西太平洋782A钻孔新生代的有孔虫

大洋钻探工程” 1 2 5航次的 782 A钻孔位于西太平洋菲律宾海东北部 ,井深 4 76.8m。基底为安山岩 ,上覆盖层为中始新统—更新统的沉积层 ,其中保存有低丰度的有孔虫。自下而上可划分出 8个浮游有孔虫带。由于出现 Catapsydrax dissimilis,C.stainforthi为 N5 、N6 带的带化石 ,表明本钻孔存在早中新世的地层。同时由于缺失浮游有孔虫带 P1 5 — P1 6 下部 ,N3上部—N4,N7—N1 1 带的带化石 ,说明在中始新世与晚始新世之间、晚渐新世与早中新世之间、早中新世与中中新世之间存在 3个沉积间断。钻孔中的有孔虫标志本区当时处于温暖亚热带环境。根据不同时期温度的变化 ,可划分出 5个阶段 ,包括 3个偏暖时期和 2个温凉时期。     

First data on the Cenozoic section of the Bering Sea Chukchi Shelf

The first deep hole (Tsentral’naya-1) drilled on the Russian shelf of the Bering Sea in 2002 recovered the Cenozoic sedimentary section up to depths of 2785 m¹ This paper discusses results from the log, core, and slime study. The section is composed of Paleocene-Quaternary sediments. It comprises nine sequences (from the top downward): upper Miocene-Pliocene sandy-silty; middle-upper Miocene tuffaceous-diatomite, silty-sandy, shale-siltstone, and coquina-sandstone-siltstone; Eocene-lower Miocene coaliferous and sandstone-shale; Paleocene-lower Eocene volcano-sedimentary. These sequences are correlated with onshore stratigraphic units. The section includes three large unconformities: at the base of the Pliocene (depth of 380 m, base of the Aleksandrovka stratigraphic horizon), at the base of the middle Miocene (depth of 1390 m, base of the Avtakul Horizon), and, presumably, at the base of middle Eocene (depth of 1390 m, base of the Tanyurer Horizon). The last unconformity is accompanied by a kaolinite weathering crust. The section drilled into by Tsentral’naya-1 Hole shows common features for the Cenozoic sedimentary cover through the entire Anadyr basin, despite its significant facies variability.     

Geological structure of the Kashevarov Trough (central Sea of Okhotsk)

This paper reports the composition and age of rocks dredged from the Kashevarov Trough (central Sea of Okhotsk) during cruise 41 of the R/V Akademik M.A. Lavrentyev in 2006. It was found that the Late Cretaceous and Eocene volcanics from the Kashevarov Trough and Okhotsk-Chukotka volcanic belt, structures of which are traceable in the Sea of Okhotsk, have similar petrographic and geochemical features. The Cenozoic sedimentary cover consists of three different-age complexes: (1) the late Oligocene (∼28.2–24.0 Ma); (2) the terminal late Oligocene-early Miocene (24.0–20.3 Ma); (3) the terminal late Pliocene-early Pleistocene (2.0–1.0 Ma). The upper Oligocene-lower Miocene sediments were deposited in relatively shallow-water settings, whereas the late Pliocene-early Pleistocene complex was formed in deeper environments, which was probably determined by tectonic processes. The geological data indicate that the Kashevarov Trough and the surrounding underwater rises represented in the Oligocene-early Miocene a single shelf zone of the Sea of Okhotsk, which is underlain by a structurally integral Mesozoic basement and is now subsided to depths of 800–1000 m.     

The geology of the Caribbean crust, I: Beata Ridge

Igneous and sedimentary rocks recently dredged and cored from the steep western slope of the Beata Ridge provide important data on the composition, age and details of crustal evolution of the rock-types responsible for recorded compressional wave velocities. The sedimentary rock samples also provide new data concerning the age and depositional environment of overlying sedimentary reflectors.

The deepest (4,100 m) dredge haul contains deeply weathered coarsegrained igneous rocks. Nine other hauls, distributed between 4,000–2,300 m, contain holocrystalline basalts and diabases. The compressional wave velocity of air-dried samples of two holocrystalline basalts and a diabase at atmospheric pressure ranges from 5.0–5.6 km/sec. Sampling in depths less than 2,300 m shows that the crest of the Beata Ridge is capped by Quaternary deposits underlain by consolidated carbonate sediment of at least Middle Eocene age. The faunal assemblages of the Mid-Eocene samples are the product of normal accumulation in a shallow shelf environment.

The dredging results coupled with previously published seismic reflection and refraction data, suggest that the 5.4–5.7 km/sec crust is composed of a layer of basalt and diabase which outcrops below 2,300 m, on a fault-generated escarpment that was produced in the Late Cretaceous-Early Tertiary. The shallow shelf samples of Eocene age indicate that the Beata Ridge was higher in the Early Tertiary and has subsided subsequently to its present depth.     

青藏高原渐新世晚期隆升的地质证据

国内外学者普遍认为,地壳缩短增厚是青藏高原隆升的主要原因,青藏高原隆升对环境变迁和东亚季风具有重要影响,但对青藏高原隆升时代存在不同认识。通过统计分析青藏高原中段新生代不同时期的地层倾角,表明区域褶皱变形主要发生于古近纪,中新世湖相沉积地层产状平缓,挤压构造变形微弱,说明地壳缩短增厚主要发生于中新世前。湖相沉积地层的孢粉分析结果表明,青藏地区热带亚热带阔叶林植被自始新世中期开始逐步减少,至中新世早期濒临消亡;暗针叶林植被自渐新世早中期开始逐步增加,至中新世早中期达到繁盛程度甚至居主导地位。根据这些地质证据,结合全球气候变化、古气温及年代学资料,综合推断青藏高原渐新世晚期隆升高度达到海拔4000m左右。     

Tectonic evolution of the Anadyr Basin,northeastern Eurasia,and its petroleum resource potential

The published data on the sedimentation conditions, structure, and tectonic evolution of the Anadyr Basin in the Mesozoic and Cenozoic are reviewed. These data are re-examined in the context of modern tectonic concepts concerning the evolution of the northwestern Circum-Pacific Belt. The re-examination allows us not only to specify the regional geology and tectonic history, but also to forecast of the petroleum resource potential of the sedimentary cover based on a new concept. The sedimentary cover formation in the Anadyr Basin is inseparably linked with the regional tectonic evolution. The considered portion of the Chukchi Peninsula developed in the Late Mesozoic at the junction of the ocean-type South Anyui Basin, the Asian continental margin, and convergent zones of various ages extending along the Asia-Pacific interface. Strike-slip faulting and pulses of extension dominated in the Cenozoic largely in connection with oroclinal bending of structural elements pertaining to northeastern Eurasia and northwestern North America against the background of accretion of terranes along the zone of convergence with the Pacific oceanic plates. Three main stages are recognized in the formation of the sedimentary cover in the Anadyr Basin. (1) The lower portion of the cover was formed in the Late Cretaceous-Early Eocene under conditions of alternating settings of passive and active continental margins. The Cenomanian-lower Eocene transitional sedimentary complex is located largely in the southern Anadyr Basin (Main River and Lagoonal troughs). (2) In the middle Eocene and Oligocene, sedimentation proceeded against the background of extension and rifting in the northern part of the paleobasin and compression in its southern part. The compression was caused by northward migration of the foredeep in front of the accretionary Koryak Orogen. The maximum thickness of the Eocene-Oligocene sedimentary complex is noted mainly in the southern part of the basin and in the Central and East Anadyr troughs. (3) The middle Miocene resumption of sedimentation was largely related to strike-slip faulting and rifting. In the Miocene to Quaternary, sedimentation was the most intense in the central and northern parts of the Anadyr Basin, as well as in local strike-slip fault-line depressions of the Central Trough. Geological and geophysical data corroborate thrusting in the southern Anadyr Basin. The amplitude of thrusting over the Main River Trough reaches a few tens of kilometers. The vertical thickness of the tectonically screened Paleogene and Neogene rocks in the southern Main River Trough exceeds 10 km. The quantitative forecast of hydrocarbon emigration from Cretaceous and Paleogene source rocks testifies to the disbalance between hydrocarbons emigrated and accumulated in traps of petroleum fields discovered in the Anadyr Basin. The southern portion of the Anadyr Basin is the most promising for the discovery of new petroleum fields in the Upper Cretaceous, Eocene, and Upper Oligocene-Miocene porous and fracture-porous reservoir rocks in subthrust structural and lithological traps.     

中太平洋海山区富钴结壳的钙质超微化石地层学研究

对“大洋一号”调查船在中太平洋采集的N1-15和N5E-06 2个富钴结壳样品进行了钙质超微化石及其生物地层学的研究与分析.这2个结壳从结构上分为3层: 致密型上层、疏松型中层和致密型下层.在研究中对各结构层和各层中有颜色或细微结构变化的层位都进行了详细的取样和分析.在识别了12个新生代钙质超微化石事件的基础上, 确定了2个结壳致密型上层结壳都为晚更新世以来的沉积, 它们的疏松型中层结壳为上新世到中更新世的沉积.对N5E-06富钴结壳来说, 其致密型下层结壳下部形成于中晚古新世到早渐新世的59.7~ 32.8 Ma期间.N1-15富钴结壳致密型下层的形成时代目前暂时定为中新世.研究注意到在2个结壳中都没有发现可信的晚渐新世到中新世的化石记录, 在个别层位之间存在着沉积间断.      

Tertiary facies architecture in the Kutai Basin,Kalimantan, Indonesia

The Kutai Basin occupies an area of extensive accommodation generated by Tertiary extension of an economic basement of mixed continental/oceanic affinity. The underlying crust to the basin is proposed here to be Jurassic and Cretaceous in age and is composed of ophiolitic units overlain by a younger Cretaceous turbidite fan, sourced from Indochina. A near complete Tertiary sedimentary section from Eocene to Recent is present within the Kutai Basin; much of it is exposed at the surface as a result of the Miocene and younger tectonic processes. Integration of geological and geophysical surface and subsurface data-sets has resulted in re-interpretation of the original facies distributions, relationships and arrangement of Tertiary sediments in the Kutai Basin. Although much lithostratigraphic terminology exists for the area, existing formation names can be reconciled with a simple model explaining the progressive tectonic evolution of the basin and illustrating the resulting depositional environments and their arrangements within the basin. The basin was initiated in the Middle Eocene in conjunction with rifting and likely sea floor spreading in the Makassar Straits. This produced a series of discrete fault-bounded depocentres in some parts of the basin, followed by sag phase sedimentation in response to thermal relaxation. Discrete Eocene depocentres have highly variable sedimentary fills depending upon position with respect to sediment source and palaeo water depths and geometries of the half-graben. This contrasts strongly with the more regionally uniform sedimentary styles that followed in the latter part of the Eocene and the Oligocene. Tectonic uplift documented along the southern and northern basin margins and related subsidence of the Lower Kutai Basin occurred during the Late Oligocene. This subsidence is associated with significant volumes of high-level andesitic–dacitic intrusive and associated volcanic rocks. Volcanism and uplift of the basin margins resulted in the supply of considerable volumes of material eastwards. During the Miocene, basin fill continued, with an overall regressive style of sedimentation, interrupted by periods of tectonic inversion throughout the Miocene to Pliocene.     

Rheological Gravity Model of the Crust in the Sinegorsk Ore Region (Southwest of Primorsky Krai)

The spatial correlation of the South Sinegorsk basin with the Paleozoic magma chamber at the depth of 5–7 km is revealed as a result of interpreting the statistical gravitation model representing the rheological properties of the crust in the Sinegorsk ore region to the depth of 30 km. The intrusion center of the volcanic formation is approached at the midst of the basin to the depths of 1–2 km, where a local volcanotectonic elevation is formed with uranium mineralization associated with the eastern flank of the latter. The western flank of this volcanic center occupying the area of the Monastyrishche volcanic depression, overlapped mainly by Cenozoic cover, is assumed to be highly promising. The distribution of density contrasts in the middle and lower layers of the crust indicates the absence of any actual relationships between the uppercrust igneous structures and the deep-seated upper-mantle formations. It is concluded that the top layer of the crust to the depth of 10 km was separated during the Late Paleozoic–Mesozoic time from the mantle “root” of the South Sinegorsk structure and displaced southwestwards synchronously to overthrust and strike–slip dislocations in the west of Sikhote Alin. The occurrence of this root is proposed because of the presence of Paleozoic andesibasalts, basite–hyperbasites, peridotites, and basalts over the entire area considered.     

Seismic profiles across the middle Tan-Lu fault zone in Laizhou Bay,Bohai Sea,eastern China

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.     

The composition and age of the Argillite Sequence (sedimentary cover of the continental slope, Sea of Japan)

The Argillite Sequence located at the base of the sedimentary cover on the continental slope of the Sea of Japan was studied by petrographic, palynological, and X-ray diffraction methods. Two spores-pollen complexes were distinguished in it: the Late Oligocene reflecting cooling and the Early Miocene corresponding to initiated warming. The data obtained indicate that the sequence is composed of terrigenous silty-clayey sediments that accumulated in shallow coastal-marine settings. The global sea-level rise at the Early-Middle Miocene transition, combined with the regional tectonic processes, determined the basin deepening, owing to which the argillite sequence was overlain by thick Middle Miocene diatomaceous-clayey sediments. Due to tectonic movement along existing faults in the terminal Late Miocene, the argillite sequence occurring initially at depths of at least 400–500 m was locally exhumed to the basin bottom.     

Evidence from the Mesta half-graben, SW Bulgaria, for the Late Eocene beginning of Aegean extension in the Central Balkan Peninsula

The ENE-tilted Mesta half-graben contains a 3-km-thick section of Priabonian (Late Eocene) to Oligocene sedimentary and volcanic rocks that rest unconformably on basement metamorphic rocks along its west side. Basal strata dip 50–60° E and dip at progressively lower angles upward, indicating synrotational deposition. The southern part of the half-graben contains nested volcanic caldera complexes, formed during the deposition of the middle part of the sedimentary sequence, which have been rotated by about half the total rotation of the sedimentary succession. The half-graben is bounded on the east by a fault that steepens from more deeply exposed structural levels in the south (8–18° W) to shallower exposed structural levels in the north (70° W) and together with the rotation of Paleogene strata during deposition indicate the Mesta half-graben is underlain by a listric detachment fault, the Mesta detachment. Subhorizontal Middle Miocene strata that unconformably overlie tilted Paleogene strata yield an upper age limit to the extension. West and northwest of the Mesta half-graben are many other NNW-trending NE-tilted Paleogene half-grabens which we suggest are part of an important extended area in SW Bulgaria and eastern Macedonia that lies above one or more west-dipping detachment faults and date the beginning of Aegean extension in the southern Balkan region as at least as old as Priabonian. The Mesta detachment is oblique to the trend of a contemporaneous Paleogene magmatic arc in the southern Balkans and the origin of the detachment is probably related to gravitationally induced spreading of thickened hot arc crust and Hellenic trench roll back.     

缅甸D区块构造特征与油气储层评价

研究区D区块位于缅甸中部,包括钦敦凹陷北部和沙林凹陷南部,面积12384km2。D区块以南分布有许多油田。其中,Letpanto油田紧临该区块,在D区块内还有许多人工井或油苗,是油气聚集的有利场所,勘探潜力很大。为了研究该区的勘探方向,笔者从区域构造和沉积演化入手,分析研究了该区的生油层、储层和盖层的沉积相带特征和有利的油气聚集带。其中,晚始新世巴当组是始新世地层中产油的储层,为区块主要生油岩系;中新世和渐新世砂岩为良好储层;渐新世尧河组泥岩为较好的盖层;晚中新世到早上新世之间形成的各类局部构造圈闭均可能成为油气聚集场所,展示了良好的油气远景。     

Wrench structural deformation in Ras Al Hilal-Al Athrun area, NE Libya: a new contribution in Northern Al Jabal Al Akhdar Belt

Al Jabal Al Akhdar is a NE/SW- to ENE/WSW-trending mobile part in Northern Cyrenaica province and is considered a large sedimentary belt in northeast Libya. Ras Al Hilal-Al Athrun area is situated in the northern part of this belt and is covered by Upper Cretaceous–Tertiary sedimentary successions with small outcrops of Quaternary deposits. Unmappable and very restricted thin layers of Palaeocene rocks are also encountered, but still under debate whether they are formed in situ or represent allochthonous remnants of Palaeocene age. The Upper Cretaceous rocks form low-lying to unmappable exposures and occupy the core of a major WSW-plunging anticline. To the west, south, and southeast, they are flanked by high-relief Eocene, Oligocene, and Lower Miocene rocks. Detailed structural analyses indicated structural inversion during Late Cretaceous–Miocene times in response to a right lateral compressional shear. The structural pattern is themed by the development of an E–W major shear zone that confines inside a system of wrench tectonics proceeded elsewhere by transpression. The deformation within this system revealed three phases of consistent ductile and brittle structures (D₁, D₂, and D₃) conformable with three main tectonic stages during Late Cretaceous, Eocene, and Oligocene–Early Miocene times. Quaternary deposits, however, showed at a local scale some of brittle structures accommodated with such deformation and thus reflect the continuity of wrenching post-the Miocene. D₁ deformation is manifested, in Late Cretaceous, via pure wrenching to convergent wrenching and formation of common E- to ENE-plunging folds. These folds are minor, tight, overturned, upright, and recumbent. They are accompanied with WNW–ESE to E–W dextral and N–S sinistral strike-slip faults, reverse to thrust faults and pop-up or flower structures. D₂ deformation initiated at the end of Lutetian (Middle Eocene) by wrenching and elsewhere transpression then enhanced by the development of minor ENE–WSW to E–W asymmetric, close, and, rarely, recumbent folds as well as rejuvenation of the Late Cretaceous strike-slip faults and formation of minor NNW–SSE normal faults. At the end of Eocene, D₂ led to localization of the movement within E–W major shear zone, formation of the early stage of the WSW-plunging Ras Al Hilal major anticline, preservation of the contemporaneity (at a major scale) between the synthetic WNW–ESE to E–W and ENE–WSW strike-slip faults and antithetic N–S strike-slip faults, and continuity of the NW–SE normal faults. D₃ deformation is continued, during the Oligocene-Early Miocene, with the appearance of a spectacular feature of the major anticline and reactivation along the E–W shear zone and the preexisting faults. Estimating stress directions assumed an acted principal horizontal stress from the NNW (N33°W) direction.     

内蒙古阿拉善地区的第三系

依据丰富翔实的地层古生物资料,首次在内蒙古西部建立了比较完整的第三纪地层层序：命名或厘订了中始新统乌兰乌珠尔组、上始新统查干布拉格组、下渐新统乌兰塔塔尔组、上渐新统、下中新统乌尔图组、上中新统呼和好来组和上新统昂冈浩特组等７个地层单元;区分出了中始新世乌兰乌珠尔、晚始新世查干布拉格、早渐新世早期克克阿木、早渐新世晚期乌兰塔塔尔、晚渐新世因德里沟、早中新世乌尔图、晚中新世呼和好来和上新世昂冈浩特等８个动物群（组合）。     

Late Mesozoic and Cenozoic volcanosedimentary complexes from the submarine Vityaz Ridge,the Island Arc slope of the Kuril-Kamchatka trench,and its evolution

This paper describes the volcanosedimentary complexes of different ages (Late Cretaceous-Early Paleocene, Paleocene-Eocene (?), Oligocene-Early Miocene, and Pliocene-Pleistocene) that compose the basement and sedimentary cover of the submarine Vityaz Ridge. It was found that the Upper Cretaceous sedimentary rocks from the basement of the Vityaz Ridge (felsic) and the Lesser Kuril Ridge (mafic) have different compositions. Matrix mineral assemblages corresponding to the smectite and corrensite stages of epigenesis of Cenozoic rocks were distinguished, and a scheme of the Late Cretaceous-Pleistocene geological evolution of the region was proposed.     

Seismic profiles across the middle Tan-Lu fault zone in Laizhou Bay, Bohai Sea, eastern China

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.     

菲律宾海盆东北部晚始新世以来放射虫及其古海洋学意义

研究了菲律宾海盆东北部“大洋钻探工程”１２５航次７８２Ａ孔晚始新世以来的放射虫化石。根据Ｓａｎｆｉｌｉｐｐｏ等１９８５年的分带,将研究区自下而上划分为１０个带。讨论了始新世与渐新世、渐新世与中新世、中中新世与晚中新世、中新世与上新世以及上新世与第四纪的界线。研究区存在两个沉积间断,分别位于晚渐新世与早中新世晚期之间和中中新世与晚中新世之间。研究区第四纪放射虫化石仍以暖水分子为主,冷水分子分布较浅。依据放射虫化石分异度曲线得出,晚第三纪以来本区存在５个相对暖水期和５个相对较凉期,渐新世时处于冷水期,这与钙质超微化石复合分异度和碳酸钙含量曲线的变化是一致的。晚渐新世与早中新世晚期之间的沉积间断是由于中新世南极冰盖扩展造成大洋底层洋流活动加剧而形成的。     

Tertiary evolution of the central Menderes Massif based on structural investigations of metamorphics and sedimentary cover rocks between Salihli and Kiraz (western Turkey)

Augen gneisses, mica schists, and marbles of the Menderes Massif and its sedimentary cover rocks are exposed south of the Gediz graben. The augen gneisses form the structurally lowest part of the studied lithological sequence, and are overlain by a schist complex. The structurally highest part is formed by a series of marbles. The ages of this lithological sequence range from Precambrian to Early Paleocene. Furthermore, this sequence records the tectonic evolution since the Precambrian. The sedimentary cover of the Menderes Massif consists of two groups of sediments from Early Miocene to Quaternary. The lower group, the Alayehir group, consists of Early- to mid-Miocene-aged fluvial and limnic sediments which form the lower and the upper parts, respectively. The Alayehir group is overlain by mainly fluvial sediments of the Gediz group. Both the Alayehir and the Gediz groups are separated by an angular unconformity. Six deformational phases could be distinguished within the metamorphic rocks of the Menderes Massif and its Tertiary cover. The structures which were interpreted to belong to deformational events predating the Paleocene are summarized as deformational phase D1. D1 structures were nearly completely overprinted by the subsequent deformation events. The second deformational phase D2 occurred between Early Eocene and Early Oligocene. D2 occurred contemporaneously with a Barrovian-type regional metamorphism. The third deformational phase D3 is characterized by folding of the axial planes which formed at the end of Early Oligocene. The deformational event D4 occurred during the Late Oligocene and is related to an extensional period. The deposition of the sedimentary rocks which belong to the Tertiary cover of the Menderes Massif that started in the Early Miocene was interrupted by a compressional phase (D5) during the Late Miocene. Sediments which were deposited since the Early Pliocene record structures which were related to a young extensional phase (D6). This extensional phase has continued to the Present.     

东海盆地形成的区域地质背景与构造演化特征

东海盆地处于西太平洋俯冲带前缘,是发育在华南克拉通基底之上的,以晚白垩世-新生代沉积为主的新生代盆地.东海盆地性质是在活动大陆边缘减薄陆壳之上的,由于洋-陆俯冲消减所引起的张裂、拉伸作用而形成的弧后裂谷型盆地,是西太平洋众多“沟-弧-盆”体系的一部分.东海盆地陆架外缘隆起控制着东海盆地的演化过程,该地质单元形成于晚白垩世,是陆缘隆起和增生楔的复合体,中新世后由于菲律宾海板块的活动而解体为现今的钓鱼岛隆褶带和琉球隆起.结合对陆架外缘隆起的研究后认为,东海盆地晚白垩世以来的演化历程具有3大构造阶段,即:第一阶段,古新世-中始新世西部坳陷形成发展期;第二阶段,中始新世-渐新世东部坳陷形成发展期,其中,中晚始新世太平洋板块的转向是东、西部坳陷构造迁移的分界点;第三阶段,中新世-全新世,东海盆地进入到菲律宾板块影响时期,原先的构造格局开始分解.