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1.
Controls on turbidite sand deposition during gravity-driven extension of a passive margin: examples from Miocene sediments in Block 4, Angola 总被引：1，自引：0，他引：1
In recent years, exploration of the Lower Congo Basin in Angola has focused on the Neogene turbidite sand play of the Malembo Formation. Gravity tectonics has played an important role during deposition of the Malembo Formation and has imparted a well-documented structural style to the post-rift sediments. An oceanward transition from thin-skinned extension through mobile salt and eventually to thin-skinned compressional structures characterises the post-rift sediments. There has been little discussion, however, regarding the influence of these structures on the deposition of the Malembo Formation turbidite sands. Block 4 lies at the southern margin of the Lower Congo Basin and is dominated by the thin-skinned extensional structural style. Using a multidisciplinary approach we trace the post-rift structural and stratigraphic evolution of this block to study the structural controls on Neogene turbidite sand deposition.In the Lower Congo Basin the transition from terrestrial rift basin to fully marine passive margin is recorded by late Aptian evaporites of the Loeme Formation. Extension of the overlying post-rift sequences has occurred where the Loeme Formation has been utilised as a detachment surface for extensional faults. Since the late Cretaceous, the passive margin sediments have moved down-slope on the Loeme detachment. This history of gravity-driven extension is recorded in the post-rift sediments of Block 4. Extension commenced in the Albian in the east of the block and migrated westwards with time. In the west, the extension occurred mainly in the Miocene and generated allochthonous fault blocks or “rafts”, separated by deep grabens. The Miocene extension occurred in two main phases with contrasting slip vectors; in the early Miocene the extension vector was to the west, switching to southwest-directed extension in the late Miocene. Early Miocene faults and half-grabens trend north–south whereas late Miocene structures trend northwest–southeast. The contrast in slip vectors between these two phases emphasises the differences in driving mechanisms: the early Miocene faulting was driven by basinward tilting of the passive margin, but gravity loading due to sedimentary progradation is considered the main driver for the late Miocene extension. The geological evolution of the late Miocene grabens is consistent with southwest-directed extension due to southwest progradation of the Congo fan.High-resolution biostratigraphic data identifies the turbidite sands in Block 4 as early Miocene (17.5–15.5 Ma) and late Miocene (10.5–5.5 Ma) in age. Deposition of these sands occurred during the two main phases of gravity-driven extension. Conditions of low sedimentation rates relative to high fault displacement rates were prevalent in the early Miocene. Seafloor depressions were generated in the hangingwalls of the main extensional faults, ultimately leading to capture of the turbidity currents. Lower Miocene turbidite sand bodies therefore trend north–south, parallel to the active faults. Cross-faults and relay ramps created local topographic highs capable of deflecting turbidite flows within the half grabens. Flow-stripping of turbidity currents across these features caused preferential deposition of sands across, and adjacent to, the highs. Turbidite sands deposited in the early part of the late Miocene were influenced by both the old north–south fault trends and by the new northwest–southeast fault trends. By latest Miocene times turbidite channels crosscut the active northwest–southeast-trending faults. These latest Miocene faults had limited potential to capture turbidity currents because the associated hangingwall grabens were rapidly filled as pro-delta sediments of the Congo fan prograded across the area from the northeast. 相似文献
2.
Growth faults in gravity-driven extensional provinces are dominated by coast-parallel trends, but coast-perpendicular (transverse) trends are far less documented. The Clemente–Tomas fault in the inner Texas shelf has corrugations that are transverse to the fault and that plunge downdip. A large (8500 km2), high-quality, 3D seismic survey allows a uniquely encompassing perspective into hanging-wall deformation above this corrugated fault surface. Synextensional strata in the hanging wall are folded into alternating transverse ridges and synclines, typically spaced 10 km apart. Forward modelling in dip profiles of an extensional fault having three ramps produces ramp basin-rollover pairs that compare with the seismically revealed ridges and synclines. As they translated down the undulose fault plane, ramp basins and rollovers were juxtaposed along strike, forming the hanging-wall ridges and synclines observed offshore Texas. Fault-surface corrugations correlate broadly with footwall structure. We infer that corrugations on the Clemente–Tomas fault formed by evacuation of an allochthonous salt canopy emplaced in the late Eocene to early Oligocene. Early salt evacuation (Oligocene) created an undulose topography that influenced incipient Clemente-Tomas fault segments as they merged to form an inherently undulose fault. Late salt evacuation (early Miocene) further deformed this fault surface. 相似文献
3.
The SW Iberian margin developed as a passive margin during Mesozoic times and was later inverted during the mainly Cenozoic Alpine orogeny. The initial syn-rift deposits include a Lower Jurassic evaporite unit of variable thickness. In the onshore, this unit is observed to thicken basinward (i.e., southward), in fault-controlled depocenters, and salt-related structures are only present in areas of thick initial evaporites. In the offshore, multiple salt-structures cored by the Lower Jurassic evaporites are interpreted on seismic reflection data and from exploratory drilling. Offshore salt structures include the allochthonous Esperança Salt Nappe, which extends over an area roughly 40 × 60 km. The abundance of salt-related structures and their geometry is observed to be controlled by the distribution of evaporite facies, which is in turn controlled by the structure of rift-related faulting. This paper presents a comprehensive study of salt tectonics over the entire onshore and offshore SW Iberian passive margin (southern Portugal and Gulf of Cadiz), covering all aspects from initial evaporite composition and thickness to the evolution of salt-related structures through Mesozoic extension and Cenozoic basin inversion. 相似文献
4.
Three wells, all offshore, in southern Alaska studied using apatite fission track dating make a transect southward from Lower Cook Inlet to the Kodiak Shelf and include ARCO Lower Cook Inlet COST #1 well (LCI well), Chevron OCS-0248 #1A well (Shelikof Strait), and Kodiak COST KSSD #1 OCS 77-1 well (Stevenson Basin, Kodiak). The ages of deep partially annealed samples from Lower Cook Inlet well suggest that the region cooled between ~100 and 75 Ma and or sometime after. Two scenarios are presented: (1) maximum heating before cooling in Late Creta ceous times and (2) maximum heating before cooling during mid-Tertiary times. Which is better is uncertain from the thermal and age data alone, but mid-Tertiary or later uplift, erosion, and cooling is preferred because data from Shelikof well suggests that the mid-Cretaceous unconformity was minor relative to the mid-Tertiary unconformity. Finally, because of the ~12 C warmer past than present bottom-hole temperature, the base of the LCI well is now ~500 m shallower than during maximum, burial (12 C/24 C/km geothermal gradient). Single-grain apatite fission track ages (20-25 Ma) from deep in the Shelikof well approach the age of the overlying mid-Tertiary (Miocene; ~23 Ma) unconform ity, suggesting significant and rapid exhumation. This suggests that strongly annealed, once deeply buried strata were uplifted and cooled quickly prior to onlap of the unconformity. The Miocene unconformity, therefore, is interpreted to be the major unconformity in the Shelikof well section. In this scenario the section was buried deepest, and was therefore hottest, until the onset of mid-Tertiary erosion. Approximately 665 m of late Tertiary and Quaternary strata have since been deposited in Shelikof Strait and have reburied the Shelikof section to within ~536 m of its original maximum burial depth. Including modern water depth, the Shelikof well section has experienced ~1 km of burial+submergence since ~25 Ma (832 m section+166 m water=998 m). It follows that the depth to the base of the well is now ~290 m shallower than it would have been during maximum burial. Single-grain apatite fission track ages deep in the Kodiak KSSD1 well are as young as 20-25 Ma and approach the age of overlap of a mid-Miocene regional unconformity (<23 Ma). The deepest Eocene samples were exhumed to within 574 m of the Miocene unconformity surface during Miocene time and were reburied by ~1.7 km of late Tertiary strata. The total section before exhumation was ~5 km; this suggests that Oligocene-age deposits may have existed in the Stevenson Basin. Together with the known Eocene strata, such deposits were exhumed during ~4.4 km of uplift and erosion during a short interval culminating in early to middle Miocene times (>25-23 Ma). Unique and anomalous apatite compositions (high F-, low Cl-, moderate OH-) from the Eocene section could provide a chemical tracer for determining their sediment source along the northeast Pacific rim prior to translation and accretion. 相似文献
5.
In the Chelif basin, the geochemical characterization reveals that the Upper Cretaceous and Messinian shales have a high generation potential. The former exhibits fair to good TOC values ranging from 0.5 to 1.2% with a max. of 7%. The Messinian series show TOC values comprised between 0.5 and 2.3% and a high hydrogen index (HI) with values up to 566 mg HC/g TOC. Based on petroleum geochemistry (CPLC and CPGC) technics, the oil-to source correlation shows that the oil of the Tliouanet field display the same signature as extracts from the Upper Cretaceous source rocks (Cenomanian to Campanian). In contrast, oil from the Ain Zeft field contains oleanane, and could thus have been sourced by the Messinian black shale or older Cenozoic series. Two petroleum systems are distinguished: Cretaceous (source rock) – middle to upper Miocene (reservoirs) and Messinian (source rock)/Messinian (reservoirs). Overall, the distribution of Cretaceous-sourced oil in the south, directly connected with the surface trace of the main border fault of the Neogene pull-apart basin, rather suggests a dismigration from deeper reservoirs located in the parautochthonous subthrust units or in the underthrust foreland, rather than from the Tellian allochthon itself (the latter being mainly made up of tectonic mélange at the base, reworking blocks and slivers of Upper Cretaceous black shale and Lower Miocene clastics). Conversely, the occurrence of Cenozoic-sourced oils in the north suggests that the Neogene depocenters of the Chelif thrust-top pull-apart basin reached locally the oil window, and therefore account for a local oil kitchen zone. In spite of their limited extension, allochthonous Upper cretaceous Tellian formations still conceal potential source rock layers, particularly around the Dahra Mountains and the Tliouanet field. Additionally they are also recognized by the W11 well in the western part of the basin (Tahamda). The results of the thermal modelling of the same well shows that there is generation and migration of oil from this source rock level even at recent times (since 8 Ma), coevally with the Plio-Quaternary traps formation. Therefore, there is a possibility of an in-situ oil migration and accumulation, even from Tellian Cretaceous units, to the recent structures, like in the Sedra structure. However, the oil remigration from deep early accumulations into the Miocene reservoirs is the most favourable case in terms of hydrocarbon potential of the Chelif basin. 相似文献
6.
Crustal features of the northeastern South China Sea: insights from seismic and magnetic interpretations 总被引：1，自引：0，他引：1
Yi-Ching Yeh Shu-Kun Hsu Wen-Bin Doo Jean-Claude Sibuet Char-Shine Liu Chao-Shing Lee 《Marine Geophysical Researches》2012,33(4):307-326
We interpret seven two-dimensional deep-penetration and long-offset multi-channel seismic profiles in the northernmost South China Sea area, which were collected by R/V Marcus G. Langseth during the TAIwan GEodynamics Research (TAIGER) project in 2009. To constrain the crustal characteristics, magnetic inversion and forward magnetic modeling were also performed. The seismic results clearly show tilted faulting blocks in the upper crust and most of the fault plane connects downward to a quasi-horizontal detachment as its bottom in the south of the Luzon-Ryukyu transform plate boundary. North of the plate boundary, a small-scale failed rifted basin (minimum 5 km in crustal thickness) with negative magnetization probably indicates an extended continental origin. Significant lower crustal material (LCM) was imaged under a crustal fracture area which indicated a continent and ocean transition origin. The thickest LCM (up to 6.5 km) is located at magnetic isochron C15 that is probably caused by the magma supply composite of a Miocene syn-rift volcanic event and Pliocene Dongsha volcanic activity for submarine volcanoes and sills in the surrounding area. The LCM also caused Miocene crustal blocks to be uplifted reversely as 17 km crustal thickness especially in the area of magnetic isochron C15 and C16. In addition, the wide fault blocks and LCM co-existed on the magnetic striped area (i.e. C15–C17) in the south of the Luzon-Ryukyu transform plate boundary. Magnetic forward modeling suggests that the whole thick crustal thickness (>12 km thick) needs to be magnetized in striped way as oceanic crust. However, the result also shows that the misfit between observed and synthetic magnetic anomaly is about 40 nT, north of isochron C16. The interval velocity derived from pre-stack time migration suggests that the crust is composed of basaltic intrusive upper crust and lower crustal material. The crustal nature should refer to a transition between continent and ocean. Thus, the magnetic reversals may be produced in two possible ways: basaltic magma injected along the crustal weak zone across magnetic reversal epoch and because some undiscovered ancient piece of oceanic crust existed. The crustal structure discrimination still needs to be confirmed by future studies. 相似文献
7.
Previous GPS-based geodetic studies and onland paleoseismologic studies in Trinidad have shown that the 50-km-long, linear, onland segment of the Central Range fault zone (CRFZ) accommodates at least 60% of the total rate of right-lateral displacement (∼20 mm/yr) between the Caribbean and South American plates. 2D and 3D seismic reflection data from a 60-km-long and 30-km-wide swath of the eastern shelf of Trinidad (block 2AB) were used to map the eastern offshore extension of this potentially seismogenic and hazardous fault system and to document its deeper structure and tectonic controls on middle Miocene to recent clastic stratigraphy. Two unconformity surfaces and seafloor were mapped using 3D seismic data to generate isochron maps and to illustrate the close control of the CRFZ and associated secondary faults on small, clastic basins formed along its anastomosing strands and the east-west-striking North Darien Ridge fault zone (NDRFZ) that exhibits a down-to-the-north normal throw. Mapped surfaces include: 1) the middle Miocene angular unconformity, a prominent, regional unconformity surface separating underlying thrust-deformed rocks from a much less deformed overlying section; this regional unconformity is well studied from onland outcrops in Trinidad and in other offshore areas around Trinidad; 2) a Late Neogene angular unconformity developed locally within block 2AB that is not recognized in Trinidad; and 3) the seafloor of the eastern Trinidad shelf which exhibits linear scarps for both the CRFZ and the east-west-striking North Darien Ridge fault zone. Clastic sedimentary fill patterns identified on these isochron maps indicate a combined effect of strike-slip and reverse faulting (i.e., tectonic transpression) produced by active right-lateral shear on the CRFZ, which is consistent with the obliquity of the strike of the fault to the interplate slip vector known from GPS studies in onland Trinidad. The NDRFZ and a sub-parallel and linear family of east-west-striking faults with normal and possibly transtensional motions also contributed to the creation of accommodation space within localized, post-middle Miocene clastic depocenters south of the CRFZ. 相似文献
8.
下刚果—刚果扇盆地油气资源丰富、油气成藏条件优越。但由于受到盐岩的活动及区域构造应力场的作用,形成了复杂的断裂系统。此文系统分析了下刚果—刚果扇盆地的断裂特征及其对油气成藏的影响,研究认为该区平面上主要发育5个断裂带,纵向上主要发育上下两套断裂系统。断裂的形成和演化可分为三个期次,相对应可将断层分为三个级别的断层。断层的形成机制主要有盐活动及盐构造、重力滑脱作用以及古地貌格局。烃源岩的排烃时间与第三期断层活动时间相匹配,非常有利于油气沿断层进行垂向和斜侧向运移。分析认为研究区主要发育沿断阶带—碳酸盐岩运聚成藏模式、沿断层垂向运聚成藏模式以及沿盐下砂体—盐窗和Focus点运聚成藏模式共三种成藏模式。断层封堵较好,油源断层高度决定了油气运移高度和油气田规模,直接控制着油气的分布层系及规模。研究成果可指导研究区或类似地区的油气勘探。 相似文献
9.
Integrated tectono-stratigraphic interpretation at MC-118 using 3D seismic, well logs and biostratigraphy reveals an area dominated by allochthonous salt and its related structures. OCS-Block MC-118 is located 130 km southeast of New Orleans on the Gulf of Mexico middle slope in ∼2600 ft of water.The area is divided into three domains based on their structural styles: (1) a western domain consisting of a basinward-dipping normal fault family and associated strata; (2) a central domain composed of a landward-plunging diapiric salt tongue canopy and associated salt welds, two flanking NE–SW trending salt-withdrawal mini-basins, and a crestal fault family; and (3) an eastern domain comprised of basinward/landward-dipping normal and listric normal fault families with their associated rollovers. These structural domains are genetically-and-kinematically related to the salt structure and extend beyond MC-118 boundaries. The salt structure is postulated to have evolved mostly passive, with punctuated active episodes, and by lateral spreading. This is part of a larger regional structure, eastern Gulf of Mexico, which involves some amalgamation between small-scale salt canopies and salt diapirs although collectively they appear mostly disconnected.A Pliocene (3.13–4.95 Ma) third-order genetic stratigraphic sequence, the focus of this study, is as much as ∼3600 ft thick within the mini-basins and contains: muddy mass transport complexes; sandy slope fans; muddy turbidites and condensed sections; and transitional facies flanking the salt structure that collectively have ponded and wedged external geometries. Mass transport complexes and muddy turbidites and condensed sections make most of the studied genetic sequence in a mud-dominated deltaic setting eastern Gulf of Mexico.Facies kinematic indicators and a matching number of genetic sequences accounted on the sea level chart support a eustatically driven mini-basin sedimentation. Nonetheless salt still plays a role in sedimentation (secondary/minor) by slumping generated during passive/active salt diapiric evolution. 相似文献
10.
E. Kokinou E. Papadimitriou V. Karakostas E. Kamberis F. Vallianatos 《Marine Geophysical Researches》2006,27(4):241-252
Information concerning two seismic lines, the first located northwest of the Lefkada Island and the second from the deep Ionian basin to the gulf of Patras, is used to trace the Kefalonia Transform Zone (KTZ) and to explore its relation with the sedimentary sequences and the deeper geologic structures in the study area. In addition, sea bottom topography and fault plane solutions are combined in order to explore the prolongation of the KTZ into the Ionian Abyssal Plain (IoAP) and to describe its properties. The boundary between the subduction of the eastern Mediterranean oceanic crust under the overriding continental crust and the KTZ is well constrained by the seismic data in association with seismicity and regional stress field. The southern prolongation of the KTZ is located in the IoAP towards the direction between Kefalonia and Zakynthos Islands at depth greater than 15 km. The southern part of the KTZ exhibits a strike–slip motion with a thrust component according to fault plane solutions of moderate and strong earthquakes. The seismic section mostly confirms the existence of the thrust component and gives information about the tectonic status east and west of the KTZ. 相似文献
11.
Superposed deformation straddling the continental-oceanic transition in deep-water Angola 总被引：3，自引：0，他引：3
The Angolan margin is the type area for raft tectonics. New seismic data reveal the contractional buffer for this thin-skinned extension. A 200-km-long composite section from the Lower Congo Basin and Kwanza Basin illustrates a complex history of superposed deformation caused by: (1) progradation of the margin; and (2) episodic Tertiary epeirogenic uplift. Late Cretaceous tectonics was driven by a gentle slope created by thermal subsidence; extensional rafting took place updip, contractional thrusting and buckling downdip; some distal folds were possibly unroofed to form massive salt walls. Oligocene deformation was triggered by gentle kinking of the Atlantic Hinge Zone as the shelf and coastal plain rose by 2 or 3 km; relative uplift stripped Paleogene cover off the shelf, provided space for Miocene progradation, and steepened the continental slope, triggering more extension and buckling. In the Neogene, a subsalt half graben was inverted or reactivated, creating keystone faults that may have controlled the Congo Canyon; a thrust duplex of seaward-displaced salt jacked up the former abyssal plain, creating a plateau of salt 3–4 km thick on the present lower slope. The Angola Escarpment may be the toe of the Angola thrust nappe, in which a largely Cretaceous roof of gently buckled strata, was transported seawards above the thickened salt by up to 20 km. 相似文献
12.
13.
《Marine Geology》2005,216(3):145-154
The Eastern Basin in the Ross Sea (Antarctica) contains a sedimentary sequence that is a direct record of advance and retreat of the West Antarctic Ice Sheet.We analyzed a sedimentary section ranging from the upper Miocene to present.The joint tomographic inversion of refracted and reflected arrivals of pre-stack multi-channel seismic data revealed in this area the presence of layers with anomalous high velocity. These anomalies are correlated with sediments that were eroded and compacted by the load of the West Antarctic Ice Sheet during its expansion on the continental shelf.The deepest and stronger velocity anomaly correspond to a basin-wide seismic unconformity (RSU2, Late Miocene–Early Pliocene in age). This anomaly is interpreted as evidence of a major advance of the West Antarctic ice sheet on the continental shelf that resulted in high velocity and low porosity in sediment immediately above the unconformity. 相似文献
14.
从实际问题出发,扼要阐述了平衡剖面技术的基本概念,并结合实例着重探讨了其应用研究.在介绍了与平衡剖面有关的基本概念的基础上,总结平衡剖面技术的研究流程和平衡剖面结果的评价标准,结合缅甸区块实际资料深入探讨其在断层相关褶皱构造模式建立和检验调整地震解释以及在恢复挤压构造发育史方面的应用情况,显示了其在缅甸区块叠瓦状断层转折褶皱的良好应用效果,并获得剖面的水平延展量,同时也认识到许多潜在的客观问题,有待进一步探索. 相似文献
15.
A detailed marine survey made to the South West of Mount Eratosthenes is described. The results show the existence of a narrow zone of WNW trending deformed sediment west of the mount surrounded by an evaporite sequence in different stages of deformation.This work was intended to settle the conflict between the results of three previous interpretations of the tectonic structure of this area. We see the area being characterised by five areas with different degrees of tectonic deformation yet showing little causal relationship to overburden of Nile Cone sediments. A fault controlled cliff coincides with the previously described salt wall and strike slip fault yet we see no evidence for its diapiric origin nor positive evidence for strike slip motion along it. We concur with the previously observed area of higher free-air gravity anomalies termed the Eratosthenes tectonic zone, although it is traversed by several boundaries between areas of different deformation. Our results thus show some agreements and some re-interpretations of the observations. This complicated region is not yet fully understood however. 相似文献
16.
Lithospheric structure along the Queen Charlotte margin in western Canada: constraints from flexural modeling 总被引：1，自引：1，他引：1
The Queen Charlotte fault zone along the western margin of Canada, a right-lateral transform, is part of the boundary between
the Pacific and North America plates. Combining reflection and refraction surveys and flexural modeling, we place limits on
the amount of underthrusting of the Pacific plate beneath the North America plate. Results from our two-dimensional elastic
modeling suggest 10–15 km of underthrusting along the northern Queen Charlotte Islands, in agreement with the amount of underthrusting
inferred from plate motion models.
Received: 12 June 1995/Revision received: 9 December 1995 相似文献
17.
Haakon Fossen Jonny Hesthammer Tord Erlend Skeie Johansen Trond Olav Sygnabere 《Marine and Petroleum Geology》2003,20(10):1105-1118
The Huldra fault block is a rotated major fault block on the east margin of the Viking Graben in the northern North Sea. Unlike the rest of the Horda Platform area, the Jurassic section in the Huldra fault block was rotated more than 20° during slip on the listric Huldra fault, which forms a low-angle detachment beneath the Huldra fault block. The fault block is interpreted as resulting from marginal collapse of the Horda Platform after relief along the eastern margin of the Viking Graben built up in early parts of the middle to late Jurassic rifting history. The collapse resulted in NW directed transport of the Huldra fault block, consistent with a previously postulated change in extension direction from W–E to NW–SE toward the end of the Jurassic period. Minor faults within the Hulrda fault block are consistent with E–W extension and thus may have formed early during the late Jurassic rifting phase. Nevertheless, the crest (Huldra Field) seems surprisingly intact, considering its proximity to a major fault zone. Deformation bands studied from core material are non-cataclastic and concentrated in zones. Evidence for smearing along a cored fault surface indicates that minor subseismic faults may be sealing. Production data from the field indicate good communication between most wells, suggesting that the subseismic faults and deformation band zones that are present in the reservoir have relatively small influence on the flow of gas in the reservoir. 相似文献
18.
莱州湾地区郯庐断裂带的构造特征及其新生代演化 总被引：22，自引：0，他引：22
郯庐断裂带中段分东西两支从莱州湾进入渤海,在莱州湾地区的构造特征与演化历史一直鲜为人知。通过对横穿研究区的两条地震测线的解释和分析,揭示了该区郯庐断裂带中段在研究区的构造差异,研究表明郯庐断裂带东西两支在该研究区表现出不同的断裂性质,西支断裂表现为正断层,东支断裂表现为走滑断层。郯庐断裂是本研究区的主控断裂,通过对本地区地层形态及其组合、断层的剖面形态和空间展布规律的深入研究,揭示了郯庐断裂带在莱州湾地区新生代以来的构造演化历史:古新世—始新世的伸展阶段、渐新世—中新世早期的挤压和右行走滑阶段、中新世中晚期至今的稳定发展阶段,这几个不同时期的演化阶段主要受太平洋板块运动的方向和速度变化的控制。 相似文献
19.
为了更有效地研究伸展盆地,论述了目前伸展盆地研究中几种常用软件的方法和原理,包括用于盆地反演研究的一维Airy均衡模型、二维挠曲回剥模型、平衡剖面技术以及用于盆地正演研究的挠曲悬臂梁模型和二维粘弹塑性热-力学数值模拟模型。综合分析了这些方法的原理、优势与不足,在此基础上进一步探讨了不同方法之间的综合运用。其中平衡剖面技术恢复得到的盆地剖面可以为裂谷期构造沉降展布范围提供约束,并与挠曲悬臂梁模型结合可以得到盆地演化过程中不同时期上地壳的伸展减薄情况。数值模拟方法则在以上盆地模拟方法得到的结果约束下,模拟伸展盆地的形成过程进而得到初始地质参数与演化过程。综合利用盆地分析的方法可以对盆地演化有更准确的认识并指导油气资源的勘探与开发。 相似文献
20.
丽水—椒江凹陷是一个中新生代断陷盆地,断裂构造组成了盆地内的主要构造样式。通过对区域断层剖面组合和平面展布特征的研究,识别出8种类型的断层剖面组合形式,在平面上划分了12个断裂系统区。总体来说本区构造具有东西分带、南北分块的特征,即断裂系统沿北东—南西方向成条带状分布,凹陷南部以地堑式组合为主,北部以地垒式为主。区域断裂系统的演变显示凹陷南北基底基岩存在差异,而且基底发育北西—南东向的断层,从而导致凹陷南部构造活动较北部强。 相似文献