Sedimentation, distribution and diagenesis of organic matter in a recent carbonate environment, Abu Dhabi, U.A.E.

In the modern hypersaline carbonate lagoon and sabkha sedimentary environments of Abu Dhabi (United Arab Emirates), three types of organic matter originate respectively from microbial mat, Avicennia mangrove, and Halodule lagoonal seagrass. The study of recent sedimentary processes and cross sections through the sabkha sediments lead to the definition of organo-sedimentary facies based on geochemical and sedimentological criteria. This permits the construction of an organo-sedimentary sequence which expresses the Holocene sedimentary record involving a transgressive and a regressive sequence. The various organic facies occur in both sequences.Heterogeneity within the individual organic facies reflects several factors, including sedimentation dynamics, mineral matrix, oxidation and reduction, and selective organic and mineral diagenesis. These parameters are discussed in terms of depositional environment and location within the organo-sedimentary sequence. Changes in distribution, quantity, and preservation potential of the buried organic matter are discussed in terms of sea level changes and sedimentary accretion rates.     

晚白垩世后青藏高原和塔里木地块的整体北移

本文根据塔里木地块及其以南的昆仑、羌塘和拉萨地块晚中生代特别是晚白垩世古地磁数据,提出青藏高原自晚白垩世后北向移动两千余公里,主要并不是通过它本身的大规模地壳缩短来完成,而是与塔里木地块一起作大规模整体北移的结果。一种可能的解释是,在欧亚大陆北部稳定区和塔里木地块之间广大的中亚构造带,自晚白垩世后发生了大规模的地壳缩短。     

离子交换法生产碳酸钾的工艺探讨

本文讨论以工业KCI和NH4HCO3为原料、采用离子交换法（国产732钠型树脂）生产K2CO3的工艺。小试验的结果：以20％KCI溶液上柱，以分段交换率在50％以前为穿漏点、流速为0．033(ml/min.ml树脂）时，总交换率达83．3％，工作交换容量达2．24（毫摩尔钾／ml树脂）；当以饱和NH4HCO3溶液进行解脱、流速在0．033(ml/min.ml树脂）时，解脱率达91．8％，产品的含量为98．2％。     

平果地区孤立碳酸盐台地风暴特征及展布规律

广西平果地区二叠纪,早三叠世发育了众多的孤立碳酸盐台地。孤立碳酸盐台地内的风暴岩至少可分出三类。Ⅰ类由下亚段粒序层和上亚段具叶状藻灰泥岩或具遗迹化石灰泥岩组成,形成在高能风暴流条件下.Ⅱ类由下亚段粒序层,中亚段纹层段和上亚段灰泥岩组成,其形成水能较Ⅰ类弱.Ⅲ类由具定向生物化石的泥粒岩组成,它是风暴流到达台地边缘后产生的回流形成的。不同类型风暴岩形成于不同环境。孤立碳酸岩台地上的风暴岩与开阔陆架风暴岩有一定差别.     

CaCO3生物矿化的研究进展——有机质的控制作用

生物CaCO₃是自然界分布最广泛的一类生物矿物,其组成除了无机相的CaCO₃外,还含有少量的有机质,包括水可溶(SM)和水不可溶有机质(IM),SM富含阴离子基团,是控制CaCO₃结晶的重要因素之一。通过有机—无机界面分子识别,有机质选择性地与CaCO₃晶体特定方向的面网相互作用,从而对CaCO₃的生长、形貌、多型及结晶学定向等产生明显的控制作用。有机—无机界面的分子识别机制包括静电、晶格几何匹配和立体化学互补等。仿生矿化的研究为进一步深入了解生物矿化的机理及制造高级复合材料提供了新的方法。     

南沙海区晚第四纪的碳酸盐旋回

根据水深200～2 800m范围内的17个沉积柱状样分析结果,讨论南沙海区晚第四纪沉积中碳酸钙相对含量的垂向和横向变化。南沙海区的碳酸盐旋回普遍属于"大西洋型",冰期时含量低、间冰期含量高,反映出陆源物输入量的控制作用。在平面上,南沙海区的碳酸钙含量与纬度几乎呈线性关系,由北向南递减,冰期时趋势不变而梯度加大。南海南部陆坡由于集水盆地处于热带湿热条件而且有大河注入海区,使碳酸钙含量相对北部陆坡为低。     

Estimation of the REV size for blockiness of fractured rock masses

The representative elementary volume (REV) is the premise of the continuous-media method of analysis, and the investigation of the REVs of fractured rock masses is a fundamental area of rock mechanics research. The existence of an REV can be determined based on a variety of physical parameters. This paper presents an analysis of the REV from the view of blockiness, which is defined as the percentage of the volume of isolated blocks formed by fractures in the total rock volume. Seventy-seven types of fractured rock mass models were developed based on 7 classes of fracture persistence and 11 classes of spacing that are suggested by the International Society for Rock Mechanics (ISRM) fracture classification. Rock blocks in each of the 77 types of fractured rock mass models were identified using GeneralBlock to determine the variation in blockiness with model domain sizes, which were changed from 2 to 20 times the fracture spacing. For each model domain size 9 random realizations were carried out to reduce the effects of randomness. The coefficient of variation (C_v) was then used to quantify the variability of the 9 random realizations. The fluctuation in blockiness with the variation in the scale of the model region was also investigated. In this way, the size of the REV in these models can be calculated using the average and the variance of the blockiness as indicators of the convergence. The blockiness of these fractured rock masses can be determined at the REV volume. The results indicate that of the 77 models, 76 REV sizes are between 2 and 20 times the fracture spacing. The fractured rock mass with a wide fracture spacing and very high persistence (WS2–VHP) has a REV size that exceeds 20 times the fracture spacing. Thus, the WS2–VHP model should be investigated further to validate this concept.     

渤海海域深层低孔渗油气藏成因机制分析——以渤中1&2区块为例

渤海深层油气藏勘探潜力大,随着渤海勘探的深入,深层低孔渗油气藏已成为渤海勘探的必然选择。而深层低孔渗油气藏在成因类型和成藏机制上明显不同于先前的构造类油气藏。以渤中12区块为例,对其深层低孔渗油气藏成因机制进行深入剖析。研究表明,研究区深层低孔渗油气藏为先致密后成藏。根据深层成藏力平衡机制和浮力成藏下限理论,主要为以浮力运移动力为主的常规油气藏,以及以分子膨胀力为主的深盆致密油气藏,是两种不同成因机制的油气藏叠加在一起组成的复合油气藏。晚期原油两期充注成藏加之晚期碳酸盐胶结作用,导致古油藏的存在。先期原油的排酸作用,异常超压带虽然碳酸盐含量高,但是粒度较粗砂体碳酸盐胶结物含量较少,且颗粒溶孔也比较发育,另外超压使压实受抑制,原生孔隙得以保存,这都是深部致密带出现"甜点"的原因。研究成果对指导渤海深层勘探,拓展勘探领域有一定的借鉴意义。     

矿床三维地质建模及储量估算——以丰村铅锌矿径口矿段为例

钦杭成矿带是我国最重要的成矿带之一,丰村铅锌矿位于钦杭成矿带南段庞西垌地区,是区内典型的沉积热液改造型矿床。依据现代成矿预测理论,结合已有的地形地质图、勘探线剖面图、钻孔数据等资料,运用三维地质建模技术建立了丰村铅锌矿径口矿段的地表模型、断裂模型、地层实体模型、矿体模型。在此基础上分别应用地质块段法和块体模型统计法进行了矿体的资源储量估算,并将两种估算结果进行了对比分析。结果表明,块体模型统计法比地质块段法应用范围更广,效果更精准,可以清晰表达矿体品位值变化特征,进而加深对矿体、矿床的空间分布规律的认识。同时,利用多元信息进行三维地质建模,可靠性高,可视化效果好。将传统的二维地质拓展到三维空间进行定位与定量化,有助于分析矿区地质构造特点与矿床成因,是现代寻找矿床的一种有效手段。     

应用去除碳酸盐法研究滇黔地区“白泥塘层”硅质成分的来源

稀土元素是研究沉积岩的形成条件及环境特征的重要指标,本文以桂林寨底地下河系统中岩石样品为研究对象,采用激光剥蚀电感耦合等离子体质谱进行稀土元素测试分析,研究了该地区碳酸盐岩的形成环境。结果表明:碳酸盐岩的稀土总量(∑REEs)偏低,不同地层岩性间的∑REEs具有一定差异性,总体上信都组泥质粉砂岩(D₂x)的∑REEs最高,其次为融县组(D₃r)厚层灰岩和桂林组灰岩(D₃g),东村组厚层灰岩(D₃d)和额头村组灰岩及白云质灰岩(D₃e)的∑REEs较低。整体上表现为重稀土元素相对于轻稀土元素富集的特征,且Ce具有较明显的负异常,而Eu无异常或异常不明显,不同于碎屑岩的轻稀土相对富集、Eu负异常、Ce无异常或异常不明显的特征。这些特征表明研究区碳酸盐岩的形成环境为氧化-海相碳酸盐岩沉积环境,可为定量化判别岩溶区碳酸盐岩形成环境提供依据。