临邑洼陷圈闭类型及成因研究          下载免费PDF全文

段双国  高志卫  王顺华 《山东国土资源》2003,19(Z1):56-61

临邑洼陷是一个含油气层系较多,结构复杂的复式油气聚集区。本文重点介绍了临邑洼陷圈闭的类型及其成因,从圈闭角度对临邑洼陷油气藏的形成进行了概述,对临邑洼陷下步的勘探工作方向进行了分析。  相似文献   

Late Quaternary vegetation changes around Lake Rutundu,Mount Kenya,East Africa: evidence from grass cuticles,pollen and stable carbon isotopes     

Dr M. J. Wooller  D. L. Swain  K. J. Ficken  A. D. Q. Agnew  F. A. Street-Perrott  G. Eglinton 《第四纪科学杂志》2003,18(1):3-15

Woody, subalpine shrubs and grasses currently surround Lake Rutundu, Mount Kenya. Multiple proxies, including carbon isotopes, pollen and grass cuticles, from a 755‐cm‐long core were used to reconstruct the vegetation over the past 38 300 calendar years. Stable carbon‐isotope ratios of total organic carbon and terrestrial biomarkers from the lake sediments imply that the proportion of terrestrial plants using the C₄ photosynthetic pathway was greater during the Late Pleistocene than in the Holocene. Pollen data show that grasses were a major constituent of the vegetation throughout the Late Pleistocene and Holocene. The proportion of grass pollen relative to the pollen from other plants was greatest at the last glacial maximum (LGM). Grass cuticles confirm evidence that C₄ grass taxa were present at the LGM and that the majority followed the cold‐tolerant NADP‐MEC₄ subpathway. Copyright © 2003 John Wiley & Sons, Ltd.  相似文献   

Palaeotemperature reconstructions of the European permafrost zone during marine oxygen isotope Stage 3 compared with climate model results     

Ko van Huissteden  Jef Vandenberghe  David Pollard 《第四纪科学杂志》2003,18(5):453-464

A palaeotemperature reconstruction based on periglacial phenomena in Europe north of approximately 51 °N, is compared with high‐resolution regional climate model simulations of the marine oxygen isotope Stage 3 (Stage 3) palaeoclimate. The experiments represent Stage 3 warm (interstadial), Stage 3 cold (stadial) and Last Glacial Maximum climatic conditions. The palaeotemperature reconstruction deviates considerably for the Stage 3 cold climate experiments, with mismatches up to 11 °C for the mean annual air temperature and up to 15 °C for the winter temperature. However, in this reconstruction various factors linking climate and permafrost have not been taken into account. In particular a relatively thin snow cover and high climatic variability of the glacial climate could have influenced temperature limits for ice‐wedge growth. Based on modelling the 0 °C mean annual ground temperature proves to be an appropriate upper temperature limit. Using this limit, mismatches with the Stage 3 cold climate experiments have been reduced but still remain. We therefore assume that the Stage 3 ice wedges were generated during short (decadal time‐scale) intervals of extreme cold climate, below the mean temperatures indicated by the Stage 3 cold climate model simulations. Copyright © 2003 John Wiley & Sons, Ltd.  相似文献   

Interpretation of transient electromagnetic soundings over three-dimensional structures for the central-loop configuration   总被引：2，自引：0，他引：2  

Gregory A. Newman  Walter L. Anderson  Gerald W. Hohmann 《Geophysical Journal International》1987,89(3):889-914

Summary. An assessment is made of the bias of fitting constrained layered-earth models to transient electromagnetic data obtained over 3-D structures. In this assessment we use the central-loop configuration and show that accurate estimates of the depth of burial of 3-D structures can be obtained with layered-earth model fitting. However, layered-earth interpretations are not reliable for estimating depth extents and resistivities of 3-D structures. When layered earths are used for interpretation, it is advantageous in some cases to use data based on the magnetic field instead of the voltage. A magnetic-field definition of apparent resistivity, in contrast to a definition based on the voltage, eliminates apparent-resistivity overshoots and undershoots in the data. A resistivity undershoot in the data can produce an extraneous and misleading layer in an interpretation of a 3-D resistive structure. Due to 3-D effects, apparent-resistivity soundings (magnetic field and voltage) may rise so steeply at late times that it may not be possible to fit a sounding to a reasonable layered-earth model. Truncating such a sounding, over a buried conductor, allows for a reasonable layered-earth fit and an accurate estimate of the depth to the conductor. However, the resistivity of the conductor is overestimated.
Measurements of the horizontal field in the central-loop configuration can map 3-D structures, provided the sensor is located accurately at the centre of the transmitting loop. Horizontal-field calculations show that the transients peak on the flanks of a 3-D structure, but are depressed over the structure's centre. Weak transient responses flanked by two large transient responses, which are opposite in sign, locate the structure. The sign reversal is caused by a corresponding reversal in the currents that are channelled through or deflected away from conductive or resistive structures, respectively.  相似文献   

Observations of the neutral gas and dust in the radio galaxy 3C 305     

N. Jackson  R. Beswick  A. Pedlar  G. H. Cole  W. B. Sparks  J. P. Leahy  D. J. Axon  A. J. Holloway 《Monthly notices of the Royal Astronomical Society》2003,338(3):643-654

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Spatial distribution of near-infrared and optical emission properties in the bipolar nebula Menzel 3     

Nathan Smith † 《Monthly notices of the Royal Astronomical Society》2003,342(2):383-398

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A Chandra observation of the X-ray environment and jet of 3C 296     

M. J. Hardcastle  D. M. Worrall  M. Birkinshaw  R. A. Laing  A. H. Bridle 《Monthly notices of the Royal Astronomical Society》2005,358(3):843-850

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The importance of oxygen isotope provenance in relation to solute content of bulk meltwaters at Imersuaq Glacier,West Greenland     

Jacob C. Yde  N. Tvis Knudsen 《水文研究》2004,18(1):125-139

Stable oxygen isotope analysis and measurement of several dissolved cations and anions of bulk meltwater samples have provided information about the hydrochemical environment of the glacial hydrological system at Imersuaq Glacier, an outlet tongue from the Greenland ice‐sheet, West Greenland. The samples were collected at frequent intervals during the period 20–28 July 2000 in a small (<20 L s^?1) englacial meltwater outlet at the glacier margin. The results document the following findings: (i) a marked diurnal variation of δ¹⁸O is related to the composition of oxygen isotope provenances, mainly near‐marginal local superimposed ice and basal up‐sheared ice further up‐glacier; (ii) a relationship is seen between all base cations (Na⁺, K⁺, Ca²⁺, Mg²⁺), SO₄^2? and δ¹⁸O, indicating that solute acquisition is provided by solid–solution contact with the up‐sheared ice—as the relationship with Cl^? is weak the influence of seasalt‐derived solutes is small in the area; (iii) when the melt rate is high, two diurnal maxima of δ¹⁸O values and solute concentrations are measured, and it is suggested that a snow meltwater component is responsible for the second maximum of δ¹⁸O—a short residence time leads to a delayed decrease in ion concentrations. Copyright © 2003 John Wiley & Sons, Ltd.  相似文献   

The radial distribution of blue straggler stars and the nature of their progenitors     

M. Mapelli  S. Sigurdsson  F. R. Ferraro  M. Colpi  A. Possenti  B. Lanzoni 《Monthly notices of the Royal Astronomical Society》2006,373(1):361-368

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大型敞流坳陷湖盆浅水三角洲与湖盆中心砂体的形成与分布   总被引：34，自引：0，他引：34  

邹才能  赵文智  张兴阳  罗平  王岚  刘柳红  薛叔浩  袁选俊  朱如凯  陶士振 《地质学报》2008,82(6):813-825

大型敞流坳陷湖盆浅水三角洲及湖盆中心砂体已成为中国陆相盆地岩性油气藏最重要的勘探目标。通过对现代典型湖盆浅水三角洲的深入分析,结合我国中、新生代大型坳陷湖盆浅水三角洲及湖盆中心砂体的地质研究,取得以下主要进展与认识：①在分析浅水三角洲形成地质背景的基础上,按照供源体系、湖水深度及三角洲前缘倾斜坡度将湖盆三角洲分为9种成因结构类型;②建立了毯式浅水曲流河三角洲的沉积模式,指出末端分流河道及末端决口扇是浅水曲流河三角洲的典型微相类型;③分析了浅水三角洲砂体大面积分布的形成条件,指出敞流湖盆是湖盆中心浅水三角洲砂体发育的重要条件,敞流通道对湖盆中心砂体分布有重要控制作用;④湖盆中心发育河流、三角洲、湖流及密度底流砂体等牵引流成因砂体,也发育洪水浊积扇及滑塌浊积扇等重力流成因砂体;⑤大型浅水三角洲体系三级层序界面对岩性（成岩）圈闭的发育有重要控制作用,三角洲平原带层序界面上覆叠置砂体富集岩性油气藏,勘探潜力大。本文研究成果希对坳陷湖盆沉积学研究及岩性油气藏勘探能有推动作用。  相似文献