华北南部地区——古生界构造演化及其油气远景

华北南部地区的地质演化与华北其他地区一样，经历了结晶基底形成，中一晚元古代台内裂谷发育、古生代稳定地台沉积和中一新生代活化等发展过程。但本区受秦岭褶皱带构造活动的强列影响。因而具有相对独特的构造演化特征和油气控制条件。早寒武世中期，古秦岭海槽伸展扩张，沉积了一套全区广泛分布的以碳酸盐岩为主夹泥页岩的地层；晚寒武世开始，古秦岭海槽向北俯冲挤压，在本区南部出现一个平行于海槽的大陆边缘隆起；中奥陶世发生     

塔里木盆地中-上奥陶统浊积岩物源分析及大地构造意义

通过地表露头及钻井取心的浊积岩沉积特征观察及古流向分析、砂岩主量元素化学成分分析及地震相分析,提出塔里木盆地奥陶系陆源碎屑浊积岩主要发育于塔东地区及塘古兹巴斯坳陷的上奥陶统之中,其浊流沉积物源主要来自盆地东南侧的阿尔金岛弧、其次来自盆地西南侧的库地活动陆缘隆起;仅盆地东北缘却尔却克山地区出露的中奥陶统顶部的却尔却克组下部陆源碎屑浊积岩的物源区,主要来自其北侧的库鲁克塔格被动陆缘隆起(台地隆起剥蚀区)。综合分析认为,晚奥陶世发生于板块南缘的阿尔金岛弧及库地活动陆缘隆起与塔里木板块的碰撞挤压运动产生的大量陆源碎屑物源,导致了板块内部多个孤立碳酸盐台地的逐步消亡及板块南部浊流盆地群的形成。     

Postcambrian stratified rocks of the northern part of the Baikal-Vitim fold area

The Ordovician stratified rocks previously referred to Riphean or Vendian are widespread in the northern part of the Baikal-Vitim fold area. They include volcanosedimentary rocks which accumulated in continental riftlike troughs after Vendian-Cambrian platform regime and were accompanied by subvolcanic bodies. The coarse-clastic facies, frequently olistostromes with olistoplaques, are abundant in the marginal parts of the troughs. The sandy-silty-clay rocks dominate in the centre. The volcanic rocks represent the contrast rhyolite-basaltic series and compose paleovolcanoes of the central type, locally, complicated by calderas. Tuffaceous material is nearly almost present in synchronous sedimentary rocks. In the Ordovician, the northern part of the Baikal-Vitim fold area was an uplift of island arc type complicated by the riftlike troughs. It occupied the central part of the Baikal-Vitim arc. The location of the troughs was subjected to its structural plan. They were formed successively after the Riphean-Vendian Baikal-Muya volcano-plutonic belt. The uplift existed within a shallow basin occupying nearly the entire Siberian Platform and Baikal-Vitim fold area. The data obtained confirm that marine sedimentary basin with islands sometimes existed within the Baikal-Vitim fold area and was a part of the basin occupying the adjacent part of the Siberian Platform. The effect of pulsating plume in the northern part of the Baikal-Vitim fold area periodically, including Ordovician, led to the origination of the uplift and to renewal of tectonic and volcano-plutonic activity.     

不整合结构构造与构造古地理环境 ——以加里东中期青藏高原北缘及塔里木盆地为例

不整合结构与不整合面结构具有不同的属性及特征.本文在分析不整合三层结构的基础上,进一步剖析了平行不整合、角度不整合、异岩不整合等3大类不整合的结构构造,划分出10个具有不同结构特征的不整合亚类.重点针对不整合面下的构造变形特征、不整合结构类型的平面分布、不整合面上的初始沉积物、物源及其层序结构等展开了精细研究,对不同结构类型的不整合形成运动学及动力学进行了初步探讨.并以塔里木盆地志留系与奥陶系不整合为例,在盆地尺度,解析不同区域不整合结构类型的特征、性质及差异.现今保留的志留系与奥陶系不整合在盆地中南部广大地区呈角度不整合,在阿瓦提-满加尔坳陷南部、巴楚隆起中西部、塔中隆起北部为低角度、北倾的单斜角度不整合;在塘古兹巴斯凹陷表现为中-低角度的断褶不整合,呈北东向展布,在巴楚隆起东部及塔中隆起的南部局部也存在北东向展布的断褶不整合.在盆地北部塔北隆起西部局部存在褶皱不整合,东部存在低角度、南倾、单斜不整合.而盆地中部在阿瓦提-满加尔凹陷中北部、塔东凹陷东北则以平行不整合为特征.结合沉积地层发育及构造演化分析,恢复了志留系沉积前构造古地理,塔里木盆地大部分为混积陆棚沉积、中部碳酸盐岩台地被逐渐淹没,满加尔及英吉苏凹陷为盆地相沉积.伴随着盆地南缘西昆仑-库地洋、南阿尔金洋的闭合及碰撞造山,在盆地南部主体为南北向的缩短,塘古兹巴斯凹陷为南东-北西向缩短,且变形强度明显大于南北向的缩短.因此,盆地南部的南东-北西向挤压作用是该期最活跃的构造作用,和田古隆起北部、塘古兹巴斯凹陷北东向加里东期褶皱带西北部,应是塔里木盆地第一期油气大规模运移聚集的有利区,值得进一步探索.本文通过对不同时期不整合结构的解剖,尝试区别分析不同期次构造事件的作用及效应,识别单一构造事件(或构造运动)在构造古地理重建及成藏、成矿中的作用.     

鄂尔多斯盆地中奥陶统马家沟组沉积环境与岩相发育特征

鄂尔多斯盆地位于华北地台西部 ,中奥陶统马家沟组含硬石膏的白云岩是盆地中主要的储层与产层之一。奥陶纪由于西侧贺兰裂谷再次开启 ,裂谷肩部发生抬升 ,以及南侧逆冲断层的左行走滑作用 ,在盆地西部和南部形成一“L”形隆起 ,又称中央隆起。在隆起东侧由均衡补偿作用伴生一西缓东陡的边侧坳陷 (盆地 ) ,称 (内 )陆棚盆地亚环境。通过沉积相研究 ,建立了两个马家沟组的沉积模式。其一为东西向穿越 (内 )陆棚盆地中心的陆棚沉积模式 ,该模式中的 (内 )陆棚盆地与中央隆起之间为水下凸起-洼地亚环境 ,其东为开阔内陆棚亚环境。马一时、马三时、马五时(内 )陆棚盆地发育为含白云岩的硬石膏岩 ,石盐岩盆地 ,盆缘主要发育白云岩-硬石膏岩坪 ,马五时西缘硬石膏岩-白云岩坪发育 ,是天然气藏主要分布区。以上表明沉积时气候干热 ,海平面下降 ,具深坳陷海水浓缩成盐特征。马二时、马四时气候湿热 ,海平面上升 ,(内 )陆棚盆地发育成石灰岩白云岩盆地 ,周围盆缘发育为 (含 )白云岩-石灰岩坪。水下凸起-洼地亚环境于马三时和马五时发育白云岩 ;马四时发育石灰岩 ,南延则过渡为白云岩、石灰岩的浅滩。东侧的开阔内陆棚亚环境 ,主要发育微晶-亮晶颗粒石灰岩、白云岩夹硬石膏岩、风暴岩。马六时 ,中央隆起以东根     

Distribution of Palaeozoic tectonic superimposed unconformities in the Tarim Basin,NW China: significance for the evolution of palaeogeomorphology and sedimentary response

Seismic and drilling well data were used to examine the occurrence of multiple stratigraphic unconformities in the Tarim Basin, NW China. The Early Cambrian, the Late Ordovician and the late Middle Devonian unconformities constitute three important tectonic sequence boundaries within the Palaeozoic succession. In the Tazhong, Tabei, Tadong uplifts and the southwestern Tarim palaeo‐uplift, unconformities obviously belong to superimposed unconformities. A superimposed unconformity is formed by superimposition of unconformities of multiple periods. Areas where superimposed unconformities develop are shown as composite belts of multiple tectonic unconformities, and as higher uplift areas of palaeo‐uplifts in palaeogeomorphologic units. The contact relationship of unconformities in the lower uplift areas is indicative of truncation‐overlap. A slope belt is located below the uplift areas, and the main and secondary unconformities are characterized by local onlap reflection on seismic profiles. The regional dynamics controlled the palaeotectonic setting of the Palaeozoic rocks in the Tarim Basin and the origin and evolution of the basin constrained deposition. From the Sinian to the Cambrian, the Tarim landmass and its surrounding areas belonged to an extensional tectonic setting. Since the Late Ordovician, the neighbouring north Kunlun Ocean and Altyn Ocean was transformed from a spreading ocean basin to a closed compressional setting. The maximum compression was attained in the Late Ordovician. The formation of a tectonic palaeogeomorphologic evolution succession from a cratonic margin aulacogen depression to a peripheral foreland basin in the Early Caledonian cycle controlled the deposition of platform, platform margin, and deep‐water basin. Tectonic uplift during the Late Ordovician resulted in a shallower basin which was followed by substantial erosion. Subsequently, a cratonic depression and peripheral or back‐arc foreland basin began their development in the Silurian to Early–Middle Devonian interval. In this period, the Tabei Uplift, the Northern Depression and the southern Tarim palaeo‐uplift showed obvious control on depositional systems, including onshore slope, shelf and deep‐water basin. The southern Tarim Plate was in a continuous continental compressional setting after collision, whereas the southern Tianshan Ocean began to close in the Early Ordovician and was completely closed by the Middle Devonian. At the same time, further compression from peripheral tectonic units in the eastern and southern parts of the Tarim Basin led to the expansion of palaeo‐uplift in the Late Devonian–Early Carboniferous interval, and the connection of the Tabei Uplift and Tadong Uplift, thus controlling onshore, fluvial delta, clastic coast, lagoon‐bay and shallow marine deposition. Copyright © 2015 John Wiley & Sons, Ltd.     

鄂尔多斯早古生代古构造

用野外露头剖面、钻井剖面和地震剖面相结合的综合研究方法,首先用人工合成记录结合11口井的VSP资料,对鄂尔多斯下古生界进行层位标定。在此基础上,对鄂尔多斯全区下古生界371条共长15 683 km的地震剖面进行了重新处理和地层解释,这大大提高了解释精度。以此为基础,把鄂尔多斯下古生界划分为5个地层单位,即寒武系中下部、寒武系中上部及冶里组和亮甲山组、马家沟群下部、马家沟群上部、平凉组和背锅山组,并作出了它们的等厚图。从这些等厚图可以看出：前4个地质时期的古构造格局为“一隆三凹”,即西缘凹陷、南缘凹陷和东缘凹陷(或东部凹陷)呈“U”形从西南东三面包围着一个中部隆起。最后一个地质时期的古构造格局为“一隆二凹”,即西缘凹陷和南缘凹陷呈“L”形镶嵌在一个巨大的鄂尔多斯隆起的西缘和南缘。到奥陶纪末,鄂尔多斯全区以及整个华北地台均变为隆起区,从而结束了鄂尔多斯隆起和凹陷并存的历史。     

鄂尔多斯奥陶纪古构造

用野外露头剖面、钻井剖面和地震剖面相结合的研究方法,对鄂尔多斯地区奥陶系213条共长8317 km的地震剖面行了重新处理和地层解释,这大大提高了解释精度。以此为基础,把鄂尔多斯奥陶系划分为10个地层单位,即冶里组、亮甲山组、马家沟一组、马家沟二组、马家沟三组、马家沟四组、马家沟五组、马家沟六组、平凉组和背锅山组,并绘制了它们的等厚图。从这些图可以看出,冶里期和亮甲山期的古构造格局为“一隆三凹”,即西缘凹陷、南缘凹陷和东缘凹陷呈“U”字形包围着一个中部隆起。到马家沟一期至六期,“一隆三凹”的古构造格局仍然基本上保持着,尽管其隆起和凹陷的形状、大小和位置均有所变化。到平凉期,古构造格局为“一隆二凹”,即西缘凹陷和南缘凹陷呈“L”形镶嵌在一个巨大的鄂尔多斯隆起的西缘和南缘。到背锅山期,古构造格局为“一隆一凹”,即一个残留的西南缘凹陷位于一个更加庞大的鄂尔多斯隆起的西南缘一隅。到奥陶纪末,鄂尔多斯地区以及整个的华北地台均变为隆起区,从而结束了鄂尔多斯地区隆起与凹陷并存的古构造格局。     

河北省兴隆煤田及邻区厚皮式逆冲推覆构造与隐伏煤田问题

在地质填图的基础上，确定了兴隆煤田南部逆冲推覆构造主逆冲带的平面展布特征，认为主逆冲断层在剖面上具有浅部缓深部陡的几何特征。运用平衡剖面基本原理估算出了由逆冲推覆所造成的水平缩短量约为１３７５ｋｍ。根据本区逆冲推覆构造的几何学与运动学特征，认为在推覆体下寻找到隐伏煤田的范围是极其有限的。     

Ordovician lithotectonic complexes in allochthons of the southern Urals

Ordovician complexes of the convergent margins of lithospheric plates are established in the Paleozoides of the southern Urals. Several types of Ordovician sections that make up allochthons and characterize different geodynamic settings are thoroughly studied and dated on the basis of conodont biostratigraphy. The geochemistry and petrology of volcanic rocks bear information on the evolution of the Paleoural ocean and the convergent relationships of plates from the end of the Llanvirnian. The suprasubduction volcanic activity in the Late Ordovician gave way to within-plate volcanism of extension zones, the development of which continued into the Early Silurian.     

基于激光U-Pb定年的埋藏白云岩形成过程——以塔里木盆地永安坝剖面下奥陶统蓬莱坝组为例

埋藏白云石化作用是形成厚层块状白云岩的主要机制之一,但其形成过程一直存在争议。本文以塔里木盆地永安坝剖面蓬莱坝组为例进行解剖,在露头和薄片岩石学研究的基础上,利用激光U-Pb定年和同位素分析,剖析了蓬莱坝组白云岩形成时期及演化过程,取得三个方面的认识：（1）蓬莱坝组发育四种类型白云岩：藻纹层白云岩、自形-半自形细中晶白云岩、雾心亮边自形中晶白云岩和他形粗晶白云岩,不同类型白云岩垂向互层发育;（2）U-Pb定年结果显示蓬莱坝组受三期云化作用改造,分别为准同生期云化作用、晚奥陶世到志留纪浅埋藏云化作用（464±12Ma到433±22Ma）及泥盆纪埋藏云化作用（382±29Ma）,浅埋藏云化作用会对准同生白云石造成重结晶,而埋藏云化作用表现为白云石次生加大,存在寒武系云化流体卷入,影响U-Pb定年;（3）规模白云岩的发育为沉积环境和构造埋藏演化史共同作用的结果,提出塔中北斜坡和塔北南缘为规模白云岩发育区,这对本区油气勘探具有重要的指导意义。     

塔里木盆地奥陶纪碳酸盐岩台地的层序结构演化及其对盆地过程的响应

塔里木盆地奥陶纪的碳酸盐岩台地发育有长达3千余千米的台地边缘带。通过综合大量的地震、钻井及野外剖面的分析,奥陶纪碳酸盐岩系中识别出4个以不整合面为界的复合（二级）层序。它们均显示出从上超的水进沉积到进积或加积的高位域的沉积结构。其内可进一步划分出10个沉积层序或三级层序。它们的组合和分布决定着碳酸盐台地沉积层序结构的基本特征。沉积层序的水进早期或高位域晚期以颗粒灰岩、生物灰岩等沉积相组合为主;而水进期或高位域早期则以泥晶-粉晶灰岩、簿层白云质灰岩等沉积相组合为主。古地貌恢复并结合钻井资料的沉积相分析揭示出,盆地东北部早、中奥陶世的碳酸盐岩台地边缘的分布受到满加尔深水凹陷的边缘斜坡带古构造地貌的控制,形成一向西凸的弧形碳酸盐岩台地边缘带,沿台地边缘发育有礁-滩沉积复合体。中奥陶世的构造古地理变革使盆内的碳酸盐岩台地分异成塔中、塔北、塘南等多个孤立台地,并由深水、半深水的凹陷所分隔。台地边缘的发育和分布常受古隆起边缘的控制。沿台地边缘的礁、滩相带为重要的有利储集层发育带。中奥陶统中央隆起带缺失中奥陶世早期和晚奥陶世早期沉积,并形成了大范围分布的喀斯特岩溶不整合面。喀斯特岩溶体系以发育垂向的、由断裂控制的串珠状洞穴和多层状分布的岩溶洞穴为特征。
     跨盆地不同构造带的井-震结合解释剖面的追踪对比表明,盆内与二级、三级层序对应的海进-海退旋回是同时变化的,并与Haq的海平面变化曲线可对比。这反映出盆地范围的或全球海平面变化对沉积旋回结构的发育具有控制作用。盆地西缘露头剖面和盆内钻井岩心的碳、氧同位素分析也为海平面变化的旋回结构分析提供了制约。主要海平面下降期的氧同位素δ18O都发生了明显的正偏。盆内晚奥陶世的海平面总体是呈上升趋势的,晚奥陶世中期海平面的上升导致了盆内碳酸盐岩台地的总体淹没。     

鄂尔多斯盆地马家沟组四段岩相古地理新认识及勘探区带优选

准确的岩相古地理恢复对鄂尔多斯盆地奥陶系马家沟组四段有利储集层预测及勘探选区选带具有重要意义。依据野外露头剖面勘查、大量新钻井岩心和岩石薄片观察、单因素图分析、测井岩石结构组分解释和地震资料解译,建立了马家沟组四段台地—台缘—盆地的沉积模式,认为台地边缘带主要沿中央古隆起展布,同时受继承性发育的寒武纪乌审旗古隆起控制,台地内发育近北东向展布的榆林—志丹次级低隆带,低隆带两侧发育台内洼地,进而形成台地内部隆洼相间的沉积格局。重磁及地震资料解释表明,鄂尔多斯盆地中晚元古代发育沿北东向展布的裂陷槽,结合怀远运动构造背景,认为该裂陷槽对马家沟期沉积格局具有重要影响。受古地貌和古裂陷槽的共同作用,马家沟组四段颗粒滩主要发育在中央古隆起和榆林—志丹低隆带,总体呈北东向近似雁列式分布,藻丘发育在盆地东部神木—米脂盐隆地区。综合构造、沉积、储集层特征及勘探实践,优选出榆林—志丹次级低隆带和神木—米脂藻丘发育带是马家沟组四段天然气大规模成藏的有利勘探区。研究结果可为鄂尔多斯盆地马家沟组四段有利储集层的预测及勘探区带优选提供重要依据。     

Holocene beach deposits for assessing coastal uplift of the northeastern Boso Peninsula, Pacific coast of Japan

This paper presents a case study that assessed spatial variations in the tectonic uplift rates of beach deposits in the relict Kujukuri strand plain, situated on the northeastern coast of the Boso Peninsula, eastern Japan. The southern Boso Peninsula is tilted downward to the northeast due to plate subduction along the Sagami Trough. However, the cause of the northeastern coast uplift creating the relict strand plain is unclear, due to the absence of a Holocene raised marine terrace sequence. Elevations and ages of beach deposits were collected from drilled cores and ground-penetrating radar profiles along three shore-normal sections in the southern Kujukuri strand plain. From this, alongshore variations in the relative sea level since the mid-Holocene could be seen. These corresponded to north-to-northeast downward tilting at a rate of 0.4 m/ka for an interval 10 km and are concordant with the longer term tilting of the last interglacial marine terrace surrounding the plain. Although it is difficult to assess shore-normal variations of uplift based on the present dataset, the recognized tilting apparently continues to the tilting of the southern Boso Peninsula, implying the Sagami Trough probably affects the uplift of the Kujukuri coast.     

Crustal deformation in the Central Ionian Islands (Greece): Results from DGPS and DInSAR analyses (1995–2006)

Ground deformation studies based on Differential GPS (DGPS) and Differential Interferometric SAR (DInSAR) analyses have been conducted in the seismically active area of the Central Ionian Islands. Local GPS networks were installed in Cephallonia (2001) and Zakynthos (2005). The Cephallonian network has been remeasured five times and Zakynthos' once as of July 2006. The studies have yielded detailed information regarding both local and regional deformations that are occurring in the area.For Lefkas Island, DInSAR analysis (March to September 2003) revealed 56 mm of uplift in the central and western parts and is attributed to the August 2003 earthquake (M_w = 6.3) that occurred offshore to the west. Synthetic DInSAR modelling of the magnitude and extent of deformation is consistent with the seismologically deduced parameters for the ruptured segment along the Lefkas Transform Fault. Subsidence (< 28 mm) along the northern part of the island is attributed to local conditions unrelated to the earthquake. For Zakynthos Island, large-magnitude earthquakes that occurred offshore to the south in October 2005 and April 2006 most likely contributed to the observed deformation as deduced from DGPS measurements for an encompassing period (August 2005 to July 2006). The largest amount of horizontal deformation occurred in the south, where its western part moved in a W–NW direction, while the eastern part moved towards the NE, with magnitudes ranging from 15 to 26 mm. The southern part of the island uplifted a maximum of 65 mm whereas the north subsided from 12 to 28 mm.For Cephallonia Island, DInSAR analysis (1995 to 1998) indicated ground deformation up to 28 mm located in small sections of the island. Further interferometric analysis for the period 2003 to 2004, encompassing the occurrence of the Lefkas earthquake in August 2003, indicated 28 mm of uplift in the northern part, while during the next two years (2004 to 2005), further uplift of at least 56 mm had taken place at the western and northern part of the island.DGPS measurements for the period 2001 to 2006 revealed a clockwise rotation of the island with respect to a centrally located station on Aenos Mt. The horizontal component of deformation generally ranged from 6 to 34 mm, with the largest values at the western and northern parts of the island. Considering the vertical deformation, two periods are distinguished. The first one (2001 to 2003) is consistent with anticipated motions associated with the main geological and tectonic features of the island. The second one (2003 to 2006) has been tentatively attributed to dilatancy in which relatively small uplift (20–40 mm) occurred along the southern and southeastern parts of the island, while larger magnitudes (> 50 mm) happened at the western part (Paliki Peninsula). These large magnitudes of uplift over an extended area (> 50 km), in conjunction with an accelerated Benioff strain determined from the analysis of the seismicity in the broader region, are consistent with dilatancy. This effect commenced some time after 2003 and is probably centered in the area between Zakynthos and Cephallonia. If this interpretation is correct, it may foreshadow the occurrence of a very strong earthquake(s) sometime during 2007 to 2008 in the above designated region.     

鄂尔多斯盆地中奥陶统马五6亚段高频旋回层序研究:论海平面升降与横山凸起沉积分异效应*

高频旋回分析有利于揭示浅水碳酸盐岩台地海平面升降、沉积物响应、古地理单元演化及对盆地内沉积分异影响等诸多沉积学信息。依据鄂尔多斯盆地横山地区丰富的钻井取心资料,通过岩石类型、典型五级旋回结构等分析,对中奥陶统马家沟组马五₆亚段开展了高频旋回研究。研究表明: (1)基于研究区内马五₆亚段碳酸盐岩与蒸发岩共生组合的9种岩石类型,识别出5种典型T-R单旋回,其中旋回Ⅰ、Ⅱ、Ⅲ为云质潟湖—颗粒滩—灰泥丘沉积,Ⅳ、Ⅴ为膏盐质潟湖沉积,并以5种单旋回为基本单元搭建骨架井五级高频旋回结构剖面;(2)依据五级高频旋回结构剖面建立的Fischer图解,认为马五₆亚段处于三级旋回晚期,内部发育“2个”四级旋回,具有初次海退—快速海侵—再次海退的相对海平面变化趋势;(3)结合五级旋回厚度统计,认为第1套四级旋回沉积期处于隆拗格局发育阶段,该时期横山凸起作为水下高地,对东西两侧海水封隔明显;至第2套四级旋回沉积阶段,填平补齐作用导致横山凸起影响减弱,海水循环得到改善,凸起东西两侧盐度明显下降。以马五₆亚段为例的高频旋回研究,在横山地区马五₆亚段地层学、沉积学研究中取得了较好的效果,以期在鄂尔多斯盆地马家沟组未来研究中得到进一步推广和实践。     

鄂尔多斯盆地中奥陶统马五6亚段高频旋回层序研究:论海平面升降与横山凸起沉积分异效应*

高频旋回分析有利于揭示浅水碳酸盐岩台地海平面升降、沉积物响应、古地理单元演化及对盆地内沉积分异影响等诸多沉积学信息。依据鄂尔多斯盆地横山地区丰富的钻井取心资料,通过岩石类型、典型五级旋回结构等分析,对中奥陶统马家沟组马五₆亚段开展了高频旋回研究。研究表明: (1)基于研究区内马五₆亚段碳酸盐岩与蒸发岩共生组合的9种岩石类型,识别出5种典型T-R单旋回,其中旋回Ⅰ、Ⅱ、Ⅲ为云质潟湖—颗粒滩—灰泥丘沉积,Ⅳ、Ⅴ为膏盐质潟湖沉积,并以5种单旋回为基本单元搭建骨架井五级高频旋回结构剖面;(2)依据五级高频旋回结构剖面建立的Fischer图解,认为马五₆亚段处于三级旋回晚期,内部发育“2个”四级旋回,具有初次海退—快速海侵—再次海退的相对海平面变化趋势;(3)结合五级旋回厚度统计,认为第1套四级旋回沉积期处于隆拗格局发育阶段,该时期横山凸起作为水下高地,对东西两侧海水封隔明显;至第2套四级旋回沉积阶段,填平补齐作用导致横山凸起影响减弱,海水循环得到改善,凸起东西两侧盐度明显下降。以马五₆亚段为例的高频旋回研究,在横山地区马五₆亚段地层学、沉积学研究中取得了较好的效果,以期在鄂尔多斯盆地马家沟组未来研究中得到进一步推广和实践。     

北山地区早古生代板块构造特征

位于甘肃省西北边界和内蒙古自治区西端的北山地区,早古生代大地构造单元由塔里木板块东段北缘和北侧贝加尔期分裂出来的旱山微板块组成,其间被石板井-小黄山蛇绿混杂岩带所分隔。在漫长的构造演化进程中发育有蛇绿岩带。同时,经历了大西洋型、安第斯型(?)和西太平洋型大陆边缘的演化阶段,陆壳增厚,地壳成熟度增加,由大洋地壳和过渡型地壳向大陆型地壳转化。晚古生代初,全区进入板内活动时期。     

塔里木盆地轮南地区奥陶系沉积储层研究新进展

近期轮南奥陶系沉积储层研究取得了几个方面的重要进展:发现了两期三套风化壳岩溶储集系统,其中海西期一套,存在于奥陶系顶部,加里东期两套,存在于奥陶系内部;确定了轮古东奥陶系储集层为风化壳岩溶缝洞性储层;发现了桑塔木组礁滩相储集层。桑塔木组沉积早期轮南地区具有成礁环境,局部发育有小型生物礁;修正了以往对奥陶系沉积相的划分,将奥陶系碳酸盐台地边缘的位置东移30km;提出了奥陶系内部风化壳储层形成的热沉降机制,认为晚奥陶世早期塔里木盆地存在一次热升降运动,该运动使轮南地区发生不均衡抬升,奥陶系良里塔格组出露剥蚀,形成轮南地区广泛分布的风化壳岩溶储集系统,从而揭示了轮南地区奥陶系更为良好的勘探前景。     

黔东南凯里—麻江—丹寨地区奥陶系红花园组古岩溶储层特征

黔东南凯里—麻江—丹寨地区(构造上位于黔南坳陷东北部)下奥陶统红花园组为一套生物碎屑灰岩。该区已发现的麻江古油藏尚未取得油气勘探进展。对区内多处露头剖面中—下奥陶统进行了宏观勘查和采样以及岩样微观薄片分析,证实该套地层曾发生古岩溶作用,并可识别出埋藏岩溶和风化壳岩溶两类古岩溶作用。基于这些岩溶剖面的对比分析,发现古风化壳岩溶受早中奥陶世古隆起及剥蚀时间控制,主要发育于古隆起区麻江古油藏一带,而其它地区为埋藏岩溶。认为古风化壳岩溶形成大量溶蚀孔洞缝,为红花园组提供了优质储层条件。此外在中—下奥陶统大湾组碎屑岩覆盖下的红花园组碳酸盐岩也可以发生埋藏岩溶并形成较好的岩溶型储层。红花园组在黔南坳陷东北部的油藏大多有过暴露或破坏。认为在坳陷西南部寻找古隆起区附近的上述两类储层应是油气勘探方向。