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1.
Doris Reischenbacher Reinhard F. Sachsenhofer 《International Journal of Earth Sciences》2013,102(2):517-543
The Miocene Lavanttal Basin formed in the Eastern Alps during extrusion of crustal blocks towards the east. In contrast to basins, which formed contemporaneously along the strike-slip faults of the Noric Depression and on top of the moving blocks (Styrian Basin), little is known about the Lavanttal Basin. In this paper geophysical, sedimentological, and structural data are used to study structure and evolution of the Lavanttal Basin. The eastern margin of the 2-km-deep basin is formed by the WNW trending Koralm Fault. The geometry of the gently dipping western basin flank shows that the present-day basin is only a remnant of a former significantly larger basin. Late Early (Karpatian) and early Middle Miocene (Badenian) pull-apart phases initiated basin formation and deposition of thick fluvial (Granitztal Beds), lacustrine, and marine (Mühldorf Fm.) sediments. The Mühldorf Fm. represents the Lower Badenian cycle TB2.4. Another flooding event caused brackish environments in late Middle Miocene (Early Sarmatian) time, whereas freshwater environments existed in Late Sarmatian time. The coal-bearing Sarmatian succession is subdivided into four fourth-order sequences. The number of sequences suggests that the effect of tectonic subsidence was overruled by sea-level fluctuations during Sarmatian time. Increased relief energy caused by Early Pannonian pull-apart activity initiated deposition of thick fluvial sediments. The present-day shape of the basin is a result of young (Plio-/Pleistocene) basin inversion. In contrast to the multi-stage Lavanttal Basin, basins along the Noric Depression show a single-stage history. Similarities between the Lavanttal and Styrian basins exist in Early Badenian and Early Sarmatian times. 相似文献
2.
In southern Poland, Miocene deposits have been recognised both in the Outer Carpathians and the Carpathian Foredeep (PCF). In the Outer Carpathians, the Early Miocene deposits represent the youngest part of the flysch sequence, while in the Polish Carpathian Foredeep they are developed on the basement platform. The inner foredeep (beneath the Carpathians) is composed of Early to Middle Miocene deposits, while the outer foredeep is filled up with the Middle Miocene (Badenian and Sarmatian) strata, up to 3,000mthick. The Early Miocene strata are mainly terrestrial in origin, whereas the Badenian and Sarmatian strata are marine. The Carpathian Foredeep developed as a peripheral foreland basin related to the moving Carpathian front. The main episodes of intensive subsidence in the PCF correspond to the period of progressive emplacement of the Western Carpathians onto the foreland plate. The important driving force of tectonic subsidence was the emplacement of the nappe load related to subduction roll-back. During that time the loading effect of the thickening of the Carpathian accretionary wedge on the foreland plate increased and was followed by progressive acceleration of total subsidence. The mean rate of the Carpathian overthrusting, and north to north-east migration of the axes of depocentres reached 12 mm/yr at that time. During the Late Badenian-Sarmatian, the rate of advance of the Carpathian accretionary wedge was lower than that of pinch-out migration and, as a result, the basin widened. The Miocene convergence of the Carpathian wedge resulted in the migration of depocentres and onlap of successively younger deposits onto the foreland plate. 相似文献
3.
This paper discusses the Neogene tectonic evolution of the Tunisia offshore Gulf of Hammamet basin. Based on seismic and well data, this basin was created during the Miocene and is currently trending NE–SW. During the Neogene, the study area was affected by geodynamic interactions controlled simultaneously by convergence of the Eurasia and Africa plates and the opening of the Atlantic Ocean. These interactions generated compressive and extensional regimes which led to a variety of structures and basin inversions.The middle Miocene extensional regime created horst and graben structures (e.g. the Halk El Menzel graben). The two major compressive phases of the Tortonian and post Villafranchian age created different structures such as Ain Zaghouan and Fushia structures and the Jriba trough, and led to the reactivation of the old normal faults as reverse faults. During the Plio-Pleistocene and the Quaternary times, the Gulf of Hammamet was affected by an extensional regime related to the Siculo-Tunisian rift, which led to the development in the area of several sedimentary basins and new normal fault patterns.The Gulf of Hammamet shows several basins ranging in age from the Tortonian to the Quaternary, which display different structural and stratigraphic histories. Two main groups of sedimentary basins have been recognized. The first group has Tortonian–Messinian sedimentary fill, while the second group is largely dominated by Plio-Quaternary sediments. The shortening during the Tortonian and post Villafranchian times has led to the tectonic inversion of these basins. This shortening could be correlated to the Europe–Africa collision.Despite the large number of hydrocarbon discoveries, the Gulf of Hammamet remains under-explored, in particular at deeper levels. This study aims to guide future exploration and to highlight some new play concepts. 相似文献
4.
尼日尔三角洲盆地泥收缩构造发育特征及对沉积的控制 总被引：1，自引：0，他引：1
泥收缩构造是发育在尼日尔三角洲盆地深水区的典型构造样式,属重力滑脱冲断构造,主要构造类型有冲断裂、塑性泥构造及相关褶皱和正断裂。基于地震地质解释,结合构造发育史分析,认为泥收缩构造主要受塑性泥构造控制,在中新世托尔托纳(Tortonian)晚期开始活动,中新世墨西拿期(Messinian)—上新世赞克勒期(Zanclean)达到最强,之后构造活动逐渐减弱,但至今仍在活动。通过古构造恢复,结合沉积展布分析,认为中新世托尔托纳晚期沉积开始受构造活动控制,托尔托纳阶上部及以上地层具有明显的同沉积特征,泥收缩构造相关的冲断裂上升盘厚度明显小于下降盘厚度,褶皱两翼的地层厚度明显厚于中间背斜顶部的地层厚度。 相似文献
5.
《Journal of Asian Earth Sciences》2009,34(5-6):383-394
The stratigraphic architecture, structure and Cenozoic tectonic evolution of the Tan-Lu fault zone in Laizhou Bay, eastern China, are analyzed based on interpretations of 31 new 2D seismic lines across Laizhou Bay. Cenozoic strata in the study area are divided into two layers separated by a prominent and widespread unconformity. The upper sedimentary layer is made up of Neogene and Quaternary fluvial and marine sediments, while the lower layer consists of Paleogene lacustrine and fluvial facies. In terms of tectonics, the sediments beneath the unconformity can be divided into four main structural units: the west depression, central uplift, east depression and Ludong uplift. The two branches of the middle Tan-Lu fault zone differ in their geometry and offset: the east branch fault is a steeply dipping S-shaped strike-slip fault that cuts acoustic basement at depths greater than 8 km, whereas the west branch fault is a relatively shallow normal fault. The Tan-Lu fault zone is the key fault in the study area, having controlled its Cenozoic evolution. Based on balanced cross-sections constructed along transverse seismic line 99.8 and longitudinal seismic line 699.0, the Cenozoic evolution of the middle Tan-Lu fault zone is divided into three stages: Paleocene–Eocene transtension, Oligocene–Early Miocene transpression and Middle Miocene to present-day stable subsidence. The reasons for the contrasting tectonic features of the two branch faults and the timing of the change from transtension to transpression are discussed. 相似文献
6.
The geologic significance of the Mn-ore existing in sediments of Serravallian and/or Tortonian age of The Matese Mts. (Central-Southern Appennines) has been reinvestigated, according to more recent criteria. Such deposits originated under the influence of peculiar environments, where the instability of the sedimentary basin, preluding to greater tectonic movements, should have created conditions cyclically euxinic, very similar to those occurring in the strata located between Longano and Pietraroia Formations. Unequal tectonics acting upon Miocene sediments after their deposition, should have caused the secondary remobilisation of Mn-minerals, resulting in irregular patterns of lenses and layers of various thickness. 相似文献
7.
Seismic profiles across the middle Tan-Lu fault zone in Laizhou Bay, Bohai Sea, eastern China 总被引：4，自引：0，他引：4
Zhaohua Yu Shiguo Wu Dongbo Zou Deyong Feng Hanqing Zhao 《Journal of Asian Earth Sciences》2008,33(5-6):383-394
The stratigraphic architecture, structure and Cenozoic tectonic evolution of the Tan-Lu fault zone in Laizhou Bay, eastern China, are analyzed based on interpretations of 31 new 2D seismic lines across Laizhou Bay. Cenozoic strata in the study area are divided into two layers separated by a prominent and widespread unconformity. The upper sedimentary layer is made up of Neogene and Quaternary fluvial and marine sediments, while the lower layer consists of Paleogene lacustrine and fluvial facies. In terms of tectonics, the sediments beneath the unconformity can be divided into four main structural units: the west depression, central uplift, east depression and Ludong uplift. The two branches of the middle Tan-Lu fault zone differ in their geometry and offset: the east branch fault is a steeply dipping S-shaped strike-slip fault that cuts acoustic basement at depths greater than 8 km, whereas the west branch fault is a relatively shallow normal fault. The Tan-Lu fault zone is the key fault in the study area, having controlled its Cenozoic evolution. Based on balanced cross-sections constructed along transverse seismic line 99.8 and longitudinal seismic line 699.0, the Cenozoic evolution of the middle Tan-Lu fault zone is divided into three stages: Paleocene–Eocene transtension, Oligocene–Early Miocene transpression and Middle Miocene to present-day stable subsidence. The reasons for the contrasting tectonic features of the two branch faults and the timing of the change from transtension to transpression are discussed. 相似文献
8.
The Bajo Segura Basin is located in the eastern Betic Cordillera, at present connected with the Mediterranean Sea to the east. It has a complete stratigraphic record from the Tortonian to the Quaternary, which has been separated into six units bounded by unconformities. This paper is concerned with the northern edge of the basin, controlled by a major strike–slip fault (the Crevillente Fault Zone, CFZ), where the most complete stratigraphic successions are found. The results obtained (summarised below) are based on an integrated analysis of the sedimentary evolution and the subsidence-uplift movements. Unit I (Early Tortonian) is transgressive on the basin basement and is represented by ramp-type platform facies, organised in a shallowing-upward sequence related to tectonic uplift during the first stages of movement along the CFZ. Unit II (lower Late Tortonian) consists of shallow platform facies at bottom and pelagic basin facies at top, forming a deepening-upward sequence associated with tectonic subsidence due to sinistral motion along the CFZ. Unit III (middle Late Tortonian) is made up of exotic turbiditic facies related to a stage of uplift and erosion of the southern edge of the basin. Unit IV (upper Late Tortonian) consists of pelagic basin facies at bottom and shallow platform facies at top, defining a shallowing-upward sequence related to tectonic uplift during continued sinistral movement on the basin-bounding fault. Units V (latest Tortonian–Messinian) and VI (Pliocene–Pleistocene p.p.) consist of shallowing-upward sequences deposited during folding and uplift of the northern margin of the basin. No definitive evidence of any major eustatic sea-level fall, associated with the ‘Messinian salinity crisis’, has been recorded in the stratigraphic sections studied. 相似文献
9.
Analyses of bathymetry, gravity and seismic reflection data of the diffusive plate boundary in the central Indian Ocean reveal
a new kind of deformed structure besides the well-reported structures of long-wavelength anticlinal basement rises and high-angle
reverse faults. The structure (basement trough) has a length of about 150 km and deepens by up to 1 km from its regional trend
(northward dipping). The basement trough includes a rise at its center with a height of about 1.5km. The rise is about 10
km wide with rounded upper surface and bounded by vertical faults. A broad freeair gravity low of about 20 mGal and a local
high of 8 mGal in its center are associated with the identified basement trough and rise structure respectively. Seismic results
reveal that the horizontal crustal compression prevailing in the diffusive plate boundary might have formed the basement trough
possibly in early Pliocene time. Differential loading stresses have been generated from unequal crust/sediment thickness on
lower crustal and upper mantle rocks. A thin semi-ductile serpentinite layer existing near the base of the crust that is interpreted
to have been formed at mid-ocean ridge and become part of the lithosphere, may have responded to the downward loading stresses
generated by the sediments and crustal rocks to inject the serpentinites into the overlying strata to form a classic diapiric
structure. 相似文献
10.
庐枞盆地位于怀宁-庐江“磁高重高”区域异常带的枞阳-庐江异常区,其区域重力场特征与区域磁场特征明显。本文利用上述特征异常,采用重磁多尺度边缘检测方法,对庐枞盆地重力和航磁数据进行了边缘检测,得到庐枞盆地不同深度的密度和磁性信息及重磁异常边界。结合重磁异常分布特点进行构造格架的推断、基底隆起区划分,建立了庐枞盆地构造格架。认为庐枞盆地基底断裂有四组方向,以北东走向断裂为主;盆地包含四块基底隆起区和一块基底残块隆起区。在此基础上,分析了庐枞盆地主要矿集区与构造格架的关系,提出了“S”形重力高异常带是寻找中深部隐伏矿床的有利部位的新认识。 相似文献
11.
洞庭湖现代构造与湖盆演变 总被引：11，自引：0，他引：11
洞庭湖区是东南地洼区北段和华中地洼区交接处的一个地洼盆地。自白垩纪形成以来,经历次构造运动,沧桑更替。第四纪全新世早期曾为河网化平原。至１９世纪后期,主要因为断裂构造活动,使长江向南分流注入洞庭,低盈水成湖,洞庭湖进入新的励衰演变阶段。根据不同年代的卫星遥感图象解译与历史资料对比分析,现代洞庭湖区的构造运动是块断差异升降运动 。该区在先期多次构造运动中形成的断理解,在现阶段活动多转化为具张性特 相似文献
12.
The Gulf of Cadiz spans the plate boundary between Africa and Eurasia west of the Betic-Rif mountain belt. A narrow east dipping subduction zone descends beneath the Gulf of Cadiz and the straits of Gibraltar. The deep crustal structure of the Gulf and the adjacent SW Iberian and Moroccan margins is constrained by numerous multi-channel seismic reflection and wide-angle seismic surveys. A compilation of these existing studies is presented in the form of depth to basement, sediment thickness, depth to Moho and crustal thickness maps. These structural maps image an E-W trending trough, with thin (< 10 km) crust beneath the Gulf of Cadiz. This trough is filled by an eastward thickening wedge of sediments, reaching a thickness of 10-15 km in the eastern Gulf. These sediments are tectonically deformed, primarily along a series of westward-vergent thrust faults and represent a 200-250 km wide accretionary wedge. The northern and especially the southern limits of the accretionary wedge are marked by sharp morphological lineaments showing evidence of recent deformation. These tectonic limits are situated in an internal position with respect to the Miocene deformation front (external Betic and Rif allocthons), which has been abandoned. At the western boundary of the accretionary wedge, near the adjacent Seine and Horseshoe abyssal plains, an E-W trending basement high (Coral Patch Ridge) can be seen indenting the deformation front in an asymmetric manner. Analog modeling is performed using granular materials accreted against a semicircular backstop (representing the basement of the Rif and Betic mountain belts). The modeling initially produces a symmetric, arcuate accretionary wedge. The ensuing collision of an oblique rigid indenter retards accretion on one side, resulting in an embayment and a locally steeper deformation front. The deformation pattern observed in morphology and high-resolution seismic profiles suggests the accretionary wedge and underlying subduction system is still active. The implications of active subduction for the source region of the 1755 Lisbon earthquake and the regional seismic hazard assessment are discussed. 相似文献
13.
Multiple slump scars in the Tortonian type area (Piedmont Basin, northwestern Italy) 总被引：1，自引：0，他引：1
Multiple intraformational discordances, recognized in the Tortonian (Upper Miocene) type area, occur at the top of a shelf sequence, directly overlain by slope sediments. The discordances display smooth, concave upward lower surfaces and are covered by sediments identical to the surrounding strata. Inferred lateral extent of single discordances is 500–700 m. Thickness of sediments overlying the discordances ranges from 5 to 25 m. The intraformational discordances are interpreted as scars formed by downslope sliding of whole packets of strata. The slumps may have been triggered by tectonic oversteepening of shelf sediments due to tilting of the sea floor. The slump scars appear comparable in position and size to some small scale modern examples recorded on margins near the shelf-break. 相似文献
14.
The pioneer compositional analysis carried out for clayey sediments from most regional Miocene stages of the Taman trough
made it possible to define the main types of clays and trace their variability through the section. It is established that
the composition of these clays is largely controlled by the sedimentary rather than postsedimentary lithogenetic factors.
The maximal hydromica (hereafter, illite) concentrations (up to 73%) are recorded in sediments deposited during orogenesis
activation and major regressions (terminal Tarkhanian, Sarmatian, and early Pontian). The dominant role and elevated concentration
of the smectite component are characteristic of sediments corresponding to transgressive phases of the basin development.
The shallow-water sediments, which show a notable facies heterogeneity, differ from their deepwater counterparts by a higher
diversity in the clay composition. These regularities in the distribution of clay minerals may be used for the lithostratigraphic
subdivision of the sequences with a lower content of the fossil mollusc assemblages. 相似文献
15.
16.
东海西湖凹陷广泛发育中新世末形成的大型反转背斜,关于背斜成因前人多认为与外力作用有关,忽视了凹陷内部结构的影响.以重磁震资料综合解释分析为基础,系统梳理中新世末反转背斜分布及其与凹陷基底结构的关系,并结合构造物理模拟实验方法探讨基底结构差异对反转背斜发育的影响.结果表明,中新世末反转背斜与高磁性火成岩基底分布呈现出明显的相关性,且均具有南北分段差异.凹陷北段火成岩基底分布在中央洼陷-反转带内,反转背斜主要在火成岩基底东缘区发育;凹陷南段火成岩基底分布在东、西两侧边缘,反转背斜主要在边缘火成岩基底内侧发育.构造物理模拟实验结果显示,在挤压背景下,压应力通过相对刚性硅胶边缘释放,控制挤压背斜褶皱的形成;表明不同岩性基底所产生的抗压强度差异能显著影响反转背斜分布.最终提出在挤压背景下,高磁性、高抗压强度的火成岩基底所引起的局部构造应力场改变是决定中新世末反转背斜强弱分布的关键因素. 相似文献
17.
多源地学数据包括遥感、地球化学和地球物理数据,介绍了利用多源地学数据进行造山带构造单元划分的方法。遥感数据在确定区域构造边界及活动断层方面的应用非常广泛,遥感影像在解译线形构造即断层方面有非常明显的效果,可以根据不同构造单元的影像差异,区分不同的地质体、线性构造及活动断层,同时用遥感数据叠加三维地形数据分析线性构造可以更加直观地解译线性构造。地球化学数据在确定大的构造边界方面具有一定的指示意义,可以根据水系沉积物的地球化学特点,运用因子分析方法确定大的构造边界。地球物理数据提供的是地质体及构造边界在深部的延伸情况,可以为研究断裂的运动学和动力学特征提供证据。 相似文献
18.
E. A. Vangengeim A. N. Lungu A. S. Tesakov 《Stratigraphy and Geological Correlation》2006,14(6):655-667
The Vallesian lower boundary and “Hipparion-datum” are estimated as ranging in age from 11.2 to 10.7 Ma in Central to Western Europe and Western Asia. Judging from complete sections of Sarmatian marine sediments in the Tamanskii Peninsula and Transcaucasia with known paleomagnetic characteristics, the above dates correspond to the lower upper Sarmatian (Khersonian) of the Eastern Paratethys, although in Moldova and Ukraine the earliest hipparion remains are associated with the middle Sarmatian (Bessarabian) sediments. The normally magnetized middle Sarmatian deposits in hipparion localities of Moldova are correlative with an upper part of Chron C5An (upper boundary 11.9 Ma old) or, less likely, with Subchron C5r2n (base 11.5 Ma old). Consequently, the first occurrence of hipparions in southeastern Europe is recorded in the Middle Miocene, i.e., 0.7 m.y. (or 0.3 m.y.) earlier than the date of 11.2 Ma formerly accepted for the Vallesian lower boundary in Europe. Possible reasons for disagreements in age determination of the Vallesian base are discussed. 相似文献
19.
钟凌林 钟康惠 秦覃 严钊 杨雄 何智远 张洪杰 彭杰 Johan De GRAVE Stijn DEWAELE 周慧文 何兴杰 韩文文 龚晓波 杨海锐 董随亮 常宇鹏 李开智 窦杰 李林 何明峰 刘毅龙 《地学前缘》2022,29(1):266-284
雅鲁藏布江洋俯冲及印度-欧亚陆陆碰撞导致了强烈的大陆岩石圈挤压变形与青藏高原的隆升。研究青藏高原内部破碎带构造-沉积演化,对理解相关变形如何向欧亚大陆腹地扩展传递至关重要。班公湖—怒江缝合带内发育一系列白垩纪—新生代陆相沉积盆地,保存了关于该时期高原内部构造-沉积演化的丰富信息。针对该类盆地的构造性质和形成机制有走滑拉分盆地、断陷盆地、前陆盆地3类不同观点。若要检定上述观点,需要开展如下工作:(1)查明盆地基底与充填建造变形特征;(2)结合构造背景探究其演化机制。鉴于此,本文对该带内尼玛盆地开展大比例尺地质填图与构造分析,结合前人成果,对盆地构造背景、构造性质和构造演化进行了探讨。主要取得了如下认识:(1)尼玛盆地基底为班公湖—怒江洋闭合形成的软碰撞缝合带内的变质岩与海相沉积岩。基底断裂为近东西走向,倾向或南或北的逆冲断裂。(2)盆地充填建造为上白垩统—新近系多旋回河湖相沉积。其变形样式主要为轴向近东西延伸的非对称褶皱,局部卷入基底断裂变形。多幕次变形自边缘向盆地中心前展式递进发展。(3)盆地可以划分为盆北掀斜隆起、南部推覆扇状隆起两处主要剥蚀物源区、中部基底断片掀斜隆起一处次要剥蚀物源区,以及北部叠瓦状压陷区与南部对冲压陷区两处主要构造沉积单元,其构造格架可以概括为“三隆夹两坳”。(4)尼玛盆地肇始于班公湖—怒江洋闭合导致的南北向地壳缩短。其后,雅鲁藏布江洋北向俯冲与印度-欧亚碰撞所致南北向挤压,导致盆地基底断裂发生周期性活动,伴有多旋回磨拉石建造与递进变形。简言之,尼玛盆地为软碰撞缝合带之上发育的山间压陷盆地。 相似文献
20.
S. V. Popov M. P. Antipov A. S. Zastrozhnov E. E. Kurina T. N. Pinchuk 《Stratigraphy and Geological Correlation》2010,18(2):200-224
Sea-level fluctuations in the terminal Eocene, Oligocene, and Neogene of the Eastern Paratethys are quantitatively assessed
on the basis of facies and old coastlines traced on the northern platform shelf, levels of river valley incisions, and the
study of seismic profiles. The first data massif allows the characterization and correlation of transgression stages in the
history of the Eastern Paratethys. The greatest transgressions fall within the first half of the Late Eocene, mid-Early Oligocene,
initial Late Oligocene, initial Early Miocene, the initial Tchokrakian, Karaganian and Sarmatian in the Middle Miocene, the
middle and late Sarmatian and early Pontian in the Late Miocene, and the Akchagylian in the Caspian basin of the Pliocene.
In contrast, the greatest incisions of northern rivers running from the platform allow us to establish the time and extent
of the main declines in the base levels of the erosion. Maximal incisions date back to the terminal Eocene-initial Oligocene,
terminal Solenovian time in the terminal Rupelian, the terminal Maikop in the Early Miocene, the terminal Sarmatian and middle
Pontian in the Late Miocene, and the Early Pliocene in the Caspian basin. Large regressions also formed unconformity surfaces,
traced on seismic profiles as erosion boundaries of several orders. The surfaces are confined to the Eocene/Oligocene boundary,
middle and late Maikop, Sarmatian/Meotian boundary, middle Pontian, and terminal Miocene-initial Pliocene, as well as being
traced even in the most deep-water basins. The synthesis of these data suggests a preliminary version for the curve of transgression-regression
cyclicity. Its correlation with the eustatic curve shows their similarity only in the lower part-prior to the initial Middle
Miocene, when Paratethys became a semi-closed basin. 相似文献