贵州独山石炭系露头层序地层学研究

通过黔南独山数条剖面的追踪，对比，从岩石和生物组合特征等方面分析和研究了石炭系的副层序，沉积体系域及层序关键面和层序。副层序反映了向上变浅的过程。在滨浅海沉积过程中，地表暴露是副层序的顶界面标志之一，但不足为层序界面的标志。独山地区，从汤粑沟组至马平组共识别出30个层序，171个副层序，其中从泥盆系Cystophrentis-石炭系Pseudouralinia间隔带中的最大海泛面至马平组Pseudoschwagerina首现之下的石炭系可识别出26个层序，156个副层序。与北美大陆相比，独山地区下石炭统的层序仅在相当Homceras带的德坞阶上部少一个层序，这与下、上石炭统之间明显的沉积间断相关继承岩关期末海退的大塘期早期的第一个层序界面，即祥摆组第一层煤，可与杜内阶／维宪阶之间的层序界面相对比。独山上石炭统的副层序大体与北美大陆上石炭统的层序大体相当，仅在达拉阶／马平阶的沉积间断面之上少1个，之下少17个。石炭纪冈瓦纳冰期冰盖面积和体积的增大，可能反映到滨浅海沉积相的层序和副层序的缺失程度的增大。     

从旋回的有序叠加形式到层序的识别和划分：层序地层学进展之三

在Exxon层序地层学概念体系中,由不整合面及其可以对比的整合面所限定的地层单位被定义为 层序,即三级沉积层序;构成三级层序的单元为体系域,体系域由若干准层序和准层序组所组成。基于海岸沉 积的层序地层模式,准层序被定义为“由海泛面所限定的层或层组组成的一个相对整合的序列”;作为准层序界 面的海泛面被进一步定义为：一个将老地层与新地层分开的面,穿过该面存在一个突然的“水深加深”。因此, 从海泛面到准层序,其定义由于不具有普遍性而表现出欠完整性。虽然类似级别的地层单元后来又被Exxon的 科学家修改为“高频层序”,但是,准层序这个欠完整的概念一直被广泛使用着。与层序地层学的Exxon时代大 致同步,或者在更早的时期,地质学家就已经注意到那些由岩层所构成的沉积旋回,以“洛非尔旋回层” 为典 型代表;这种类似的旋回性沉积记录,后来被进一步定义为“米级旋回”,而且将米级旋回进一步解释为异成因 机制控制下的自旋回沉积过程（间断-加积-旋回机制;PAC机制） 的产物,这种异成因机制是与米兰柯维奇 旋回相关的极地冰盖的消长所造成的海水体积变化,以及由这种数万年至数十万年级别的海水体积变化所产生 的高频海平面变化旋回。这些厚度为数厘米至数米的沉积旋回,在长周期三级层序中常常构成有序的叠加形式, 这种叠加形式成为研究三级层序内沉积趋势变化的主要标志。再者,对与米兰柯维奇旋回存在成因关联的沉积 旋回的研究,成为另一个地层学分支---旋回地层学的主要内容。如果说对Exxon层序地层学概念体系不协调 的研究是第1个进展、对长周期层序的形成机制的探索为层序地层学的第２个进展,那么,从旋回的有序叠加 形式到层序的识别与划分,不但表现出了旋回地层学和层序地层学的交融,而且也代表了层序地层学的第3个 重要进展。     

Facies and sequence stratigraphic analysis in an intracratonic, thermal-relaxation basin: the Early Proterozoic, Lower Quilalar Formation and Ballara Quartzite, Mount Isa Inlier, Australia

The Quilalar Formation and correlative Mary Kathleen Group in the Mount Isa Inlier, Australia, conformably overlie rift-related volcanics and sediments and non-conformably overlie basement rocks. They represent a thermal-relaxation phase of sedimentation between 1780 and 1740 Ma. Facies analysis of the lower siliciclastic member of the Quilalar Formation and the coeval Ballara Quartzite permits discrimination of depositional systems that were restricted areally to either N-S-trending marginal platform or central trough palaeogeographic settings. Four depositional systems, each consisting of several facies, are represented in the lower Quilalar Formation-Ballara Quartzite; these are categorized broadly as storm-dominated shelf (SDS), continental (C), tide-dominated shelf (TDS) and wave-dominated shoreline (WDS). SDS facies consist either of black pyritic mudstone intervals up to 10 m thick, or mudstone and sandstone associated in 6–12-m-thick, coarsening-upward parasequences. Black mudstones are interpreted as condensed sections that developed as a result of slow sedimentation in an outer-shelf setting starved of siliciclastic influx. Vertical transition of facies in parasequences reflects flooding followed by shoaling of different shelf subenvironments; the shoreface contains evidence of subaerial exposure. Continental facies consist of fining-upward parasequences of fluvial origin and tabular, 0·4–4-m-thick, aeolian parasequences. TDS facies are represented by stacked, tabular parasequences between 0·5 and 5 m thick. Vertical arrangement of facies in parasequences reflects flooding and establishment of a tidal shelf followed by shoaling to intertidal conditions. WDS facies are preserved in 0·5–3-m-thick, stacked, tabular parasequences. Vertical transition of facies reflects initial flooding with wave reworking of underlying arenites along a ravinement surface, followed by shoaling from lower shoreface to foreshore conditions. Parasequences are stacked in retrogradational and progradational parasequence sets. Retrogradational sets consist of thin SDS parasequences in the trough, and C, TDS and probably WDS parasequences on the platforms. Thick SDS parasequences in the trough, and TDS, subordinate C and probably WDS parasequences on the platforms make up progradational parasequence sets. Depositional systems are associated in systems tracts that make up 40–140-m-thick sequences bounded by type-2 sequence boundaries that are disconformities. Transgressive systems tracts consist of C, TDS and probably WDS depositional systems on the platforms and the SDS depositional system and suspension mudstone deposits in the trough. The transgressive systems tract is characterized by retrogradational parasequence sets and developed in response to accelerating rates of sea-level rise following lowstand. Condensed-section deposits in the trough, and the thickest TDS parasequences on the platforms reflect maximum rates of sea-level rise and define maximum flooding surfaces. Highstand systems tract deposits are progradational. Early highstand systems tracts are represented by TDS and probably WDS depositional systems on the platforms and suspension mudstone deposits in the trough and reflect decreasing rates of sea-level rise. Later highstand systems tracts consist of the progradational SDS depositional system in the trough and, possibly, thin continental facies on the platforms. This stage of sequence development is related to slow rates of sea-level rise, stillstand and slow rates of fall. Lowstand deposits of shelf-margin systems tracts are not recognized but may be represented by shoreface deposits at the top of progradational SDS parasequence sets.     

Facies analysis and high-resolution sequence stratigraphy of the Lower Eocene shallow marine Ametlla Formation, Spanish Pyrenees

The Lower Eocene Ametlla Formation of the Ager Basin, Spanish Pyrenees, is a rapidly deposited shallow marine unit formed in a setting characterized by syn-sedimentary tectonic activity. Mapping of the formation over a distance of 25 km was conducted according to sequence stratigraphical principles with emphasis on facies analysis. Twelve facies, grouped in five facies associations, have been recognized in the Ametlla Formation. The studied succession records a vertical transition from deltaic systems prograding onto a sediment-starved shelf, via estuarine deposits associated with incised valleys, to sandbar complexes in a tidal seaway. In terms of sequence stratigraphy, three scales of genetic sedimentary units were recognized. (1) At the regional scale, elements of two 3rd-order composite sequences (sensu Exxon) have been recognized. These include a 3rd-order highstand sequence set encompassing the lowermost part of the Ametlla Formation and the underlying Passarella Formation, and a 3rd-order transgressive sequence set that constitutes the middle parts of the Ametlla Formation. The sequence sets are separated by an unconformity with up to 35 m of incision that is interpreted as a major sequence boundary. It is argued that the incised valleys associated with this unconformity were infilled during landward-stepping of the shelfal depositional system. Basinwards, the unconformable surface becomes subhorizontal and is overlain by a 2 m thick oyster bed formed in a sediment-starved setting subsequent to flooding of the incised valleys (which still acted as sediment conduits). Sandstones dominate the transgressive sequence set, whereas the highstand sequence set is dominated by siltstones, particularly in the lower part. In the transgressive sequence set, an upward increase in sand content and calibre is observed, relatable to punctuations of the transgressive trend by high-frequency sea-level fluctuations, and to downslope redistribution of sand. (2) At the subregional scale, detailed mapping indicates the presence of five 4th-order sequences. The 4th-order sequence boundaries are associated with sediment bypassing and minimal erosional relief, and were created by forced regressions during periods of relative sea-level fall. Sharp-based sandstones overlying these unconformities are believed to have accumulated during subsequent rise of relative sea-level. Where 4th-order maximum flooding surfaces can be recognized, the sequences may be subdivided into a sandstone-dominated transgressive systems tract and a siltstone-dominated highstand systems tract. (3) At the local scale, 2–9 5th-order parasequences are present within the 4th-order sequences. Superimposed parasequences are separated by flooding surfaces characterized by bioclastic accumulations, pervasive burrowing and extensive calcite cementation. The parasequences are commonly stacked in a landward-stepping manner.     

Facies and sequence stratigraphy of a Late Barremian wave-dominated deltaic deposit, Agadir Basin, Morocco

The late Barremian succession in the Agadir Basin of the Moroccan Western High Atlas represents wave-dominated deltaic deposits. The succession is represented by stacked thickening and coarsening upwards parasequences 5–15 m thick formed during fifth- or fourth-order regression and building a third-order highstand systems tract. Vertical facies transitions in parasequences reflect flooding followed by shoaling of diverse shelf environments ranging from offshore transition interbedded mudstones, siltstones and thin sandstones, lower shoreface/lower delta front hummocky bedforms to upper shoreface/upper delta front cross-bedded sandstones. The regional configuration reflects the progradation of wave-dominated deltas over an offshore setting. The maximum sea-level fall led to the development of a sequence boundary that is an unconformity. The subsequent early Aptian relative sea-level rise contributes to the development of an extensive conglomerate lagged transgressive surface of erosion. The latter and the sequence boundary are amalgamated forming a composite surface.     

Application of sequence stratigraphic concepts to the Upper Cretaceous Tununk Shale Member of the Mancos Shale Formation,south-central Utah: Parasequence styles in shelfal mudstone strata

Although sequence stratigraphic concepts have been applied extensively to coarse-grained siliciclastic deposits in nearshore environments, high-resolution sequence stratigraphic analysis has not been widely applied to mudstone-dominated sedimentary successions deposited in more distal hemipelagic to pelagic settings. To examine how sequence stratigraphic frameworks can be derived from the facies variability of mudstone-dominated successions, the Tununk Shale Member of the Mancos Shale Formation in south-central Utah (USA) was examined in detail through a combination of sedimentological, stratigraphic and petrographic methods. The Tununk Shale accumulated on a storm-dominated shelf during the second-order Greenhorn sea-level cycle. During this eustatic event, the depositional environment of the Tununk Shale shifted laterally from distal middle shelf to outer shelf, then from an outer shelf to an inner shelf environment. At least 49 parasequences can be identified within the Tununk Shale. Each parasequence shows a coarsening-upward trend via upward increases in silt and sand content, thickness and lateral continuity of laminae/beds, and abundance of storm-generated sedimentary structures. Variations in bioturbation styles within parasequences are complex, although abrupt changes in bioturbation intensity or diversity commonly occur across parasequence boundaries (i.e. flooding surfaces). Due to changes in depositional environments, dominant sediment supply and bioturbation characteristics, parasequence styles in the Tununk Shale show considerable variability. Based on parasequence stacking patterns, eleven system tracts, four depositional sequences and key sequence stratigraphic surfaces can be identified. The high-resolution sequence stratigraphic framework of the Tununk Shale reveals a hierarchy of stratal cyclicity. Application of sequence stratigraphic concepts to this thick mudstone-dominated succession provides important insights into the underlying causes of heterogeneity in these rocks over multiple thickness scales (millimetre-scale to metre-scale). The detailed sedimentological characterization of parasequences, system tracts and depositional sequences in the Tununk Shale provides conceptual approaches that can aid the development of high-resolution sequence stratigraphic frameworks in other ancient shelf mudstone successions.     

断陷湖盆层序地层单元与油气的关系

陆相湖盆层序地层单元与油气存在密切关系，目前对两关系的研究还远远不够，因此深入研究层序地层界面及所夹持的地层，对分析油气形成、聚集过程具特殊的意义．针对层序地层单元与油气的关系，通过实例分析，总结了体系域中4种成藏模式和主要层序地层界面(初次湖泛面，最大湖泛面)对油气成藏的影响和控制．同时进行了高精度层序地层学研究，以准层序单元为单位，结合实例对准层序与油气的关系进行了探讨，并进行了单井及连井剖面分析，把层序地层单元研究与沉积相有机地结合起来，取得了很好的效果．     

鲁西煤田内陆表海含煤层序的小层序类型及煤聚积规律

小层序（Ｐａｒａｓｅｑｕｅｎｃｅ）为Ⅲ级含煤层序的内部构成单元—体系域单元。研究表明，海陆交替型含煤层序可识别出稳定的能作为区域对比的周期性小层序，其顶底界面多为事件型海侵面和泥炭化事件界面。根据小层的成因特点和含煤情况，将小层序划分为:波浪作用为主形成的总体向上变细小层序、潮汐流作用为主形成的含煤小层序（有向上变细、向上变粗又变细两类）、河流作用为主受潮汐流影响形成的具有向上变粗又变细的二元结构的含煤小层序。小层序类型和小层序组的形成与内陆表海海平面变化特点具有十分密切的关系，海水的退却致使沉积体系进入废弃阶段而泥炭沼泽化，标志着小层序发育的终结。因此，研究小层序的形成与研究煤聚积规律具有密切关系。     

层序地层学应用于古地貌分析——以塔河油田为例

层序界面的形成伴随着剥蚀夷平、水道下切、构造抬升等古地貌改造作用; 层序的样式、层序-体系域-准层序的平面分布及削截、超覆尖灭、前积角度、退积幅度等地震反射特征也受古地貌的直接影响.因而, 层序地层提供了可供古地貌分析的信息.通过对塔河油田石炭系层序地层研究, 应用初始海泛面、最大海泛面上超尖灭线、坡折线、褶皱形态等标志, 识别了SQ1、SQ3层序发育时期的隆起、差异压实低凸起、斜坡、缓坡、凹陷等古地貌单元, 揭示了SQ3层序发育之前的构造挤压活动, 应用Ⅱ油组的砂体平面分布验证了古地貌分析结果.综合上述分析, SQ1、SQ3层序发育时期, 斜坡带和凹陷带有助于低位体系域砂体局部聚集, 是研究区岩性圈闭发育的有利场所.      

塔里木盆地东河1油藏低渗层层序控制特征及其对注气开发的影响

通过测井和岩心分析,将塔里木东河1油藏东河砂岩段从下到上划分为前滨-上临滨-下临滨相带,并进一步划分出11个准层序。经岩相学分析,将砂岩段低渗层分为钙质胶结低渗层、杂基充填低渗层和混合低渗层。钙质胶结低渗层主要分布在准层序内部,以方解石胶结砂岩为主,受成岩作用控制;杂基充填低渗层主要分布在准层序边界处,多为海侵背景下的滞后沉积产物;混合低渗层在准层序内部及边界均有分布,但数量很少,无明显规律性,砂粒间主要由杂基和方解石胶结物混合充填,充填物含量低。结合测压资料认为,发育在准层序边界处的杂基低渗层保留了更多的初始沉积特征,易形成横向连续性好的低渗层,是注气开发的重点关注对象。     

Firmgrounds – key surfaces in the recognition of parasequences in the Aptian Lower Greensand Group, Isle of Wight (southern England)

Aptian Lower Greensand Group exposures in the cliffs of the Isle of Wight (southern England) display a consistent coarsening-up cyclicity on the scale of centimetres to tens of metres that reflects the bed, bed-set, parasequence, parasequence set and sequence hierarchy. These coarsening-up cycles are most commonly recognized at the scale of parasequences (20 cm to 10 m thick), genetically related groups of which form parasequence sets. Both parasequences and parasequence sets contain the succession of biofacies that culminate in firmground development. Numerous episodes of erosion, deposition and colonization are recorded, reflecting multiple erosion/bypass events. The increase in mean grain-size through each cycle is reflected by changes in physical sedimentary structures; ichnofauna or bioturbational fabric; fossil fauna and diagenesis. Interbedded mudstones, siltstones and sandstones in the lower beds of each cycle display a variety of structures ranging from low-angle, hummocky, or tabular cross-strata, sandstone-filled erosional gutters and planar lamination. The cleaner sandstones found in the upper parts to each cycle are often completely bioturbated with only rare stratification and pebble/plant debris-filled scours preserved. Bioturbational fabrics change upward through each cycle from small, subhorizontal, mud- or sandstone-filled burrows to large, branching, clay-filled or cemented burrow systems. The top surface of each cycle is marked by a fossil epifauna indicative of firm to hard substrate conditions. Concentrations of bivalves, brachiopods, bryozoa, crinoids and corals are preferentially cemented by iron oxide, carbonate or phosphate. Such cements were early and thus utilized by firm or hard substrate dwellers. This fossiliferous, cemented sandstone is overlain by a flooding surface marked by the mudstone and silt-rich sandstones at the base of the next cycle. Together, the fauna and ichnofauna in each cycle represent the gradual development of firm substrate conditions, culminating in the diverse firmground fauna preserved at the top of each cycle. The fauna and changing substrate conditions reflect the hiatuses developed during successive episodes of marine flooding. High species diversity is matched by complex patterns of taphonomic feedback in the mature firmground faunas that mark major flooding surfaces. Increasing faunal maturity allows recognition of a hierarchy of hiatuses. This hierarchy is analogous to the parasequence–parasequence set division. The stratigraphic condensation of firmgrounds can be used to empirically define the condensed section, the thickness of sediment between firmgrounds being a function of sediment supply and water depth (accommodation space).     

豫西地区中、新元古代地层沉积特征及层序地层学研究

摘　要　从沉积特征研究入手‚确定各种沉积相、微相及沉积体系‚将区内中、新元古界划 分为6种沉积体系、13种沉积相和38种微相‚对副层序的主要类型及其特征进行了分析‚结 合层序界面和最大海泛面的研究确定了沉积体系域和层序。在中元古代汝阳群中划分出6个 层序‚新元古代洛峪群划分出2个层序‚震旦系划分出3个层序。在此基础上对华北地台南 部中、新元古代相对海平面变化特征进行了探讨。     

High-resolution sequence stratigraphy of a complex, incised valley succession, Cobequid Bay — Salmon River estuary, Bay of Fundy, Canada

The post-glacial succession in the Cobequid Bay — Salmon River incised valley contains two sequences, the upper one incomplete. The lower sequence contains only highstand system tracts (HST) deposits which accumulated under microtidal, glacio-marine deltaic conditions. The upper sequence contains two, retrogradationally stacked parasequences. The lower one accumulated in a wave-dominated estuarine environment under micro-mesotidal conditions. It belongs to the lowstand system tract (LST) or early transgressive system tract (TST) depending on the timing and location of the lowstand shoreline, and contains a gravel barrier that has been overstepped and preserved with little modification. The upper parasequence accumulated in the modern, macrotidal estuary, and is assignable to the late TST. Recent, net progradation of the fringing marshes indicates that a new HST has begun. The sequence boundary separating the two sequences was formed by fluvial incision, and perhaps also by subtidal erosion during the relative sea level fall. Additional local erosion by waves and tidal currents occurred during the transgression. The base of the macrotidal sands is a prominent tidal ravinement surface which forms the flooding surface between the backstepping estuarine parasequences. Because fluvial deposition continued throughout the transgression, the fluvial-estuarine contact is diachronous and cannot be used as the transgressive surface. The maximum flooding surface will be difficult to locate in the macrotidal sands, but is more easily identified in the fringing muddy sediments. These observations indicate that: (1) large incised valleys may contain a compound fill that consists of more than one sequence; (2) relative sea level changes determine the stratal stacking patterns, but local environmental factors control the nature of the facies and surfaces; (3) these surfaces may have complex origins, and commonly become amalgamated; (4) designation of the transgressive surface (and thus the LST) is particularly difficult as many of the prominent surfaces in the valley fill are diachronous facies boundaries; and (5) the transgression of complex topography may cause geologically instantaneous changes in tidal range, due to resonance under particular geographical configurations.     

测井数据小波变换用于准层序研究

层序界面的识别及其内部特征是层序地层学研究的关键问题。准层序地层单元的分界面上物理性质变化明显,测井曲线表现为突变,测井数据小波变换能够表征这种突变。以东营凹陷某井为例,选取高斯小波对SP测井数据进行小波变换,得到时频色谱图和不同尺度上的小波系数曲线。选定最佳分解尺度后,依据该尺度下小波系数模极值的位置能准确识别出准层序界面。并利用测井多尺度分析方法对不同井段GR测井曲线进行分析,得到不同尺度下的低频和高频信息能够识别出准层序内部的沉积旋回类型,建立了相应的频谱响应特征。这些探索为层序界面的定量划分及其内部特征研究提供了一种新的思路。     

塔里木盆地柯坪地区中下奥陶统碳酸盐岩露头层序地层学研究

在前人岩石地层、生物地层、年代地层研究基础上,作者运用层序地层学理论结合沉积微相分析,对柯坪地区中下奥陶统露头碳酸盐岩进行了层序地层解剖。研究区共识别出二种界面类型 (暴露层序不整合界面和淹没层序不整合界面 )、三种准层序组构特征 (潮坪、浅滩和滩下陆棚 )和两种主要类型的体系域构成 (海侵体系域和高位体系域 ),在此基础上把该套碳酸盐岩划分为 7个三级层序,其中Sq1～ 2对应于蓬莱坝组地层、Sq3～ 6对应于鹰山组地层和Sq7对应于大湾沟组地层。Sq1～ 2三级层序由潮坪旋回的藻纹层白云岩、细粉晶白云岩和灰岩组成;Sq3～ 4三级层序由潮坪旋回的藻纹层灰岩和颗粒灰岩组成;Sq5～ 6三级层序由潮下浅滩相旋回的颗粒灰岩组成;Sq7三级层序由滩下陆棚环境藻灰岩和泥质瘤状灰岩组成     

北京西山寒武系——奥陶系主要副层序类型及其形成机制探讨

北京西山寒武系－奥陶系出露良好，根据岩性组合特征，结合沉积结构，生物，地球化学等指杆标志，可区分出的副层序类型主要有６种，它们形成于不同的环境，其厚度一般几米，少数几十厘米或十几米，每类副层序中岩性可达４－６种，但单个副层序可仅由两种岩性构成，每一副层序反映的水叫是自下而上持续变浅，而在每两个副层序之间总是由浅水到深水的相跳跃。根据这些副层序的特征，可以推断在每两个副层序之间有一次海水突然加深过程     

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。     

高分辨露头层序地层学的研究基础──准层序的识别

以塔里木盆地西南缘下石炭统和什拉甫组为例，将微相分析及古生态分析应用于准层序研究之中。在此基础之上，分析沉积层序及其内部各体系域、各种界面的沉积特征。同时，根据准层序垂直叠加的特征来寻找沉积层序内部更高级次的旋回，以达到提高沉积层序的分辨率之目的，恢复该地区维宪期多级次古海平面变化特征。强调准层序分析是高分辨露头层序地层学的研究基础。     

内陆表海聚煤盆地的曾想到处分析

在华北石炭二叠纪内陆表海聚煤盆地，海侵的突发性和事件性，泥炭沼泽化的广泛性和等时性，是划分其层序内部构成单元的良好界面。研究表明，华北石炭二叠纪内陆表海聚煤盆地的层序结构为“二元结构型”，即“海侵－高位”，缺少低位体系域。海侵体系域由１～２个小层序构成，而高位体系域由小层序构成。体系域恰与小层序组对应，海侵小层序组表现为弱退积－加积型，而高位体系域则表现为弱进积－加积型。小层序为高精度的岩相古地理编图单位，它为解析层序格架和煤聚积规律提供了最可靠的依据。     

半咸水湖盆碳酸盐岩层序地层分析——以东营凹陷南坡中段沙四上亚段为例

湖相碳酸盐岩分布于淡水湖盆和咸水湖盆地中,不同类型湖盆碳酸盐岩层序发育特征与构成样式明显存在差异。综合利用岩芯、录井、测井及地震等资料,对东营凹陷南坡中段地区进行了层序地层分析,发现湖相碳酸盐岩主要分布在湖侵体系域,研究区主要存在五种准层序类型：油页岩—白云岩型、油页岩—泥（晶）灰岩型、深水（泥）页岩—颗粒灰岩型、（泥...