首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   45篇
  免费   7篇
  国内免费   4篇
地球物理   6篇
地质学   38篇
海洋学   9篇
综合类   2篇
自然地理   1篇
  2021年   1篇
  2020年   3篇
  2019年   2篇
  2018年   1篇
  2017年   6篇
  2016年   1篇
  2015年   1篇
  2014年   1篇
  2013年   5篇
  2012年   2篇
  2010年   5篇
  2009年   6篇
  2008年   2篇
  2007年   2篇
  2006年   1篇
  2005年   4篇
  2004年   3篇
  2003年   2篇
  2002年   2篇
  2000年   1篇
  1998年   2篇
  1997年   1篇
  1989年   1篇
  1986年   1篇
排序方式: 共有56条查询结果,搜索用时 31 毫秒
41.
盖层研究现状及发展趋势   总被引:7,自引:0,他引:7  
从盖层分类、封闭机理和盖层评价等三个方面对国内外盖层的研究现状进行了综述,指出了其发展趋势,即日趋综合化、动态化和定量化。  相似文献   
42.
从微观到宏观研究了盖层封闭特征,从垂向和侧向两个方面研究了断层的封闭特征,通过古流体势场恢复,研究了本区油气运聚形式。根据封盖条件、生储特征、运移特征,将延吉盆地东部坳陷划分了三个油气运聚系统,即德新地区封闭型运聚成藏系统、广兴—东风地区半封闭型油气运聚系统、延吉—东盛涌地区油气逸散系统。在油气运聚系统划分的基础上,对有利探区进行了预测。  相似文献   
43.
Triassic basins of England developed under a regime of largely W–E extension and progressed from non-marine fluvial and aeolian sedimentation (Sherwood Sandstone Group), through marine-influenced playa lacustrine deposits (Mercia Mudstone Group) to marine environments (Penarth Group). A new tectono-stratigraphic model for the Sherwood Sandstone Group is proposed in which two major long-distance river systems developed under conditions of relative fault inactivity in the Early Triassic (Budleigh Salterton Pebble Beds and equivalent) and Middle Triassic (Otter Sandstone and equivalent). These are separated by a late Early Triassic syn-rift succession of fluvio–aeolian sandstones (Wildmoor Sandstone and Wilmslow Sandstone formations) and playa lacustrine muds (Nettlecombe Formation) which show major thickness variation and localisation with hanging wall basins. The partitioning of syn-rift deposits into mudstones within upstream basins (close to the source of water and sediment) and clean aeolian or fluvio–aeolian sandstones in downstream basins is similar to the pattern observed in the underlying late Permian. Under conditions of rapid tectonic subsidence chains of extensional basins may become disconnected with upstream basins (Wessex Basin) acting as traps for fines and water permitting more aeolian activity in temporarily unlinked downstream basins (Worcester and Cheshire basins). In addition to tectonic controls, fluctuating climate, relief related to limestone resilience in arid settings, the smoothing effect of fill and spill sedimentation and Tethyan sea-level change all contributed toward the observed Triassic stratigraphy in England.  相似文献   
44.
老挝龙湖矿区ZK309孔泥岩层矿物学与地球化学特征   总被引:1,自引:1,他引:0       下载免费PDF全文
老挝龙湖钾盐矿区是呵叻高原钾盐矿在老挝境内最主要的钾盐矿区之一,ZK309钻孔是龙湖矿区打穿最好、取样最完整和最典型的钻孔之一,通过对该钻孔盐岩上覆碎屑层的地层、矿物、元素的分析,得出泥岩层作为成盐沉积旋回中的一部分,其矿物元素变化和与其接触的下伏盐层的类型、特征等密切相关。同一旋回中自下而上泥岩颜色由青灰色变为红色,明显表现出沉积环境由还原性转变为氧化性。盐类矿物在垂向上表现出自下而上的淡化序列。矿物和元素在103~107 m处的突变显示盐岩沉积后期曾明显有水流体的淋滤作用,通过微量元素含量等的分析,该水流体表现为偏向淡水的淡水、海水混合水。碳酸盐矿物组合及含量显示当时可能有高Mg流体的活动。将粘土矿物组合与中国其它海相和陆相盆地粘土矿物组合相比较,得出粘土矿物组合与海相更相似,加上绿泥石含量较高,初步推测粘土矿物可能来源于海相沉积环境。  相似文献   
45.
Mudstone experience periodic swell and shrink behavior due to alternate wetting and drying cycles at arid and semi-arid regions with distinctive seasonal changes. This paper examines the influence of cyclic wetting and drying on swelling strain and swelling pressure to simulate the behavior of such rocks under heavy structures (such as building foundations) and behind the stiff support systems (such as concrete linings). Mudstone samples from Bakhtiari formation of Masjed-Soleiman region in south west of Iran were chosen to perform the laboratory tests. The swelling strain under different dead pressures and also swelling pressure under oedometeric condition were measured over time. The maximum swelling strain and pressure increased with each cycle but it had a bound. Increasing the number of wetting and drying cycles reduces the time required to reach ultimate swelling of mudstone. This is a very important conclusion which helps to determine ultimate swelling behavior in a faster way as opposed to performing standard swelling tests for very long periods. The laboratory’s results are also in good correspondence with field measurements.  相似文献   
46.
The Late Cretaceous to Early Tertiary sequence of the Vøring and Møre Basins from the Norwegian Sea has been examined with respect to mineralogy based on 319 cutting samples from five wells. A clear relationship between mineralogy and well log data is demonstrated. A significant change with respect to velocity, porosity and density occurs within the depth interval corresponding to 80–90 °C. At shallow depths/temperatures (<2.0 km/70 °C), compaction is mainly mechanical and the physical properties are similar to what has been measured by experimental compaction of mudstones. At greater depths, however, the log derived velocities and densities are higher than those produced by experimental compaction indicating significant chemical compaction. XRD analyses show a progressive alteration of smectite to illite (S–I) within this depth/temperature interval which results in the release of significant amounts of silica into solution. Detrital silt and fine-grained quartz showed no secondary quartz overgrowths. These grains are isolated within a clay matrix and surrounded by clay minerals, thus limiting the available surface area and pore space for quartz overgrowths. Chemical analyses (XRF) indicate that silica is conserved within this depth interval, and the amount released from S–I alteration was locally precipitated. Field emission gun-scanning electron microscopy (FEG-SEM) and cathode luminescence (CL) identified authigenic micro-crystalline quartz cement within the clay matrix at temperatures above ∼85 °C. This is accompanied by an increase in velocity and density indicating that the S–I reaction and the precipitation of authigenic quartz caused a significant change in the rock stiffness.  相似文献   
47.
Late Cretaceous mudstones from two wells located in the northern North Sea and the Norwegian Sea have been examined with respect to quartz cement. Two different types of quartz cement (Type 1 and Type 2) have been identified using SEM/EDS/CL-analysis of drill-bit cuttings at depths 2370–2670 m (80–85 °C). Type 1 appears as relatively large aggregates (30–100 μm) of depth/temperature related crypto- or microcrystalline to macrocrystalline irregular quartz cement formed by local re-crystallization of biogenic silica. The CL-responses of Type 1 quartz cement give a clear indication of an authigenic origin. Type 2 quartz cement represents relatively high amounts of extremely fine-grained micro-sized (1–3 μm) crystals embedded as discrete, short chains or small clusters/nests within the illitized clay matrix. The CL-responses of micro-quartz crystals indicate an authigenic origin. The micro-quartz is most probably sourced from silica released during the smectite to illite dissolution–precipitation reaction. The petrographic evidence indicates that most of the silica released by the smectite to illite reaction has not been exported out of the mudstones. The silica released produce a subtle inter-connected micro-quartz network interlocked with aggregates of micro-quartz and authigenic clay crystals. This micro-quartz cementation process causes a significant and sharp change in the mudstone stiffness at the onset of the chemical compaction regime. This is indicated by an abrupt increase in well log velocity (Vp) and change in seismic facies close to 2500 m (80/85 °C).  相似文献   
48.
工业界计算孔隙压力系数普遍应用的Eaton和Fillippone方法都需要构建能够准确表征低速层的层速度模型,层速度模型精度及效率成为制约孔隙压力预测的关键参数,但目前工业界层速度建模的精度及效率很难满足孔隙压力预测的要求.本文由正常压实情况下的背景速度场出发,基于时距曲线公式及角道集抽取公式,创新推导了以角度域共成像点道集(ADCIGS)剩余曲率为自变量的孔隙压力系数计算公式,该公式完全由去噪后的地震数据进行驱动,不需要构建层速度模型,该方法大幅提高了计算孔隙压力系数的效率.由模型测试及实际数据应用证明,利用本文提出方法进行孔隙压力预测是有效可行的,该方法可以有效提高预测孔隙压力精度,还可以有效提高预测孔隙压力效率.  相似文献   
49.
Disintegration of rock is one of the primary processes of soil formation and geomorphology and is affected considerably by water and heat.This study focused on the disintegration characteristics under laboratory conditions of typical purple mudstone from the Tuodian group of Jurassic red beds(J3t) in Tuodian Town,Shuangbai county,Yunnan Province of southern China.The fresh mudstone was subjected to alternating applications of water,heat and hydrothermal interaction during five treatments:wetting-drying(WD),saturation(ST),refrigeration-heating(RH),a combination of wetting-drying and refrigeration-heating(WDRH),and a combination of saturation and refrigeration-heating(STRH).Each treatment was run in twenty-four cycles.The results showed that there are three types of disintegration:collapsing disintegration,exfoliation disintegration and imperceptible disintegration.The cumulative disintegration rate(percentage of cumulative disintegrated mass to the initiative sample mass passed through a 2 mm sieve) produced a ’S’-shape function when related to treatment cycle time and closely fit a logistic model(R2 > 0.99).The rank order of the cumulative disintegration rate resulting from the five treatments was as the following:WDRH > STRH > ST > WD > RH.Because of alternating periods of moisture and dryness,WD caused the most disintegration,while RH alone resulted in imperceptible disintegration.Additionally,there was a negative correlation between the disintegration rate of each treatment cycle(percentage of disintegrated mass to the treated sample mass) and treatment cycle number.There was a positive correlation between this rate and temperature change under moist conditions,indicating that a change in temperature greatly accelerates the disintegration of parent rock when water was supplied.  相似文献   
50.
近年来,硼同位素研究在指示沉积环境及物源方面取得了良好进展。通过开展清江盆地盐岩矿床泥岩段矿物组成、硼含量及XRD衍射实验、热电离质谱法测量硼同位素等实验手段,研究δ11B值变化与物源、沉积环境和气候作用的关系,分析影响清江盆地盐岩矿床硼同位素分馏因素,发现多源性可能成为δ11B发生变化的原因之一,粘土矿物优先吸附10B从而导致δ11B值降低,同时盐矿物序列变化和伊利石的减少表明该时期整体气候变化为干冷向温湿改变,可能伴随有河流改道而导致物源发生变化,从而影响δ11B值的变化。  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号