共查询到20条相似文献，搜索用时 22 毫秒
1.
Heterogeneous stretching, simple shear and basin development 总被引：1，自引：0，他引：1
M.P. Coward 《Earth and Planetary Science Letters》1986,80(3-4):325-336
The models of basin development which involve either homogeneous stretching of the whole lithosphere or displacement on a lithospheric-scale shear zone, are but two end members of a range of possible extensional models. The homogeneous extension model thins the lower lithosphere beneath the thinned upper crust and superimposes a thermal subsidence basin on the earlier fault bounded basin. The shear zone model offsets the zone of lower lithospheric stretching and thermal subsidence. It is more likely that the zones of upper and lower lithospheric stretching will be heterogeneous and patchy, but will often overlap in plan view. This will produce localised uplift and subsequent thermal subsidence within the faulted basin and may explain many of the anomalies between the various stretching estimates made using different structural, stratigraphic and geophysical techniques. The model which combines heterogeneous lithospheric stretching and associated simple shear may explain: (1) variations in dip of the major detachment zones in the large basins, (2) variations in types of strain on or beneath the detachment zones, (3) regional uplift of part of a basin, to erode the earlier fault blocks, and (4) the development of volcanism in basins with only low values of upper crustal extension. The zone of stretched lower crust and lithospheric mantle may lie beneath the centre of the zone of upper crustal stretching, or to one side. It may be linked to the upper crustal zone by faults which dip consistently in one direction, or by extensional systems which change their dominant dip direction with depth, pulling out the mid-crust as one or more wedges. Possible examples are discussed from the Basin and Range province and northwest European continental shelf. 相似文献
2.
A method has been developed that allows temporal changes in tectonic force during rift basin formation to be inferred from observed tectonic subsidence curves and has been applied to the Gulf of Lions (the Provençal Basin) and the Valencia Trough in order to gain some understanding of the dynamical aspects of back-arc basin rifting in the western Mediterranean Sea. Two distinct tectonic force regimes active at different times during the evolution of each of these back-arc basins are identified. The first, which can be seen in both basins, is characterized by tensional forces that gradually abate with time to vanish some ～ 20 my after the onset of rifting. The magnitude of tectonic force required to initiate the rifting process is significantly greater in the Valencia Trough than in the Provençal Basin. Subsequently, the dynamic development of these back-arc basins differs. In the Provençal Basin, there is a renewal of force, with extensional deformation concentrated in the central part of the rift whereas, in the Valencia Trough, the second tectonic force regime is inferred to be one that causes compression that subsequently relaxes. Such temporal patterns of tectonic force are interpreted to be related to the causative driving processes, allowing constraints to be placed on the transient interaction between the overriding and subducting plates in a back-arc setting. The models also allow inferences to be made about the rheological structure of the lithosphere. A significant variation of initial crustal thickness is inferred for the Provençal Basin but not for the Valencia Trough. In both basins, a wet rheology is required in order to initiate rifting given currently accepted bounds on tectonic force magnitudes; adoption of a dry rheology leads to insufficiently high strain rates for significant lithosphere extension in both cases. 相似文献
3.
基于地球动力学的构造-热演化方法是沉积盆地热史研究的重要方法之一.本文以江汉盆地宜随大剖面为例,采用平衡剖面方法对叠合盆地复杂、漫长的演化历史进行构造恢复,采用多期有限拉张-挤压应变速率法进行古热流反演,最后得到盆地的古地温场.由此,建立了构造恢复—盆地基底热流反演—岩石圈尺度温度结构—沉积盆地尺度温度结构的多期伸展、挤压模型的热模拟方法流程,实现了岩石圈尺度的热模拟与盆地尺度的热模拟相结合. 相似文献
4.
We present an analysis of the consequences of foreland basin development on thinned continental lithosphere, inherited from pre-orogenic phases of extension. Bathymetry at the transition from pre-orogenic extensional basin to foreland basin and compaction of pre-orogenic sediments contribute to the accommodation space for foreland basin sediments and thrust loads. In addition, the extension-induced transient thermal state of the lithosphere, results in ongoing thermal subsidence, and a flexural rigidity which changes through time. Quantitative modelling of the phase of extension and the foreland basin stage of the Aquitaine basin (southern France) shows that the inherited transient thermal state of the lithosphere contributes significantly to (1) the total foreland basin depth and width, (2) the post-compressional subsidence history, and (3) the cratonward onlap pattern. Accounting for the thermo-mechanical effects of pre-orogenic extension significantly reduces the estimates of both the flexural rigidity (30–43% for the Aquitaine basin) and the required topographic or thrust load (40% for the Aquitaine basin) at foreland basins. Emplacement of thrust loads below sea level, as expected in a pre-orogenic extensional basin setting, further reduces the required topographic load. This sheds light on the wide range of flexural rigidity values reported for continental lithosphere from foreland basin modelling studies, and explains, in many instances, the inferred ‘hidden load’ or subsurface load in flexural modelling studies at foreland basins. The present study has shown that pre-orogenic extension phases significantly affect the record of vertical motion and the stratigraphy of the Aquitaine basin and is probably important for foreland basin evolution in general. 相似文献
5.
Guojiang Liu 《Geophysical Prospecting》1994,42(4):277-302
The Bjøirnøya West Basin lies between latitudes 73° and 74°, longitudes 16°E and 18°E, contains at least 8 km of sediments deposited from the Late Jurassic, and is of considerable interest for hydrocarbon exploration. The Cenozoic extensional tectonics in the basin can be clearly seen from seismic data with normal faulting and from subsidence curves with rapid subsidence. The extension occurred during the Late Palaeocene with active extension lasting about 6 million years (m.y.) followed by thermal cooling. The tectonic subsidence within the study area shows a three-phase development: phase 1, synrift (58–52 Ma (million years before the present day)), is characterized by rapid subsidence; phase 2, postrift (52–5 Ma), by slow subsidence with occasional uplift; and phase 3 (5–0 Ma), by rapid subsidence. An adaptive finite-element model, with consideration of the radiogenic heat production in the lithosphere, has been used to model the subsidence and heat flow. The modelling of subsidence shows the β-factor distribution varying from 1.9 to 3.5 with an average of 2.4 for the uniform lithospheric extension. The heat-flow modelling predicts a rapid increase of heat flow during the Early Palaeocene. The maximum heat flow at about 52 Ma, which could be as much as 3.0 hfu (10?6 cal/cm2/s), was followed by a decrease in heat flow. A plate-weakening model has been proposed to explain the rapid subsidence for the last 5 m.y. by flexure of the elastic lithosphere which is weakened by a decrease in elastic thickness caused by an increase of the temperature gradient in the lithosphere. The plate-weakening model predicts a heat-flow increase at 5 Ma of up to 2.0 hfu. Our study, using quantitative modelling of the tectonic subsidence, provides a partial (if not a full) understanding of the tectonic development and thermal evolution of the Bjønøya West Basin. 相似文献
6.
The time history and magnitude of the subsidence in a sedimentary basin depends on the extent to which the lithosphere is thinned by stretching and on its original thickness. Hence the history and stratigraphic thickness of early Precambrian sedimentary basins, preserved as greenstone belts, should provide estimates of lithospheric thickness during the first half of the earth's history. Only the thickness of shallow-water sediments deposited without faulting is of relevance, and the best available estimates are compatible with all lithospheric thicknesses which have been suggested. The same is true of the estimates of the duration of the subsidence. Nonetheless radiometric dating can probably now provide estimates of the duration of the subsidence which are sufficiently accurate to constrain the models of the earth's thermal history if carried out for this purpose. 相似文献
7.
拉分盆地是走滑断层系中受拉伸作用形成的断陷盆地.一般在两条平行断层控制下发育.盆地形似菱形,几何形态主要受两条主控走滑断层错距和叠接长度影响.本文以青藏高原东北缘海原断裂带老龙湾拉分盆地第四纪所处的构造环境为基础,参考盆地周围断层几何分布,建立了三维有限元数值模型,模拟该拉分盆地的演化过程;进一步分析了断层力学性质、地壳分层结构等各因素对盆地形成和演化的影响.模拟结果显示,盆地地表沉降伴随有下地壳物质的上涌,此上涌对盆地地表沉降存在阻碍作用.各因素的影响具体表现为:(1)断层力学性质(弹性模量和黏滞系数)越弱,其对构造应力较低的传递效率导致盆地两端差异性运动越明显,从而形成较大的盆地地表沉降和明显的上地壳减薄.(2)平行主控断层的叠接长度反映盆地形成的拉伸作用范围,叠接长度越大,相同的差异性运动在单位面积形成的拉伸应力越小,盆地地表沉降较小.(3)下地壳流变性影响其物质的上涌量,下地壳黏滞系数越小,其对上部拉伸作用的响应越明显,上涌量越大,此上涌对上地壳沉降形成的阻碍作用也越明显.根据老龙湾拉分盆地所处的构造格局,将平行断层的叠接长度取20km,当断层黏滞系数取值为周围基岩的1/10,参考该盆地第四纪构造演化历史,模拟得到的盆地第四纪下沉量与盆地内第四系沉积层厚度在规模上近似,下地壳黏滞系数取值在(2.5~5.0)×1021 Pa·s范围内时,盆地下沉量模拟结果与老龙湾拉分盆地第四系地层厚度吻合较好. 相似文献
8.
构造热演化模拟是研究沉积盆地的重要手段之一，其模型依赖于沉积盆地的成因机制.裂谷盆地构造热演化的定量模型在描述盆地沉降和热流演化方面取得了极大的成功，实现了构造和热的完美结合.而前陆盆地的定量模型更多关注的是构造沉降，在构造与热的结合方面尚不够完善.关于克拉通盆地目前还没有很成熟的定量模型，构造热演化研究程度远远低于裂谷盆地和前陆盆地.随着我国陆域海相沉积盆地油气勘探的突破，对海相沉积盆地热体制的研究迫在眉睫.而我国陆域海相沉积盆地，如塔里木和四川盆地，演化历史长且复杂，是古生代海相克拉通与中、新生代前陆盆地组成的叠合盆地.现有的关于沉积盆地构造热演化的单一模式难以适应复杂的构造—热历史.对我国陆域海相大型沉积盆地进行深入全面的动力学分析，发展叠合盆地的构造—热演化模型，建立相应的构造热演化模式及模拟方法技术，将是一项具有开拓意义并极具挑战性的工作. 相似文献
9.
10.
Yu. I. Galushkin G. L. Leitchenkov Yu. B. Guseva E. P. Dubinin 《Izvestiya Physics of the Solid Earth》2018,54(1):79-90
The burial history and thermal evolution of the lithosphere within the passive nonvolcanic Antarctic margin in the region of the Mawson Sea are numerically reconstructed for the margin areas along the seismic profile 5909 with the use of the GALO basin modeling system. The amplitudes of the lithosphere stretching at the different stages of continental rifting which took place from 160 to 90 Ma ago are calculated from the geophysical estimates of the thickness of the consolidated crust and the tectonic analysis of the variations in the thickness of the sedimentary cover and sea depths during the evolution of the basin. It is hypothesized that the formation of the recent sedimentary section sequence in the studied region of the Antarctic margin began ~140 Ma ago on a basement that was thinned by a factor of 1.6 to 4.5 during the first episode of margin stretching (160–140 Ma) under a fairly high heat flux. The reconstruction of the thermal regime of the lithosphere has shown that the mantle rocks could occur within the temperature interval of serpentinization and simultaneously within the time interval of lithospheric stretching (–160 < t <–90 Ma) only within separate segments of profile 5909 in the Mawson Sea. The calculations of the rock strength distribution with depth by the example of the section of pseudowell 4 have shown that a significant part of the crust and uppermost mantle fall here in the region of brittle deformations in the most recent period of lithosphere stretching (–104 to–90 Ma ago). The younger basin segments of profile 5909 in the region of pseudowells 5 and 6 are characterized by a high heat flux, and the formation of through-thickness brittle fractures in these zones is less probable. However, serpentinization could take place in these areas as in the other margin segments at the stage of presedimentation ultra slow basement stretching. 相似文献
11.
Most thermo-mechanical models for the development of sedimentary basins have assumed that the rifting responsible for the formation of the basin occurred instantaneously and have examined the post-rift development of the basin. This assumption greatly simplifies the mathematical treatment, but is not in accord with what is found in nature, where 10-to 50-m.y. rifting events commonly accompany the formation of sedimentary basins and continental margins. The effects of a finite rifting time on the development of sedimentary basins are examined using an analytic technique which allows an arbitrary rifting history in both time and space and which considers the effects of both vertical and horizontal heat transfer. This technique allows the thermal structure of the lithosphere to be calculated throughout the rifting event and thus permits the subsidence history and surface heat flow of the developing basin to be traced.The effect of a finite-duration extension event is that heat is lost during rifting increasing the syn-rift subsidence at the expense of the post-rift. Lateral heat flow, which was not included in previous studies of the effect of finite rifting times, has a significant effect on the subsidence history, distribution of sediments and thermal history. In particular, the post-rift subsidence is decreased by more than 25% for a 20-m.y. rifting event and by more than 10–15% for a rifting event as short as 10 m.y. This will significantly decrease the subsidence rates in the post-rift stage and implies that inferences concerning the structure, development and thermal history of the basin derived from using “β-curves” to interpret backstripped subsidence can be greatly in error.Variations in syn-rift sediment accumulation and lithospheric thermal structure at the end of rifting resulting from different rifting histories can interact with other factors, such as the flexural response of the lithosphere to sediment loading, to affect the final width of the basin, the total amount of sediments that accumulate and the basin stratigraphy. 相似文献
12.
地温梯度和大地热流是揭示盆地现今热状态的重要参数,它们对理解盆地的构造-热演化过程及油气资源评价等方面均具有重要意义.利用塔里木盆地约470口井的地层测试温度资料和941块岩石热导率数据,本文计算了塔里木盆地38个新的大地热流数据,进而揭示了该盆地现今地热分布特征.研究表明,塔里木盆地现今地温梯度变化范围为17～32 ℃/km,平均为22.6±3.0 ℃/km;大地热流变化范围为26.2～65.4 mW/m2,平均为43.0±8.5 mW/m2.与我国其他大中型沉积盆地相比,它表现为低地温、低大地热流的冷盆的热状态,但仍具有与世界上典型克拉通盆地相似的地热背景.整体而言,盆地隆起区地温梯度和热流相对较高,坳陷区地温梯度和热流则偏低.此外,我们还发现塔里木盆地现有的油气田区一般位于高地温梯度区域,这可能与下部热流体的向上运移和聚集有关.影响塔里木盆地现今地热特征的因素包括盆地深部结构、构造演化、岩石热物理性质、盆地基底构造形态和烃类聚集等. 相似文献
13.
The Elbistan Basin in the east-Central Anatolia is an intramontane structural depression in the interior part of the Anatolide-Tauride Platform. The Neogene fill in and around Elbistan Basin develops above the Upper Devonian to lower Tertiary basement and comprises two units separated by an angular unconformity: (1) intensely folded and faulted Miocene shallow marine to terrestrial and lacustrine sediments and (2) nearly flat-lying lignite-bearing lacustrine (lower unit) and fluvial (upper unit) deposits of Plio-Quaternary Ahmetçik Formation. The former is composed of Lower-Middle Miocene Salyan, Middle-upper Middle Miocene Gövdelidağ and Upper Miocene Karamağara formations whereas the latter one is the infill of the basin itself in the present configuration of the Elbistan Basin. The basin is bound by normal faults with a minor strike-slip component. It commenced as an intramontane pull-apart basin and developed as a natural response to Early Pliocene tectonic escape-related strike-slip faulting subsequent to post-collisional intracontinental compressional tectonics during which Miocene sediments were intensely deformed. The Early Pliocene time therefore marks a dramatic changeover in tectonic regime and is interpreted as the beginning of the ongoing last tectonic evolution and deformation style in the region unlike to previous views that it commenced before that time. Consequently, the Elbistan Basin is a unique structural depression that equates the extensional strike-slip regime in east-Central Anatolia throughout the context of the neotectonical framework of Turkey across progressive collision of Arabia with Eurasia. Its Pliocene and younger history differs from and contrasts with that of the surrounding pre-Pliocene basins such as Karamağara Basin, on which it has been structurally superimposed. 相似文献
14.
本文利用热导率、热容、热膨胀系数等参数随温度变化的经验表达式,在板块模型的基础上用隐式有限差分方法解非线性热传导方程,并利用北太平洋和北大西洋海底年龄与水深数据反演了大洋岩石圈厚度与底界温度等参数,结果表明大洋岩石圈的厚度在105 km左右,岩石圈底界温度在1450℃左右,这与Stein等用全球大量数据反演的结果一致.将变参数模型用到岩石圈拉张成盆的模拟中,结果表明当考虑岩石圈热参数随温度变化之后,预测的地表热沉降要大于常参数均匀伸展模型的预测量.由此我们指出：McKenzie的均匀伸展模型预测的初始沉降偏大而热沉降偏小,可能与该模型没有考虑热参数随深度(即温度)变化有关. 相似文献
15.
16.
ZHAI Mingguo ZHU Rixiang LIU Jianming MENG Qingren HOU Quanlin HU Shengbiao LIU Wei LI Zhong ZHANG Hongfu & ZHANG HuafengKey Laboratory of Mineral Resources Institute of Geology Geophysics Chinese Academy of Sciences Beijing China Correspondence should be addressed to Zhai Mingguo 《中国科学D辑(英文版)》2004,47(2):151-159
An important tectonic inversion took place in eastern North China Block(NCB) during Mesozoic, which caused a great lithosphere thinning, reconstruction of basin-range series, powerful interaction between mantle and crust, a vast granitic intrusion and volcanism, and large-scale metallogenic explosion. The time range of the Mesozoic tectonic regime inversion in the eastern North China Block is one of the key issues to understand mechanism of tectonic regime inversion. Our updated results for recognizing the time range are mainly obtained from the following aspects: structural analyses along northern and southern margins of the NCB and within the NCB for revealing tectonic inversion from compression to extension and structural striking from -EW to NNE; geothermic analyses of the eastern sedimental basins for a great change of thermal history and regime; basin analysis for basin inversion from compression to extension and basin migration from -EW to NNE; petrological and geochemical studies of volcanic roc 相似文献
17.
Some remarks on the development of sedimentary basins 总被引：15，自引：0，他引：15
Dan McKenzie 《Earth and Planetary Science Letters》1978,40(1):25-32
A simple model for the development and evolution of sedimentary basins is proposed. The first event consists of a rapid stretching of continental lithosphere, which produces thinning and passive upwelling of hot asthenosphere. This stage is associated with block faulting and subsidence. The lithosphere then thickens by heat conduction to the surface, and further slow subsidence occurs which is not associated with faulting. The slow subsidence and the heat flow depend only on the amount of stretching, which can be estimated from these quantities and from the change in thickness of the continental crust caused by the extension. The model is therefore easily tested. Preliminary investigations of the Great Basin, the Aegean, the North Sea and the Michigan Basin suggest that the model can account for the major events in their evolution. 相似文献
18.
为了考察渤海湾盆地济阳坳陷新生代裂后不整合及加速沉降事件并探讨其成因机制,利用悬臂梁模型和二维挠曲回剥模型的正反演模拟,对济阳坳陷2条NS向剖面新生代的构造演化进行了重建.正演计算表明,要反映14 Ma的盆地结构,需要叠加断陷阶段及裂后不整合时期发生的构造抬升事件,叠加的构造抬升量在坳陷东北部比西南部大;反演计算表明,要恢复到14 Ma的盆地结构,按照断层估算的拉张系数产生的热沉降不足以恢复当时的古水深,如果要通过人为增加构造沉降以恢复到14 Ma的古水深,那么坳陷东北部比西南部需要更大的沉降量.结果说明,济阳坳陷在新生代发育时,除了水平伸展产生的岩石圈被动减薄外,可能还叠加了垂向因素引起的岩石圈主动减薄;14 Ma以来发生的裂后加速沉降有从坳陷东北部向西南部推进的趋势.分析表明除了水平伸展诱发软流圈热扰动及随后快速热衰减外,岩石圈拆层作用、岩石圈地幔交代作用等主动因素,也会产生裂后不整合及加速沉降事件. 相似文献
19.
盆地热历史可以为揭示深部动力学过程提供时间和空间上的连续信息. 本文利用镜质体反射率古温标模拟了鄂尔多斯盆地从东到西7口典型井的热历史, 并在此基础上计算了盆地中生代晚期、古近纪初期以及现今的"热"岩石圈厚度. 结果显示, 鄂尔多斯盆地在早白垩世末期经历了一次热流高峰, 热流值为73~78 mW/m2, 此后的热流值一直降低至今,现今的平均值61.8 mW/m2; 早白垩世末期盆地"热"岩石圈厚度也经历了一次减薄高峰, 平均"热"岩石圈厚度为65 km左右, 此后逐渐增厚至现今的125 km左右. 鄂尔多斯盆地现今"热"岩石圈厚度中等, 早古生代200 km的厚岩石圈已不存在; 早白垩世末期是其地质发展历史的一个重大变革期, 此时"热"岩石圈厚度发生减薄, 深部构造活动强烈导致浅部盆地抬升剥蚀剧烈, 周缘岩浆活动强烈, 多种能源矿产形成, 这与华北克拉通东部构造转折的时间以及华北克拉通破坏的高峰时限具有一致性. 相似文献
20.
沉积盆地的热历史是盆地的构造演化研究和油气资源评价及油气成藏的重要参数.本文利用磷灰石裂变径迹和镜质体反射率古温标模拟计算了济阳坳陷70口单井新生代以来的热演化历史,在此基础上分析了济阳坳陷内东营、沾化、惠民和车镇4个凹陷的地温梯度演化特征.研究结果表明,济阳坳陷新生代以来的古地温梯度是逐渐降低的,但在早第三纪时期下降的幅度较大,而在晚第三纪－第四纪则下降的幅度明显较小;济阳坳陷在孔店组沉积时期的地温梯度为540～500℃/km之间,沙河街沉积时期为500～400℃/km,东营组沉积时期为400～385℃/km,晚第三纪时期为385～355℃/km,第四纪以来基本未变.坳陷内4个凹陷的古地温梯度演化存在差异,特别是在早第三纪末期的东营构造运动以后,各凹陷的地温梯度演化差异更加明显.在晚第三纪时期,济阳坳陷各凹陷的地温梯度变化均较小,地温梯度的高低依次为东营凹陷、沾化凹陷、惠民凹陷和车镇凹陷.车镇凹陷的古地温梯度在整个新生代演化历史中均是济阳坳陷最低的.这种地温演化的差异与各凹陷的构造沉降演化史密切相关,同时地温演化差异也导致了各凹陷的烃源岩在生烃门限深度的差异.济阳坳陷的古地温梯度演化特征反映了济阳坳陷由断陷向坳陷的构造演化特征. 相似文献