl River) derived sediment in the Holocene

High-resolution Chirp profiling and coring reveals an elongated(ca. 400 km) Holocene Zhujiang River(Pearl River)-derived mud area(maximum thickness 20 m) extending from the Zhujiang River Delta, southwestward off the Guangdong coast, to the Leizhou Peninsula. Two depo-centers, one proximal and one distal, are identified. On the continental shelf off the west Guangdong Province, the mud is deposited in water depth shallower than 50 m; while to the southeast of the Zhujiang River Estuary, the mud area can extend to the-120 m isobath. A combined analysis with the stratigraphic sequences of other muddy deposits in the Western Pacific marginal seas(mainly Changjiang(Yangtze) and Huanghe(Yellow) Rivers derived) indicates that the initiation of the Zhujiang River muddy deposit can be further divided into two stages: Stage 1 is before the mid-Holocene sea-level highstand(ca. 7.0 cal. ka BP), the proximal mud was mostly deposited after 9.0 cal. ka BP, when the sea-level rose slowly after the Meltwater Pulse-1C; Stage 2, after the mid-Holocene sealevel highstand, clinoform developed on the continental shelf off the west Guangdong Province, extending ca. 400 km from the Zhujiang River Estuary. The proximal clinoform thins offshore, from ca. 10 m thickness around 5–10 m water depth to less than 1–2 m around 20–30 m water depth. In addition, we also find a developed distal clinoform in the east of the Leizhou Peninsula.     

商业平板式超滤膜包完整性检验：对海洋胶体生物地球化学研究的启示

The performance and integrity of a cassette cross-flow ultrafilter(Pellicon 2, Millipore) are examined with a suite of macromolecules of different molecular masses. The retention coefficient during the cross-flow ultrafiltration experiments increases with increasing molecular mass and reaches 90% with 10 kDa dextran in both milli-Q water and ultrafiltered seawater media. Based on a 90% retention coefficient, the molecular mass cut-off for the ultrafiltration membrane is defined at 10 kDa, which is ten times(1 kDa) that rated by the manufacturer. To further validate the accuracy of the laboratory calibration, the samples from the lower Zhujiang River and the Jiulong River Estuary are ultrafiltered with the cassette ultrafiltration membrane and the colloidal organic carbon abundances in these samples are quantified with the ultrafiltration permeation model based on time series permeation subsamples. The colloidal organic carbon abundances are 5.8%–21.1% in the Jiulong River Estuary and 5.6%–11.0% in the lower Zhujiang River. These are consistent with the reported values for both estuaries as well as with the colloidal organic carbon abundances in marine environments over the coastal and open oceans with 10 kDa cut-off membranes. Therefore, these field data support the laboratory calibration result and indicate the validity of the experimental and quantification procedure adopted. The discrepancy between the nominal molecular mass cut-off and the actual pore size of the ultrafiltration membrane should be of great concern for research in colloidal and nanoparticle biogeochemistry. Careful examination of the membrane integrity should be taken during ultrafiltration experiments in order to avoid misleading molecular mass cut-off information.     

An improved dark object method to retrieve 500 m-resolution AOT (Aerosol Optical Thickness) image from MODIS data: A case study in the Pearl River Delta area,China

This paper presents an improved Dark Dense Vegetation (DDV) method for retrieving 500 m-resolution aerosol optical depth (AOT) based on MOD04-C005 arithmetic with the Moderate Resolution Imaging Spectroradiometer (MODIS) from the National Aeronautics and Space Administration (NASA). The improvements include change of the movement pattern of retrieval window, selection of a more suitable aerosol type, and storage of the look-up table. The method is then applied to obtain the AOT over the Pearl River Delta region (PRD). By comparing the results with the co-temporal ground sunphotometer observations in 2010, the correlation coefficient is found to be 0.794 with RMSE 0.139 and their variations remain consistent. Contrasts between model values in 2008 and MODIS AOT products in the same date also reveal a high accuracy of the improved DDV method. We also performed sensitivity tests to analyze the impacts of several parameters on apparent reflectance at different bands, and the results show that apparent reflectance is much more sensitive to surface reflectance and AOT than to elevation.     

珠江口盆地东沙隆起生物礁地质及地震特征

东沙隆起珠江组生物礁是珠江口盆地重要的储层类型,礁灰岩主要为珊瑚藻灰岩,分为骨架岩、粘结岩及障积岩。研究区生物礁发育于开阔台地、台地边缘及台地前缘斜坡3类沉积相中,生物礁类型可分为台内点礁、台地边缘堡礁及台缘斜坡塔礁,以台地边缘堡礁为主。珠江组沉积早期,东沙隆起发育滨岸砂质沉积;中期海水逐渐淹没东沙隆起,形成镶边浅水碳酸盐台地,发育生物礁;晚期海侵台地逐渐淹没消亡,被浅海陆棚泥质沉积代替。流花台地厚度最大,最厚达563m,台地顶面地震强反射使外形轮廓清晰,台地内部中-弱振幅至空白反射,连续性降低;惠州台地厚度较流花台地薄,厚度多大于100m,顶界面强反射轮廓清晰,内部层状反射能量强-中振幅、高-中连续、中-低频,局部空白反射;陆丰台地厚约30m,只有一个高连续的强振幅。生物礁地震响应以丘形、箱型、低丘-透镜状为特征,礁顶常为强振幅,内部为波状、有时见前积结构,翼部可见上超和披覆现象等。     

黄河三角洲地下水动态变化及其与地面沉降的关系

为了分析黄河三角洲地下水动态及其与地面沉降的关系, 利用多年地下水和地面沉降监测数据, 发现黄河三角洲广饶县和东营区的地下水动态变化剧烈且地面沉降严重, 含水层多处于超采状态, 浅、深层地下水降落漏斗先后出现.深层地下水降落漏斗中心水位下降速度达2~3m/a.近年来, 东营和广饶地面沉降漏斗中心沉降量和速率分别为155.1mm、28.2mm/a和356.0mm、64.7mm/a.借助GIS技术及数理统计法, 发现深层地下水降落漏斗与沉降漏斗空间耦合良好, 深层地下水位与地面高程呈线性正相关, 相关系数为0.92, 深层地下水过度开采已成为影响沉降的最根本因素.井灌区第三粘性压缩层成为地面沉降主要贡献层, 且深层地下水降落漏斗中心的地下水位已低于第三承压含水层临界水位, 沉降趋于严重.      

长三角创新产学合作与企业创新绩效:尺度与效应北大核心CSCDCSSCI

产学合作网络是长三角创新共同体建设的重要方面,而当前经济地理学相关研究集中在“本地/全球”二元尺度讨论上,缺乏多尺度产学合作效应的比较分析。基于IncoPat专利数据,本文从尺度和效应视角探讨了长三角创新产学合作与企业创新绩效的关系,得到以下结论:①长三角创新产学合作的空间格局呈现以省会城市为中心的星芒状结构,核心城市占据的网络优势地位能够助力其在网络中获取创新资源,并且高校资源的不均衡分布特征进一步巩固了省会城市的优势地位,使得长三角创新产学合作格局具有明显的路径依赖特征。②本省与长三角区域尺度创新产学合作对企业创新绩效的影响要显著高于其他尺度。从区域尺度客观看待高校在空间创新进程中的作用尤为重要。③长三角创新产学合作的平均距离与企业创新绩效间呈现显著的倒“U”型关系,并且工科院校产学合作的作用和极值点均要大于综合院校和其他院校。由此,本文提出以下建议:一方面应该加快推进以区域尺度创新产学合作为重点的产学合作体系建设;另一方面应当强化薄弱地区产学合作的多尺度耦合网络建设,着力提升薄弱地区的网络地位。