饶阳凹陷古近系沙河街组层序地层分析及沉积体系研究

利用地震、测井、岩心等资料,对该区进行层序地层学的分析和研究,在层序地层单元划分和对比的基础上,将饶阳凹陷古近系沙河街组划分出6个三级层序,并对每个层序的主控成因进行了详细的研究,总结出各层序的不同特点。同时对每个层序内部的沉积特点和沉积体系进行了分析,指出了层序发育对沉积体系的控制作用。研究过程中,还对层序不同体系域的油气藏类型和油气聚集规律进行了研究,并指出了各体系域可能发育的最有利的油气藏类型。     

山东滩海地区下第三系生物地层与沉积环境初探

<正> 山东滩海地区位于胜利油气区东部沿海一带,自北向南依次为埕北凹陷、埕子口凸起及沾化凹陷东部的桩西、五号桩和孤东等地(图1)。多年来的石油地质勘探表明本区下第三系构造单元复杂,沉积类型多样,地层的超覆、剥失现象普遍,为地层油气藏     

冀东柳赞油田古近系沙河街组层序地层及岩相古地理?

柳赞油田位于河北省滦南县与唐海县交界处,是冀东油田的主力油田之一。构造上处于燕山褶皱带前缘，渤海湾盆地南堡凹陷的东部。受柏各庄断层活动及古斜坡地形的影响，该区古近系沙三段地层属于近源快速堆积沉积，分选差，成熟度低，岩相复杂，为典型的扇三角洲沉积。通过对沉积特征和沉积相带展布的分析，建立了工区扇三角洲的沉积模式。以层序地层学原理和方法为手段，应用测井和三维地震资料，通过不整合面、湖泛面等层序界面和沉积旋回的识别，将柳赞油田沙河街组地层划分为4个准层序组，12个准层序，建立了高分辨率的层序地层格架，分析了准层序在垂向上的叠置样式，把准层序组归纳为进积式和退积式两种类型，确定了优质储层在准层序和准层序组中出现的位置及分布规律。论文在分析沙河街组沉积时期古地形、古气候与古生态特征的基础上，应用砂岩厚度等值线图，恢复了柳赞油田古近系沙河街组岩相古地理面貌。研究表明，工区内发育扇三角洲前缘亚相，分支水道是主要的砂体微相，砂体沿北东－南西向延伸，与古物源方向基本一致。     

青藏高原东缘古近纪粗碎屑岩沉积学及其构造意义

青藏高原东缘古近纪盆地的填图和沉积学研究表明,在青藏高原东缘区域性走滑-挤压构造背景下形成的古近纪盆地内广泛发育厚层—巨厚层状的紫红色粗碎屑岩系。其沉积特征指示为一种近源快速堆积的泥石流和辫状河道沉积体,形成于干旱炎热气候条件下的典型陆内冲积扇环境。盆地充填序列、粗碎屑岩层序、动植物化石和盆地内岩浆岩~(40)Ar-~(39)Ar年代学等综合研究结果表明,古近纪盆地内粗碎屑岩大约形成于38～29 Ma。该时期与青藏高原东缘北段(横断山地区)古近纪盆地的形成和南段(兰坪—思茅地区)大盆地的裂解时间基本一致,这很可能预示着青藏高原在晚始新世—早渐新世期间曾发生过整体的快速构造隆升。     

Paleogene island arc collision-related conglomerates, Yarlung–Tsangpo suture zone, Tibet

Coarse clastic rocks in the Liuqu Conglomerate, formed in both terrestrial and subaqueous settings, record a Paleogene phase in the tectonic evolution of Tibet. Facies changes are commonly abrupt with rapid changes in clast types, grain size and stratal patterns. Sediments were derived from the leading (northern) edge of the Indian margin and a Late Jurassic–Cretaceous intraoceanic island arc that lay within Tethys. The coarse clastic sedimentary rocks of the Liuqu conglomerates are extremely proximal, but are locally offset relative to their original source terranes. They record aspects of the history of collision between these terranes and are interpreted to have been deposited in oblique–slip basins that developed along the zone of collision. The absence of clasts derived from terranes to the north of the Yarlung–Tsangpo suture suggests that basins associated with deposition of the Liuqu Conglomerate developed prior to the final collision between India and Asia.     

New paleomagnetic pole and magnetostratigraphy of Faroe Islands flood volcanics, North Atlantic igneous province

A paleomagnetic sampling was carried out along four sections (altogether 86 lava flows, 548 samples) in the North Atlantic Igneous Province outcropping in Faroe Islands, Denmark. The four polarity zones in the 700-m-thick exposed part of the Faroes lower formation can be correlated with the geomagnetic polarity time scale as C26n-C25r-C25n-C24r. The seven lava flows erupted during C25n indicate a very low eruption rate in the upper part of the Faroes lower formation of ∼1/70 kyr. The Faroes middle and upper formations (composite thickness ∼2300 m) are all reversely magnetized corresponding to C24r. The eruption rate at the onset of middle formation volcanism was very high as evidenced by several thick lava sequences recording essentially spot readings of the paleomagnetic field. The shift in eruption rate between the Faroes lower and middle formations and evidence that onset of the Faroes middle formation volcanism took place in C24r are of particular importance, placing onset of middle formation volcanism in close temporal relation to North Atlantic continental break-up and the late Paleocene thermal maximum. After grouping flows recording the same field directions, we obtained 43 independent readings of the paleomagnetic field, yielding a paleomagnetic pole with coordinates 71.4°N, 154.7°E (A₉₅=6.0°, K=14, N=43); age 55-58 Ma. The pole is supported by a positive reversal test. Paleosecular variation, estimated as the angular standard deviation of the virtual geomagnetic pole distribution 21.7°+3.9°/−2.8°, is close to expected for the given age and paleolatitude. Our new Faroes paleomagnetic pole is statistically different from the majority of previously published poles from the British and Faroes igneous provinces, and we suggest that these older data should be used with care.     

准噶尔盆地北部古近系挤压推覆构造与沉积耦合分析

通过对准噶尔盆地北部古近系沉积充填特征及古近纪-新近纪挤压推覆构造的分析，初步确定了准噶尔盆地北缘同沉积挤压推覆作用下构造与沉积的联系，讨论了的挤压背景下后生轴成矿的问题，并试图确定古近系沉积和准噶尔盆地北缘逆冲挤压断裂带的时空对应关系。     

Sequence stratigraphic framework and distribution of depositional systems for the Paleogene in Liaodong Bay area

With a comprehensive geological and geophysical data base,the Paleogene in the Liaodong Bay area,which consists of the Kongdian,Shahejie and Donghying Formations from the base to top,was divided into 4 second-order sequences and 8 third-order sequences based on the characteristics of the se-quence boundaries. Each third-order sequence is subdivided into the lowstand,lake transgressive and highstand systems tracts. The Lowstand systems tract (LST) is mainly composed of progradational parasequence sets,while the lake transgressive systems tract (TST) largely consists of the retrograda-tional parasequence sets and the highstand systems tract (HST) is dominated by the progradational parasequence sets. The main types of depositional systems include the shallow lake,semi-deep lake,deep lake,delta,fan delta,braided fluvial delta and nearshore subaqueous fan. The braided fluvial delta and fan delta depositional systems are mainly confined to the sequences of the lower SEs4-Ek,SEs3 and SEs1 2,while the sequences of SEd3,SEd2 and SEd1 are dominated by the delta and nearshore subaqueous fan depositional systems with the latter being developed at the downthrown side of the basin-bounding fault in each sequence. The evolution of the depositional systems is always con-trolled by the paleo-tectonic setting and the ancient landform in the space and geological time. It is concluded that the most favorable reservoirs are distributed in the Liaoxi low uplift and the central Liaozhong sag.     

濮城油田沙三中亚段高分辨率层序地层学

以东濮凹陷濮城油田沙三中亚段水下扇沉积地层为例,进行了水下扇储层高分辨率层序地层学研究。通过岩心和测井资料的综合分析,在濮城油田沙三中亚段水下扇中识别出超短期、短期、中期及长期4个级次基准面旋回及其地层响应特征,在研究区划分出1个长期旋回、5个中期旋回、27个短期旋回及多个超短期旋回。在此基础上建立了研究区高分辨率等时地层格架,对基准面旋回控制下砂体发育规律进行了预测。     

Paleogene and Plio-Pleistocene basin formation around northwestern Kyushu, Japan

Cenozoic basin-forming processes in northwestern Kyushu were studied on the basis of geological and geophysical data. Gravity anomaly analysis delineated four sedimentary basins in the study area: Goto-nada, Nishisonogi, Amakusa-nada, and Shimabara. Borehole stratigraphy and reflection seismic interpretation suggest that the Goto-nada Basin was subdivided into the Paleogene and Plio-Pleistocene depocenters (Goto-nada 1 and 2). In the Paleogene, Amakusa-nada Basin was rapidly subsiding together with the Shimabara Basin as part of a large graben. Goto-nada 1 and Nishisonogi basins belonged to another depositional area. After stagnant subsidence stage in the early Miocene, the study area became a site of basaltic activity (since 10 Ma) and vigorous subsidence in the Plio-Pleistocene. Goto-nada 2 Basin is accompanied with numerous east–west active faults, and separated from the Amakusa-nada Basin by a northeast– southwest basement high, Nomo Ridge. Plio-Pleistocene subsidence of the Amakusa-nada Basin is related with low-angle normal faulting on the eastern flank of the Nomo Ridge. Shimabara Basin is a composite volcano-tectonic depression which is studded by east–west faults. Focal mechanism on active faults suggests transtensional stress regime in the study area.