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1.
The results of studies in the paleochannel of the Volga River, which was discovered earlier on the northwestern slope of the Derbent Basin, Caspian Sea, are presented. Seismoacoustic profiling in the paleochannel, combined with placement of submerged buoy stations equipped with current gauges, water temperature gauges, and sediment traps showed that the channel is not silted and cold heavy water is transported along it to the deep sea part of the sea, avoiding the general water transit along the western coast of the Central Caspian Sea. The preliminary calculations show that water discharge through the channel to the near-bottom part of the sea can be about 8–10 km3/yr.
相似文献2.
Doklady Earth Sciences - Data on the assessment of the dynamics of sedimentary waves over the western slope of the Caspian Sea are presented. The process of formation of the wave structure of... 相似文献
3.
The paper presents a comprehensive analysis of new data for drilling and seismic survey of the oil and gas potential of deep-seated Paleozoic horizons of the Caspian Basin in Kazakhstan. The features of the development and occurrence of large Paleozoic uplifts and sedimentary strata promising for prospecting are specified. A set of geological and geophysical methods was applied, and magnetic and gravitational anomalies of potential fields were analyzed in the southern, southeastern, and eastern marginal parts of the southeastern sector of the Caspian Basin. This is supplemented with new data obtained by a set of reconnaissance methods, and the section attributed to the Paleozoic at depths up to 5.5–8.0 km and its Devonian–Lower Carboniferous sequence are specified. New data were obtained on the area of distribution and occurrence of Upper Devonian and Lower Carboniferous sediments, geological conditions and prerequisites were revealed that refined the trace of the pre-Devonian complex and of the Lower–Middle Devonian sediments. Analysis of the distribution of large local prospecting objects has confirmed the presence and development of megauplifts, which are zones of hypsometrically elevated Devonian–Lower Carboniferous sediments. In the contour of the megauplift, structural elements have developed that are less significant, but promising in terms of hydrocarbon content. Based on the results of studying and refining the distribution patterns of large Devonian‒Lower Carboniferous objects and identifying megauplifts, it is possible to optimize regional studies in the Caspian Basin for the period of 2020–2030.
相似文献4.
Based on data of high-resolution acoustic profiling performed in the upper part of the sedimentary succession at the western continental slope of the Middle Caspian Sea (at a depth range from 100 to 400 m), we revealed specific accumulative forms of a running wave type. Examination of their morphology and inner structure allowed us to suggest two mechanisms of their formations: (a) by means of flank growth due to migration of channels of sedimentary flow associated with the Samur and other rivers and (b) due to flows of sedimentary material forming sedimentary waves. 相似文献
5.
Late Cretaceous-Eocene marginal seas in the Black Sea-Caspian region: Paleotectonic reconstructions 总被引：1，自引：0，他引：1
A series of seven reconstructions is presented to illustrate the evolution of marginal seas in the Black Sea-South Caspian segment of the margin of the Tethys Ocean from the Late Jurassic to the middle Eocene. After Middle Jurassic inversion and until the Aptian Age, no marginal (backarc) basins were formed in the region, while the Pontides-Rhodope margin developed in the passive regime. The retained relict of the Late Triassic-Early Jurassic backarc basin includes the southeastern part of the Greater Caucasus, the northern part of the South Caspian Basin, and the shallow-water Kopetdagh Basin. The basins of the southern slope of the Greater Caucasus, Balkans (Nish-Trojan Trough), and Dobrogea developed as flexural foredeeps in front of the Middle Jurassic fold systems. The next, Aptian-Turonian epoch of opening of marginal seas was related to the origination of subduction zones at the Pontides-Rhodope margin and to the incipient consumption of the Vardar Basin lithosphere with formation of the West Black Sea Basin and its western continuation in the Bulgarian Srednogorie. The backarc rifting in the Greater Caucasus resulted in transformation of the foredeep into the backarc basin. Two basins approximately 2000 km in total extent were separated by the bridge formed by the Shatsky and Andrusov rises. The last, late Paleocene-middle Eocene epoch of the formation of backarc basins was associated with the newly formed subduction zone south of the Menderes-Taurus Terrane that collided with the active margin in the early Paleocene. The Greater Caucasus Basin widened and deepened, while to its south the East Black Sea Basin, the grabens in the Kura Depression, and the Talysh Basin, all being separated by a chain of uplifts, opened. The Paleogene South Caspian Basin opened in the course of the southward motion of the Alborz volcanic arc at the late stage of closure of the Iranian inner seas. 相似文献
6.
I. S. Patina 《Stratigraphy and Geological Correlation》2017,25(3):333-341
The paper reports on the structure of the Oligocene–Lower Miocene Maikop complex of the Caspian Sea and its margin on the basis of seismic and geological data. It is shown that the regional structure of Maikop deposits of Ciscaucasia and the Middle Caspian is characterized by large clinoform sedimentary bodies. New data on formation, structure, and occurrence of clinoforms in Maikop deposits are generalized for the researched region. Two main systems of clinoforms were defined in the Maikop complex: the single large cone located in the Middle Caspian and Eastern Ciscaucasia and the southeastern system of clinoforms located in the area of Kazakh Bay. Structural characteristics and sedimentogenesis of a clinoform formation are revealed using seismic and sequence stratigraphic methods. 相似文献
7.
This paper analyzes the composition and distribution of coastal phytoplankton in the western portion of the Middle Caspian
in the context of changes in the hydrological and hydrochemical regime under the conditions of the rising level of the Caspian
Sea. It has been demonstrated that the changes in the water regime led to an increase in the taxonomic diversity, the quantitative
characteristics of phytoplankton, and the succession of the size groups. 相似文献
8.
The results of detailed seismological observations with bottom recording systems carried out in 2004 and 2006 near the Dagestan coast of the Middle Caspian are considered. The records of more than 550 micro- and weak earthquakes with ML = 0.1–4.7 (MLH = ?0.7 to 4.3) were obtained during 165 days of recording; a fifth of these earthquakes occurred in the upper mantle at a depth of 50–200 km. Over the entire period of instrumental recording since the 1930s, only 10 mantle earthquakes with MLH = 3.5?6.3 have been recorded by on-land systems. The highest density of earthquake epicenters with source depths down to 50 km is established on the Middle Caspian coast between Derbent and Izberbash and in the adjacent water area. The mantle earthquakes with hypocenters at a depth of 60–80 km cluster beneath the western wall of the Derbent Basin, whereas deeper hypocenters are located beneath both the wall of this basin and the Middle Caspian coast. The sporadic mantle earthquakes recorded in 2004 (about 30 shocks), determined by a network of systems with a small aperture, depicted a zone plunging beneath the Greater Caucasus with indications of a peculiar “subduction” of the Scythian Plate beneath the Caucasus. Subsequent observations based on a more extensive network were carried out in 2006. They substantially changed the pattern of mantle earthquake hypocenters. According to this evidence, the sources of mantle earthquakes make up a dispersed cloud extended in the vertical direction beneath the Middle Caspian coast and water area, which may be regarded as a relic of tectonic activity of a bygone tectonic epoch. A comprehensive tectonic interpretation of the detected seismological phenomenon is given. 相似文献
9.
The Devonian reef formation in the Caspian Basin framing is related to two different formations. The Middle Devonian reefs are confined to an autochthonous terrigenous?carbonate sequence of the Eifelian–lower Frasnian interval marked by the appearance of isolated domal reefs. The middle–upper Frasnian reefs are related to the carbonate formation and represented by two types: (i) asymmetric reefs on walls of the deep-water bays opening toward the Caspian microcean-bay; and (ii) solitary, relatively symmetric (in transverse section) reefs within these bays. The reef formation was characterized by prominent cyclic pattern. The framework reef formation ended before the terminal Frasnian, i.e., before the Kellwasser Event, with which the biotic crisis and faunal mass extinction was related. 相似文献
10.
This paper reports the results of field observation and the study of coastal tectonic deformations related to the Nevelsk tsunamigenic earthquake (August 2, 2007, M ～ 6.1) obtained in August-September of 2007. The earthquake caused a 0.5- to 1.5-m rise of and partial desiccation of the southern, central, and northern benches and the formation of longitudinal structural ridges seaward of Lovetskaya Bay. In the framework of the new model of the Kamyshovy (West Sakhalin) Anticlinorum as a structure of the Quaternary and Middle Quaternary crustal detachment, the relationships between the earthquake and the slow gravitational creep of the upper crust on its western slope with local squeezing of the Middle Miocene Nevelsk siltstones are discussed. 相似文献
11.
为缩小等深流沉积研究中的现代海洋研究与地层记录研究之间的不平衡和探索中-晚奥陶世鄂尔多斯盆地西缘大洋环流体系在海相深水油气勘探中的意义,在详细的野外观测的基础上,对有关沉积构造进行了古水流和流体动力学分析.结果表明:（1）非水道环境下约有1/3的小型交错层理古水流方向与区域斜坡方向垂直;（2）水道环境下普遍发育双向递变沉积构造,包括平行层（沙纹层）-均匀层-平行层（沙纹层）、条纹条带和双向粒序层3种类型.上述特征可解释为深水斜坡环境下的等深流沉积,并识别出非水道型和水道型2类,后者又分为部分改造型和完全改造型2亚类. 相似文献
12.
Lithofacies of the productive Upper Triassic-Lower Jurassic deposits of the Eastern Caspian region, studied in wells on the Caspian coast and exposed in the outcrops of the Mountainous Mangyshlak, are described and analyzed. The similarity of the structure of the Mesozoic sedimentary beds of the Middle Caspian Basin and of those of the land adjacent to its eastern coast is confirmed. Comparative analysis of lithofacies allowed the reconstruction of the paleogeographic setting and depositional environments in the studied region during the Early Jurassic. A unique fossil plant occurrence is discovered in the upper part of the Lower Jurassic series (in the lower subformation of the Kokala Formation; Eastern Caspian region). Fossil plant taphonomy and the lithology of host rocks in the occurrence resulted from unusual paleogeographic settings that existed in the Middle Caspian Basin at the time of the Early-Middle Jurassic boundary. 相似文献
13.
等深流与重力流在深水环境中较为常见,两者在地质历史时期中可存在相互作用进而形成交互作用沉积。结合近20年研究成果,对深水等深流与重力流交互作用的沉积类型、鉴别标志、形成机理及地质意义进行了总结。1）等深流与重力流交互作用沉积可分为等深流与重力流沉积互层、等深流改造重力流及等深流与重力流同时作用沉积。2）等深流沉积和重力流沉积的有效鉴别是等深流与重力流沉积互层沉积研究的前提。3）等深流改造重力流沉积发育重力流和牵引流沉积构造,双向交错层理最为典型;常具顺斜坡向下及大致平行斜坡的两个水流方向;概率累积曲线呈1~3段式等特征。4）等深流与重力流同时作用沉积主要发育单向迁移水道、不对称的水道—堤岸体系及偏转型朵叶。5）交互作用形成过程主要受等深流与重力流相对能量大小的影响。当重力流活跃时,发育重力流沉积,在重力流末期及间歇期,等深流沉积发育,进而形成重力流与等深流沉积互层。等深流能量较强时,可改造重力流沉积,形成等深流改造重力流沉积。高能等深流在重力流能量较弱时,可对重力流沉积物进行横向搬运,形成迁移水道、不对称水道—堤岸体系及偏转型朵叶。6）主要问题及下一步的主攻方向主要包括四个方面:①重视综合研究,增加实例分析;②完善鉴别标志,推广研究成果;③多方法、多尺度、多条件、多维度综合探讨交互作用沉积过程及主控因素;④加强油气勘探潜力、古环境演化及地质灾害预防等方面的研究。 相似文献
14.
黔南桂西早中三叠世碳酸盐台地边缘和斜坡沉积模式及其演化 总被引：3，自引：0，他引：3
牟传龙 《沉积与特提斯地质》1989,9(2):1-10
黔南桂西地区(东经105°-107°,北纬24°20＇-26°40＇)地跨扬子准地台和加里东褶皱带(华南褶皱带)两个一级大地构造单元。属于南盘江沉积盆地的北部或西北边缘。区内早、中三叠世碳酸盐地层出露良好、层序完整,为台地边缘和斜坡沉积。详细研究该区碳酸盐台地边缘和斜坡沉积,对了解台地边缘特征和演化、海平面变化以及边缘的构造作用等有着重要的理论意义,为确定三叠糸南盘江沉积盆地的西北或北部边缘的构造性质提供可靠的沉积学依据。 相似文献
15.
西湖凹陷西斜坡是东海盆地当前油气勘探的现实选择和主要领域，但以往研究在烃源岩形成条件和分布规律等基本地质问题方面尚未形成共识.在沉积学、煤岩学和有机地球化学等理论指导下，利用钻井、烃源岩有机地球化学及古生物等资料，对西湖凹陷西斜坡钻井揭示的平湖组烃源岩成因类型和形成条件进行了全面系统分析，建立了与沉积环境相对应的有机相划分方法，并总结了平面分布规律.研究表明，烃源岩主要为煤系烃源岩，次要为海相泥岩；西斜坡中北部以受潮汐影响的三角洲-障壁海岸沉积体系为主，西斜坡中南部为潮坪-半封闭海湾体系；沉积环境差异决定了烃源岩类型的不同，潮坪-泻湖比三角洲具有更高的煤系发育程度和生烃能力.研究结果对西斜坡烃源岩评价和储层预测及勘探部署有较大指导作用. 相似文献
16.
Marco Wunsch Christian Betzler Sebastian Lindhorst Thomas Lüdmann Gregor P. Eberli 《Sedimentology》2017,64(3):631-657
Hydroacoustic and sedimentological data in the Santaren Channel covering both the leeward slope of Great Bahama Bank and the windward slope of Cay Sal Bank allow new insights into carbonate platform slope sedimentation. The data document the interplay between depositional and erosive processes on both slopes through time and provide information on the current regime and its influence on the slope sedimentary processes. This study emphasizes the diversity and complexity of the slope morphology and the sediment distribution of the youngest high‐frequency sequence, which has developed since the last glacial maximum. The processes triggering slope failures and the formation of channels and gullies differ on both slopes. At the leeward slope of the Great Bahama Bank, extensive slope failures occurred primarily during sea‐level lowering following an interglacial. These slope failures created a slope morphology that channelizes the exported platform sediments during the subsequent highstand. At the windward slope of Cay Sal Bank, contour currents and the local tectonic regime are responsible for slope failures. During sea‐level lowstands, downwelling induces turbidity currents. The interaction of turbidity and contour currents leads to the formation of a system of furrows and slope‐parallel sediment ridges. The discovered heterogeneities in slope sedimentation improve the understanding of carbonate slope sedimentation and provide implications for sequence stratigraphic interpretation of carbonate platform slopes. 相似文献
17.
扬子台地西缘由于构造的逆冲推覆与平移走滑而受到严重破坏，因此，对其古地理重建就不能简单地依据现今露头岩相分布原封不动地来拟定古地理格架。为此，本文尝试采用“构造岩块分析法”，对这些位移了的岩块（断块）进行构造复位后，再编制早、中三叠世古地理复原图，重建其古地理演化格架。扬子台地西部边缘在早三叠世发育了进积的碳酸盐鲕粒浅滩，滩后为海湾或局限台地，滩前为碳酸盐缓坡；中三叠世时，边缘的南、北段有差异，北段滩前由缓坡（早世）演化成末端变陡的碳酸盐缓坡，而南段则发展成镶边陆架。 相似文献
18.
Source rocks are present in all the stratigraphic units of the Mesozoic-Cenozoic deposits of the Turkmen shelf in the Caspian
Sea. The highest source rock potential is characteristic of I terrigenous and carbonate-terrigenous rocks of Middle Jurassic
age, and the Aptian, Paleogene, Neogene and Apsheron stages of the Quaternary system. To reveal the formation conditions of
hydrocarbon deposits within Southwestern Turkmenistan, the principle of chemical thermodynamics is primarily used via the
calculation of the free energy of gaseous hydrocarbons. This showed that hydrocarbon deposits within the topmost depositional
complex (the red-colored strata of the Middle Miocene at the Akchagyl and Apsheron stages) are syngenetic; their formation
was due to lateral migration from even-aged deposits from depression zones neighboring the uplifts. 相似文献
19.
海底上发育深水牵引流形成的各种床形单元,包括等深岩丘及大型沉积物波在内的不同床形单元有规律地组合在一起,对于此类床形组合的确切形成机理,目前仍在探讨之中。本文经详细研究得出以下几点进展：① 运用内波理论可对海底上大型沉积物波各组成单元的成因作出较为合理的解释,向深海方向传播的内波可形成向上坡方向迁移的大型沉积物波;② 在等深流与上覆低密度水体之间的界面上具备产生大规模界面内波的条件;③ 某些底流成因的床形单元组合属于等深流与等深流所引发内波的联合作用的产物,首次提出了等深流－内波沉积组合的概念;④ 在现代海底上及古代地层记录中均发现了等深流－内波沉积组合的实例;⑤ 建立了一个古代地层记录中的深水牵引流沉积组合综合模式。 相似文献
20.
E. G.-M. Aliyeva 《Lithology and Mineral Resources》2005,40(3):267-278
Based on the study of geophysical log diagrams and outcrops of the Lower Pliocene productive series at the western flank of the South Caspian Basin, paleofacies settings of their accumulation are interpreted. Twenty high-frequency cycles of sealevel fluctuation in the Paleocaspian Sea are identified within the major productive Kirmaki, Suprakirmaki sandy, Suprakirmaki clayey, Hiatus, and Balakhany formations. Such short-term fluctuations of the Caspian Sea level in the Early Pliocene played a crucial role in the variation of sedimentation conditions and the formation of structures of productive series (PS) reservoirs.__________Translated from Litologiya i Poleznye Iskopaemye, No. 3, 2005, pp. 307–320.Original Russian Text Copyright © 2005 by Aliyeva. 相似文献