铁岭凡河地区元古宙地层格架建立初探

铁岭凡河地区元古宙地层始于凡河元古宙坳拉谷沉积，根据岩石地层学、生物地层学、年代地层学等研究成果，结合现代层序地层学理论，自下而上划分六个层序，即关门山层序，虎头岭层序、二道沟层序、石门层序、杨士屯层序、于北沟层序。每个层序仅由海侵体系域和高水位体系域组成，分别代表海侵退积地层结构和海退进积地层结构，而中间饥饿段则以加积为主。各层序间均为不整合，其类型包括海岸暴露带和海侵面。在此基础上，建立了区域地层格架。     

Formation and evolution of the tertiary carbonate reefs in the Madura Strait Basin of Indonesia

Analysis of 2D seismic data over 4 500 km in length from the Madura Strait Basin in the East Java Sea reveals seismic reflection characteristics of reefs and associated sedimentary bodies, including asymmetrical or symmetrical dome reflections, slope progradational reflections, chaotic reflections and discontinuous strong reflections inside the reef, which onlap the flank of the reef. It is concluded that the developmental paleo-environment of most reefs is mainly conducive to shallow marine carbonate platform facies and platform margin facies, based on well core data, variations in seismic facies and strata thickness. The formation and evolution of all reefs are primarily influenced by the tectonic framework of the Madura Strait Basin. Platform margin reefs are principally controlled by two types of structures: one is a series of E-W trending Paleogene normal faults, and the other is an E-W trending Neogene inversion structures. In addition, wave actions, tidal currents and other ocean currents play an accelerated role in sorting, rounding and redeposition for the accumulation and evolution of reefs. Tertiary reefs in the MSB can be divided into four types: 1) an open platform coral reef of Late Oligocene to Early Miocene, 2) a platform margin coral reef controlled by normal faults in Late Oligocene to Early Miocene, 3) a platform margin Globigerina moundreef controlled by a “hidden” inversion structure in Early Pliocene, and 4) a platform margin Globigerina mound-reef controlled by thrust faults in the early Pliocene. Patterns of the formation and evolution of reefs are also suggested.

     

浅析造礁生物演化及生物绝灭事件对礁丘发育的控制作用──以中国南方震旦纪至三叠纪生物礁丘为例

造礁生物演化经历了六个主要发展阶段，具有全球性演化规律特征，其盛衰变化在中国南方礁丘的时代分布上反映较为醒目。早泥盆世至晚泥盆世早期，为生物礁发育的首次鼎盛期，已发现的礁体达９７个，而至今尚未发现晚泥盆世晚期（法门期）的生物礁；二叠纪是第二次鼎盛期，已发现该时期的礁丘达１４８个之多，生物特征明显，而至今也尚未发现早三叠世时期的礁体。中国南方这一礁丘时代分布特征恰好与 Ｆ／Ｆ和Ｔ／Ｐ两次全球性巨大生物绝灭事件相吻合。因此在南方寻找生物礁型油气藏时，除了应当重视本区构造演化的控制作用外，还应极大地注意全球性生物演化规律的控制作用。     

Structural characteristics and hydrocarbon accumulation in Bashituo area,Tarim Basin

According to well logs, core, seismic and other geological data, the authors studied the tectonic evolution stages, trap formation stages, fault and fracture development in the Bashituo area, and furthermore, analyzed the time of hydrocarbon accumulation, hydrocarbon migration pathways and related controversial issues in the study area. It is believed that the tectonic evolution in the study area can be divided into three stages, namely Late Hercynian, the Early Himalayan and the Late Himalayan. In the Late Hercynian, tectonic movement led to folding and faulting, resulting in the embryonic form of anticlinal traps. In the Early Himalayan, affected by both tectonic movement and transformation, deep faults reactivated and cut through the Lower Tertiary strata. After the Early Himalayan tectonic movement, faulting stopped and no vertical migration pathway was available. Then hydrocarbon migrated laterally along the sand bodies in the Bachu Formation and accumulated in the Carboniferous reservoirs. However, the Carboniferous accumulation was formed late, and the tectonic movement was weak at the Late Himalayan, and faults were underdeveloped, so the reservoirs in the deep Bachu Formation were not disturbed.     

伊宁地块构造单元划分之新见

伊宁地块是西天山造山带的重要组成部分,其上广泛出露晚古生代火山岩浆岩和沉积建造,对剖析该地块的形成演化具有重要意义。伊宁地块以中部近EW向展布的乌孙山—塔勒得断裂为界可划分为南、北两大构造带,两者在基底建造、岩浆岩的组成与时代及其地球化学特征、盆地形成和构造演化等方面均呈现显著不同。其中,南构造带由晚泥盆世—早石炭世早期大哈拉—喀勒峻岛弧带和阿腾套弧后伸展盆地构成,推测海沟位于岛弧带之南(那拉提南缘断裂附近);北构造带由早石炭世中晚期阿吾拉勒叠加岛弧带、特克斯—新源弧前盆地和清水河—苏布台弧后盆地-扇三角洲构成。在重新梳理并详细总结伊宁地块的最新划分依据及方案基础上,首次提出伊宁地块形成与演化的南、北构造带两拼接和演化三阶段新认识:①晚泥盆世—早石炭世早期,南构造带初始弧-盆构造体系形成;②早石炭世中晚期,北构造带的沟-弧-盆构造体系形成并增生;③早—晚石炭世,初始的南构造带与增生的北构造带拼贴缝合,完成地块拼贴与增生,最终形成统一的伊宁地块。     

Late Ordovician and Early Devonian conodonts from Onoo Tolgoi area of Mongolia

Conodont samples were collected from three localities in the Onoo Tolgoi area,Mongolia, and many conodonts have been found. Conodonts from the Onoo Tolgoi Formation (M288-M294) lack index fossils; its age could be Late Silurian. Samples from the Hutul us hudag Formation (M295-M299) contain Ozarkodina pandora alpha Morph. (P element), clearly indicating that this formation is Early Devonian late Lochkovian in age. Samples collected from so-called Silurian Onoo Tolgoi Formation at other localities(M300-M303) yield many Ordovician conodonts, including Icriodella baotaensis, Icriodella cf.baotaensis, Eoplacognathus jianyeensis, Eoplacognathus protoramosus; Baltoniodus alobatus; and ?Ambalodus triangularis; the age is Late Ordovician,more precisely, early-middle Late Ordovician.     

Lower Permian formations of different geodynamic environments in A'nyemaqen ophiolitic zone (Buqingshan Mts., eastern Kunlun, Qinghai Province, China)

Lower Permian formations within the Buqingshan Mountains (A'nyemaqen ophiolitic zone, eastern sector of the eastern Kunlun) were formed in the following paleogeodynamic environments (from north to south): ( 1 ) shelf and slope of a passive continental margin in a marginal sea; (2) partially Permian metamorphic rocks of subduction-accretion complexes and volcanogenic rocks of an ensimatic island arc, of the age limited from above by the Asselian - Sakmarian;and (3) an island arc slope and oceanic trench. Subduction-accretion complexes and the island arc volcanites are overlain with a sharp angular unconformity by a carbonate-conglomerate sequence, which presents as local molasse of the Early Permian age. Based on fusulinids from the basal limestone, the age of the local molasse is first defined as the Yakhtashian-Bolorian, i.e. Artinskian-Kungurian (?). The thorough investigations revealed that the initial closure of the eastern Paleotethys within the eastern Kunlun corresponded to the Sakmarian-Yakhtashian (Artinskian) boundary, whereas in the western Paleotethys sector (Northern Pamirs) the closure occurred considerably earlier, prior to the Late Bashkirian.Thus, the idea that the Paleotethys in the eastern Kunlun reached its maximum width in the Permian, is highly questionable.During the Early Permian the A'nyemaqen branch of the Paleotethys intensely decreased. Beginning from the Bolorian (Kungurian) and up to the end of the Permian this branch represented its relict in the form ora marginal sea depression. It may be suggested that the Paleotethys closure in the A'nyemaqen took place gradually from the west to the east and covered a long period from the Late Carboniferous to the terminal Early Permian.     

Lower Permian formations of different geodynamic environments in A'nyemaqen ophiolitic zone (Buqingshan Mts., eastern Kunlun, Qinghai Province, China)

Lower Permian formations within the Buqingshan Mountains (A'nyemaqen ophiolitic zone, eastern sector of the eastern Kunlun) were formed in the following paleogeodynamic environments (from north to south): (1) shelf and slope of a passive continental margin in a marginal sea; (2) partially Permian metamorphic rocks of subduclion-accretion complexes and volcanogenic rocks of an ensimatic island arc, of the age limited from above by the Asselian - Sakmarian; and (3 ) an island arc slope and oceanic trench. Subduction-accretion complexes and the island arc volcanites are overlain with a sharp angular unconformity by a carbonate-conglomerate sequence, which presents as local molasse of the Early Permian age. Based on fusulinids from the basal limestone, the age of the local molasse is first defined as the Yakhtashian-Bolorian, i.e. Artinskian-Kungurian (?). The thorough investigations revealed that the initial closure of the eastern Paleotethys within the eastern Kunlun corresponded to the Sakmarian-Yakhtashian (Artinskian) boundary, whereas in the western Paleotethys sector (Northern Pamirs) the closure occurred considerably earlier, prior to the Late Bashkirian. Thus, the idea that the Paleotethys in the eastern Kunlun reached its maximum width in the Permian, is highly questionable. During the Early Permian the A'nyemaqen branch of the Paleotethys intensely decreased. Beginning from the Bolorian (Kungurian) and up to the end of the Permian this branch represented its relict in the form of a marginal sea depression. It may be suggested that the Paleotethys closure in the A'nyemaqen took place gradually from the west to the east and covered a long period from the Late Carboniferous to the terminal Early Permian.     

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Structural Evolution of the Eastern Margin of Eurasia in Late Mesozoic and Cenozoic

This paper features the structural evolution of the eastern margin of Eurasia in Late Mesozoic and Cenozoic.It is characterized by three stages of development: the riftogenic stage (Jurassic-Early Cretaceous), the platform stage (Late Cretaceous) and the neotectonic one (Paleogene-Quarternary). The boundaries between these stages are distinctly fixed by the geological time limits of planetary range. It is demonstrated that the riftogenic and neotectonic stages were characterized by a high degree of geodynamic activity, and the platform one by a decrease in contrast of tectonic movements. The main river net was formed in the Early Cretaceous and in the Neogene. It experienced a serious reconstruction accompanied by the formation of the Amur River valley being similar to the modem one.