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1.
The Black Sea region comprises Gondwana-derived continental blocks and oceanic subduction complexes accreted to Laurasia. The core of Laurasia is made up of an Archaean–Palaeoproterozoic shield, whereas the Gondwana-derived blocks are characterized by a Neoproterozoic basement. In the early Palaeozoic, a Pontide terrane collided and amalgamated to the core of Laurasia, as part of the Avalonia–Laurasia collision. From the Silurian to Carboniferous, the southern margin of Laurasia was a passive margin. In the late Carboniferous, a magmatic arc, represented by part of the Pontides and the Caucasus, collided with this passive margin with the Carboniferous eclogites marking the zone of collision. This Variscan orogeny was followed by uplift and erosion during the Permian and subsequently by Early Triassic rifting. Northward subduction under Laurussia during the Late Triassic resulted in the accretion of an oceanic plateau, whose remnants are preserved in the Pontides and include Upper Triassic eclogites. The Cimmeride orogeny ended in the Early Jurassic, and in the Middle Jurassic the subduction jumped south of the accreted complexes, and a magmatic arc was established along the southern margin of Laurasia. There is little evidence for subduction during the latest Jurassic–Early Cretaceous in the eastern part of the Black Sea region, which was an area of carbonate sedimentation. In contrast, in the Balkans there was continental collision during this period. Subduction erosion in the Early Cretaceous removed a large crustal slice south of the Jurassic magmatic arc. Subduction in the second half of the Early Cretaceous is evidenced by eclogites and blueschists in the Central Pontides and by a now buried magmatic arc. A continuous extensional arc was established only in the Late Cretaceous, coeval with the opening of the Black Sea as a back-arc basin. 相似文献
2.
The continental margins of Atlantic Canada described in this paper show the effects of plate tectonic motions since Precambrian time and thus represent an ideal natural laboratory for geophysical studies and comparisons of ancient and modern margins. The Grenville Province shows vestiges of Helikian sedimentation on a pre-existing continental block beneath which there may have been southeastward late-Helikian subduction resulting in collision between the Grenville block and the continental block comprised of the older shield provinces to the north. The Grenville block was subsequently split in Hadrynian time along an irregular line so that the southeastern edge of the Grenville exhibited a series of promontories and re-entrants similar to those seen at the present Atlantic continental margin of North America. That margin, which had a passive margin history perhaps comparable with that of the present Atlantic margin, was separated by the lapetus ocean from the Avalon zone whose Precambrian volcanism has been attributed both to that associated with an island arc and with intra-cratonic rifting. However, the lapetus ocean appears to have been subducted in early Paleozoic time with a southeastward dip beneath the Avalon zone, leaving exposures of oceanic rocks in place as in Notre Dame Bay, or transported onto Grenville basement as at Bay of Islands.Plate motions proposed for Devonian and Carboniferous time are numerous, but resulted in the welding of the Meguma block to the Avalon zone of New Brunswick and northern Nova Scotia, extensive faulting within Atlantic Canada which can be correlated with contemporaneous European faulting and extensive terrestrial sedimentation within the fault zones. Graben formation, continental sedimentation and basaltic intrusion in the Triassic represent the tensional prelude to the Jurassic opening of the present Atlantic Ocean.This Jurassic opening produced a rifted margin adjacent to Nova Scotia and a transform margin along the southern Grand Banks. The width of the ocean-continent transition across the transform margin (approx. 50 km) is narrower than for the rifted margin (approx. 100 km). The eastern part of the transform margin is associated with a complex Cretaceous (?) volcanic province of seamounts and basement ridges showing evidence of subsidence. The western portion of the transform margin is non-volcanic, adjacent to which lies the 350 km wide Quiet Magnetic Zone floored by oceanic crust.Development of the margin east of Newfoundland was more complicated with continental fragments separated from the shelf by deep water basins underlain by foundered and atypically thin continental crust. Although thin, the crust appears unmodified, the similarities between the crustal sections of the narrow Flemish Pass and the wide Orphan Basin suggesting that the thinning is not simply due to stretching. The Newfoundland Basin shows evidence for two-stage rifting between the Grand Banks and Iberia with both lateral separation and rotation of Spain, leaving a wide zone of transitional crust in the south. The overall pattern of variations in crustal section for the margin east of Newfoundland is comparable with that of the British margin against which it is located on paleogeographical reconstructions.The major sedimentary unconformities on the shelves (such as the Early Cretaceous unconformity on the Grand Banks) reflect uplift accompanying rifting. Tracing of the sedimentary horizons across the shelf edge is complicated by paleocontinental slopes, which separate miogeocline and eugeocline depositional environments. The subsidence of the rifted margins is primarily due to cooling of the lithosphere and to sediment loading. The subsidence due to cooling has been shown to vary linearly with (time)
, similar to the depth—age behaviour of oceanic crust. The consequent thermal history of the sediments is favourable for hydrocarbon generation where other factors do not preclude it. 相似文献
3.
The Late Cretaceous Brezová and Myjava Groups of the Western Carpathians in Slovakia and formations of the Gosau Group of the Northern Calcareous Alps in Lower Austria comprise similar successions of alluvial/shallow marine deposits overlain by deep water hemipelagic sediments and turbidites. In both areas the heavy mineral spectra of Late Cretaceous sediments contain significant amounts of detrital chrome spinel. In the Early Tertiary the amount of garnet increases. Cluster analysis and correspondence analysis of Coniacian/Santonian and Campanian/Early Maastrichtian heavy mineral data indicate strong similarities between the Gosau deposits of the Lunz Nappe of the north-eastern part of the Northern Calcareous Alps and the Brezova Group of the Western Carpathians. Similar source areas and a similar palaeogeographical position at the northern active margin of the Adriatic/Austroalpine plate are therefore suggested for the two tectonic units.Basin subsidence mechanisms within the Late Cretaceous of the Northern Calcareous Alps are correlated with the Western Carpathians. Subsidence during the Campanian-Maastrichtian is interpreted as a consequence of subduction tectonic erosion along the active northern margin of the Adriatic/Austroalpine plate. Analogous facies and heavy mineral associations from deep water sandstones of the Manin Unit and the Klape Unit indicate accretion of parts of the Pieniny Klippen Belt during the Late Cretaceous along the Adriatic/Austroalpine margin. 相似文献
4.
N. Kharazizadeh W. P. Schellart J. C. Duarte M. Hall 《Australian Journal of Earth Sciences》2016,63(2):159-174
The southern margin of Australia is a passive continental margin, formed during a Late Jurassic–Cretaceous rifting phase. The development of this passive margin is mainly associated with extensional processes that caused crustal thinning. In this work, we have measured the amount of extension and the stretching factor (β factor) across seven transect profiles approximately evenly distributed across the margin. The obtained results show that the amount of extension and the β factor along the margin vary from west to east. The lowest amount of extension, low–intermediate β factors and a very narrow margin are observed in the western part with 80 km of extension and is underlain mostly by the Archean Yilgarn Craton and the Albany–Fraser Orogen. The Gawler Craton in the centre of the south Australian margin is another region of low extension and low–intermediate β factor. The largest amount of extension (384 km) and the largest β factor (β = 1.88) are found in the eastern part of the passive margin in an area underlain by Phanerozoic Tasman Orogen units. Our results imply that there is a strong control of the age and thickness of the continental lithosphere on the style of rifting along the Australian passive margin. Rifting of old and cold lithosphere results in a narrow passive margin, with the formation of relatively few faults with relatively wide spacing, while rifting of younger, warmer lithosphere leads to wide rifting that is accommodated by a large number of faults with small spacing. 相似文献
5.
目前对珠江口盆地中生代以来的演化过程及其与沉积环境演变的响应关系尚缺乏系统性认识.基于珠江口盆地中-新生代岩浆活动、断陷结构样式及其改造、典型构造变形样式、沉积中心的转换等特征的对比分析,将盆地中-新生代的构造演化划分为4个阶段、7个期次:（1）中侏罗世-晚白垩世早期（~170~90 Ma）为古太平洋板块俯冲主控的陆缘岩浆弧-弧前盆地演化阶段;（2）晚白垩世-始新世中期（~90~43 Ma）为太平洋板块俯冲后撤背景下弧后周缘前陆/造山后塌陷-主动裂谷演化阶段;（3）始新世中期-中中新世（~43~10 Ma）为华南挤出-古南海俯冲拖曳主导的被动陆缘演化阶段;（4）晚中新世以来（~10~0 Ma）为菲律宾板块NWW向仰冲主导的挤压张扭演化阶段.~90 Ma、~43 Ma、~10 Ma分别实现了由安第斯型俯冲向西太平洋型俯冲、由主动裂谷向被动陆缘伸展、由被动陆缘伸展向挤压张扭的转换.在此过程中,伴随着古南海和南海的发育-消亡,新生代裂陷期沉积环境由东向西、由南向北逐渐海侵,裂后期由南向北阶段性差异沉降,由陆架浅水向陆坡深水转换,这使得珠一/三、珠二、珠四坳陷的石油地质条件具有显著的分带差异性. 相似文献
6.
本篇讨论大陆岩石圈拆沉、伸展与裂解作用过程。由于大陆岩石圈厚度大而且很不均匀,产生裂谷的机制比较复杂。大陆碰撞远程效应的触发,岩石圈拆沉,以及板块运动的不规则性和地球应力场方向转折,都可能产生岩石圈断裂和大陆裂谷。岩石圈拆沉为在重力作用下"去陆根"的作用过程,演化过程可分为大陆根拆离、地壳伸展和岩石圈地幔整体破裂三个阶段。大陆碰撞带、俯冲的大陆和大洋板块、克拉通区域岩石圈,都可能产生岩石圈拆沉。大陆岩石圈调查表明,拉张区可见地壳伸展、岩石圈拆离、软流圈上拱和热沉降;它们是大陆岩石圈伸展与裂解早期的主要表现。从初始拉张的盆岭省到成熟的张裂省,拆离后地壳伸展成复式地堑,下地壳幔源玄武岩浆侵位,断裂带贯通并切穿整个岩石圈,表明地壳伸展进入成熟阶段。中国东北松辽盆地和西欧北海盆地曾处于成熟的张裂省。岩石圈破裂为岩浆侵位提供了阻力很小的通道网。岩浆侵位作用伴随岩石圈破裂和热流体上涌,成熟的张裂省可发展成大陆裂谷。多数的大陆裂谷带并没有发展成威尔逊裂谷带和洋中脊,普通的大陆裂谷要演化为威尔逊裂谷带,必须有来自软流圈的长期和持续的热流和玄武质岩浆的供应。威尔逊裂谷带岩石圈地幔和软流圈为地震低速带,其根源可能与来自地幔底部的地幔热羽流有关。 相似文献
7.
松辽盆地位于中国东北,是晚中生代在活动大陆边缘上发育的裂谷-坳陷盆地。松辽盆地有两个特点:一是裂谷期前火山岩分布以盆地西部的大兴安岭厚度大、面积大,盆地东部靠近俯冲边缘火山岩分布厚度、面积变小;二是裂谷期主要发育东倾控坳断层。由此推测在板块俯冲牵引作用下,在楔形区产生单向环流。单向环流在大兴安岭一带上升,在地表形成强烈的火山作用,然后沿岩石圈底部向东运动,并逐渐转变为下降流,火山作用也逐渐减弱。单向环流由上升流逐渐转入近平流后,对岩石圈底面施加单向剪切牵引作用,岩石圈伸展在脆性上地壳形成主要东倾控坳断层。单向环流可以源源不断地从深部将热能和动能带到浅部,满足岩石圈减薄和伸展的需要。而且用单向环流解释活动大陆边缘和弧后区火山岩的成分极性可能更趋于实际。 相似文献
8.
In western Tasmania, small Precambrian regions are surrounded by a ramifying system of troughs filled with Cambrian sedimentary and volcanic rocks, and ophiolite complexes. The volcanic associations include a rift-related olivine tholeiite association, dacite-rhyolite and andesite associations, and a low-Ti, high-Mg andesite-tholeiite ophiolite association, and may have formed during a long-lived period of crustal thinning, punctuated by episodes of crustal rupturing, magmatism, and small scale rifting. Such extensional tectonism could occur in an active continental margin associated with strike-slip faulting of regional scale, and the volcanic associations may together constitute an igneous assemblage characteristic of magmatism in a transcurrent tectonic regime within an active continental margin undergoing break-up.
The western Tasmanian Cambrian palaeogeography and volcanism preserve a transitional stage between the Late Proterozoic Kanmantoo regime of sedimentary basins with little volcanism developed at the rifting margin of the Proterozoic craton, and the tectonic regime of the Palaeozoic Lachlan Fold Belt where the Cambrian volcanic rocks are dominated by island-arc associations and the rift-related olivine tholeiite association is absent. Eastern Australian lithosphere may have grown by the insertion of newly-formed igneous complexes within the stretched and rifted continental margin, as well as by the accretion of “terrenes” and the addition of packets of subduction complexes which developed off-shore. 相似文献
9.
Three sources of stress at active (Andean) continental margins are considered: body forces on the plates which drive their motion, thermal stresses generated within the cooling lithosphereand bending stresses due to the flexure of the lithosphere at an ocean trench. It is argued that the bending stresses dominate. The evolution of passive (Atlantictype) continental margins is also considered. Models for the free and locked flexure of the continental and oceanic lithosphere are given. Based on observed gravity anomalies, it is argued that the continental margin fault system must remain active throughout much of the evolution of the margin. These displacements accommodate both the subsidence of the oceanic lithosphere due to its cooling and thickeningand the sedimentary loading. This loading may be responsible for the seismicity on the eastern continental margin of the United States e.g., the Charleston, South Carolina earthquake of 1884. 相似文献
10.
位于青藏高原南部的冈底斯岩浆弧形成于中生代新特提斯大洋岩石圈的长期俯冲过程中,而且在印度与亚洲大陆碰撞过程中叠加了强烈的新生代岩浆作用,是世界上典型的复合型大陆岩浆弧,已经成为研究汇聚板块边缘岩浆作用和大陆地壳生长与再造的天然实验室。基于对现有研究成果的总结,我们将冈底斯岩浆弧的岩浆构造演化划分为5个阶段：第1阶段发生在晚白垩世之前,以新特提斯洋岩石圈长期正常俯冲和钙碱性弧岩浆岩的发育为特征;第2阶段发生在晚白垩世时期,以活动的新特提斯洋中脊发生俯冲和强烈的岩浆作用与显著的新生地壳生长为特征;第3阶段发生在晚白垩世晚期,以残余的新特提斯大洋岩石圈俯冲和正常弧型岩浆作用为特征;第4阶段发生在古新世至中始新世,以印度与亚洲大陆碰撞、俯冲的新特提斯洋岩石圈回转和断离,及其诱发的幔源岩浆作用、新生和古老地壳的强烈再造为特征;第5阶段为发生在晚渐新世到中中新世的后碰撞阶段,深俯冲印度岩石圈的回转和断离,或加厚岩石圈地幔的对流移去导致了加厚下地壳的部分熔融和埃达克质岩石的广泛发育,同时伴随幔源钾质超钾质岩浆作用。冈底斯弧岩浆作用与岩浆成分的系统时空变化很好地记录了从新特提斯洋俯冲到印度亚洲大陆碰撞的完整构造演化过程。 相似文献
11.
Marián Putiš Hans-Jürgen Gawlick Wolfgang Frisch Marián Sulák 《International Journal of Earth Sciences》2008,97(4):799-819
The Cretaceous orogen of the Western Carpathians comprises fragments of the destructed northern Centrocarpathian domain, which
is defined as Infratatric unit and formed a continental margin facing the Penninic Ocean in Jurassic and Cretaceous times.
The breakup event and opening of the Penninic Ocean occurred in the Early Jurassic (Pliensbachian), which is recorded by an
abrupt deepening event from shallow-water sediments to deep-water nodular limestone in the Infratatric sediment succession.
The transformation of the passive into an active continental margin by the onset of subduction of the Penninic oceanic crust
occurred in Santonian times and is reflected by the beginning of flysch deposition in the Infratatric Belice domain, which
took the position of a forearc basin in the convergent margin setting. The forearc basin was supplied by clastic material
from the more internal part of the Infratatric unit, which experienced nappe stacking, metamorphism, and subsequent exhumation
in Late Cretaceous times. In the frontal part of the forearc basin an accretionary wedge was built up, which formed an outer-arc
ridge and delivered detrital material into the forearc basin in Maastrichtian time. Final collision between the European and
the Adriatic plate occurred in the Eocene period and is responsible for weak metamorphism in the Infratatric unit. 相似文献
12.
The Late Tertiary history of the Mediterranean region exemplifies processes of ocean basin closure and continental collision, as determined from integrated land and marine evidence. During the Mesozoic–Early Tertiary, tectonic settings were dominated by evolution of Neotethys. This ocean generally widened eastwards, with a number of oceanic strands in the Eastern Mediterranean area. Great diversity of tectonic settings and palaeo-environments developed during the Tertiary closure history of these oceanic basins. In the Eastern Mediterranean region, more northerly Neotethyan strands were closed by the Mid Tertiary, while oceanic crust remained in the south in the present Eastern Mediterranean Sea area. Northwards subduction of the remaining southerly Neotethyan strand was probably active by the Early Miocene. Different areas exhibit different stages of convergence and ocean basin closure. In the east, the amalgamated Eurasian plate had collided with the Arabian margin (Africa) by the Late Miocene, while oceanic crust still persisted further west. Steady-state subduction during the Late Tertiary gave rise to the Mediterranean ridge, as a substantial mud-dominated accretionary wedge. In the Aegean area, sufficient northward subduction took place to activate arc volcanism and pervasive back arc extension, short of marginal basin opening. In the easternmost Mediterranean, only limited subduction took place, associated with supra-subduction zone extension (e.g. in Cyprus). Today, steady state-subduction continues only locally, where vestiges of Neotethys remain (e.g. Herodotus abyssal plain). In the Western Mediterranean area, suturing of the African and Eurasian plates initially took place in the Betic region (Early–Mid Tertiary), where the Neotethys had existed only as a narrow connection with the Central North Atlantic. In the Central Mediterranean region, where the Western Neotethys was wider, northward subduction was active, apparently as early as the Late Cretaceous. In a widely accepted interpretation, an Andean-type magmatic arc developed along the southern margin of Europe and was then rifted off in the Late Oligocene-Early Miocene, to form the Corsica-Sardinia Block, opening the North Balearic marginal basin in its wake. The migrating subduction zone and microcontinent then collided diachronously with North Africa-related continental units (North Africa and Apulia) from Late Oligocene-Early Miocene, giving rise to collisional thrust belts in the Northern and Southern Apennines and along the North African continental margin (i.e. the Maghrebian chain) to the Betic-Rif area. From the Early Miocene onwards, a separate subduction system became active, related to removal of Neotethyan oceanic crust to the southeast (Ionian Sea), fueling suprasubduction zone extension and opening of the Tyrrhenian Sea. ‘Orogenic collapse’ is an alternative mechanism of such extension, and is widely believed to have caused divergent thrusting in the Betic and Rif regions of the westernmost Mediterranean, at the same time as crustal extension and subsidence of the Alboran Sea. 相似文献
13.
《地学前缘(英文版)》2022,13(6):101454
Southeastern Eurasia is a global window to the Cretaceous paleoclimate and lithosphere coupling. China contains one of the most complete and complex sedimentary records of Mesozoic desert basins on planet Earth. In this study, we perform the spatio-temporal tracking of 96 Cretaceous palaeoclimate indicators during 79 Myr which reveal that the plateau paleoclimate archives from East Asia resulted from an Early to Mid-Cretaceous ocean–atmosphere coupling and a shift to a preponderant role of Late Cretaceous lithosphere dynamics and tectonic forcing on high-altitude depositional systems linked to the subduction margins of the Tethys and Paleo-Pacific realms beneath the Eurasian plate. The crustal response to tectonic processes linked with the spatio-temporal evolution of the Tethyan and Paleo-Pacific margins defined the configuration of major sedimentary basins on this region. The significant increase and decrease in the number of active sedimentary basins that occur during the Cretaceous, from 16 in the Early Cretaceous, to 28 in the Mid-Cretaceous, and a decreasing to 20 sedimentary basins in the Late Cretaceous, is a direct response of lithospheric dynamics associated with the two main subduction zones (Tethys and Pacific domains). A shift in subduction style from an Early Cretaceous Paleo-Pacific Plate slab roll back to a Late Cretaceous flat-slab mode might have triggered regional plateau uplift, blocked intraplate volcanism, thus enhancing the denudation and sediment availability, and created wind corridors that led to the construction and accumulation of extensive Late Cretaceous aeolian sandy deserts (ergs) that covered Mid-Cretaceous plateau salars. At the same time, plateau uplift associated with crustal thickening following terrane assembly in the Tethyan margin triggered altitudinal cryospheric processes in sandy desert systems. Evidence of an active Cretaceous cryosphere in China include Valanginian-Hauterivian glacial debris flows, Early Aptian geochemical signature of melt waters from extensive ice sheets, and Cenomanian–Turonian ice-rafted debris (IRD). These cryospheric indicators suggest an already uplifted plateau in southeastern Eurasia during the Cretaceous, and the marked correlation between cold plateau paleoclimate archives and marine records suggests a strong ocean-atmosphere coupling during Early and Mid-Cretaceous cold snaps. We thus conclude that lithospheric tectonics during Cretaceous played a fundamental role in triggering high-altitude basin desertification and spatio-temporal plateau paleohydrology variability in the Cretaceous of south-eastern Eurasia. 相似文献
14.
The Yarlung–Zangbo Suture Zone, a major geological structure in Tibet, is well known as the locus of tectonic emplacement of the Tethyan ophiolites. Current models propose that most of the East Tethyan oceanic lithosphere was subducted within a single subduction zone, active during the Middle or Late Cretaceous, which was completed during the Paleogene collision between India and Asia. The Early Cretaceous sedimentary Giabulin Formation in southern Tibet, includes conglomeratic members that contain ultramafic and mafic plutonic pebbles, as well as radiolarian chert clasts, that record the erosion of oceanic lithosphere involved in a subduction event which occurred earlier than previously believed. Geochemical analyses, mineral chemistry, stratigraphic chronology, and sedimentary analysis, including source provenance, suggest that the pebbly conglomerate was formed through erosion of an unknown ophiolitic source that was geochemically distinguishable from the Xigaze ophiolites within the Yarlung–Zangbo Suture Zone, southern Tibet. We infer the existence of an older ophiolitic source, termed the Yarlung–Zangbo paleo-ophiolite, that was dismembered and eroded during an earlier subduction stage not taken into account in current models. 相似文献
15.
文章评述了增生造山作用的研究历史和进展,认为增生造山作用贯穿地球历史,是大陆增生的重要方式。用大陆边缘多岛弧盆系构造理解造山带的形成演化,提出巨型造山系的形成与长期发育的大洋岩石圈俯冲制约的两侧或一侧的多岛弧盆系密切相关。在多岛弧盆系演化过程中的弧 弧和弧 陆碰撞,弧前和弧后洋盆的消减冲杂岩的增生,洋底高原、洋岛/海山、外来地块(体)拼贴等一系列碰撞和增生造山作用形成大陆边缘增生造山系。大洋岩石圈最终消亡形成对接消减带,大洋岩石圈两侧的多岛弧盆系转化的造山系对接形成造山系的联合体。拼接完成后往往要继续发生大陆之间的陆 陆碰撞造山作用、陆内汇聚(伸展)作用,后者叠加在增生造山系上,使造山过程更加复杂。对接消减带是认识造山系形成演化的关键。大洋两侧多岛弧盆系经历的各种造山过程可以从广义上理解为一个增生造山过程。多岛弧盆系研究对于划分造山带细结构非常重要,是理解造山系物质组成、结构和构造的基础,并制约了造山后陆内构造演化。大陆碰撞前大洋两侧多岛弧盆系及陆缘系统更完整地记录了威尔逊旋回,记录的信息更加丰富。根据多岛弧盆系的思路对特提斯大洋演化提出新的模式,认为西藏冈底斯带自石炭纪以来受到特提斯大洋俯冲制约,三叠纪发生向洋增生造山作用,特提斯大洋于早白垩世末最终消亡。 相似文献
16.
Intraplate compressional features, such as inverted extensional basins, upthrust basement blocks and whole lithospheric folds, play an important role in the structural framework of many cratons. Although compressional intraplate deformation can occur in a number of dynamic settings, stresses related to collisional plate coupling appear to be responsible for the development of the most important compressional intraplate structures. These can occur at distances of up to ±1600 km from a collision front, both in the fore-arc (foreland) and back-arc (hinterland) positions with respect to the subduction system controlling the evolution of the corresponding orogen. Back-arc compression associated with island arcs and Andean-type orogens occurs during periods of increased convergence rates between the subducting and overriding plates. For the build-up of intraplate compressional stresses in fore-arc and foreland domains, four collision-related scenarios are envisaged: (1) during the initiation of a subduction zone along a passive margin or within an oceanic basin; (2) during subduction impediment caused by the arrival of more buoyant crust, such as an oceanic plateau or a microcontinent at a subduction zone; (3) during the initial collision of an orogenic wedge with a passive margin, depending on the lithospheric and crustal configuration of the latter, the presence or absence of a thick passive margin sedimentary prism, and convergence rates and directions; (4) during post-collisional over-thickening and uplift of an orogenic wedge. The build-up of collision-related compressional intraplate stresses is indicative for mechanical coupling between an orogenic wedge and its fore- and/or hinterland. Crustal-scale intraplate deformation reflects mechanical coupling at crustal levels whereas lithosphere-scale deformation indicates mechanical coupling at the level of the mantle-lithosphere, probably in response to collisional lithospheric over-thickening of the orogen, slab detachment and the development of a mantle back-stop. The intensity of collisional coupling between an orogen and its fore- and hinterland is temporally and spatially variable. This can be a function of oblique collision. However, the build-up of high pore fluid pressures in subducted sediments may also account for mechanical decoupling of an orogen and its fore- and/or hinterland. Processes governing mechanical coupling/decoupling of orogens and fore- and hinterlands are still poorly understood and require further research. Localization of collision-related compressional intraplate deformations is controlled by spatial and temporal strength variations of the lithosphere in which the thermal regime, the crustal thickness, the pattern of pre-existing crustal and mantle discontinuities, as well as sedimentary loads and their thermal blanketing effect play an important role. The stratigraphic record of collision-related intraplate compressional deformation can contribute to dating of orogenic activity affecting the respective plate margin. 相似文献
17.
《Geodinamica Acta》2013,26(1-2):71-97
Most of the tectonic units cropping out in Western Tuscany are fragments of the Jurassic oceanic crust, ophiolitic successions, overlaid diachronously by Upper Cretaceous-middle Eocene carbonate and siliciclastic flysch successions with their Cenomanian-lower Eocene shalycalcareous basal complexes. These units, so called Ligurian, have been emplaced during the closure of the Ligurian-Piedmont Ocean. Ophiolite bearing debris flows are common in the flysch basins and their relationship with ophiolitic tectonic slices points to a strong relation between tectonics and sedimentation from the early compressive events of the Late Cretaceous. The tectonic activity reflects in a rough morphology of the ocean floor. It progressively influences the distribution and sedimentology of the turbidites. During middle Eocene this relationship begun very important and a paleogeographic reconstruction with prominent linear ophiolitic reliefs that bounded some turbiditic basins can be done. In our reconstruction the sedimentary and structural evolution can be framed in the context of strain partitioning, developed during the ocean closure, between subduction processes and ancient weakness zones crosscutting both the ocean and the Adria continental margin and reactivated in compressive regime. These weakness zones can be interpreted as transform faults of the Ligurian-Piedmont Ocean with prolongations in the Adria passive margin. The weakness zones crosscut the oceanic lithosphere and the Adria continental margin and interfered with the subduction processes. The activity of the weakness zones is reflected in the Ligurian Units architecture where two main structural strike trends of thrusts and folds axial planes occur. The first trend is WSW-ENE oriented and it is connected with the reactivation of the weaknesses zones. This first orientation developed progressively from Late Cretaceous to Pliocene, from oceanic to ensialic convergence (D1, D2, and D4 deformation phases). The second trend is NNE-SSW oriented and is related to the late Eocene continental collision and the subsequent translation to the NE of the oceanic units onto the Adria continental margin (D3 deformation phase). 相似文献
18.
Plate tectonic evolution of the southern margin of Eurasia in the Mesozoic and Cenozoic 总被引：4，自引：0，他引：4
Thirteen time interval maps were constructed, which depict the Triassic to Neogene plate tectonic configuration, paleogeography and general lithofacies of the southern margin of Eurasia. The aim of this paper is to provide an outline of the geodynamic evolution and position of the major tectonic elements of the area within a global framework. The Hercynian Orogeny was completed by the collision of Gondwana and Laurussia, whereas the Tethys Ocean formed the embayment between the Eurasian and Gondwanian branches of Pangea. During Late Triassic–Early Jurassic times, several microplates were sutured to the Eurasian margin, closing the Paleotethys Ocean. A Jurassic–Cretaceous north-dipping subduction boundary was developed along this new continental margin south of the Pontides, Transcaucasus and Iranian plates. The subduction zone trench-pulling effect caused rifting, creating the back-arc basin of the Greater Caucasus–proto South Caspian Sea, which achieved its maximum width during the Late Cretaceous. In the western Tethys, separation of Eurasia from Gondwana resulted in the formation of the Ligurian–Penninic–Pieniny–Magura Ocean (Alpine Tethys) as an extension of Middle Atlantic system and a part of the Pangean breakup tectonic system. During Late Jurassic–Early Cretaceous times, the Outer Carpathian rift developed. The opening of the western Black Sea occurred by rifting and drifting of the western–central Pontides away from the Moesian and Scythian platforms of Eurasia during the Early Cretaceous–Cenomanian. The latest Cretaceous–Paleogene was the time of the closure of the Ligurian–Pieniny Ocean. Adria–Alcapa terranes continued their northward movement during Eocene–Early Miocene times. Their oblique collision with the North European plate led to the development of the accretionary wedge of the Outer Carpathians and its foreland basin. The formation of the West Carpathian thrusts was completed by the Miocene. The thrust front was still propagating eastwards in the eastern Carpathians.During the Late Cretaceous, the Lesser Caucasus, Sanandaj–Sirjan and Makran plates were sutured to the Iranian–Afghanistan plates in the Caucasus–Caspian Sea area. A north-dipping subduction zone jumped during Paleogene to the Scythian–Turan Platform. The Shatski terrane moved northward, closing the Greater Caucasus Basin and opening the eastern Black Sea. The South Caspian underwent reorganization during Oligocene–Neogene times. The southwestern part of the South Caspian Basin was reopened, while the northwestern part was gradually reduced in size. The collision of India and the Lut plate with Eurasia caused the deformation of Central Asia and created a system of NW–SE wrench faults. The remnants of Jurassic–Cretaceous back-arc systems, oceanic and attenuated crust, as well as Tertiary oceanic and attenuated crust were locked between adjacent continental plates and orogenic systems. 相似文献
19.
徐强 刘宝珺 余光明 G. Einsele W. Frisch 刘光华 J. Wendt A. Wetzel L. Ratschbacher H. P. Luterbacher 《沉积与特提斯地质》1993,(1):58-65
喜马拉雅特提斯中、新生代属印度板块北部被动大陆边缘。对充填这个被动大陆边缘的沉积物用“反剥法”(backstrippiog)进行研究,恢复了从被动大陆边缘到前陆盆地的抓降史。对分离出的盆地构造沉降曲线与McKenzie模式图版进行对比相关性分析,判断认为被动大陆边缘成熟期主要为热耗散沉降,前陆盆地时逆冲推覆动力为主要影响因素。 相似文献
20.
冈底斯弧弧后早白垩世裂谷作用的沉积学证据 总被引：9，自引：0，他引：9
冈底斯弧弧后地区早白垩世地层的一个显著特点是 ,由下而上普遍从陆相 -海陆交互相碎屑岩变化为海相碳酸盐岩。该地区在早白垩世中期开始了广泛的海侵 ,沉积范围由早期仅局限于班公湖 -怒江缝合带附近而扩展至羌塘地体南缘和拉萨地体 ,沉积了巨厚的台地相灰岩 ;与塔里木南部和思茅地区同期海平面变化非常不同 ,那里在晚白垩世才出现海侵。砂岩组分研究显示 ,早白垩世早期碎屑物源主要来自北侧的造山带 ,向上则逐步受到南侧火山弧的控制。在海侵层系的下部 ,发现了丰富的双峰型火山岩和双峰式火山岩碎屑。因而推断该区在早白垩世发生了强烈的裂谷沉降作用。与此同时的在印度和巴基斯坦境内的 L adakh- Kohistan弧后裂谷作用还形成了具有洋壳基底的Shyok边缘海。因此 ,在早中白垩世 ,欧亚大陆南缘为西太平洋型的活动大陆边缘 ,因强烈的弧后裂谷作用产生了一系列边缘海盆地 ;在包括青藏高原南部在内的欧亚大陆南缘 ,既没有构造动力、也没有古地理和古地形证据支持在早白垩世末 ( 99Ma± )即出现强烈的抬升。 相似文献