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1.
汾渭裂谷系与造山带耦合关系及其形成机制研究 总被引：19，自引：3，他引：16
试图运用盆山耦合等地学理论,对汾渭裂谷系进行初步的定量半定量研究。认为在区域拉张应力场作用下,汾渭裂谷系为盆山耦合形成,其形成模型为“伸展造山,断陷沉盆,后推成台”;运用盆内沉积与造山带剥蚀量互补法、地震剖面拟合法、裂变径迹法等计算方法对其进行计算的结果表明,铲式断裂一侧造山带隆升与盆地下沉呈完全镜像对称关系。同时对大同一带新生代玄武岩特征进行了分析,认为软流圈上涌是该带玄武岩喷发的根源,并通过对该区地震层析和大地电磁测深的剖析,推断汾渭裂谷系主体形成机制应为被动机制,而其北部的桑干河断陷形成机制则为主动机制。此外,对汾渭裂谷系的地热资源及地震震中分布规律等进行了探讨。 相似文献
2.
The Blue Nile Basin, situated in the Northwestern Ethiopian Plateau, contains ∼1400 m thick Mesozoic sedimentary section underlain by Neoproterozoic basement rocks and overlain by Early–Late Oligocene and Quaternary volcanic rocks. This study outlines the stratigraphic and structural evolution of the Blue Nile Basin based on field and remote sensing studies along the Gorge of the Nile. The Blue Nile Basin has evolved in three main phases: (1) pre‐sedimentation phase, include pre‐rift peneplanation of the Neoproterozoic basement rocks, possibly during Palaeozoic time; (2) sedimentation phase from Triassic to Early Cretaceous, including: (a) Triassic–Early Jurassic fluvial sedimentation (Lower Sandstone, ∼300 m thick); (b) Early Jurassic marine transgression (glauconitic sandy mudstone, ∼30 m thick); (c) Early–Middle Jurassic deepening of the basin (Lower Limestone, ∼450 m thick); (d) desiccation of the basin and deposition of Early–Middle Jurassic gypsum; (e) Middle–Late Jurassic marine transgression (Upper Limestone, ∼400 m thick); (f) Late Jurassic–Early Cretaceous basin‐uplift and marine regression (alluvial/fluvial Upper Sandstone, ∼280 m thick); (3) the post‐sedimentation phase, including Early–Late Oligocene eruption of 500–2000 m thick Lower volcanic rocks, related to the Afar Mantle Plume and emplacement of ∼300 m thick Quaternary Upper volcanic rocks. The Mesozoic to Cenozoic units were deposited during extension attributed to Triassic–Cretaceous NE–SW‐directed extension related to the Mesozoic rifting of Gondwana. The Blue Nile Basin was formed as a NW‐trending rift, within which much of the Mesozoic clastic and marine sediments were deposited. This was followed by Late Miocene NW–SE‐directed extension related to the Main Ethiopian Rift that formed NE‐trending faults, affecting Lower volcanic rocks and the upper part of the Mesozoic section. The region was subsequently affected by Quaternary E–W and NNE–SSW‐directed extensions related to oblique opening of the Main Ethiopian Rift and development of E‐trending transverse faults, as well as NE–SW‐directed extension in southern Afar (related to northeastward separation of the Arabian Plate from the African Plate) and E–W‐directed extensions in western Afar (related to the stepping of the Red Sea axis into Afar). These Quaternary stress regimes resulted in the development of N‐, ESE‐ and NW‐trending extensional structures within the Blue Nile Basin. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
3.
Martin Bak Hansen Holger Lykke-Andersen Ali Dehghani Dirk Gajewski Christian Hübscher Morten Olesen Klaus Reicherter 《International Journal of Earth Sciences》2005,94(5-6):1070-1082
A dense grid of multichannel high-resolution seismic sections from the Bay of Kiel in the western Baltic Sea has been interpreted
in order to reveal the Mesozoic and Cenozoic geological evolution of the northern part of the North German Basin. The overall
geological evolution of the study area can be separated into four distinct periods. During the Triassic and the Early Jurassic,
E–W extension and the deposition of clastic sediments initiated the movement of the underlying Zechstein evaporites. The deposition
ceased during the Middle Jurassic, when the entire area was uplifted as a result of the Mid North Sea Doming. The uplift resulted
in a pronounced erosion of Upper Triassic and Lower Jurassic strata. This event is marked by a clear angular unconformity
on all the seismic sections. The region remained an area of non-deposition until the end of the Early Cretaceous, when the
sedimentation resumed in the area. Throughout the Late Cretaceous the sedimentation took place under tectonic quiescence.
Reactivated salt movement is observed at the Cretaceous Cenozoic transition as a result of the change from an extensional
to compressional regional stress field. The vertical salt movement influenced the Cenozoic sedimentation and resulted in thin-skinned
faulting. 相似文献
4.
F.I. Zhimulev M.M. Buslov S. Glorie J. De Grave M.A. Fidler A. Izmer 《Russian Geology and Geophysics》2011,52(12):1634-1642
Granites from the Tunka pluton of the Sarkhoi complex, located in the eastern Tunka bald mountains (East Sayan), have been dated at the Middle Ordovician (462.6 ± 7.8 Ma) by LA ICP MS. The granites of the Sarkhoi complex within the studied area cut a foldthrust structure consisting of deformed fragments of the Vendian (Ediacaran)–Early Cambrian cover of the Tuva–Mongolian microcontinent (Upper Shumak metaterrigenous formation, Gorlyk carbonate formation). The red-colored conglomerates and sandstones of the Late Devonian–Early Carboniferous(?) Sagan-Sair Formation overlie the eroded surface of the Tunka pluton granites in the eastern Tunka bald mountains. The Sagan-Sair Formation, in turn, is overlain along a low-angle thrust by a group of tectonic sheets, which comprises the volcanic and carbonate sediments of the Tolta Formation, biotitic schists, and plagiogneisses with garnet amphibolite bodies. Two nappe generations have been revealed on the basis of the described geologic relationships, the Middle Ordovician age of the Tunka pluton granites, and numerous Late Paleozoic Ar–Ar dates of syntectonic minerals from the metamorphic rocks in the area. The first thrusting stage was pre-Middle Ordovician, and the second, Late Carboniferous–Permian. The Lower Paleozoic thrust structure resulted from the accretion of the Tuva–Mongolian microcontinent to the Siberian Platform. The Late Paleozoic nappes resulted from intracontinental orogeny and the reactivation of an Early Paleozoic accretionary belt under the effect of the Late Paleozoic collisional events. 相似文献
5.
In this paper we present a review of sedimentological, geomorphological, lithological, geochronological and geophysical data from major, minor and satellite basins of the Baikal Rift Zone (BRZ) and discuss various aspects of its evolution. Previously, the most detailed sedimentological data have been obtained from the basins of the central BRZ, e.g., Baikal, Tunka and Barguzin, and have been used by many scientists worldwide. We add new information about the peripheral part and make an attempt to provide a more comprehensive view on BRZ sedimentation stages and environments and their relations to local and regional tectonic events. A huge body of sedimentological data was obtained many years ago by Soviet geologists and therefore is hardly accessible for an international reader. We pay tribute to their efforts to the extent as the format of a journal paper permits. We discuss structural and facial features of BRZ sedimentary sequences for the better understanding of their sedimentation environments. In addition, we review tectono-sedimentation stages, neotectonic features and volcanism of the region. Finally, we consider the key questions of the BRZ evolution from the sedimentological point of view, in particular, correlation of Mesozoic and Cenozoic basins, bilateral growth of the Baikal rift, Miocene sedimentation environment and events at the Miocene/Pliocene boundary, Pliocene and Pleistocene tectonic deformations and sedimentation rates. The data from deep boreholes and surface occurrences of pre-Quaternary sediments, the distribution of the Pleistocene sediments, and the data from the Baikal and Hovsgol lakes sediments showed that 1) BRZ basins do not fit the Mesozoic extensional structures and therefore hardly inherited them; 2) the Miocene stage of sedimentation was characterized by low topography and weak tectonic processes; 3) the rifting mode shifted from slow to fast at ca. 7–5 Ma; 4) the late Pleistocene high sedimentation rates reflect the fast subsidence of basin bottoms. 相似文献
6.
The main episode of Cenozoic volcanic activity occurred simultaneously with formation of the Sayan—Baikal uplift, before the rift depressions were initiated. Volcanism and rifting in this region have developed as independent processes, connected with each other only by an ultimate primary mantle energy source. The volcanic regions do not coincide with the rift depressions, except in the Tunka graben.Chemical features of the volcanics show that during the entire period of volcanic activity there was a complex alternation of basaltic lavas of alkaline, intermediate and tholeiitic composition. Both alkaline and subalkaline lavas are distributed over the entire volcanic region, excepting the Tunka depression where tholeiitic lavas are predominant. However, there is neither mineralogical nor chemical evidence for the existence of two separate magma types within the Baikal rift zone.Judging by the presence of high-pressure, lherzolitic megacrysts of clinopyroxene, and to a lesser extent titaniferous biotite and amphibole in alkaline basalts, variations of lava chemistry are connected with high-pressure fractionation of initial melts, which was more complete for sources outside the rift zone. The predominance of tholeiitic lavas in the Tunka depression is likely to have been caused by a higher degree of partial melting and quick ascent of magma to the surface, facilitated by a high geothermal gradient under the depression where crustal extension is taking place. 相似文献
7.
Abstract— The composite nappe of the Spongtang ophiolite is thrust over Mesozoic and Cenozoic sediments of the North-Indian margin and shelf. The ophiolitic peridotiles tectonic-ally overlie a sedimentary melange, the detailed stratigraphy of which reveals the evolution of the South-Tethyan margin from its opening to its closure. The matrix of the melange is dated as Upper Campanian to Lower Eocene. Volcano-sedimentary olistoliths indicate carbonate platform sedimentation associated with alkaline lavas in the Permian, followed by more pelagic sedimentation of Upper Triassic and mid- Cretaceous age. They derived from external platforms near to the Indian shelf, but separated from it. Composite olistoliths of mid to late Cretaceous age, containing Permian elements, are found in the upper Cretaceous to lower Eocene wildflysch. Primary contacts of melange upon serpentinites indicates that the deeply eroded oceanic crust served partly as a substratum for the melange. 相似文献
8.
上扬子西部地区磷灰石裂变径迹年龄数据的统计为该区的新生代构造活动建立了宏观的图景,初步构建了区域上新生代构造活动和陆内变形的时空联系。揭示新生代构造活动在时间上存在大约61～43 Ma和大约24 Ma以来两个阶段的显著差异,约24 Ma是上扬子板块西部地区新生代构造活动显著增强的一个重要转折时期。在空间上大致以松潘-安县为界构成南、北分段。构造活动和区域抬升-剥露总体表现为南强北弱,西强东弱的格局。南段是新生代活动的主控区,以强烈地构造抬升和构造改造为主,而北段总体上受制于白垩纪的抬升-剥露,新生代以来主要表现出剥蚀和弱构造改造的特征。新生代的构造活动受制于青藏高原抬升作用向东扩展的影响。上扬子西部地区新生代构造活动在一定程度上制约了该区油气的圈闭环境和成藏条件。 相似文献
9.
10.
The Cenozoic paleostress state of the Earth’s crust at the southwestern flank of the Baikal Rift System (Tunka system of basins) is reconstructed. With allowance for known facts about the geologic history of the Tunka system of basins, the evolution of the stress field and its formation conditions are established by comparison of the obtained reconstructions, including the dated stress fields, with the Pleistocene-Holocene deformations in active fault zones and the present-day stress state (seismotectonic deformations calculated from the focal mechanisms of earthquakes). The opening of basins in the NW-SE direction was proceeding in the transtensional regime from the Oligocene to the late Miocene or early Pliocene. At the early-late Pliocene boundary, this process was followed by the transpressional regime with compression in the NW direction. In the late Pliocene, the situation at the southwestern flank changed drastically. Since that time, deformation has occurred in the transpressional regime and the compression axis has been oriented in the NE direction. The alternative models of the evolution of the Tunka system of basins—oblique extension, the transform fracture zone, or a pull-apart system—are considered. Both models are combined in the framework of the suggested stress-field reconstruction. The oblique extension (transtension) was related to the early stages of evolution, whereas a possibility of forming pull-apart basin was existent at the late stages. 相似文献
11.
Emilio Ramos-Guerrero Antonio Rodriguez-Perea Francesc Sabat Josep Serra-Kiel 《Geodinamica Acta》2013,26(1):53-72
AbstractThe results of recent biostratigraphic, sedimentologic and structural work concerning the island of Mallorca have led us to elaborate a synthesis of the Cenozoic tectosedimentary evolution of this area. The recognition in the field of several unconformities enabled us to distinguish four Depositional Sequences embracing the pre and syntectonic deposits.From Paleocene to part of Middle Eocene there was no sedimentation in the Mallorca area. This stratigraphie gap follows the onset of Africa-Europe convergence.The area was stable during the first sequence (Upper Lutetian-Bartonian), which is trangressive towards the NW. Tectonic activity is recorded by the conglomeratic wedges of Depositional Sequence 11 (Priabonian-Lower Chattian). A dramatic paleogeographic change ocurred between Depositional Sequence II and III. Observed thrusts and unstable platform sediments of Depositional Sequence III (Upper Chattian-Lo-wermost Burdigalian) indicate the onset of thrust tectonics in the area. Turbiditic deposits of Depositional Sequence IV (Burdigalian-Langhian) are clearly syntectonic. Post-orogenic deposits range from Serravalian to recent and are not discussed in this paper.Synthetic regional geological cross-sections have been constructed. They are used to restore the cartographic structural units to their relative pre-tectonic position and a palinspastic map for each Depositional Sequence has been obtained. These maps show both the sedimentary environment distribution and the active tectonic structures; hence they illustrate the tectosedimentary evolution of the Mallorca area through the Cenozoic.This work has evident limitations arising from the small area studied in relation to the Cenozoic Betic basin and from the lacking subsurface data. 相似文献
12.
贝加尔裂谷带通京盆地呼兰霍博克火山的玄武岩岩石学和地球化学特征 总被引：1，自引：0，他引：1
位于贝加尔裂谷带西南端通京盆地的呼兰霍博克火山为玄武岩质碎屑锥,玄武岩由高拉长石、贵橄榄石、普通辉石和火山玻璃组成,其矿物组成及SiO2-（Na2O＋K2O）图和Hf-Th-Ta图指示为碱性玄武岩.CIPW标准矿物特征、岩石化学成分和单斜辉石化学成分特征表明岩石属碱性系列,钠质型.稀土元素和微量元素的地球化学特征表明岩石为裂谷初期玄武岩.初步推断原始岩浆来源于上地幔,斑晶可能于16.5 km深处的次生壳层岩浆房结晶. 相似文献
13.
The Pernambuco marginal basin is located on the eastern continental margin of northeastern Brazil, covers an area of 20,800 km2, and represents one of the most prominent frontiers for deep water oil and gas exploration off the Brazilian coast. The onshore region of this basin was highly affected by extrusive and intrusive magmatism during the Upper Albian, and the relation of that event with the volcanic structures observed in the offshore sector has not been thoroughly characterized to date. This study aims to characterize the major extrusive and intrusive volcanic structures of the offshore portion of this basin, which is dominated by the Pernambuco Plateau, and its stratigraphic relations. A set of 143 2D multichannel seismic sections that cover the Pernambuco Plateau region are used to interpret the major tectono-stratigraphic sequences and describe the distribution of volcanoes, sills, vent complexes and related volcaniclastic sequences. The interpretations are supported by aeromagnetic and gravimetric geophysical surveys. Volcanoes are classified into two groups that differ in terms of their morphology: shield-like structures and cone-shaped volcanic structures. Sill intrusions are mainly identified beneath the volcanic structures and are characterized by high-amplitude reflectors with short extensions and abrupt terminations. Volcaniclastic sequences are found adjacent to the volcanoes and are characterized by high-amplitude, disrupted reflections with local chaotic configurations. Vent complexes are classified on the basis of their morphologies as either eye-shaped or crater-shaped. The volcanic features identified within the available seismic dataset are concentrated in two main areas: in the centre of the plateau and near its northeastern border. These two regions are host basement outer highs and are surrounded by hyper-extended continental crust, which forms the plateau itself. The extrusive and intrusive features described in the offshore region were formed during the post rift Cretaceous and Cenozoic intervals and point to the continuation of magmatic events after the rifting process. The findings presented in this report provide a better understanding of the magmatism on the northeastern passive margin of Brazil and can also be useful for future modelling of the Pernambuco Basin petroleum system. 相似文献
14.
《International Geology Review》2012,54(3):310-335
The geology and paleogeography of the Pavlodar section of the Irtysh valley and the northern Aral region is reviewed, incorporating pertinent fossil evidence concerning the Cenozoic deposits surrounding the Kazakh highland. It gives a summary of the stratigraphy and evolution of vegetation in an area of just under 150, 000 square miles which went from littoral to forest to desert over the span of Cenozoic time. Particular attention is given the evolution of the gymnosperms. The relations between vegetation, sedimentation and soil development are discussed.—M. E. Burgunker. 相似文献
15.
The traditional concept of the rift development of flank depressions in the Baikal rift zone is now doubted in view of some indicators for compression deformations identified by the seismogeological and geodetic methods. Besides, the paleoseismological investigations revealed seismogenic strike-slips and reverse faults in the Tunka fault zone that is a major structure-controlling element of the Tunka rift depression. However, a detailed study of the upslope-facing scarp in the Arshan paleoseismogenic structure zone has shown that its formation might be due to rift mechanism of basin formation. Age estimation has been made for the previously unknown pre-historic earthquake whose epicentral area coincides with the western flank of the Arshan paleoseismogenic structure. Judging from previously determined ages of paleoearthquakes, the mean recurrence period for faulting events on the central Tunka fault is 2780–3440 years. 相似文献
16.
Disperse and punctual studies; absence of integration of data ranging from local to regional focus; interpretations based only on lithostratigraphic features; and interpretation of data premised on an allochthonous origin of the Caribbean plate, are some of factors that increase the confusion and uncertainty in understanding the Sinú-San Jacinto Basin. The sedimentary record of Upper Cretaceous to Eocene has been traditionally interpreted as the record of deep-water settings. However, recently these sediments have been related to shallow marine and deltaic settings. Second problematic point is about the deposition environment of the Oligocene to Late Miocene succession. Some studies suggest canyons, turbidites and sediments deposited in deep-water settings. However, recent studies propose deltaic and shallow marine settings. The last stratigraphic problem is related to the controversial fluvial vs. shallow marine interpretations of the Pliocene sediments. Based upon seismic stratigraphic analysis in recent and reprocessed 2D seismic data, integrated with well data, we propose chronostratigraphic charts for the northern, central and southern zones of the Sinú-San Jacinto Basin. Twenty seismic facies based on amplitude, continuity, frequency and geometry of seismic reflectors and twelve seismic sequences were recognized. The seismic stratigraphic analysis in this study suggests that the sediments of Upper Cretaceous to Paleocene/Eocene were associated to continental to shallow marine settings. Lagoons, coastal plain and carbonate platform dominated during this period. The Oligocene to Middle Miocene record was characterized by deep-water deposition, whereas the Late Miocene to recent sedimentation was characterized by falling base level, characterized by deltaic and fluvial deposits. Five syn-rift sequences with wedge-shaped geometry were identified in this study. Three Triassic to Jurassic syn-rift sequences were characterized by seismic facies typical of fluvial to lacustrine and flood plain sedimentation. Two Cretaceous to Paleocene syn-rift sequences were characterized by seismic facies related to lagoons to coastal plain settings. Normal high-angle faults with a northeast-southwest direction related to rifting processes controlled the development of these sequences. The sheet-drape post-rift section was characterized by passive margin settings in the northern part of the Sinú-San Jacinto Basin and by diachronic tectonic inversion of older normal faults during Cenozoic, predominantly in the central and southern zones. The stratigraphic record related to the Mesozoic to Early Cenozoic rifting; the shallow marine sedimentation during Eocene and the tectono-stratigraphic continuity across the northern Colombia and northwestern Venezuela is coherent and well explained by the in situ origin of the Caribbean plate and is not explained by the “allochthonous” model. 相似文献
17.
O. B. Kuzmina Z. N. Gnibidenko L. B. Khazin I. V. Khazina 《Stratigraphy and Geological Correlation》2017,25(3):342-361
New micropaleontological and paleomagnetic data were obtained by studying core samples of Cenozoic continental deposits from two boreholes drilled in the south of Tyumen oblast (Western Siberia). Palynological assemblages in deposits of the Tavda (upper part), Novomikhailovka, Turtas, Abrosimovka, Tobolsk, Smirnovka, and Suzgun formations were described. Deposits of these formations are enriched in spore-pollen assemblages, which can be correlated with assemblages of regional palynozones of the West Siberian Plain. Ostracods were described in Quaternary deposits. On the basis of biostratigraphic and paleomagnetic data, the Late Eocene (Priabonian)–Holocene age of deposits was substantiated. For the first time, beds with dinocysts of genus Pseudokomewuia were identified in deposits of the Turtas Formation (Upper Oligocene) of the Ishim lithofacial area. In total, nine regional magnetozones were distinguished in the paleomagnetic section. On the basis of palynological and paleomagnetic data, sections of two boreholes were correlated, and hiatuses in sedimentation were revealed. A large hiatus is at the Eocene-Oligocene boundary (Western Siberia): the Lower Oligocene Atlym Horizon and Miocene–Pliocene and Eopleistocene sediments are missing. The Oligocene interval of the section is represented in a reduced volume. 相似文献
18.
攀西裂谷存在吗？ 总被引：12，自引：0，他引：12
大陆裂谷以地幔上隆、岩石圈伸展、减薄、断陷和沉降为特征，伸展构造环境是大陆裂谷形成的必要条件和本质特征。中国学者以前所认为攀枝花-西昌裂谷的主要标志是海西期层状堆晶杂岩、晚二叠世峨眉山玄武岩、印支期环状碱性杂岩和晚三叠世裂谷盆地沉积。最近一系列研究成果表明攀西地区海西期-印支期构造岩浆热事件是地幔柱和岩石圈相互作用的结果，不是裂谷作用的产物。进一步对上扬子西缘二叠纪-三叠纪的沉积作用和构造特征综合分析表明攀西地区不存在裂谷盆地沉积。该区晚二叠世-中三叠世为古陆隆起遭受剥蚀，晚三叠世断陷型类磨拉石建造是前陆走滑复合盆地的产物。本文根据对攀西地区二叠纪-三叠纪的岩浆活动、沉积作用、构造特征和地球物理资料等方面综合研究对攀西裂谷的存在提出质疑，并以峨眉山地幔柱活动为主线探讨了攀西地区古生代和中生代的地质构造演化历史。 相似文献
19.
E. E. Karnyushina N. I. Korobova E. V. Kozlova N. V. Pronina G. G. Akhmanov 《Moscow University Geology Bulletin》2007,62(4):269-276
The paper discusses new data resulting from petrographic examination of the composition and structure of Cenozoic sediments penetrated by Well 10 to a depth of 2350 m in the Upper Telekai oil-and-gas field within the Anadyr Basin. An alluvial-deltaic sedimentation environment of tuffaceous-sedimentary and terrigenous producing Lower Miocene rocks was found and their secondary alterations examined, including formation of clay minerals, carbonates, and zeolite. The vitrinite reflectance indices allowed determination of the catagenic zoning of the Miocene succession, and a significant catagenic unconformity related to pre-Pliocene erosion was recorded at its top. 相似文献