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1.
塔里木盆地库车坳陷中新生代构造应力场分析   总被引:18,自引:0,他引:18  
盆地覆盖区古构造应力场分析一直是盆地动力学研究的一个难题。本文在对库车坳陷不同层位地层进行系统取样的基础上,初步探讨了用岩石磁组构恢复古构造应力场最大主压应力方向,测试结果与构造变形分析相一致;用岩石声发射测量系统筛分不同构造运动期次,并确定各期次有效最大主压应力大小,研究结果表明,测试构造期次与研究区构造地质分析期次基本吻合。  相似文献   

2.
《四川地质学报》2022,(2):319-321
音频大地电磁测深测量(V8)在寻找构造中的作用比较突出,近年来取得了较为突出的成果。五龙沟金矿地处秦—祁—昆成矿域(Ⅰ1)东昆仑成矿省(Ⅱ2)伯喀里克—香日德印支期成矿带(Ⅲ12)五龙沟金矿田,是青海省重要的金矿产区域,矿床成因为构造蚀变岩型,本文通过大地电磁测深测量对构造的解译,定位深部含金构造,从而指导金矿找矿工作。  相似文献   

3.
渤海湾盆地是在中生代华北克拉通破坏基础上,经由新生代深埋形成的叠合盆地,遭受了多期不同性质构造叠加改造。渤海海域油气资源的勘探逐步走向深层,深部潜山油气藏成为重要的勘探目标。本文以石臼坨东428潜山构造(以下简称428构造)为例,探索渤海湾盆地潜山的形成和构造演化。基于前人对渤海湾盆地内构造和储层特征的研究成果,通过对地震剖面的精确解析,结合相干切片和其他地质资料,系统研究428构造各个阶段的变形特征,特别是对428构造的断裂特征进行了平面和剖面上的解析与断裂组合分析。结果发现:428构造东、西侧现今差异主要是由一条斜跨该构造的NEE向断裂导致的,对比邻区野外应变测量分析,识别出五期构造应力场,分别对应于印支期、燕山期和喜山期的各阶段应力场变化,并结合428构造及其周缘残留地层等方面的证据,进而认为428构造经历了中生代印支期-燕山早期逆冲、燕山中-晚期伸展、燕山末期挤压及新生代右行右阶的走滑-拉分构造叠加的多期复合构造模式。  相似文献   

4.
音频大地电磁测深测量(V8)在寻找构造中的作用比较突出,近年来取得了较为突出的成果。五龙沟金矿地处秦—祁—昆成矿域(Ⅰ1)东昆仑成矿省(Ⅱ2)伯喀里克—香日德印支期成矿带(Ⅲ12)五龙沟金矿田,是青海省重要的金矿产区域,矿床成因为构造蚀变岩型,本文通过大地电磁测深测量对构造的解译,定位深部含金构造,从而指导金矿找矿工作。  相似文献   

5.
通过大量的节理测量与分析,对研究区的构造形态进行了深入的调查研究,系统总结了研究区的构造特征,恢复了研究区的古构造期次及古构造应力场特征,并对现代构造应力场进行了分析与研究,为下一步煤层气勘探开发提供了可靠的地质依据和有效的指导,探讨了现代构造应力场对煤层含气性的影响。  相似文献   

6.
储东如  童劲松  耿小光 《安徽地质》2010,20(4):241-243,259
繁昌地区推覆构造由前缘主底板逆掩断层、中部小淮山楔状褶皱冲断体及后缘小淮窑断裂组成,构成了该地区北东向构造格架。构成逆冲系统的多条逆掩断层所夹持的构造岩片由南东向北西呈后展式(上叠式)依次扩展。该逆冲推覆构造系统是喜山期构造反转的产物,并非印支—燕山期前陆带对冲构造系统的组成部分。  相似文献   

7.
采用构造岩相学分带和变形筛分、宏观与微观构造岩相学研究相结合的方法,对云南个旧矿集区构造和叠加成矿系统进行研究,深入揭示了该矿集区内锡铜钨钴铯铷多金属战略矿产富集机制、叠加成矿作用与构造岩相学结构样式之间的内在关系。研究认为,该区发育前岩浆侵入期三叠纪弧后裂谷盆地、同岩浆侵入期岩浆侵入构造系统和构造样式、后岩浆侵入期岩溶构造样式,它们在不同时间域内发生了异时同位叠加成相成矿与同时异相分异作用,对个旧叠加成矿系统和锡铜钨钴铯铷多金属成矿作用具有显著不同的控制作用。锡铜钨铯铷多金属叠加成矿系统具有9个垂向构造岩相分带结构样式,从深到浅依次为:浅色花岗岩相(VTZ8)和岩浆气成热液结晶核相(VTZ9)为黑云母花岗岩(γK2a-b-c)同岩浆侵入期构造岩相带,分布在花岗岩侵入体顶部和边部; 岩浆接触交代构造岩相带矽卡岩化相-矽卡岩相带(VTZ7),是同岩浆侵入期地层-岩浆系统耦合反应的构造岩相带; 富含残余岩浆的高温气液体系发生了岩浆-气液隐爆角砾岩化,形成进入个旧组内岩浆热流柱构造和电气石热液隐爆角砾岩相带(VTZ6);同岩浆侵入期在个旧组内构造-流体耦合作用,形成了上覆断褶式碳酸盐岩层(VTZ4)和碎裂岩化大理岩化相-电气石碎裂岩化大理岩相带(VTZ5)、远端的似层状碎裂岩化相含锡白云岩(VTZ3);三叠纪弧后裂谷盆地内碱性苦橄岩-碱性火山岩相带和火山喷发机构为前岩浆侵入期构造; 云贵高原侵蚀面(VTZ1)和表生岩溶构造系统(VTZ2)为后岩浆侵入构造系统,它们叠加在同岩浆侵入构造系统(VTZ3、VTZ4、VTZ5、VTZ6、VTZ7、VTZ8、VTZ9)之中。这些新成果为该矿集区深部探测和隐伏构造岩相的预测建模提供了新的理论依据。   相似文献   

8.
在构造变形研究的基础上,通过野外露头共轭剪节理的产状测量,采用数学统计方法进行分期配套,并结合前人的研究成果,开展了大洲火山断陷盆地古构造应力场及其与铀成矿关系的研究。总结了主要经历的四期构造应力:前晚侏罗世构造期、磨石山期、衢江期、始新世—渐新世构造期,分别讨论了各个期次对铀成矿的控制作用,指出后三个构造期与铀成矿关系密切,即磨石山期构造应力场为成矿准备了储矿空间,衢江期构造应力场为成矿准备了导矿空间,而始新世—渐新世构造期构造应力场对已形成矿体进行了破坏或改造。  相似文献   

9.
在构造变形研究的基础上,通过野外露头共轭剪节理的产状测量,采用数学统计方法进行分期配套,并结合前人的研究成果,开展了大洲火山断陷盆地古构造应力场及其与铀成矿关系的研究.总结了主要经历的四期构造应力:前晚侏罗世构造期、磨石山期、衢江期、始新世—渐新世构造期,分别讨论了各个期次对铀成矿的控制作用,指出后三个构造期与铀成矿关系密切,即磨石山期构造应力场为成矿准备了储矿空间,衢江期构造应力场为成矿准备了导矿空间,而始新世—渐新世构造期构造应力场对已形成矿体进行了破坏或改造.  相似文献   

10.
塔里木盆地北部油田古应力的AE法测量   总被引:8,自引:1,他引:7  
本文在阐述了声发射(简称AE-Acoustic Emission)法测量古构造应力的可行性之后,着重介绍了测量古应力与测量现今应力在方法上的不同之处。作者采用AE法测量了塔里木盆地北部油田古应力,并得出该区喜马拉雅期有2幕主要构造运动;燕山期有3幕主要构造运动;古生代有2-3幕主要构造运动的认识。喜马拉雅构造运动在该区占主导地位。   相似文献   

11.
Structural–geological inhomogeneities in the northeastern Barents Sea are zoned based on an analysis of various components of the gravity and magnetic fields. The objects revealed in the basement and sedimentary cover of the Barents Sea Plate form anomalies in potential fields at coexisting complex geological structures and contrasting petrophysical properties. Cluster analysis reveals the fault-marked boundaries of individual blocks in the basement. A numerical model of faults in the sedimentary cover and basement of the Barents Sea Plate is constructed.  相似文献   

12.
The paper is focused on the two tectonic-geodynamic factors that made the most appreciable contribution to the transformation of the lithospheric and hydrocarbon potential distribution at the Barents Sea continental margin: Jurassic-Cretaceous basaltic magmatism and the Cenozoic tectonic deformations. The manifestations of Jurassic-Cretaceous basaltic magmatism in the sedimentary cover of the Barents Sea continental margin have been recorded using geological and geophysical techniques. Anomalous seismic units related to basaltic sills hosted in terrigenous sequences are traced in plan view as a tongue from Franz Josef Land Archipelago far to the south along the East Barents Trough System close to its depocentral zone with the transformed thinned Earth’s crust. The Barents Sea igneous province has been contoured. The results of seismic stratigraphy analysis and timing of basaltic rock occurrences indicate with a high probability that the local structures of the hydrocarbon (HC) fields and the Stockman-Lunin Saddle proper were formed and grew almost synchronously with intrusive magmatic activity. The second, no less significant multitectonic stress factor is largely related to the Cenozoic stage of evolution, when the development of oceanic basins was inseparably linked with the Barents Sea margin. The petrophysical properties of rocks from the insular and continental peripheries of the Barents Sea shelf are substantially distinct as evidence for intensification of tectonic processes in the northwestern margin segment. These distinctions are directly reflected in HC potential distribution.  相似文献   

13.
Ice-proximal sedimentological features from the northwestern Barents Sea suggest that this region was covered by a grounded ice sheet during the Late Weichselian. However, there is debate as to whether these sediments were deposited by the ice sheet at its maximum or a retreating ice sheet that had covered the whole Barents Sea. To examine the likelihood of total glaciation of the Late Weichselian Barents Sea, a numerical ice-sheet model was run using a range of environmental conditions. Total glaciation of the Barents Sea, originating solely from Svalbard and the northwestern Barents Sea, was not predicted even under extreme environmental conditions. Therefore, if the Barents Sea was completely covered by a grounded Late Weichselian ice sheet, then a mechanism (not accounted for within the glaciological model) by which grounded ice could have formed rapidly within the central Barents Sea, may have been active during the last glaciation. Such mechanisms include (i) grounded ice migration from nearby ice sheets in Scandinavia and the central Barents Sea, (ii) the processes of sea-ice-induced ice-shelf thickening and (iii) isostatic uplift of the central Barents Sea floor.  相似文献   

14.
Based on analysis and interpretation of seismic and other geological-geophysical data, duplex rifting is identified in the Paleozoic evolution of the South Barents Basin. Its first, pre–Late Devonian, phase was manifested on the southeastern side zone that limited the Pechora Plate structures. After a certain pause, a second, pre–Late Carboniferous phase involved the western Barents Sea region, including the slope of the Central Barents Rise and the western South Barents Basin. Thus, Late Paleozoic riftogenic structures in the western and southeastern South Barents Basin formed at different times. All this caused an asymmetric structure profile and asynchronicity of evolution of the rift system sides. In the Mesozoic, under the effect of formation of the Novaya Zemlya fold-and-thrust structure, the asymmetry of the riftogenic trough became even more contrasting.  相似文献   

15.
The creation of the huge fans observed in the western Barents Sea margin can only be explained by assuming extremely high glacial erosion rates in the Barents Sea area. Glacial processes capable of producing such high erosion rates have been proposed, but require the largest part of the preglacial Barents Sea to be subaerial. To investigate the validity of these proposals we have attempted to reconstruct the western preglacial Barents Sea. Our approach was to combine erosion maps based on prepublished data into a single mean valued erosion map covering the whole western Barents Sea and consequently use it together with a simple Airy isostatic model to obtain a first rough estimate of the preglacial topography and bathymetry of the western Barents Sea margin. The mean valued erosion map presented herein is in good volumetric agreement with the sediments deposited in the western Barents Sea margin areas, and as a direct consequence of the averaging procedures employed in its construction we can safely assume that it is the most reliable erosion map based on the available information. By comparing the preglacial sequences with the glacial sequences in the fans we have concluded that 1/2 to 2/3 of the total Cenozoic erosion was glacial in origin and therefore a rough reconstruction of the preglacial relief of the western Barents Sea could be obtained. The results show a subaerial preglacial Barents Sea. Thus, during interglacials and interstadials the area may have been partly glaciated and intensively eroded up to 1 mm/y, while during relatively brief periods of peak glaciation with grounded ice extending to the shelf edge, sediments have been evacuated and deposited at the margins at high rates. The interplay between erosion and uplift represents a typical chicken and egg problem; initial uplift is followed by intensive glacial erosion, compensated by isostatic uplift, which in turn leads to the maintenance of an elevated, and glaciated, terrain. The information we have on the initial tectonic uplift suggests that the most likely mechanism to cause an uplift of the dimensions and magnitude of the one observed in the Barents Sea is a thermal mechanism.  相似文献   

16.
Based on a revised chronostratigraphy, and compilation of borehole data from the Barents Sea continental margin, a coherent glaciation model is proposed for the Barents Sea ice sheet over the past 3.5 million years (Ma). Three phases of ice growth are suggested: (1) The initial build-up phase, covering mountainous regions and reaching the coastline/shelf edge in the northern Barents Sea during short-term glacial intensification, is concomitant with the onset of the Northern Hemisphere Glaciation (3.6–2.4 Ma). (2) A transitional growth phase (2.4–1.0 Ma), during which the ice sheet expanded towards the southern Barents Sea and reached the northwestern Kara Sea. This is inferred from step-wise decrease of Siberian river-supplied smectite-rich sediments, likely caused by ice sheet blockade and possibly reduced sea ice formation in the Kara Sea as well as glacigenic wedge growth along the northwestern Barents Sea margin hampering entrainment and transport of sea ice sediments to the Arctic–Atlantic gateway. (3) Finally, large-scale glaciation in the Barents Sea occurred after 1 Ma with repeated advances to the shelf edge. The timing is inferred from ice grounding on the Yermak Plateau at about 0.95 Ma, and higher frequencies of gravity-driven mass movements along the western Barents Sea margin associated with expansive glacial growth.  相似文献   

17.
On the basis of geomorphological and sedimentological data, we believe that the entire Barents Sea was covered by grounded ice during the last glacial maximum. 14C dates on shells embedded in tills suggest marine conditions in the Barents Sea as late as 22 ka BP; and models of the deglaciation history based on uplift data from the northern Norwegian coast suggest that significant parts of the Barents Sea Ice Sheet calved off as early as 15 ka BP. The growth of the ice sheet is related to glacioeustatic fall and the exposure of shallow banks in the central Barents Sea, where ice caps may develop and expand to finally coalesce with the expanding ice masses from Svalbard and Fennoscandia.The outlined model for growth and decay of the Barents Sea Ice Sheet suggests a system which developed and existed under periods of maximum climatic deterioration, and where its growth and decay were strongly related to the fall and rise of sea level.  相似文献   

18.
The Barents Sea shelf is an attractive target as a prospective large petroleum province. Further development of geological and geophysical exploration in the area requires high-resolution biostratigraphic constraints and update stratigraphic charts. The zonal succession of Lower and Middle Jurassic assemblages of foraminifers and ostracodes of the Barents Sea fits well the division for northern Siberia based on correlated independent Jurassic and Cretaceous zonal scales on all main microfossil groups, of which some scales were suggested as the Boreal Zonal Standard. The stratigraphic range of the Barents Sea microfossil assemblages has been updated through correlation with their counterparts from northern Siberia constrained by ammonite and bivalve data. Joint analysis of foraminiferal and ostracode biostratigraphy and lithostratigraphy of the sections allowed a revision to the stratigraphic position and extent of lithological and seismic units. The discovered similarity in the Lower and Middle Jurassic lithostratigraphy in the sections of the Barents Sea shelf and northern Siberia, along with their almost identical microfossil taxonomy, prompts similarity in the Early and Middle Jurassic deposition and geological histories of the two areas.  相似文献   

19.
The oil and gas potential of Jurassic deposits of the shelf zone of the Barents Sea is confirmed by the discovery of a series of fields, both in the Russian sector of the Barents Sea, and in the Norwegian one. Along with known large gas and gas-condensate fields, the first oil field was opened in the western Norwegian part in April 2011. Peculiarities of the stratigraphy of the Jurassic complex indicate that cyclicity occurred in the development of the basin. The results of the works that were carried out demonstrate that the search for oil and gas fields in sandy reservoirs, deposited at the periods of regression is promising. Regionally extended clayey beds, which were deposited during periods of transgression, are considered as a seal. New oil and gas fields can be found, not only in the anticline structures, but also in lithological traps.  相似文献   

20.
Late Pleistocene glacial and lake history of northwestern Russia   总被引:1,自引:0,他引:1  
Five regionally significant Weichselian glacial events, each separated by terrestrial and marine interstadial conditions, are described from northwestern Russia. The first glacial event took place in the Early Weichselian. An ice sheet centred in the Kara Sea area dammed up a large lake in the Pechora lowland. Water was discharged across a threshold on the Timan Ridge and via an ice-free corridor between the Scandinavian Ice Sheet and the Kara Sea Ice Sheet to the west and north into the Barents Sea. The next glaciation occurred around 75-70 kyr BP after an interstadial episode that lasted c. 15 kyr. A local ice cap developed over the Timan Ridge at the transition to the Middle Weichselian. Shortly after deglaciation of the Timan ice cap, an ice sheet centred in the Barents Sea reached the area. The configuration of this ice sheet suggests that it was confluent with the Scandinavian Ice Sheet. Consequently, around 70-65 kyr BP a huge ice-dammed lake formed in the White Sea basin (the 'White Sea Lake'), only now the outlet across the Timan Ridge discharged water eastward into the Pechora area. The Barents Sea Ice Sheet likely suffered marine down-draw that led to its rapid collapse. The White Sea Lake drained into the Barents Sea, and marine inundation and interstadial conditions followed between 65 and 55 kyr BP. The glaciation that followed was centred in the Kara Sea area around 55-45 kyr BP. Northward directed fluvial runoff in the Arkhangelsk region indicates that the Kara Sea Ice Sheet was independent of the Scandinavian Ice Sheet and that the Barents Sea remained ice free. This glaciation was succeeded by a c. 20-kyr-long ice-free and periglacial period before the Scandinavian Ice Sheet invaded from the west, and joined with the Barents Sea Ice Sheet in the northernmost areas of northwestern Russia. The study area seems to be the only region that was invaded by all three ice sheets during the Weichselian. A general increase in ice-sheet size and the westwards migrating ice-sheet dominance with time was reversed in Middle Weichselian time to an easterly dominated ice-sheet configuration. This sequence of events resulted in a complex lake history with spillways being re-used and ice-dammed lakes appearing at different places along the ice margins at different times.  相似文献   

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