南黄海及相邻陆区松散沉积层磁性地层的研究

本文通过研究区5个钻孔松散沉积岩心磁性地层的划分对比,获知布容与松山极性带的界线,南黄海和陆区北部位于80.0—99.5m。陆区的南部此界线于270.4m深处。松山和高斯极性带的界线,海区未揭露到,其沉积起始时间都小于1.7Ma。而陆区的南、北部分别位于117m和328.2m。高斯和吉尔伯特极性带的界线,陆区北部为140m,而南部区为460.15m。沉积起始时间为3.4Ma。吉尔伯特底界仅北部陆区所揭示,为190.5m。松散沉积层与下伏白垩纪(?)石灰岩接触面位于400.35m,沉积起始时间约17.0Ma。     

Growth Aspects and Magnesium Carbonate Concentrations of the Reef Building Octocoral Heliopora coerulea (Pallas) after Transplantation

Abstract. An experiment to test C have's hypothesis on temperature dependent MgCO₃ concentrations in marine calcareous skeletons was undertaken by transplanting colonies of Heliopora coerulea. The corals were transferred from a shallow lagoon with high average temperatures to the outer bottom of a fringing reef, 16 m depth, with low average temperatures. Against expectation, a statistically significant increase of average mol % concentrations from 0.48 to 0.54 % for upper growth regions and from 0.49 to 0.62% for lower growth regions was obtained. Temperature records during the experimentation period and the above data indicate that the mol% MgCO₃ concentration in the skeleton of living Heliopora colonies increases when transplanted to an environment with a lower temperature average than that of their original growth site, and with seasonal temperature fluctuations which are smaller in the experimental site than in the control site. Temperature fluctuations at the control site were up to 2.5 times greater than at the experimental site for most of the observation months. This supports the conclusion that the parameters a) minimum temperature and b) temperature stability of the environment are essential for the incorporation of Mg into the carbonate skeleton matrix of marine organisms. Within this study the results of a quantitative chemical analysis of the carbonate skeleton of H. coerulea are presented and growth data of transplanted colonies compared with those from the control site.     

珠江口盆地流花碳酸盐台地灰岩坑的地震反射特征及成因探讨

早中新世东沙隆起带上发育了大规模的流花碳酸盐台地,上覆巨厚未固结-弱固结泥岩。基于三维地震数据,利用相干体及可视化等方法,在台地上发现了由溶蚀垮塌作用形成的数量众多的椭圆形的灰岩坑。灰岩坑直径一般为200~700 m,最大超过900 m,深度10~90 m;灰岩坑在地震反射上表现为碳酸盐岩顶部垮塌,并导致上覆泥岩地层塌陷;灰岩坑一般沿NWW向断层分布,这些NWW向断层切割中新世碳酸盐岩和上覆海相泥岩地层,绝大多数终止于T₁₀的不整合面。综合分析东沙海区构造和沉积过程认为：发生在晚中新世末期的东沙运动形成了NWW向张扭性断层,为酸性流体提供了运移通道和物质交换场所;东沙运动伴生的基底岩浆活动可能产生了酸性热液流体;东沙运动末期发生强烈的构造抬升和大规模海底暴露,造成地表水沿断层注入,加快了碳酸盐岩的溶蚀速率。在台地底部珠海组砂岩层的高压流体、地表水和岩浆活动可能产生的酸性热液流体的共同溶蚀作用下,碳酸盐岩地层内部产生溶洞,并且越来越大,最终顶部无法承载上覆巨厚泥岩而发生垮塌,形成灰岩坑。流花碳酸盐台地灰岩坑的形成不是简单的暴露溶蚀,而是构造活动影响下深埋藏溶蚀作用的产物。     

Levels and distribution of tris-(2,3-dibromopropyl) isocyanurate and hexabromocyclododecanes in surface sediments from the Yellow River Delta wetland of China

The levels and distribution of tris-(2,3-dibromopropyl) isocyanurate (TBC) and hexabromocyclododecanes (HBCDs) of surface sediments in the Yellow River Delta wetland had been investigated. The concentrations of TBC and ∑ HBCDs ranged from 0.20 to 29.03 ng·g^? 1 dw and below limits of detections (LODs) to 20.25 ng·g^? 1 dw. The average composition profile of three HBCDs isomers were 10.1%, 6.1% and 83.8% for α-, β- and γ-HBCD, respectively. Moreover, correlation analysis indicated there are similar sources among three isomers and positive correlations between total organic carbon (TOC) content and concentrations of TBC and HBCDs. The mass inventory of TBC,α-, β-, γ-HBCD, ΣHBCDs in surface sediments of Yellow River Delta wetland were estimated about 725.50, 72.76, 44.29, 548.34, 665.39 kg. Therefore, further investigations on potential human health and environmental risk assessments of TBC and HBCDs were needed.     

塔河油田奥陶系储层构造应力场研究

油气储层构造应力场的分布特征,对油气运移、注采井网布置、储层改造等具有重要意义。为此,文章从塔河油田AD13井区的地质构造演化入手,基于油田测井资料,结合弹性力学及有限元理论,建立研究区地应力弹性力学计算模型,利用有限元软件对研究区储层地应力进行模拟研究,并将模拟结果与现场地应力实测值进行对比分析。结果表明,研究区最大水平主应力为102~130 MPa,最小水平主应力为87~110 MPa,均为压应力;研究区东部及南部最大水平主应力方向为北东向,西北部最大水平主应力方向为北东东向,西南部最大水平主应力方向为南东向,地应力大小及方向均与实际结果相符。研究结果可为研究区油气勘探开发工程提供科学依据。      

Strontium and neodymium isotopic compositions of detrital sediment of NS90-103 from South China Sea: Variations and their paleoclimate implication

Strontium, neodymium isotopic compositions and trace elements of the detrital sediments of Core NS90-103 from South China Sea were analyzed. The results show that the⁸⁷Sr/⁸⁶Sr ratios of the detritus during the last glacial range from 0.722 4 to 0.723 0. They are significantly higher than those during the Holocene and the maximum of the last interglacial, which range from 0.721 0 to 0.721 7. This indicates stronger continental weathering during the last glacial. On the other hand, the¹⁴³Nd/¹⁴⁴Nd ratios of these detritus are higher during the last glacial too, similar to the variation of the⁸⁷Sr/⁸⁶Sr ratios. The trace element geochemistry of these detritus indicates that more authigenic sediments, such as ferromanganese, during the last glacial may partly contribute to the increase of¹⁴³Nd/¹⁴⁴Nd ratios. Furthermore, much more detritus from continent of South China to the north of the South China Sea may probably contribute to¹⁴³Nd/¹⁴⁴Nd ratios increase during the last glacial, which was the result of the enhancement of northeast monsoon.     

裂缝性碳酸盐岩裂缝的双侧向测井响应特征及解释方法

裂缝评价是裂缝性碳酸盐岩储层评价的关键, 其常规评价方法受到裂缝发育的不均匀性及储层各向异性的影响而存在诸多困难.采用三维数值算法, 利用宏观各向异性地层模型, 研究不同的裂缝参数条件下双侧向测井响应特征, 由此导出一种用于裂缝孔隙度计算的快速算法.分析表明, 裂缝的双侧向响应同裂缝孔隙度与孔隙流体电导率之间存在明显的线性关系, 裂缝的倾角造成双侧向测井曲线幅度差异的变化; 不同倾斜情况下, 将双侧向测井响应近似表示为岩石基岩电阻率、裂缝孔隙度、裂缝流体电导率的函数, 用于裂缝孔隙度的快速计算.实际资料处理表明, 利用双侧向依据该方法确定的裂缝参数同成像测井资料具有良好的对应性.      

Seismic characterization of switching platform geometries and dominant carbonate producers (Miocene,Las Negras,Spain)

The primary goals of seismic interpretation and quantification are to understand and define reservoir architecture and the distribution of petrophysical properties. Since seismic interpretation is associated with major uncertainties, outcrop analogues are used to support and improve the resulting conceptual models. In this study, the Miocene carbonates of Cerro de la Molata (Las Negras, south‐east Spain) have been selected as an outcrop analogue. The heterogeneous carbonate rocks of the Cerro de la Molata Platform were formed by a variety of carbonate‐producing factories, resulting in various platform morphologies and a wide range of physical properties. Based on textural (thin sections) and petrophysical (porosity, density, carbonate content and acoustic properties) analyses of the sediments, eleven individual facies types were determined. The data were used to produce synthetic seismic profiles of the outcrop. The profiles demonstrate that the spatial distribution of the facies and the linked petrophysical properties are of key importance in the appearance of the synthetic seismic sections. They reveal that carbonate factory and facies‐specific reflection patterns are determined by porosity contrasts, diagenetic modifications and the input of non‐carbonate sediment. The reflectors of the seismograms created with high‐frequency wavelets are coherent with the spatial distribution of the predefined facies within the depositional sequences. The synthetic seismograms resulting from convolution with lower frequency wavelets do not show these details – the major reflectors coincide with: (i) the boundary between the volcanic basement and the overlying carbonates; (ii) the platform geometries related to changes in carbonate factories, thus sequence boundaries; and (iii) diagenetic zones. Changes in seismic response related to diagenesis, switching carbonate producers and linked platform geometries are important findings that need to be considered when interpreting seismic data sets.     

云南腾冲青海湖泊沉积物物化参数的特点、环境意义及末次冰消期以来气候环境变化

根据对云南腾冲青海湖泊沉积钻孔样品的粒度特征、总有机碳、碳酸盐、磁化率及年代学分析测试, 探讨了各指标的变化特点及其环境指示意义, 指出了云南高原湖泊沉积物化指标的特殊性及其变化特点。在此基础上, 重建了云南腾冲地区末次冰消期(15830a B.P.)以来沉积环境与气候干湿变化历史。通过青海沉积物年代序列的重建和综合各物化参数分析得出, 云南腾冲地区自15830a B.P.以来总体呈现冷湿-温湿-暖干-温和偏干的气候演变过程, 并可分为4个阶段, 即15830~12790a B.P.气候温凉偏湿; 12790~4680a B.P.为温暖湿润期, 湖泊水位高, 气候湿暖, 降水多; 4680~312a B.P.气候特征呈现出从温湿到暖干气候逐渐演化, 降水减少, 湖泊水位下降; 312a B.P.以来气候特征为前期温和湿润, 后期具有暖干化特征, 反映了近几十年来全球气候变暖导致的气候变化趋势并叠加了研究区人类活动对区域环境的影响。     

甘肃第四纪沉积物的成因类型及特征

甘肃第四纪沉积物为陆相沉积,依据沉积物搬运介质、气候条件、沉积环境、搬运动力,将成因划分为风化作用系列、坡地重力作用系列、水流作用系列、湖沼作用系列、冰川作用系列、风力作用系列、生物作用系列、人为作用系列、混合作用系列共9大系列,22种成因类型。