Layering in the lower crust   总被引：1，自引：0，他引：1  

Satish C. Singh  Dan McKenzie 《Geophysical Journal International》1993,113(3):622-628

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南极长城站积雪及其消融过程          下载免费PDF全文

陈肖柏  张永萍 《极地研究》1991,3(3):8-14

南极长城站区稳定积雪期始于4月中至6月初,8月中至10月达最大深度。1988年沿海地带一般积雪深度为0.6～0.8m,低洼处及建筑物附近可达1.2～1.6m,甚至超过1.8m;潮汐带雪盖下部温度受海冰影响普遍偏低;11月底至来年1月初的消融过程中,积雪表层常常处于相变区,雪层底部温度比冰点低0.02℃,融水下渗形成雪盖下部潜流;积雪相态及其温度变化与大气-雪感热通量的变化过程相对应,大气-雪感热交换是积雪消融的重要因子之一。  相似文献   

利用阿拉斯加台阵资料分析2008年汶川大地震的破裂过程   总被引：9，自引：4，他引：5       下载免费PDF全文

杜海林  许力生  陈运泰 《地球物理学报》2009,52(2):372-378

2008年5月12日,四川省汶川县发生M_S8.0地震.我们利用美国阿拉斯加区域台网的部分宽频带地震台构成广义台阵, 应用非平面波台阵技术——迁移叠加方法,获得了这次地震的高频（>0.1 Hz）能量辐射源随时间和空间变化的图像.图像表明,这次地震破裂从震中开始向北东方向扩展约300 km,震源过程至少长达90 s,平均破裂速度为3.4 km/s;整个过程可分为两大阶段,前段持续时间50 s,破裂长度约110 km,破裂传播的平均速度为2.2 km/s,后段持续时间约40 s,长度约190 km,平均破裂速度为4.8 km/s.这意味着地震过程的后期似乎发生了超S波破裂,而且后段很可能为前段动态触发所致.  相似文献   

东营凹陷沙一段断层封闭性研究   总被引：4，自引：3，他引：1  

肖淑明  王国壮  钟建华  孟玮 《地质力学学报》2009,15(3):296-304

东营凹陷位于济阳坳陷的东南部, 区内断层平面组合特征复杂, 剖面组合类型多样, 导致了该凹陷内断层体系的复杂性和构造类型的多样性。通过对东营凹陷沙一段断层封闭性研究的总结, 概述了该区断层封闭性的主要原理和机理以及影响因素, 从定量和定性的角度分析了评价断层封闭性的方法, 讨论了泥岩涂抹、挤压和地球化学作用对断层封闭性的影响。   相似文献   

Water Quality Modeling and Dissolved Oxygen Balance in Streams: A Point Source Streeter‐Phelps Application in the Case of the Harsit Stream     

S. Serkan Nas  Evin Nas 《洁净——土壤、空气、水》2009,37(1):67-74

The Harsit Stream flowing into the Black Sea is an important watershed in the northeastern part of Turkey. The monthly averages of dissolved oxygen, carbonaceous biochemical oxygen demand, temperature, pH, total suspended solids, total phosphorus and total nitrogen were obtained for the water samples taken from the Tekke, Akcakale and Haciemin sites of the Harsit Stream. Water quality parameters were analyzed and evaluated according to the WHO standards and the Turkish Water Pollution Control Regulation. Initially, the variations in the dissolved oxygen profile were determined from dissolved oxygen, temperature and carbonaceous biochemical oxygen demand measurements by using the point source Streeter‐Phelps equation. Critical dissolved oxygen deficit values were calculated for the monthly average from January–December 2005, which are below the limit value (4 mg L^–1) excluding April (7.26 mg L^–1) and May (5.98 mg L^–1) in the Harsit Stream, resulting in it having second class water quality in terms of dissolved oxygen concentration, temperature, pH and biochemical oxygen demand. It is also seen that the minimum dissolved oxygen limit value (8 mg L^–1), which is a desired quantity for drinking water, is under the limit value for all months in the case of the water mixture. In particular, during the summer months, the consumption speed of oxygen is greater than the production speed of oxygen with increasing temperature and decreasing discharge, and negative values (anoxia) of dissolved oxygen sag are seen. These situations call for significant precautions and treatment criteria.  相似文献   

Assessment of the relative importance of major sediment‐transport mechanisms in the central Great Barrier Reef lagoon     

A. R. Orpin  P. V. Ridd  L. K. Stewart 《Australian Journal of Earth Sciences》2013,60(6):883-896

The delivery, flux and fate of terrigenous sediment entering the Great Barrier Reef lagoon has been a focus of recent studies and represents an ongoing environmental concern. Wave‐induced bed stress is the most significant mechanism of sediment resuspension in the Great Barrier Reef, and field data and mathematical modelling indicates that the combined effects of short‐period wind waves, longer period swell waves, and tidal and wind‐driven currents can often exceed the critical bed stress for resuspension. Suspended‐sediment concentrations at 20 m water depth indicate resuspension seldom occurs on the middle shelf under normal wave conditions. Non‐cyclonic turbidity events are generally confined to the inner shelf. The wave climate in the southern sector of the central Great Barrier Reef lagoon is the most erosive, and resuspension of outer shelf sediments was hindcast for recorded cyclones. Wind‐driven, longshore currents are fundamental to the northward movement of sediment, and the annual northward mass flux from embayments undergoing resuspension in the Burdekin region is estimated to be one order of magnitude larger than the mass of sediment introduced by a moderate flood plume. Strong onshore winds are estimated to generate significant three‐dimensional bottom return currents on approximately 30–70 days per year, forming a potentially significant offshore‐directed sediment flux during high suspended‐sediment concentration events on the inner shelf.  相似文献   

渤中环形构造带特征和成因分析及其石油地质意义探讨   总被引：1，自引：0，他引：1       下载免费PDF全文

黄雷  王应斌 《地质科学》2012,47(2):318-332

渤中凹陷为我国东部少有的富生烃凹陷,具有极大地油气勘探潜力。本文通过对渤中凹陷和其周缘各构造单元的展布关系、断裂系统的发育情况进行了系统梳理分析,认识到以渤中凹陷和渤东凹陷为中心的构造带具有环形构造的特征,以此为基础提出了"渤中环形构造带"的概念; 进一步对环形构造带的成因加以分析,认为可能是中生代末至始新世的深部热力构造作用(地幔热柱上涌)造成的; 最后依照环形构造带这一新思路,将渤中—渤东凹陷看作环形构造带内统一的烃源灶,对环形构造带的石油地质特征进行了分析,以期能进一步对油气勘探工作有所启发。  相似文献   

马朗凹陷芦草沟组源岩油储集空间特征及其成因     

黄志龙  郭小波  柳波  张代生  张建波  齐永安  王瑞 《沉积学报》2012,30(6):1115-1122

通过场发射环境扫描电子显微镜,背散射电子衍射,X射线能谱,X衍射等分析手段对马朗凹陷芦草沟组源岩油储层储集空间类型及其特征与成因进行研究。结果表明,该区源岩层的储集空间可分为5大类:原生孔,包括粒间孔、晶间孔;次生溶蚀孔隙,包括粒间溶蚀孔、粒内溶蚀孔、溶蚀缝和基质型溶蚀孔隙;有机质热演化生烃残留孔;裂缝,包括构造缝和非构造缝;纹层间由于岩石物理性质差异形成滑脱缝和破裂缝。从微观孔隙结构分析,各类微孔隙、微裂缝是源岩中烃类的主要储集空间,裂缝、微裂缝起主要的输导作用,改善储层渗透性。  相似文献   

高邮凹陷真武断裂带断层活动及演化规律   总被引：2，自引：1，他引：1       下载免费PDF全文

华 伟陈廷东  季红军李春雷 罗申玥 《中国地质》2012,39(3):605-611

真武断裂带是高邮凹陷主要含油构造带之一,圈闭落实是该区油气勘探关键;断层活动及演化规律研究是建立地震解释模式、提高构造解释精度的前提。通过真武断裂带区域构造背景、构造样式、断层活动速率及平衡剖面等研究,明确了该区构造特征、断层活动及演化规律,为该区复杂小断块精细解释及断层组合提供了地质依据,取得较好的应用效果。  相似文献   

Estimation on organic carbon content of source rocks by logging evaluation method as exemplified by those of the 4th and 3rd members of the Shahejie Formation in western sag of the Liaohe Oilfield     

Luofu Liu  Xiaoqing Shang  Ping Wang  Yongqiang Guo  Weili Wang  Lin Wu 《中国地球化学学报》2012,31(4):398-407

One of the most important tasks of evaluating natural resources of petroliferous basins is to determine the organic matter abundance of source rocks in the basin.The usual method for assessing the organic carbon content of source rocks is based on laboratory analyses.There is a deviation in calculating organic carbon content due to the heterogeneous distribution of organic matter and the artificial factors when sampling.According to the continuous characteristics of information logging,the conventional logging curves(mainly acoustics and resistivity,etc.) were calibrated with the organic carbon experimental data of cores,cuttings or sidewall cores.The organic carbon content of source rocks of the 4 th(Es 4) and 3 rd(Es 3) members of the Shahejie Formation in western sag in the Liaohe depression was estimated directly by a great amount of continuous data including resistivity and acoustic logging,etc.Comparison between the results from computer processing and lab analysis of logging data shows that the organic carbon contents derived from the computer processing of logging data have the same reliability and accuracy as the lab analysis results.The present data show that this method is suitable to evaluate the source rocks of western sag in the Liaohe depression and has great potential in evaluating natural resources of sedimentary basins in the future.On the basis of logging data of source rocks,experimental data and existing geochemical analyses of the Liaohe Oilfield,the corresponding total organic carbon(TOC) isograms of source rocks were plotted.The source rocks of Es 4 and Es 3 of the Shahejie Formation are thought to be beneficial to hydrocarbon accumulation due to the high TOC.  相似文献