早-中奥陶世之交笔石动物群全球分布及其控制作用

为研究笔石动物群在早一中奥陶世之交全球分布的控制因素,从以下3个方面进行了分析和研究:①分析了穿越扬子地台笔石动物群的分布特征;②在对笔石体形态功能分析的基础上,探讨了水体深度对笔石动物群分布的影响;③根据当时的古地理格局,并参考现今的洋流分布,建立了早一中奥陶世之交的洋流分布图.在以上研究的基础上,对前人以水体深度作...     

黔南宾夕法尼亚亚纪礁环境中腕足动物古生态研究

黔南地区宾夕法尼亚亚纪逍遥阶礁相地层中腕足动物普遍发育,主要产长身贝类和石燕贝类。本文主要研究该区腕足动物与造礁生物叶状藻和Fomitchevella 珊瑚之间的生态关系。在叶状藻礁内,小个体腕足动物常附着在藻叶上营假漂浮生活; 但藻叶密集处,小个体腕足动物也难见,可能藻丛造成水流循环不畅使腕足动物难以获得充足的食料; 藻叶稀疏处,腕足动物个体加大,数量增加。在大型Fomitchevella 珊瑚格架礁内,腕足动物与Fomitchevella 之间不存在食物上的竞争。腕足动物介壳层为Fomitchevella 幼虫定殖提供了生物成因的硬质基底,在此基础之上发育了大型珊瑚礁。腕足动物在 Fomitchevella 进入统殖阶段由于生态空间受到局限而退居次要地位。     

Flow Behavior of Clay-Silt to Sand-Silt Water-Rich Suspensions at Low to High Shear Rates: Implications for Slurries, Transitional Flows, and Submarine Debris-Flows

Water-rich clay to sand suspensions show a shear rate dependent flow behavior and knowledge of the appropriate rheological model is relevant for sedimentological, industrial and hydraulic studies. We present experimental rheological measurements of water-rich (40 to 60 wt%) clay to silt (population A) and silt to sand (population B) suspensions mixed in different proportions. The data evidence a shear rate dependent shear thinning-shear thickening transition. At lower shear rates, the suspensions organize in chains of particles, whereas at higher shear rates, these chains disrupt so increasing the viscosity. The viscosity, consistency and yield stress decrease as the A+B fraction decreases as the content of B particles increases. This behavior reflects the competing effects of the lubrication and frictional processes as a function of particle size and water content. Transitional flows form by the incorporation of small amounts of the finer fraction while ‘oceanic floods’ form at the estuary of rivers and the submarine debris-flows increase their velocity by incorporating water. The critical Reynolds number of the studied suspensions is ~2000±100 suggesting that the grainsize plays a major role in the laminar to turbulent transition. Our results have implications for the modeling of sediment flows and the hazard related to floods.     

Middle Jurassic continental to marine transition in an extensional tectonics context: the Genna Selole Fm depositional system in the Tacchi area (central Sardinia,Italy)

In Eastern Sardinia during the early Middle Jurassic, Alpine Tethys opening triggered the rise of a temporary tectonic high. The high collapsed rapidly, was fragmented into separate blocks, and subsequently covered by continental, transitional, and finally shallow marine deposits forming a narrow depositional system comprising the Genna Selole Fm. Present‐day exposures in the southern part of the palaeo‐high allow the sedimentological evolution of the transgressive cover sequence to be ascertained. Initial terrestrial deposits comprise alluvial fan deposits located at the mouths of palaeovalleys. These pass into braid‐deltas and in the coastal areas located between adjacent valleys mouths, palustrine and coastal plain tidally‐influenced environments developed. These environments interfingered laterally and passed seaward into a transitional, siliciclastic to carbonate tidal environment. With the collapse of the tectonic high, the continental to transitional environments were transgressed with deposition of marine carbonates. A comparison with similar coeval deposits of the W‐Mediterranean domain has been undertaken. Copyright © 2015 John Wiley & Sons, Ltd.     

北京南部地壳精细结构深地震反射探测研究

为了研究北京平原区的地壳结构特征、断裂的空间展布、断裂活动性以及深浅构造关系,在北京平原区的南部完成了1条长90 km的深地震反射剖面.探测结果表明,该区地壳以双程反射时间(TWT)6～7 s的强反射带Tc为界分为上地壳和下地壳,上地壳厚约18～19 km,下地壳厚约16～17 km,Moho界面深度约为34～35 km.该区结晶基底起伏变化较大,上、下地壳分界面和Moho界面都是一个具有一定厚度的过渡带.上地壳反射层位丰富,断裂构造发育,构造形态清晰.在夏垫断裂西北,剖面揭示了4～5组能量较强的反射震相,表现为典型的隆起区特征;在夏垫断裂东南,上部为一套向东南倾伏的密集强反射层,下部为一套形态各异、结构复杂的强反射层,这些反射具有典型的沉积盆地特征,盆地最深处约为11 km.剖面揭示的地壳深断裂倾角较陡,向上切穿了上、下地壳分界面,延伸到上地壳沉积盆地的底部,向下切穿了壳幔过渡带,与上部断裂和沉积盆地构成了独特的组合关系.     

鹿邑凹陷海陆过渡相页岩气地质调查鹿页1井钻井技术

南华北盆地鹿邑凹陷具有页岩气形成和发育的良好地质条件,区域内设计的页岩气地质调查鹿页1井井深3506.5 m。区域内属于海陆过渡相地层,地层复杂,构造发育,山西组及上石盒子组地层泥岩层段较多,施工中易出现坍塌、掉块等孔内复杂情况。针对钻井工程施工难点,通过优选钻探设备、钻头、钻井液体系等措施,总结了泥浆护壁、深孔取心、防斜等技术措施,保障了钻井工程的顺利实施,形成了一套适应于南华北盆地鹿邑凹陷海陆过渡相地层的页岩气深井钻井施工技术方法。为下一步实施同类钻井、安全优质高效开发页岩气提供了有益借鉴。     

基于线性过渡体介质理论的薄砂层厚度预测技术

薄砂层厚度预测是油气田勘探开发的难点之一。本文引入线性过渡介质理论,建立更为接近实际的楔状线性过渡介质模型,通过时域理论模型正演及频域响应特征分析,提出利用调谐频率信息预测薄砂层厚度的研究思路,并在实际应用中建立起一套相应的预测流程。实钻验证表明,预测出的薄砂体空间展布范围及厚度与实际情况吻合度较高,该方法具有良好的应用和推广价值。     

柴达木盆地东部石炭系海陆过渡相煤系页岩气地球化学特征及成因

为了弄清柴达木盆地东部石炭系海陆过渡相页岩气特征和成因,选取柴页2井石炭系克鲁克组泥页岩和页岩气样品展开地球化学研究。通过对泥页岩样品热解和镜检实验,页岩气现场解析、室内气体组分测试和碳同位素分析,取得以下认识：柴达木盆地上石炭统海陆过渡相煤系地层发育暗色泥页岩、碳质泥页岩、煤和泥灰岩4类富有机质沉积,TOC含量平均值分别为3.46%、12.34%、77.62%和1.89%,以Ⅲ型和Ⅱ2型干酪根为主,处于高成熟演化阶段,具备生成大量页岩气的物质基础。柴页2井现场解析气中氮气含量较高,含极少量Ar和He,烃类气体以甲烷为主,总体为干气;甲烷稳定碳同位素组成主要分布在-48.6‰～-39.8‰,介于海相和陆相页岩气之间,随深度增大,呈现碳同位素偏重的现象;页岩气以热成因气为主,其次是生物成因气。     

ZONATION OF GLACIOMARGINAL ENVIRONMENT INFERRED FROM PLEISTOCENE DEPOSITS OF MYSLIBORZ LAKELAND, NW POLAND

The study area in Mysliborz Lakeland (Western Pomerania), NW Poland, is located in the glaciomarginal zone of the Pomeranian Phase (Weichselian glaciation). Three subenvironments of deposits are exposed in the six analysed pits: glacial ice-contact subenvironment, transitional subenvironment and glaciofluvial subenvironment. The glacial ice-contact subenvironment is dominated by coarse-grained, massive and thick beds derived from debris flows and also horizontally laminated sand and gravel deposited by sheet flows. The transitional subenvironment represents deposits between end moraine and proximal outwash plain (sandur). The transitional subenvironment is dominated by coarse-grained diamicton derived from debris flows, horizontally laminated beds deposited by sheet flows, and additionally cross-stratified sediments from channel flows and massive sand from hyper-concentrated flows. The glaciofluvial subenvironment corresponds with the distal part of the glaciomarginal zone. The processes of sediment deposition in the glaciofluvial subenvironment are derived from shallow sheet flows and channelized flows. Architectural element analysis highlights the change in lithofacies associations from glacial ice-contact, through transitional to glaciofluvial subenvironments. This sedimentological zonation of the glaciomarginal zone may have been developed in other glaciomarginal belts and remains to be recognized.     

自动优化设计在过渡带三维地震勘探中的应用

在复杂过渡带三维地震勘探项目中,施工设计包括海陆观测系统设计、从属线束设计、偏点设计等,其优化对于提高地震数据采集效率,保证资料品质,减少空炮、废炮和重炮,实现资料无缝连接至关重要。这就要求技术人员针对工区特点提前合理设计特殊观测系统,优化炮点布设,从而最大限度地满足覆盖次数均匀的需要。通过自动优化设计施工方式,可以减少人工误差,使采集结果最大限度地实现设计要求,从而提高效率、节约成本。