南极无冰区生态与环境变化在粪土层中的记录     

孙立广  刘晓东 《气候变化研究进展》2007,3(Z1):35-40

The accumulative profiles of seabird and sea animal excrement together with the depositional sequences influenced by the excrement have been utilized to reconstruct the historical populations of Antarctic penguins and seals, also to study the eco-geology in the ice-free areas of Antarctica and Arctic. The historical populations of Antarctic penguins show dramatic fluctuations, the period of sharp decrease coincides well with Neoglaciation, and extremely cold or warm climate conditions are unfavorable for the survival of Antarctic penguin. The historical change of seal population seems to be related to climatic variations, sea-ice coverage and its forage behavior. The fluctuations of Hg (mercury) in the seal hairs and the sediments influenced by seal excrement were found to be closely associated with ancient gold and silver mining activities and the ancient civilization over the past several thousand years.  相似文献   

Levels and temporal trends of PCDD/PCDFs and non-ortho PCBs in ringed seals from East Greenland     

Riget F  Vikelsøe J  Dietz R 《Marine pollution bulletin》2005,50(12):1523-1529

The levels and temporal trend of polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) and non-ortho substituted PCBs (c-PCBs, i.e. CB77, CB126 and CB169) were determined in ringed seal blubber from central East Greenland collected in 1986, 1994, 1999 and 2003, respectively. Since 1986 the concentrations of PCDDs, PCDFs and c-PCBs all show a decreasing trend. The annual decreases were estimated to 5.2% and 5.3% for pg/g WHO-TEQ ww of PCDD/Fs and c-PCB, respectively. The annual median concentrations of PCDDs ranged from 5.4 to 24.4 pg/g WHO-TEQ ww and those of PCDFs from 2.5 to 5.1 pg/g WHO-TEQ ww. Compared to PCDD/Fs concentrations in ringed seals from other Arctic areas the levels of PCDD/Fs found in 1986 were the highest recorded. The annual median concentrations of c-PCBs decreased 24.2 to 9.1 pg/g WHO-TEQ ww. The levels of c-PCBs observed in 1986 are similar to levels found in ringed seals from Svalbard in 1990 and from eastern Hudson Bay in 1989–1992. The dominant and most TEQ-contributing PCDD congener was 1,2,3,7,8-PeCDD. CB126 was the dominating and most TEQ-contributing c-PCB congener. The concentrations of PCDDs, PCDFs and c-PCBs were highly significantly inter-correlated. Principal component analysis of the PCDD/PCDF congeners and c-PCBs was performed to analyse the pattern of compounds during time.  相似文献   

倾斜裂缝垂向封闭性演化特征研究——以海拉尔盆地贝尔凹陷布达特群为例   总被引：6，自引：0，他引：6       下载免费PDF全文

付广  王有功  黄劲松 《地质科学》2008,43(1):23-33

岩心观察和成像测井资料分析,发现海拉尔盆地贝尔凹陷布达特群断裂伴生和派生的裂缝以倾斜裂缝为主,其形成与分布主要受区域构造演化控制,3期不同特征的构造裂缝反映了区域构造应力场经历了挤压、剪切和伸展3大阶段。利用裂缝面压力和泥岩塑性变形极限,对贝尔凹陷布达特群倾斜裂缝目前的垂向封闭性进行了评价,结果是:不同角度的倾斜裂缝在凹陷中部均是封闭的,仅在凹陷西北和东南边部开启,且随裂缝倾角增大,开启区面积增大。通过布达特群倾斜裂缝古裂缝面压力的恢复,对其垂向封闭性演化特征进行了研究,认为不同角度倾斜裂缝垂向开启区从伊敏组沉积末期至今逐渐减小。目前已发现的油气藏表明倾斜裂缝不是主要的储集空间,凹陷周边(缘)地区才是倾斜裂缝储集油气的有利地区。  相似文献   

Temporal changes of fault seal and early charge of the Maui Gas-condensate field,Taranaki Basin,New Zealand     

《Marine and Petroleum Geology》2016

Fault seal due to juxtaposition or the generation of low-permeability fault rock has the potential to change through time with displacement accumulation. Temporal variations in cross-fault flow of hydrocarbons have been assessed for the Cape Egmont Fault (CEF), Taranaki Basin New Zealand, using displacement backstripping, juxtaposition and Shale Gouge Ratio (SGR) analysis. The timing of hydrocarbon migration and charge of the giant Maui Gas-condensate Field across the CEF have been assessed using seismic reflection lines (2D & 3D), coherency cubes, VShale curves from the Maui-2 well and PetroMod modelling. Displacement–backstripping analysis suggests that between the Late Miocene and early Pleistocene (5.5 and 2.1 Ma) sandstone reservoir units of the Maui Field (Mangahewa, Kaimiro and Farewell Formations) and underlying source rocks (Rakopi Formation) were partly juxtaposed across the CEF with low SGRs (< 0.2) present in the fault zone. Following 2.1 Ma SGRs increased to 0.2–0.55 adjacent to the Eocene–Palaeocene reservoir succession which was not in juxtaposed contact with source rocks. PetroMod modelling using these SGR values and juxtaposition relationships supports cross-fault flow prior to 2.1 Ma with later charge across the fault being less likely. Gas chimneys and the gas–water contact in the Eocene reservoir proximal to the fault suggest that despite limited cross-fault flow, upward leakage of hydrocarbons from the reservoir occurred after 2.1 Ma, possibly associated with active fault movement or fracturing related to faulting, and may account for the loss of an early oil phase.  相似文献   

Detailed 3-D depositional architecture of Late Jurassic carbonate–anhydrite cycles (Brightling Mine,Weald Basin,UK)     

《Marine and Petroleum Geology》2016

Quantifying the geometries of evaporite deposits at a <1 km scale is critical in our understanding of similar ancient depositional systems, but is challenging given evaporite mineral dissolution at surface conditions. A high-resolution stratigraphic study of the basal Purbeck Beds in Brightling Mine, UK, provides insight into the three-dimensional architecture, lateral continuity and vertical heterogeneity within an evaporite seal. We conducted a field mapping study, combined with X-ray diffraction, petrographic microscopy, and δ¹³C and δ¹⁸O isotope analysis. The stratigraphic interval contains five facies. In stratigraphic order, these include supratidal porphyritic nodular evaporite, shallow subtidal peloidal packstone with evaporite and two overlying rhythmic sequences of intertidal microbial laminite, subtidal shale, and subtidal laminar marl, capped by nodular anhydrite. The interpreted environment of deposition is a supratidal sabkha subject to periodic flooding in which intertidal (tidal flat) facies and subtidal (shallow marine) facies laterally passed into the evaporative sabkha. The cycles are interpreted as meter-scale shoaling-upward sequences, likely controlled by localized high-frequency changes in relative sea level and/or sabkha hydrology. Spatial patterns in the geometries of key stratigraphic surfaces reveal a subtle depression towards the central western region of the mine seam. The variation in stratal geometries is interpreted as paleotopography and is a function of individual or composite processes related to dissolution, eolian processes, and coastal erosion. These observations indicate a similar mode of deposition to the modern-day sabkha of the Persian Gulf. We conclude that the dynamic process of evaporite deposition led to subtle stratigraphic heterogeneities and changes in bed thicknesses, but largely continuous lateral bedding at an interwell-scale.  相似文献   

Tectonic control of the oil-rich large igneous-carbonate-salt province of the South Atlantic rift     

《Marine and Petroleum Geology》2016

The Early Cretaceous South Atlantic Magmatic Province (SAMP), which includes the Paraná-Etendeka LIP, produced about 8 million km³ of tholeiitic basalt and diabase over an area of 4 million km². Huge pre-salt oil reserves, discovered in 2007 by Petrobras in non-marine carbonates, are estimated at more than 45 billion barrels. Here we show the close causal relationship of the southward increasing width of the wedge-shaped South Atlantic rift with the similarly southward increase in igneous activity, in the thicknesses of non-marine carbonate and salt, and in the size of oil reserves, all controlled mainly by South America’s early clockwise rotation away from Africa about a pole in its northeast. Large diabase dike swarms transversal to the rift witness to South America’s rotation that opened in its wake the southward widening South Atlantic rift. Westward increasing pressure on the Equatorial margin by South America’s clockwise rotation forced open the Benue trough and created pre-late-Aptian folds in the Demerara Plateau and in Brazil’s Solimões (Upper Amazonas) basin. Prerift and synrift volcanic activity increases southward, culminating in the Parana-Etendeka LIP and in the offshore volcanic SDRSs that continue southward to the Cape Basin. Berriasian-Valanginian rift sediments deposited from about 145 Ma, 10 Ma before the flood basalts of the Parana-Etendeka LIP. The largest transversal dike swarm continued in the proto-Walvis Ridge that separated the central South Atlantic endorheic rift basin from the sea in the south; erosion and leaching of basalts supplied Ca, Mg, and SiO₂ to the endorheic basin for the deposition of non-marine carbonates and authigenic clays. Basalt flows intercalated with carbonates nearly until salt deposition about 113 Ma. Hypogenic leaching of carbonates by mantle-derived CO₂ created optimal reservoirs. Supergiant oil deposits occur where the widest endorheic basin and the volcanic province overlap.  相似文献   

双通道水龙头设计使用中的几个问题          下载免费PDF全文

何跃文  孟庆鸿  赵春波 《探矿工程》1998,(3):29-30,38

简要介绍了双通道水龙头设计和使用中遇到的问题及相应的解决办法。  相似文献   

储集层地质学和封盖条件研究的进展     

贾振远  蔡忠贤  肖玉茹 《地质科技情报》1992,(2)

近十多年来储层研究在理论和方法上都有迅速发展,并逐渐形成“储层地质学”、“储层沉积学”和“储层地震学”等新兴学科。储层研究已进入定量化、构型化和模型化的新阶段,具体进展包括以下几个方面:(1)深部次生孔隙带、微孔储层、低渗透储层以及储层不均一性的研究;(2)储层的几何形态、结构、成因和演化的研究;(3)储层类型描述;(4)储层的地质和地球化学模拟;(5)三维构型研究和不同构型单元的划分多方面。  相似文献   

南象海豹(Mirounga leonina)喉的形态解剖和测量          下载免费PDF全文

董金海  王广洁  肖志忠 《海洋科学》1993,17(3):48-51

对一头雌性南象海豹的喉做了解剖和测量。喉骨架由11块软骨构成:一块会厌软骨,一对杓状软骨,一块甲状软骨,一块环状软骨和三对小角状软骨,这些软骨与韧带纤维膜、肌肉组成了喉。喉室内有声带,这与鲸类,海牛类的喉室有明显差别。  相似文献   

Trends in numbers of Cape gannets (Morus capensis), 1956/1957-2005/2006, with a consideration of the influence of food and other factors     

Crawford  Robert J. M.; Dundee  Benedict L.; Dyer  Bruce M.; Klages  Norbert T. W.; Meyer  Michael A.; Upfold  Leshia 《ICES Journal of Marine Science》2007,64(1):169-177

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