Mesophotic coral buildups in a prodelta setting (Late Eocene,southern Pyrenees,Spain): a mixed carbonate–siliciclastic system

Lower Priabonian coral bioherms and biostromes, encased in prodelta marls/clays, occur in the Aínsa‐Jaca piggyback basin, in the South Central Pyrenean zone. Detailed mapping of lithofacies and bounding surfaces onto photomosaics reveals the architecture of coral buildups. Coral lithosomes occur either isolated or amalgamated in larger buildups. Isolated lithosomes are 1 to 8 m thick and a few hundred metres wide; clay content within coral colonies is significant. Stacked bioherms form low‐relief buildups, commonly 20 to 30 m thick, locally up to 50 m. These bioherms are progressively younger to the west, following progradation of the deltaic complex. The lowermost skeletal‐rich beds consist of bryozoan floatstone with wackestone to packstone matrix, in which planktonic foraminifera are abundant and light‐related organisms absent. Basal coral biostromes, and the base of many bioherms, consist of platy‐coral colonies ‘floating’ in a fine‐grained matrix rich in branches of red algae. Corals with domal or massive shape, locally mixed with branching corals and phaceloid coral colonies, dominate buildup cores. These corals are surrounded by matrix and lack organic framework. The matrix consists of wackestone to packstone, locally floatstone, with conspicuous red algal and coral fragments, along with bryozoans, planktonic and benthonic foraminifera and locally sponges. Coral rudstone and skeletal packstone, with wackestone to packstone matrix, also occur as wedges abutting the buildup margins. Integrative analysis of rock textures, skeletal components, buildup anatomy and facies architecture clearly reveal that these coral buildups developed in a prodelta setting where shifting of delta lobes or rainfall cycles episodically resulted in water transparency that allowed zooxanthellate coral growth. The bathymetric position of the buildups has been constrained from the light‐dependent communities and lithofacies distribution within the buildups. The process‐product analysis used here reinforces the hypothesis that zooxanthellate corals thrived in mesophotic conditions at least during the Late Eocene and until the Late Miocene. Comparative analysis with some selected Upper Eocene coral buildups of the north Mediterranean area show similarities in facies, components and textures, and suggest that they also grew in relatively low light (mesophotic) and low hydrodynamic conditions.     

北京西郊下苇甸剖面寒武系崮山组叠层石生物丘的沉积组构

北京西郊下苇甸剖面的崮山组,属于寒武系第三统顶部,自下而上从陆棚相泥灰岩向上变浅至鲕粒滩相灰岩,组成一个淹没不整合型三级沉积层序。在该组上部的一层块状鲕粒滩相颗粒灰岩中,发育串珠状分布的、可以归为叠层石生物丘的穹窿状构造。这些叠层石生物丘,典型的地势隆起和突变的边界代表了明显的早期石化作用特征。叠层石生物丘中的柱状叠层石,为典型的泥晶相叠层石,其内部除了黏结较多的三叶虫生物碎屑外,还不均匀地分布着放射-纤维状方解石(或文石？)组成的底栖鲕粒。这些底栖鲕粒,以其较小的粒径、多样的类型、平滑但不连续的鲕粒圈层以及外部边缘的泥晶套等特征,明显区别于宿主岩石中的颗粒滩相悬浮鲕粒,而且表现出较为明显的与微生物活动相关的微组构。鉴于叠层石是典型的微生物席建造物,该叠层石生物丘特别的宏观和微观沉积组构还可以进一步将其归为较为典型的"微生物礁",从而成为研究中奥陶生物大辐射事件之前贫乏骨骼的浅海环境的沉积作用样式、以及更加深入理解这一特殊时期的微生物造礁作用特征提供了一个较为典型的实例。     

Facies distribution of the Lower Cambrian cryptic microbial and epibenthic archaeocyathan-microbial communities, western Anti-Atlas, Morocco

Marine microbial communities recorded in the Moroccan Anti‐Atlas were unaffected across the Neoproterozoic–Cambrian transition. A stromatolite‐dominated consortium was replaced at the beginning of the Atdabanian (ca 20 Myr after the Neoproterozoic–Cambrian boundary) by shelly metazoan and thromboid consortia, which contain the oldest biostratigraphically significant fossils of the Moroccan Cambrian. The associated collapse of microbial mat (stromatolitic) growth appears to coincide with a change from pre‐Atdabanian shallow‐water restricted conditions into Atdabanian deeper, open‐sea conditions. It is postulated that this environmental change led to an episode of improved water circulation over carbonate platform interiors, promoting shelly metazoan immigration into the region. The Tiout/Amouslek lithostratigraphic contact in the early Atdabanian marks the end of an episodically unstable seafloor as suggested by the abundance of slumping and sliding structures, and synsedimentary microfaults and cracks recorded in the underlying Tiout Member. Concurrent with the transition is the occurrence of a network of cryptic fissures and cavities that provided habitats for a coelobiontic chemosynthetic–heterotrophic microbial community composed of stromatolitic crusts, Renalcis–Epiphyton–Girvanella intergrowths, and Kundatia thalli. In the overlying Amouslek Formation, archaeocyathan–thromboid reefs were constrained by substrate stability, water depth and subsidence rate. Four reef geometries are distinguished: (i) patch reefs surrounded by shales, (ii) bioherms in which flank beds intercalate laterally with carbonate and shale inter‐reef sediments, (iii) biostromes or low‐relief structures formed as a result of lateral accretion of patch reefs, and (iv) kalyptrate complexes that nucleated because of a marked tendency for aggregation, and in which patch reefs and bioherms occur stacked together bounded by clay–marl–silt seams.     

Platforms: Shorikha formation of the Turukhansk uplift, Siberia

the shorikha basin characterized by a thick (>800 m) sequence of carbonate sediments in the upper part of the riphean section in the turukhansk uplift of siberia illustrates the dynamics of taxonomic diversity and abundance of stromatolite buildups related to changes in the structure of a carbonate platform (replacement of the relatively deep ramp by a spacious shallow shelf) and fluctuations of the relative sea level. it is shown that abundance and taxonomic diversity of stromatolite buildups were maximal in deep zones of the outer ramp being reduced to almost zero values in shallow settings of the carbonate shelf. the appearance of columnar stromatolites coincided in this basin only with brief sea-level rises (second-order transgressions). stromatolite-forming microbial communities represented an active producer of carbonate sediments for the entire basin, while the distribution of stromatolites through ramps was determined by geochemical barriers. disappearance of stromatolites from shallow carbonate shelves was controlled by rapid reduction in carbonate-production rates.     

Reefs in the Early Paleozoic Taebaek Group, Korea: A Review

Various early Paleozoic (Cambrian Series 3–Middle Ordovician) reefs are found in the Taebaek Group, eastern Korea, located in the eastern margin of the Sino-Korean Block. They occur in every carbonate-dominant lithostratigraphic unit of the group, but their morphology and composition differ markedly. The Daegi Formation (middle Cambrian: Cambrian Series 3) contains siliceous sponge-Epiphyton reefs formed in a shallow subtidal environment, which is one of the earliest metazoan-bearing microbial reefs after the archaeocyath extinction. The Hwajeol Formation (upper Cambrian: Furongian) encloses sporadic dendrolites consisting of Angulocellularia, which developed in a relatively deep subtidal environment, representing a rare deeper water example. The onset of the Ordovician radiation resulted in the formation of microbialite–Archaeoscyphia–calathiid patch reefs in shallow subtidal deposits of the Lower Ordovician Dumugol Formation. Subsequent late Early Ordovician relative sea-level fall established extensive peritidal environments, forming microbial mats and stromatolites of the Lower–Middle Ordovician Makgol Formation. Ensuing Ordovician radiation resulted in one of the earliest metazoan skeletal reefs of the Middle Ordovician Duwibong Formation, constructed by stromatoporoid Cystostroma and bryozoan Nicholsonella, and developed around shallow shoals. These reefs reflect ongoing evolution and sea-level change during the early Paleozoic, and exemplify a rare glimpse of peri-Gondwanan records of reef evolution, which warrant detailed investigations and comparison with their counterparts in other regions.     

Facies, geometry and geological significance of Late Ordovician (early Caradocian) coral bioherms: Lourdes Formation, western Newfoundland

Late Ordovician coral bioherms in the Lourdes Formation of western Newfoundland exhibit a complex mixing of architectural elements, including framework, boundstone and suspension deposits. The bioherms occur within a narrow (16 m) stratigraphic interval, and a prominent unconformity truncates the interval of bioherm growth and tops of many of the bioherms. The buildups developed along a carbonate ramp. They occur isolated and in groups, individuals in groups are aligned in parallel orientation. The sizes of the bioherms range from small (50–100 cm) coral piles to columnar and dome‐shaped masses (1–15 m); however, topographic relief was never more than ≈1 m. Bioherm construction reflects: (i) stacking of the tabulate coral Labyrinthites chidlensis, and less common stromatoporoids; (ii) accumulation of microbial‐stromatoporoid boundstone and suspension deposits within shelter cavities between corals; and (iii) detrital bioherm‐flank skeletal grainstone beds. Trypanites borings are common in the tops of coral heads. The bioherms exhibit three growth‐development stages: (i) seafloor stabilization, wherein rare, abraded coral colonies lie scattered within pelmatozoan/skeletal grainstone lenses; (ii) colonization, wherein corals (L. chidlensis), rare stromatoporoids (Labechia sp.), and other biota (bryozoans) produced a bioherm overlying the basal sediment base; and (iii) diversification, which is marked by a more diverse range of fauna and flora as well as occurrence of shelter‐cavity deposits. The diversification stage usually makes up more than 70% of a bioherm structure, and, in some defines multiple periods of start‐up and shut‐down of bioherm growth. The latter is defined by bored omission surfaces and/or deposition of inter‐bioherm sediment. The Lourdes bioherms have a similar ecological structure, biotic diversity and depositional environment to patch reefs in the equivalent Carters Limestone in Tennessee. The mixture of coral stacking and boundstone as architectural elements identify an Early Palaeozoic transition of reef‐design development along shallow‐water platforms that began to displace the muddy (boundstone, bafflestone) carbonate buildups more typical of the Early and Middle Ordovician time.     

Organic (coral) buildups in the carboniferous at the southwestern margin of the East European Platform

Organic buildups (biostromes and bioherms) were established for the first time in the coal-bearing formation of the Lvov-Volynsk coal basin. Colonial rugose corals of the Siphonodendron genus represented the main bioherm-builders. Coral buildups were formed under shallow marine conditions and located within the active tectonic region at the southwestern margin of the East European Platform. The region represents a northwest-trending band (10–12 km wide) extending over more than 70 km. The studied late Visean coral bioherms and biostromes are similar to coeval ones from some European regions.     

龙门山北段志留系宁强组沉积特征和空间相变

丘状隆起、链状相连的北东向带状堤礁是龙门山北段地区志留系宁强组的一个突出特点。详细的剖面研究和路线地质追踪表明：(1)狭长带状的堤礁夹持于南东侧杂色砂／泥质滨岸沉积带和北西侧陆架泥页岩带之间，指示了一个清晰的向西北渐深的古陆架形态和古海岸边缘轮廓；(2)丘状礁灰岩体、层状生物碎屑灰岩体与东南侧陆缘滨岸带的砂体及北西侧的陆架泥岩呈现明显的指状穿插和渐变过渡关系，代表了海平面、陆源碎屑输入量频繁变化背景下的沉积响应；(3)点状零星分布的礁灰岩体是在面状礁灰岩或生物碎屑灰岩层基础上发育起来的；(4)晚志留世，杂色砂／泥质滨岸沉积向北西进积并超覆于礁灰岩之上，并最终导致本区隆升成陆，则表明加里东构造运动末期发生的上扬子地块隆升、西北缘古陆扩展及海平面的相对下降趋势，是沉积盆地演变的主控因素。     

Lower Cambrian shelf and shelf margin buildups,Flinders Ranges,South Australia1

Carbonate buildups in the Flinders Ranges of mid-Early Cambrian age grew during a period of high archaeocyath diversity and are of two types: (1) low-energy, archaeocyath-sponge-spicule mud mounds, and (2) high-energy, archaeocyath-calcimicrobe (calcified microbial microfossil) bioherms. Mud mounds are composed of red carbonate mudstone and sparse to abundant archaeocyath floatstone, have a fenestral fabric, display distinct stromatactis, contain abundant sponge spicules and form structures up to 150m wide and 80 m thick. Bioherms are either red or dark grey limestone and occur as isolated small structures 2–20 m in size surrounded by cross-bedded calcarenites and calcirudites or as complexes of mounds and carbonate sands several hundreds of metres across. Red bioherms comprise masses of white Epiphyton with scattered archaeocyaths and intervening areas of archaeocyath-rich lime mudstone. Grey bioherms are complex intergrowths of archaeocyaths, encrusting dark grey Renalcis and thick rinds of fibrous calcite cement. The bioherms were prone to synsedimentary fracturing and exhibit large irregular cavities, up to 1.5 m across, lined with fibrous calcite. The buildups are isolated or in contiguous vertical succession. Mud mounds occur alone in low-energy, frequently nodular, limestone facies. Individual bioherms and bioherm complexes occur in high-energy on-shelf and shelf-margin facies. The two types also form large-scale, shallowing-upward sequences composed of basal (deep water) mud mounds grading upward into archaeocyath-calcimicrobe bioherm complexes and bioherms in cross-bedded carbonate sands. The uppermost sequence is capped by ooid grainstone and/ or fenestral to stromatolitic mudstone. The calcimicrobe and metazoan associations form the two major biotic elements which were to dominate reefs throughout much of subsequent Phanerozoic time.     

河北柳江盆地中晚寒武世藻类丘礁的演化

河北柳江盆地中晚寒武世藻类丘礁十分发育，并形成完好纵向演化序列。藻礁具有两个演化方向，其一是骨骼钙藻Ｅｐｉｐｈｙｔｏｎ向非骨骼蓝绿藻方向演化；其二是块状藻丘向厚层状叠层石礁方向演化。藻类丘礁的演化特征及其沉积相序揭示了该区中晚寒武世时从碳酸盐台地边缘斜坡至台缘浅滩和潮坪环境的演化历史。     

The carbonate factory of Middle Triassic buildups in the Dolomites, Italy: a quantitative analysis

Middle Triassic carbonate buildups of the Dolomites were high in relief (500–1000m) and small in size (one to a few square kilometres in area). A paradox results from the carbonate platform model that invokes the platform top, including reef rims, as the carbonate factory and flanking beds as talus deposits. Most buildups consist largely of clinoforms (inclined at 10-50°) whereas massive reef rocks and stratified buildup interiors are poorly developed or absent. Facies and modal analysis of 323 thin sections from buildups of the Marmolada indicate that clinoforms are: (i) predominantly composed of in situ boundstones (56% of all samples); (ii) primarily made up of early cements (37 vol.%), microbial crusts (17 vol.%), micritic intraclasts (10 vol.%) and Tubiphytes (8 vol.%); and (iii) contain diagnostic shallow water grains (dasyclads, coated grains) that are less abundant by 1-2 orders of magnitude compared with buildup interior facies. These data suggest that the clinoforms themselves were the main carbonate factory of the Triassic buildups. Stratified buildup interior rocks and massive reef rocks were apparently not a prerequisite for buildup growth and clinoform progradation.     

Platform and off-platform carbonates of the Upper Cambrian of western Maryland, U.S.A.

Upper Cambrian carbonates in western Maryland are comprised of platform facies (Conococheague Limestone) west of South Mountain and basin facies (Frederick Limestone) east of South Mountain. Conocheague platform carbonates contain interbedded non-cyclic and cyclic facies. Non-cyclic facies consist of cross-stratified grainstones, thrombolitic bioherms, and graded, thin-bedded dolostones. These were deposited in shallow, subtidal shelf lagoons. Cyclic facies are composed of repeated sequences of cross-stratified grainstone; ribbon-rock; wavy, prism-cracked laminite; and planar laminated dolostone. The cyclic facies are shallowing-upward cycles produced by lateral progradation of tidal flats over shallow, nearshore subtidal environments. Cyclic and non-cyclic facies are interbedded in the Conococheague in a layer cake fashion, but no higher-order cyclicity can be found. The Frederick Limestone is dominated by monotonously thick sequences of graded, thin-bedded limestones, interbedded with massive peloidal grainstones and beds of breccia up to 10 m thick in the lower Frederick. The breccias contain transported megaclasts of Epiphyton-Girvanella boundstones. The basal Frederick was deposited in a slope-to-basinal setting east of a rimmed shelf. An Epiphyton-Girvanella marginal reef along the shelf edge was the source of the blocks in the breccias. The upper Frederick Limestone formed on a carbonate ramp.     

Carbonate ramp-to-deeper shale shelf transitions of an Upper Cambrian intrashelf basin, Nolichucky Formation, Southwest Virginia Appalachians

The Nolichucky Formation (0–300 m thick) formed on the Cambrian pericratonic shelf in a shallow intrashelf basin bordered along strike and toward the regional shelf edge by shallow water carbonates and by nearshore clastics toward the craton. Lateral facies changes from shallow basinal rocks to peritidal carbonates suggest that the intrashelf basin was bordered by a gently sloping carbonate ramp. Peritidal facies of the regional shelf are cyclic, upward-shallowing stromatolitic carbonates. These grade toward the intrashelf basin into shallow ramp, cross-bedded, ooid and oncolitic, intraclast grain-stones that pass downslope into deeper ramp, subwave base, ribbon carbonates and thin limestone conglomerate. Ribbon limestones are layers and lenses of trilobite packstone, parallel and wave-ripple-laminated, quartzose calcisiltite, and lime mudstone arranged in storm-generated, fining upward sequences (1–5 cm thick) that may be burrowed. Shallow basin facies are storm generated, upward coarsening and upward fining sequences of green, calcareous shale with open marine biota; parallel to hummocky laminated calcareous siltstone; and intraformational flat pebble conglomerate. There are also rare debris-flow paraconglomerate (10–60 cm thick) and shaly packstone/wackestone with trace fossils, glauconite horizons and erosional surfaces/hardgrounds. A 15-m thick tongue of cyclic carbonates within the shale package contains subtidal digitate algal bioherms which developed during a period of shoaling in the basin. Understanding the Nolichucky facies within a ramp to intrashelf basin model provides a framework for understanding similar facies which are widely distributed in the Lower Palaeozoic elsewhere. The study demonstrates the widespread effects of storm processes on pericratonic shelf sedimentation. Finally, recognition of shallow basins located on pericratonic shelves is important because such basins influence the distribution of facies and reservoir rocks, whose trends may be unrelated to regional shelf-edge trends.     

四川盆地下寒武统筇竹寺组沉积特征及其对构造的响应

随着四川盆地页岩油气的勘探和开发,下寒武统筇竹寺组页岩受到广泛关注,但是由于埋藏深度大、钻井资料有限,该套地层在四川盆地的沉积特征差异尚不清晰。通过露头剖面观测、岩芯描述、主微量元素地球化学分析等,对四川盆地筇竹寺组页岩沉积特征进行综合研究。通过分析了四川盆地不同地区筇竹寺组岩性纵向上的变化及组合关系划分出4种不同岩性组合类型。针对不同构造背景下岩性组合类型的异同,总结了筇竹寺组沉积相类型。受构造运动影响,四川盆地早寒武世各地区构造背景有一定区别。筇竹寺页岩沉积厚度大且有机质富集的川东北城口地区、川中绵阳—长宁地区、川东南石柱等地区均与拉张槽、热水沉积以及特殊的构造位置相关。通过对四川盆地不同地区内筇竹寺组岩相组合和沉积旋回的划分、对比,以及古环境的氧化—还原性、气候、生产力等差异,明确了早寒武世不同构造背景下筇竹寺组沉积演化差异。本研究建立了四川盆地下寒武统筇竹寺组川东北浅水缓斜坡沉积体系、川东南浅水陆棚区沉积体系、滨岸海滩—陆棚沉积体系和陆棚内凹陷（拉张槽）沉积体系,为筇竹寺组海相页岩进一步勘探开发提供参考。     

Cryptalgal-metazoan bioherms of early Ordovician age in the St George Group, western Newfoundland

Bioherms are common in the St George Group, a sequence of shallow-water carbonate rocks deposited on the western continental shelf of Iapetus Ocean. They range from small heads and metre-sized mounds to extensive banks and complexes many metres thick and hundreds of metres in lateral extent. The cores of these bioherms are principally composed of thrombolites (unlaminated, branching, columnar stromatolites), structures quite distinct from laminated stromatolites which are common in intertidal beds. Associated with thrombolites is a diverse fauna of burrowing invertebrates, trilobites, nautiloids, pelmatozoans, brachiopods, gastropods, rostroconchs and archaeoscyphiid sponges. On the basis of framework-building components, three main bioherm types are distinguished: (1) thrombolite mounds, (2) thrombolite-Lichenaria or -sponge mounds and (3) thrombolite-Lichenaria-Renalcis reef complexes. The framework of the last is the most complex, with abundant cavities and a demonstrably uneven growth surface of thrombolites, corals and free-standing Renalcis heads, walls and roofs. Some cavities were active sediment conduits while others were protected, their roofs draped with Renalcis and their walls coated by cryptalgal laminites. These bioherms possess the attributes of shallow-water ecologic reefs. They span a critical time gap in the development of reefs, the transition period from algal-dominated bioherms of the Precambrian and Cambrian to the metazoan-dominated bioherms of the Middle Ordovician and remaining Phanerozoic.     

川东—武陵山地区下寒武统牛蹄塘组页岩有机质富集模式

有机质富集、保存对页岩气资源评价、勘探选区和开发具有重大的指导意义。以川东—武陵山地区下寒武统牛蹄塘组页岩为例,利用岩石地球化学、油气地球化学和沉积岩石学方法和技术对牛蹄塘组有机质丰度、有机质来源及古环境演化进行了分析,对川东—武陵山地区页岩有机质富集和保存条件进行了评价。结果表明:牛蹄塘组页岩有机质主要来自于蓝藻、红藻、褐藻等自生海洋藻类;相比于牛蹄塘组高位体系域,在牛蹄塘组海侵体系域页岩沉积期,温暖湿润的古气候和大规模海侵使得海平面快速上升,海侵导致深水陆棚、斜坡甚至部浅水陆棚处于贫氧—缺氧环境,该深水贫氧—缺氧还原环境（部分硫化还原环境）有利于有机质保存,在川东—武陵山地区上形成大面积富有机质页岩。      

上扬子黔北地区下寒武统海相黑色泥页岩特征及页岩气远景区评价

依据大量野外页岩实测地质剖面和2口页岩气钻井、样品岩石矿物组分分析、有机地球化学实验等大量分析测试资料,系统研究了上扬子黔北地区下寒武统牛蹄塘组黑色泥页岩的发育特征与分布,并结合北美海相页岩气形成地质条件及我国页岩气选区评价标准,预测了黔北地区页岩气勘探的有利区。结果表明:黔北地区下寒武统牛蹄塘组海相黑色泥页岩厚度大、分布广泛,早期海侵体系域水体相对较深,沉积和沉降中心位于研究区的东南部,主要的物源来自西北部,沉积相类型主要为砂质陆棚、浅水陆棚和深水陆棚相沉积,深水陆棚相分布在东南部地区,呈北西-南东向带状展布。晚期高位体系域,水体深度逐渐降低,随着相对海平面的下降,研究区陆棚砂体范围进一步扩大,浅水陆棚和深水陆棚向东南迁移,范围缩小。黑色页岩的有机质类型为Ⅲ型干酪根,有机碳含量很高,平均值为4.880%,普遍大于2%;有机质成熟度平均值为2.7%,总体演化程度较高; 黑色页岩的矿物成分主要为碎屑矿物和粘土矿物,碎屑矿物含量平均值为61.3%,成分主要为石英和少量的长石;粘土矿物含量平均值为31.1%,主要为伊利石和伊蒙混层矿物。与美国产气页岩的各项指标相比较,黔北地区下寒武统海相黑色页岩具有厚度较大、有机质丰度平均值高、热演化成熟度高、脆性矿物含量低、粘土矿物含量中等,页岩孔隙度低的特征。具备了页岩气形成的基本地质条件,是我国海相页岩气勘探的主要地区之一。综合评价预测了黔北地区下寒武统牛蹄塘组页岩气的有利、较有利远景区。     

河北承德路通沟剖面寒武系层序地层划分

层序地层学是地层学研究中的第三次革命,其强调年代地层框架内的沉积相关系和地层结构。河北路通沟剖面寒武系地层连续,层序界面清楚而独特,沉积现象丰富,是进行华北地台寒武系层序地层划分的典型地点之一。该剖面岩相类型以泥晶灰岩、鮞粒灰岩及白云岩为主,发育潮坪相、颗粒滩相、缓坡相及陆棚相等沉积相。在新的年代地层框架下,依据沉积相的垂向叠加样式及其反映的长周期旋回特征,将路通沟剖面寒武系划分为9个三级层序,以第三统徐庄组组成的三级层序(TST+CS+HST)为界,整个沉积序列从混积潮坪相沉积变为缓坡型碳酸盐岩沉积,层序也从以"TST+HST"为主的沉积序列转变为以"CS+HST"为特征的淹没不整合型层序序列。芙蓉统中众多的叠层石生物丘暗示:寒武系末期贫乏骨骼的风暴海洋中微生物碳酸盐岩随后生动物辐射也在增加的特殊沉积现象。基于沉积相叠置方式及旋回特征对路通沟剖面寒武系的层序地层研究,将为探索华北地台东北部广泛分布的寒武系地层的层序划分提供一个典型的实例,为今后大范围的追索和对比提供更多的思考途径。