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A. Milia 《Geo-Marine Letters》1999,19(4):237-244
High-resolution seismic reflection data are used in the identification of the stratigraphic succession filling Naples Bay,
a tectonically active half-graben located in the extensional margin of the eastern Tyrrhenian Sea. The architecture of the
basin infill is characterized by fourth-order depositional sequences correlated to Quaternary eustatic oscillations. These
depositional sequences form aggrading and prograding stacking patterns bounded by tectonically enhanced unconformities. The
changes that the stacking patterns undergo record variations in accommodation space rates. These variations are a result of
the tectonic subsidence produced during the evolution of the half-graben.
Received: 7 July 1998 / Revision received: 29 March 1999 相似文献
3.
The sedimentology and sequence stratigraphy of the central Apennine lower Miocene carbonate deposits (Guadagnolo Formation) are the goal of this paper. The Guadagnolo carbonate ramp deposits consist of a thick succession of three main lithofacies: marls, marly limestones and cross-bedded limestones. The lateral and vertical facies distribution, as well as the biota assemblages, suggests a deposition of these sediments along the middle-outer ramp sector of the Latium-Abruzzi carbonate platform. All the data suggest sedimentation under the influence of tidal currents that were responsible of bedforms generation as simple and compound dunes. These bodies are developed on metric and decametric scale, and are stacked one to other to form complex sedimentary bodies extending both in strike and dip section for several tens to hundred meters. The dune system developed in a semiclosed basin (the Paleoadriatic sea), open in the southern and closed in the northern sector respectively. Within this basin a probably amphidromic system developed. The flow sediment transport was dominantly westward, and was conditioned by the ramp paleotopography. From a sequence stratigraphic point of view several high and low rank depositional sequences that were differentiated basing on their relative physical scale (thickness of each unit) and on the lateral extension of the unconformities and the correlative conformities bounding them were recognized. The hierarchy of recognized sequence-stratigraphic units include, from the smallest to the largest: simple depositional sequences, low-rank composite depositional sequences and high-rank composite depositional sequences. In the Guadagnolo succession four high-rank composite depositional sequences having a duration variable from 0.9 to 1.6 Ma, and named Guadagnolo 1, 2, 3, and 4, were recognized. These high-rank composite sequences are internally constituted by a stacking of simple and low-rank composite depositional sequences, having a duration ranging from 40 ka to 200 ka. All these units constitute part of a higher-rank composite sequence developing between 21 and 14.80 Ma that we name “The Guadagnolo Depositional Sequence”. The wedge-shaped geometry, the thickness variation and the stacking pattern of the Guadagnolo succession are the response to eustasy and tectonic subsidence. The glacial eustasy mostly controlled the formation of the high-frequency depositional sequences, tectonic subsidence, related to the roll-back of the hinge west-directed subduction in turn connected to the advancement of the Apennine thrust modulated the accommodation space. 相似文献
4.
Rift sequence stratigraphy 总被引：2，自引：0，他引：2
Conventional sequence stratigraphy has been developed primarily for passive-margin basins. Despite the conceptual advances within the last 30 years, a suitable model for rift basins has not yet been devised. Many authors have attempted to adapt the passive-margin model to all other tectonic settings, including rifts, despite the fundamental differences in terms of the mechanisms controlling the formation and evolution of these sedimentary basins. Passive margins have their stratigraphic framework controlled largely by cyclic sea-level fluctuations superimposed on long-term thermal subsidence. By contrast, rift basins have their accommodation history strongly related to their mechanical subsidence regime, with episodic pulses of extension that create space for sediment accumulation at very fast rates. Stages of rapid mechanical subsidence are typically followed by longer periods of tectonic quiescence, when sediment supply gradually consumes and fills the available accommodation. This cyclicity results in depositional sequences that display overall progradational trends and coarsening-upward vertical stacking patterns. Sequence boundaries are often marked by sharp flooding surfaces related to the transgression of lacustrine or marine systems in response to rapid tectonic subsidence and the consequent ‘instantaneous’ generation of accommodation. As such, a typical rift depositional sequence starts with a flooding surface overlain by a relatively thin transgressive systems tract and a much better developed highstand systems tract. A renewed subsidence pulse leads to the drowning of the previous deposits and the start of a new depositional sequence. The strong asymmetry of the base-level curve resembles the shape of glacio-eustatic cycles, with fast transgressions followed by longer term regressions, although at potentially different temporal scales. 相似文献
5.
Pozzuoli Bay is located in the eastern Tyrrhenian Sea and is an area characterized by active tectonics and volcanism. On the basis of high-resolution seismic reflection profiles, it was possible to reconstruct the stratigraphy and three-dimensional stratal architecture of the Holocene succession. Two volcanic units and three sedimentary ones were recognized. The basal unit NC consists of volcanic deposits and dates at 10.0-8.0 ka B.P. It is followed by unit D, deposited between 8.0 and 5.5 ka B.P., which displays a backstepping configuration in the central area and a forestepping configuration in the northern area. Unit D is covered by the progradational unit B which is elongated in a SE-NW direction. Unit C is interbedded between unit B and is interpreted as the volcanic products of the Agnano-Monte Spina eruption which occurred 4.4 B.P. Unit A, the youngest unit, shows a progradational configuration and is elongated in a E-W direction. The sedimentary units record the transgressive and highstand of the eustatic sea level. They show vertical and lateral variations in the depositional architecture. Changes in the stacking pattern record variations in tectonic subsidence and hydrodynamic regimes. 相似文献
6.
The demise of the high-relief, steep-slope, prograding Ladinian-Early Carnian carbonate platforms of the Esino Limestone (Central Southern Alps of Italy) is marked by subaerial exposure of the platform top associated with different erosional (mainly karst-related), depositional and diagenetic processes (Calcare Rosso). The exposure-related deposits consist of three major facies associations: 1) residual soils with thin lenses of conglomerates with black pebbles, and, locally, weathered vulcanites; 2) chaotic breccia lenses irregularly distributed in the uppermost part of the Esino Limestone carbonate platform, interpreted as collapse breccias in karstic setting: 3) inter-supratidal carbonate cycles with dissolution and development of paleosols and tepee structures.Facies distribution follows the sub-environments of the underlying Esino Limestone. Facies 1 and 2 typically characterize the core of the platform, covering the underlying inner platform facies. Facies 3 instead develops toward the edge of the platform, above reef-upper slope facies of the prograding facies of the Esino Limestone. The thickness of facies 3 decreases toward the core of the platform. Facies distribution reflects differences in the accommodation space and sedimentary processes from the rim (highest accommodation, favouring the deposition of peritidal-supratidal carbonates) to the core (reduced accommodation, causing pedogenesis and karstification) of the carbonate system.The observed thickness changes may be controlled by different factors: 1) syndepositional tectonics, 2) subsidence induced by magmatic activity or 3) differential subsidence controlled by the stratigraphic architecture of the Esino Limestone platform and adjoining basins. As evidence of tectonics was not observed and the presence of volcanic bodies is only documented tens of km away from the study area, the scenario involving the creation of accommodation space by compaction of the basinal sediments (resedimented, fine-grained calciturbidites) during the progradation of the carbonate platform is here investigated. Numerical modelling was performed to verify the compatibility of compaction-induced subsidence with the observed depositional architecture. The models were built to simulate the architectural evolution of the platform by progressively adding layers from deepest to shallowest, while compacting the underlying sediments, in order to evaluate compaction-induced subsidence (and accommodation space for the Calcare Rosso) after the deposition of the youngest platform strata. Modelling results allow us to conclude that the wedge geometry of the Calcare Rosso, deposited on top of the extinct Esino carbonate platform, can be explained by subsidence controlled by compaction of the basinal sediments present below the early-cemented, fast prograding platform slope deposits. 相似文献
7.
Eocene carbonate deposits of the Barru area, Sulawesi, Indonesia, provide a rare insight into sedimentation prior to and during propagation of normal faults to the surface. Three main successions; late prerift, latest prerift/earliest synrift and synrift, are characterised by distinctive facies associations and sequence development. Shallow water foraminiferal shoals and intervening lower energy depositional environments occurred during the late prerift in areas which latter formed footwall highs and hangingwall depocentres, respectively. During the latest prerift/earliest synrift, shallow water shelves deepened laterally into slope environments in developing hangingwall depocentres. In both these sequences, sections in developing hangingwall areas are thickest, deepen up-section and thin laterally towards growing footwall highs. Active faulting resulted in rapid drowning of hangingwall depocentres and massive reworking of material derived from collapse of the platform margin and adjacent shallow water/emergent footwall highs.Differential subsidence, controlling water depths and accommodation space, types of carbonate producers and active faulting were the main factors affecting depositional environments and facies distributions. Carbonate producers are extremely sensitive indicators of depositional water depth and energy, hence rapid lateral and vertical facies variations in the Barru area provide quantifiable insight into environmental changes prior to and during active faulting. 相似文献
8.
《Marine and Petroleum Geology》2003,20(6-8):789-807
The lower part of the Carboniferous Shannon Basin of Western Ireland contains a deep-water succession which exceeds 1200 m in thickness that comprises five lithologically different units deposited within a confined, relatively narrow basin: (i) a calciclastic debris-flow and turbidite unit formed by resedimentation from nearby carbonate platforms, (ii) a siliciclastic black shale succession with former source potential which onlaps basin margins (Clare Shales), (iii) a sandstone-dominated turbidite formation, controlled by ponded accommodation and deposited axially in the basin (Ross Formation), (iv) a mudstone-rich turbidite-bearing succession, which onlaps basin margins (lower Gull Island Formation), and (v) a mudstone-dominated prograding slope succession (upper Gull Island Formation and lower Tullig Cyclothem), which grades transitionally upwards into deltaic deposits. The top unit records progradation at a time when basin differential subsidence had diminished significantly and local basin topography did not control deposition. The two upper mudstone-dominated units are different in terms of both sandstone content and their genetic significance within the overall basin-fill, and their potential relevance as reservoir analogues.The lower part of the Gull Island Formation contains three principal facies associations: (a) shallow turbidite channels and sheets representing channel margin and levee deposits, (b) mud-rich slumps, and (c) less than 1 m thick, rare, hemipelagic shales. More than 75% is deformed by soft-sediment deformation, but only to a smaller degree affecting sandstone units. The turbidites record transport to the ENE, along the axis of the basin, while the slumps were derived from an unstable northern slope and transported transversely into the basin towards the southeast. The distribution of turbidite sandstone and slumps is inversely proportional. Sandstones decrease in importance away from the basin axis as slumps increase in number and thickness. The lower part of the Gull Island Formation is interpreted to record progressive fill of a deep basin controlled by local, healed slope accommodation with onlap/sidelap of the basin margins. The instability resulted from a combination of fault-controlled differential subsidence between basin margin and basin axis, and high rates of sedimentation.The upper part of the Gull Island Formation is entirely dominated by mudstones, which grade upwards into siltstones. It contains rare, up to 15 m thick, isolated channels filled by turbidites, showing transport towards the east. The upper part records easterly progradation of a deep-water slope genetically tied to overlying deltaic deposits, and controlled by regional accommodation.The contrasts between the lower and upper parts of the Gull Island Formation show that onlapping/sidelapping turbidite successions have reservoir potential near basin axes, but that prograding deep-water slopes are less likely to have reservoir potential of significance. A suggested regional downlap surface between the two parts is a significant break and marker in terms of reservoir potential. 相似文献
9.
Normal faults occur in a variety of geodynamic environments, both in areas of subsidence and uplift. Normal faults may have slip rates faster or slower than regional subsidence or uplift rates. The total subsidence may be defined as the sum of the hangingwall subsidence generated by the normal fault and the regional subsidence or uplift rate. Positive total subsidence obviously increases the accommodation space (e.g., passive margins and back-arc basins), in contrast with negative total subsidence (e.g., orogens). Where the hangingwall subsidence rate is faster than the sedimentation rate in cases of both positive and negative total subsidence, the facies and thickness of the syntectonic stratigraphic package may vary from the hangingwall to the footwall. A hangingwall subsidence rate slower than sedimentation rate only results in a larger thickness of the strata growing in the hangingwall, with no facies changes and no morphological step at the surface. The isostatic footwall uplift is also proportional to the amount and density of the sediments filling the half-graben and therefore it should be more significant when the hangingwall subsidence rate is higher than sedimentation rate. 相似文献
10.
珠江口盆地白云凹陷陆坡区10.5 Ma以来的沉积体系 总被引：1，自引：0，他引：1
通过对珠江口盆地白云凹陷陆坡区10.5Ma以来的地震相分析,共识别出席状平行亚平行地震相、透镜状前积地震相、深切河谷地震相、帚状地震相和杂乱地震相,不同的地震相分别代表不同的沉积体系类型。综合所识别的地震相类型,分析了陆架边缘下切谷、浊积扇和陆架边缘三角洲3种主要的沉积体系及其配置关系。物源供给是影响陆坡区沉积体系发育的最重要因素,是沉积体系发育的物质基础,海平面变化和构造运动为沉积体系发育提供了可容纳空间,3种影响因素共同影响了陆坡区沉积体系的发育。 相似文献
11.
The southern Makran fold-thrust belt, Pakistan, displays unique outcrop examples of well-exposed, kilometre-scale, listric growth faults that displace Miocene-age deltaic growth strata by several hundreds of metres to kilometers. The largest growth faults are counter-regional (landward-dipping), bounding major clastic depocentres exposed over areas > 1000 km2. Stratal offset along these faults can exceed 1.5 km. Fault-zone thicknesses range between ca. 100 and 400 m, and average fault thickness-displacement ratios are around 1:10. High-resolution satellite data show in unprecedented detail the faults and the stratigraphic architecture of associated growth sequences, which comprise kilometre-scale progradational clinoforms, thick mudstone units and basinwards wedging sandstone-shale deposits. The true vertical thickness of the syn-kinematic record is, in places, up to 8 km, making the outcrop examples equivalent to major growth faulted successions known from seismic data of large deltas, and at least an order of magnitude larger than other outcrop examples. A comparison of the Makran outcrops with seismic-reflection examples offshore NW Borneo reveals distinct similarities in the gross depocentre geometries and internal architecture. The key control for growth faulting is interpreted to result from sedimentary loading, with rapid sedimentary progradation causing the development of rollover synclines by differential compaction and fluid expulsion, and counter-regional growth faults preferentially forming on the basinward side of these synclines. The data and interpretations presented can be used to assess the key parameters that contribute to the development of growth faults and growth successions above shale, reinforcing structural and stratigraphic observations from seismic interpretation and modelling studies in demonstrating their occurrence in exposure. 相似文献
12.
Cenozoic sedimentary evolution of deepwater sags in the Pearl River Mouth Basin, northern South China Sea 总被引：2，自引：0，他引：2
Hui Xie Di Zhou Xiong Pang Yuanping Li Xiangjie Wu Ning Qiu Pengchun Li Guanghao Chen 《Marine Geophysical Researches》2013,34(3-4):159-173
Recent exploration revealed the high potential for hydrocarbon in the deepwater sags, Pearl River Mouth Basin, northern South China Sea. This paper reports its Cenozoic sedimentary evolution through backstripping of high precision depth data of interpreted sequence boundaries. Local backstripping parameters were mapped based on well and geophysical data. Sensitivity analysis indicates that the reliability of decompaction results were largely improved by using the local porosity parameters and the lithological parameters that vary with grid nodes. Maps of sedimentation rates of 17 sequences from 65 Ma to the present were constructed, showing the spatial–temporal variation of the sedimentation rate. Three rapid depositional stages, 65–32, 29–23.3, 18.5–10.5 Ma, and three slow depositional stages, 32–29, 23.3–18.5, 10.5–0 Ma, were identified with abrupt changes of sedimentary patterns. The three rapid depositional stages were in accord with syn-rifting stage, the first post-rifting depositional stage, and the second post-rifting depositional stage, respectively. And the three slow depositional stages were in keeping with three tectonic events respectively. Several significant sedimentary discontinuities at 32, 23.3 and 10.5 Ma were observed and discussed. The comparison between the study area and the ODP Site 1148 at 32–23.3 Ma indicates that before ~29 Ma the ODP Site 1148 was at similar sedimentation regime as that in the Baiyun and Liwan sags, but significant diversity appeared after ~29 Ma, when a large quantity of terrigenous sediments was trapped by strong post-rifting subsidence in the Baiyun and Liwan sags and could not reach the lower slope areas. Study revealed that the most rapid accumulation from 18.5 to 17.5 Ma might be mainly owing to the large sediment supply during this strong monsoon period. 相似文献
13.
Pauline Durand-Riard Lise Salles Mary Ford Guillaume Caumon Jeanne Pellerin 《Marine and Petroleum Geology》2011,28(8):1530-1539
The analysis of basin dynamics and burial evolution requires a good understanding of sediment compaction. Classically, decompaction of sediments is performed in one dimension at a well location, using either a simple compaction/depth relationship or more complex elasto-plastic models. This paper presents a new approach combining sequential decompaction with 3D restoration to allow for a true 3D basin analysis. Decompaction is performed in 3D after each restoration step, thus taking into account possible tectonic events and lateral thickness variations. Care is taken to apply decompaction to ensure volume continuity especially around faults. This approach is particularly suitable for syn-depositional folds whose growth strata constrain tectonic evolution through time.The proposed approach is applied to the sand-rich turbiditic reservoir analogue of Annot (SE France) where two fictitious wells are used to compare the new 3D technique to a well decompaction analysis. Coupling restoration and decompaction leads to an improved assessment of the basin history: an uplift of the underlying units is identified, which was not detected using decompaction on wells only. Such differences may have a significant impact on possible hydrocarbon maturation models of the basin. Moreover, the geometry of the restored and decompacted models can better constrains the basin history, and influence our understanding of potential hydrocarbon migration pathways. 相似文献
14.
Predicting the hydrodynamics, morphology and evolution of ancient deltaic successions requires the evaluation of the three-dimensional depositional process regime based on sedimentary facies analysis. This has been applied to a core-based subsurface facies analysis of a mixed-energy, clastic coastal-deltaic succession in the Lower-to-Middle Jurassic of the Halten Terrace, offshore mid-Norway. Three genetically related successions with a total thickness of 100–300 m and a total duration of 12.5 Myr comprising eight facies associations record two initial progradational phases and a final aggradational phase. The progradational phases (I and II) consist of coarsening upward successions that pass from prodelta and offshore mudstones (FA1), through delta front and mouth bar sandstones (FA2) and into erosionally based fluvial- (FA3) and marine-influenced (FA4) channel fills. The two progradational phases are interpreted as fluvial- and wave-dominated, tide-influenced deltas. The aggradational phase (III) consists of distributary channel fills (FA3 and FA4), tide-dominated channels (FA5), intertidal to subtidal heterolithic fine-grained sandstones (FA6) and coals (FA7). The aggradational phase displays more complex facies relationships and a wider range of environments, including (1) mixed tide- and fluvial-dominated, wave-influenced deltas, (2) non-deltaic shorelines (tidal channels, tidal flats and vegetated swamps), and (3) lower shoreface deposits (FA8). The progradational to aggradational evolution of this coastal succession is represented by an overall upward decrease in grain size, decrease in fluvial influence and increase in tidal influence. This evolution is attributed to an allogenic increase in the rate of accommodation space generation relative to sediment supply due to tectonic activity of the rift basin. In addition, during progradation, there was also an autogenic increase in sediment storage on the coastal plain, resulting in a gradual autoretreat of the depositional system. This is manifested in the subsequent aggradation of the system, when coarse-grained sandstones were trapped in proximal locations, while only finer grained sediment reached the coastline, where it was readily reworked by tidal and wave processes. 相似文献
15.
Jian Cao Zhijun Jin Wenxuan Hu Yijie Zhang Suping Yao Xulong Wang Yueqian Zhang Yong Tang 《Marine and Petroleum Geology》2010
Calcite veins and cements occur widely in Carboniferous and Permian reservoirs of the Hongche fault zone, northwestern Junggar Basin in northwest China. The calcites were investigated by fluid inclusion and trace-element analyses, providing an improved understanding of the petroleum migration history. It is indicated that the Hongche fault behaved as a migration pathway before the Early Cretaceous, allowing two oil charges to migrate into the hanging-wall, fault-core and footwall reservoirs across the fault. Since the Late Cretaceous, the Hongche fault has been sealed. As a consequence, meteoric water flowed down only into the hanging-wall and fault-core reservoirs. The meteoric-water incursion is likely an important cause for degradation of reservoir oils. In contrast, the footwall reservoirs received gas charge (the third hydrocarbon event) following the Late Cretaceous. This helps explain the distribution of petroleum across the fault. This study provides an example of how a fault may evolve as pathway and seal over time, and how reservoir diagenetic minerals can provide clues to complex petroleum migration histories. 相似文献
16.
The Wollaston Forland Basin, NE Greenland, is a half-graben with a Middle Jurassic to Lower Cretaceous basin-fill. In this outcrop study we investigate the facies, architectural elements, depositional environments and sediment delivery systems of the deep marine syn-rift succession. Coarse-grained sand and gravel, as well as large boulders, were emplaced by rock-falls, debris flows and turbulent flows sourced from the immediate footwall. The bulk of these sediments were point-sourced and accumulated in a system of coalescing fans that formed a clastic wedge along the boundary fault system. In addition, this clastic wedge was supplied by a sand-rich turbidite system that is interpreted to have entered the basin axially, possibly via a prominent relay ramp within the main fault system. The proximal part of the clastic wedge consists of a steeply dipping, conformable succession of thick-bedded deposits from gravity flows that transformed down-slope from laminar to turbulent flow behaviour. Pervasive scour-and-fill features are observed at the base of the depositional slope of the clastic wedge, c. 5 km into the basin. These scour-fills are interpreted to have formed from high-density turbulent flows that were forced to decelerate and likely became subject to a hydraulic jump, forming plunge pools at the base of slope. The distal part of the wedge represents a basin plain environment and is characterised by a series of crude fining upward successions that are interpreted to reflect changes in the rate of accommodation generation and sediment supply, following from periodic increases in fault activity. This study demonstrates how rift basin physiography directly influences the behaviour of gravity flows. Conceptual models for the stratigraphic response to periodic fault activity, and the transformation and deposition of coarse-grained gravity flows in a deep water basin with strong contrasts in slope gradients, are presented and discussed. 相似文献
17.
Tanan sub-basin is an active-fault bounded basin. The spatial distribution and temporal evolution of depositional systems were significantly influenced by tectonics. Fault movement and stages of basin development controlled the subsidence rates and the potential for erosion and the rate of sediment supply. Distinct stages of rift evolution during the early Cretaceous can be recognized, namely the early syn-rift, rift climax and late syn-rift stages. Three types of lacustrine sequence, consisting of distinctive depositional systems, are distinguished: (1) the early syn-rift sequences (SQ1 + SQ2), which are composed mainly of fan delta and shallow lacustrine depositional systems; (2) the rift climax sequences (SQ3) which developed in response to rapid and differential tectonic subsidence rates, and consist of fan delta, deep lacustrine and sublacustrine fan depositional systems; and (3) the late syn-rift sequences (SQ4) which are comprised of braided-delta and shallow lacustrine depositional systems. Each of the three lacustrine sequence architectures stands for a particular stage of basin fill and reflects variable rates of basin subsidence. Within each sequence, depositional systems and their stacking patterns are interpreted to have been a function of the interaction between tectonics and sediment supply. Differential subsidence across the basin, related to rotation of fault blocks, resulted in the formation of distinct paleomorphologies in different structural settings. These settings were fault-scarp zones controlling the development of fan-deltas, fault-terrace zones controlling the development of fan-delta and sublacustrine fans, half-graben dip-slope zones controlling the development of braided river and braided deltas, and intra-basinal fault-break zones controlling the development of sublacustrine fans. During the late syn-rift stage, active tectonism, displacement on the boundary faults had ceased. At this stage the depositional systems and their stacking patterns were dominantly related to the sediment supply rates, and not to tectonic activity. 相似文献
18.
南昆嵩地区是万安盆地西部负向构造单元,其中部N–S向断裂贯穿南北,独特的构造特征使其成为研究万安盆地西部构造演化与区域断裂走滑活动的窗口。将研究区沉积地层划分为3套构造层,通过回剥法绘制南昆嵩地区构造–沉积充填剖面,并计算南昆嵩地区构造沉降量以及构造沉降速率,论述南昆嵩地区构造演化史与沉降过程以及控制因素。研究结果表明:下部构造层和中部构造层中断裂组合样式主要为卷心型断层、“Y”型断层、阶梯状断层和高角度花状构造等,断裂延伸方向大致可分为:N–S向、W–E向和NE–SW向3种;上部构造层断裂不发育,为稳定沉积;在区域走滑断裂以及南海扩张运动的控制下,南昆嵩地区始新世以来构造演化经历4个阶段:初始裂谷期、伸展断拗期、走滑改造期和热沉降期,新生代地层构造性质也表现为以伸展与走滑作用为主–走滑断裂控制–热沉降的三段式转变。 相似文献
19.
构造地貌是指由新构造运动直接形成的一种动态的、积极活跃的地貌类型。南海南部海域新构造运动强烈,类型众多,它们是控制海底构造地貌形成和发育的主要内动力因素。根据地质地球物理资料,对该区区域构造沉降、海底扩张、断裂作用、褶皱作用和火山活动等新构造运动类型及其形成的构造地貌进行了分析。区域构造沉降形成规模较大的构造台地、深水阶地和陆坡盆地等;海底扩张形成西南海盆、中央海盆及其内部的众多构造地貌类型;断裂作用形成断层崖、断阶、海底谷、断块山、断陷盆地等;褶皱作用形成山地和挤压构造盆地;火山作用形成海山、海丘。 相似文献
20.
The Plio-Pleistocene succession of the Venice area represents part of the infill of a foreland region located between three mountain chains: the Northern Apennines, the Southern Alps and the Dinarides. This structural setting favored the development of a complex stratigraphic architecture of the succession, mostly due to the conveying of sediments from the Southern Alps to the north and the Northern Apennines to the south, in particular since the activation of strong subsidence related to the NE-ward migration of the Apennine foredeep in the early Pleistocene. Accordingly, the studied succession is composed of five third-order sequences mostly controlled by tectonics, the most recent of which display complex patterns due to the interfingering of sedimentary bodies showing contrasting directions of progradation and pinch-out. Despite this, the sequence stratigraphic method still can be applied in the present context, allowing to recognize diagnostic stratal architectures and reconstruct the relative sea-level history of the region. Moreover, the recognized peculiar stratigraphic architecture of the basin fill may serve as an analogue that needs to be taken into account to predict the distribution of porous coarse-grained sedimentary units in similar contexts, aiding for a profitable exploration and production of reservoirs and source/sealing rocks. 相似文献