德国泥盆纪生物礁的基本特征

德国泥盆纪的层孔虫十分繁盛，不同形态，不同规模的层孔虫礁体广泛发育于台地内部，台地边缘和深海盆地内的火山周围。块状层孔虫是主要的造礁生物，四射珊瑚也参与了造礁，但数量极少。礁区岩相分异业显，盆地相，礁前相，礁核相和礁后泻湖相清晰可辨。部分礁体，如布瑞降礁显示清楚的初殖，拓殖，繁殖和衰亡四个演化阶段。层孔虫礁的主要繁盛期为吉维特期－弗拉斯期。德国泥盆纪生物礁的基本特征类似于加拿大同时期的生物礁，但在     

德国泥盆纪生物礁的基本特征

德国泥盆纪的层孔虫十分繁盛，不同形态、不同规模的层孔虫礁体广泛发育于台地内部、台地边缘和深海盆地内的火山周日。块状层孔虫是主要的造礁生物，四射珊瑚也参与了造礁，但数量极少。礁区岩相分异明显，盆地相、礁前相、礁核相和礁后泻湖相清晰可辨。部分礁体，如布瑞隆环礁显示清楚的初殖、拓殖、繁殖和衰亡四个演化阶段。层孔虫礁的主要繁盛期为吉维特期－弗拉斯期。德国泥盆纪生物礁的基本特征类似于加拿大同时期的生物礁，但在德国泥盆纪的礁灰岩杂体内至今尚未发现有经济价值的石油和天然气。这可能与莱茵海西地槽复杂的地质发展史有关。     

华南泥盆纪生物礁演化及其控制因素

通过对华南泥盆纪生物礁现有资料和作者获得的实际材料的分析研究,编制了华南早、中、晚泥 盆世生物礁分布图。华南泥盆纪生物礁最早出现在埃姆斯晚期,分布层位由西南向北东逐渐上升。华南泥盆纪 生物礁分布和演化具有 3方面的特征：(1)不同类型生物礁演化差异很大：浅水礁变化最大,台缘礁变化次之, 深水礁几乎没有变化;(2)主要造礁生物随时间演替明显：床板珊瑚 （ 埃姆斯期）→床板珊瑚、四射珊瑚和层 孔虫 （ 艾菲尔期）→层孔虫和四射珊瑚 （ 吉维特期）→层孔虫 （ 弗拉期）→菌藻类 （ 法门期） ;(3)生物礁数 量和规模在吉维特期出现峰值。研究表明：华南泥盆纪生物礁的发育受区域和全球性因素的共同制约,其中温 度、大气中 CO₂ 分压 （ P_CO2）和植被-森林生态系等全球性因素对华南泥盆纪生物礁有重要影响。     

广西南丹县六寨泥盆纪生物礁

南丹县六寨生物礁,产于中泥盆世东岗岭组中。它长4.5km、宽300m,最大厚度达158m,是广西最大的生物礁之一。该礁体属台地边缘相中的堤礁,可细分为六个亚相。岩石类型有棘屑灰岩,塌积角砾岩,生物屑灰岩,层孔虫——珊瑚灰岩、泥晶灰岩等。造礁生物有层孔虫、刺毛类,附礁生物有珊瑚、腕足类、棘皮类等。礁体生长经历了二个阶段,五个造礁时期,至东岗岭末期即告结束。     

西秦岭中带弗拉斯—法门期生物绝灭事件的研究

晚泥盆世弗拉斯—法门期(Frasnian—Famennian)之间存在一次全球性生物绝灭事件(简称F—F事件)。这次事件在西秦岭地区有所表现。西秦岭中带西成地区吉维特到弗拉斯期为碳酸盐台地和生物礁沉积。法门期以暗灰色和灰绿色板岩、粉砂质板岩沉积为主。弗拉斯期末(相当于gigas最上亚带),该区大量的层孔虫、珊瑚、腕足及兰绿藻等生物绝灭。沉积相、矿物及地球化学特征都表明该事件是山于海水急剧加深引起的。事件发生的时间为gigas上亚带和最上亚带之间。     

黔南惠水下石炭统上司组礁滩灰岩微相

黔南惠水雅水剖面下石炭统上司组底部含有厚度约7m的生物沉积和建造灰岩,为上下生屑滩夹含5m厚的珊瑚格架礁,微相类型丰富,可划分出4种类型:1泥粒状灰岩;2粒泥状灰岩;3珊瑚障积岩;4层孔虫盖覆岩。在生屑滩沉积生物碎屑泥粒状灰岩中,珊瑚、腕足类、钙藻、介形类、海百合茎等破碎程度高,分选性低,为较强水动力条件远距离或频繁搬运后快速沉积的产物,此时不适宜大型珊瑚原地生长保存,仅见少量而单调的单体四射珊瑚和复体四射珊瑚。珊瑚格架礁以生物碎屑粒泥状灰岩、珊瑚障积岩为主,发育少量层孔虫盖覆岩和藻类粘结作用。腕足类、钙藻、有孔虫、海百合茎、介形类、腹足类较为丰富,苔藓虫以及层孔虫的丰度未达到支撑程度,昭示珊瑚格架礁生长期的水动力条件减弱,为单体四射珊瑚、笛管珊瑚(Syringopora)和丛管珊瑚(Siphonodendron)为主体的珊瑚群落形成原地礁灰岩创造了条件。     

甘肃西成铅锌矿田泥盆纪吉维特-弗拉斯期沉积古地理及控矿意义

本文在牙形石生物地层对比的基础上.着重讨论吉维特-弗拉斯期的沉积相和沉积古地理。将该期地层红岭山组分为陆棚、开阔台地、局限台地、生物礁和丘、礁前斜坡及泻湖六个相及十二个微相.提出西成地区泥盆纪存在-南北两侧均有镶边礁的小型碳酸盐台地.礁间泻湖区是该区铅锌矿成矿的有利部位.也是今后寻找铅锌矿的重点靶区。     

陕南川北志留系兰多维列统特列奇阶宁强组的生物礁

志留纪兰多维列世（Llandovery）扬子地台持续上升。特列奇期（Telychian）griestoniensis笔石带上部至spiralis-grandis带代表的时限内,地处扬子地台西北缘的宁强湾,在温暖浅海的环境中沉积了宁强组巨厚的泥页岩,其中夹含8套碳酸盐岩。在与之对应的8期小型局限碳酸盐岩台地的不同部位建造了生物礁和生物滩。生物礁的类型包括骨架礁、生物层和灰泥丘。生物礁群落由底栖固着的造礁珊瑚、苔藓虫、海百合、藻类、层孔虫,以及非固着的附礁生物腕足类、鹦鹉螺、三叶虫等组成。通过宁强广元地区不同地点和层位的生物礁组合分析,论述它们在生态组合、生长形状和发育过程中的多样性。     

塔中地区中上奥陶统台地镶边体系分析

塔里木盆地塔中地区中上奥陶统碳酸盐岩台地边缘以发育良好的多种粒屑滩和生物礁组成的镶边沉积体系为特征。通过精细的单井相分析,识别出砂屑滩、砾屑滩、生屑滩以及鲕粒滩等,并且区分出3种不同类型的生物礁：①隐藻灰泥丘;②主要由枝状苔藓虫、海绵或（和）珊瑚建造的障积礁;③由石质海绵、托盘类、层孔虫、珊瑚、管孔藻等建造的骨架礁。在面向深水盆地的台缘外带,以发育中～高能粒屑滩和骨架礁组合为特征。在背靠开阔海台地的台缘内带,主要表现为中低能粒屑滩、隐藻灰泥丘以及障积礁的组合。这个台缘镶边沉积体系总体上沿塔中1号断层西侧呈北西-南东向长带状展布,长度100多公里,是本区重要的油气聚集带之一。储层质量台缘外带总体上优于台缘内带,其中骨架礁礁核和粒屑滩灰岩最好,礁间海和滩间海沉积物较差。     

广西桂林晚泥盆世弗拉斯期珊瑚礁

桂林地区中、晚泥盆世从吉微特期到法门期都有不同的礁、滩发育，而且在不同时期造礁生物的面貌有所不同。晚泥盆世藻类的崛起取代了层孔虫和珊瑚的位置，成为造礁的主要角色。但在桂林以西５公里处的侯山，其沉积相位置为桂林台地的西北台缘，除发育藻－层孔虫礁外，还发育了层状的珊瑚礁体，这在晚泥盆世地层中还极为少见。这种礁体由原地生长的丛状珊瑚体构成，以Ｓｍｉｔｈｉｐｈｙｌｌｕｍｇｕｉｌｉ－ｎｅｎｓｅ为主，其生长高度可达一米多，分异度低，其它的造礁生物主要是一些藻类和少量层孔虫，附礁生物以腕足类为主。纵向上礁序列由以下几种微相组成:（１）隐藻泥晶灰岩；（２）藻砂屑灰岩；（３）斑马构造隐藻泥晶灰岩；（４）珊瑚灰岩。横向上礁组合可识别出:（１）礁后亚相；（２）礁坪和礁缘亚相；（３）礁坡亚相。从礁体的生物组成，微相内容特征，成岩变化及横向上与周边环境的关系可以推测，其并非真正的台缘礁体，而是礁后外带靠近台缘的层状补丁礁。     

Microbial mounds prior to the Frasnian‐Famennian mass extinctions,Hantang, Guilin,South China

Late Frasnian mounds of the Yunghsien Formation, Guilin, South China, developed as part of the Guilin platform, mostly in reef‐flat and platform margin settings. Microbial mounds in platform margin settings at Hantang, about 10 km west of Guilin, contain Frasnian biota, such as Stachyodes and Kuangxiastraea and, thus, occur below the Frasnian‐Famennian mass extinction boundary. Platform margin facies were dominated by microbes, algae and receptaculitids. Massive corals and stromatoporoids are not common and rarely show reef‐building functions as they did in Givetian time. The margin mounds are composed of brachiopod‐receptaculitid cementstone, and a variety of boundstones that contain Rothpletzella, Renalcis, thrombolite and stromatolite. Other microbial communities include Girvanella, Izhella, Ortonella and Wetheredella. Solenoporoid algae are abundant locally. Zebra structures and neptunian dykes are well‐developed at some intervals. Pervasive early cementation played an important role in lithification of the microbial boundstones and rudstones. Frasnian reefs of many regions of the world were constructed by stromatoporoids and corals, although a shift to calcimicrobe‐dominated frameworks occurred before the Famennian. However, the exact ages of many Frasnian margin outcrops are poorly constrained owing to difficulties dating shallow carbonate facies. The Hantang mounds represent a microbe‐dominated reef‐building community with rare skeletal reef builders, consistent with major Late Devonian changes in reef composition, diversity and guild structure occurring before the end of the Frasnian. A similar transition occurred in the Canning Basin of Western Australia, but coeval successions in North America, Western Europe and the northern Urals are either less well‐known or represent different bathymetric settings. The transition in reef‐building style below the Frasnian‐Famennian boundary is documented here in the two best exposed successions on two continents, which may have been global. Set in the larger context of Late Devonian and Mississippian microbial reef‐building, the Hantang mounds help to demonstrate that controls on microbial reef communities differed from those on larger skeletal reef biota. Calcimicrobes replaced stromatoporoids as major reef builders before the Frasnian‐Famennian extinction event, and increasing stromatoporoid diversity towards the end of the Famennian did not result in a resurgence of skeletal reef frameworks. Calcimicrobes dominated margin facies through the Famennian, but declined near the Devonian‐Carboniferous boundary. Stromatolite and thrombolite facies, which occurred behind the mound margin at Hantang, rose to dominate Mississippian shallow‐water reef frameworks with only a minor resurgence of the important Frasnian calcimicrobe Renalcis in the Visean when well‐skeletonized organisms (corals) also became volumetrically significant frame builders again.     

A Study of Devonian Reefs from Southern China

Three Devonian reefs (bioherms) from Yunnan and Guangxi, southern China, are studied in detail. Six microfacies types are differentiated. Colonial rugose corals (Columnaria, Disphyllum and Hexagonaria) at Qujing, tabulate corals (Alveolites) with massive stromatoporoids (Actinostroma and Stromatoporella) and sponges at Panxi, and massive stromatoporoids (Actinostroma, Trupetostroma and Stromatoporella) at Yangshuo belong to the most important reef builders. All the three reefs studied clearly reveal a successive evolution history. They developed on the carbonate banks, shallow carbonate platforms and platform margins in the Late Givetian and terminated in the Frasnian due to sea-level falls related to local uplifts of platforms. This coincides with a eustatic fall of relative sea level at the Frasnian/Famennian transition.     

Reef Formations in the West Canada Basin and Their Oil and Gas Potential

Devonian reefs are widespread in the West Canada Basin in three regions: lower Givetian in the north (Elk Point subbasin), upper Givetian and middle Frasnian in the central part (framing of the Peace River Arch), and middle Frasnian (southern end of the basin). Each stage of reef formation ended with regression, and the last reefs terminated long before the Frasnian/Famennian biotic crisis and mass extinction. Reefs of this basin are petroliferous. Moreover, the structure of reservoirs is determined by the reef type, and the highest reservoir properties are related to bioherm varieties in reefs.     

Famennian microbial reef facies, Napier and Oscar Ranges, Canning Basin, western Australia

Following the Frasnian–Famennian mass extinction, which eliminated most skeletal reef-building fauna, the early Famennian reefs of the Canning Basin were constructed primarily by reef-framework microbial communities. In the Napier and Oscar Ranges, the Famennian reef complexes had high-energy, reef-flat depositional environments on a reef-rimmed platform that transitioned into low-energy, deep-water reefs growing in excess of 50 m below sea level. High-energy, reef-flat depositional environments contain doming fenestral stromatolites that grade into porous thrombolites and are associated with coarse-grained sandstones and grainstones. The reef-margin subfacies contains mounds of microdigitate thrombolites, which are more delicate than the reef-flat thrombolites and locally contain abundant red algae, Girvanella, renalcids and sediment-filled tubes. Within the thrombolites, the red algae are in upright growth positions, suggesting that the thrombolites are largely composed of carbonate that precipitated in situ. Reefal-slope environments are dominated by Wetheredella and Rothpletzella with locally abundant Girvanella, renalcids and Uralinella. In reefal-slope strata, delicate fans and microdigitate stromatolites of Wetheredella and Rothpletzella are often oriented horizontal or diagonal to bedding and are interpreted as syndepositionally toppled over. Most mesoscale microbial community structures contain several species of microbial fossils, and no single microbial species appears to have controlled the morphology of the community structure. Therefore, the depositional environment must have determined the distribution and morphology of the stromatolites, thrombolites and other microbial community structures. The adaptability of microbial communities to various reef environments allowed them to fill ecological niches opportunistically after the Frasnian–Famennian mass extinction.     

四川龙门山甘溪泥盆纪生态地层、层序地层与海平面变化

龙门山甘溪剖面是我国泥盆系重要典型剖面之一,倍受中外同行关注。本文着重对生态地层、事件地层、层序地层进行研究,为研究全球海平面变化提供区域背景资料。龙门山甘溪剖面含十分丰富的底栖生物化石,从洛赫柯夫阶-弗拉斯阶自下而上可识别出24个腕足动物群落,另外还建立了若干礁复体群落和浮游群落
本文对以上群落的特征、性质、分异度、成分、底栖组合及其与沉积环境的关系作了分析和讨论,并识别了11个海进海退事件(生物的或非生物的)
本区泥盆系是加里东构造旋回后的第一个沉积盖层,属海平面主体上升和海侵同步条件下的旋回超覆地层,由砂质海岸环境向碳酸盐台地环境推进,构成了区内泥盆纪沉积层序序列的组合特征。根据海平面的变化及其相旋回的变迁,划分出6个三级沉积层序。6个沉积层序代表6次海平面的相对升降周期,大致相当于Vail,P.R.(1977)划分的三级地层旋回的海平面变化周期(延续时限1-12Ma),包括4个较大的海平面上升周期与2个较大的海平面下降周期,即洛赫柯夫期、布拉格晚期至埃姆斯早期,吉维中期及弗拉斯早、中期的海平面上升期与艾费尔期中晚期至法门期的海平面下隆期。
上述沉积层序特征和海平面变化,说明区内泥盆纪台缘断陷盆地的形成经历了由陆向海转化和盆地发展演化过程,反映了上扬子地台西缘陆架沉积发展的历史大致可划分为:盆地的雏形阶段(碎屑岩陆架的形成阶段),盆地的发展阶段(碎屑岩与碳酸盐岩混积陆架的形成阶段)和盆地形成与消亡不同性质的三个阶段。它们的形成与演化主要是构造断陷活动和龙门山海水不断向东侵进、古特提斯海北支向东扩展的结果,展示了由滨岸陆架转变为碳酸盐台地,由陆源碎屑充填转化为碳酸盐岩沉积的发展史。     

桂林泥盆纪碳酸盐台地的发育

桂林地区中、晚泥盆世大量发育的碳酸盐岩构成了一个东西宽近４０ｋｍ、南北长近８０ｋｍ的浅海碳酸盐台地，其岩相变化复杂，生物群落丰富。本文论述了碳酸盐台地形成各阶段的岩相和生物相特征，阐明了影响碳酸盐台地形成的因素，认为从滨岸碎屑环境变为成熟碳酸盐台地中间阶段的沉积物──混积岩及滩（补丁礁）和滩间沉积物在碳酸盐台地形成过程中不可忽视。     

广西弗拉阶—法门阶之交碳同位素与分子地层对比研究

对广西 7条碳酸盐台地、斜坡和盆地相剖面的碳同位素与分子地层的对比研究表明 ,在牙形石生物地层带或偏心率轨道旋回层建立的等时地层格架内 ,跨越弗拉阶—法门阶 (F—F)之交的碳同位素组成在 1 4Ma内不具一致性 ,表现为正偏、负偏和无偏 3种模式。主要的分子化石包括正构烷烃、类异戊二烯烃、萜类、甾类 ;其母体生物源主要为海源浮游植物、浮游动物、底栖非光合作用的菌类和陆源高等植物。其中浮游植物和浮游动物是构成F—F事件期碳酸盐台地、斜坡和盆地相生物量的主体。分子地层参数及其与碳同位素的关系显示 ,F—F之交广西海域高温、高盐、缺氧、多风 ;Pr Ph与δ1 3C曲线的变化表现为负相关。地层的加积方式 (加积、进积和退积 )、堆积速率、缺氧程度、分子化石类型和丰度是影响广西F—F之交碳同位素组成变化的主要因素。退积序列、快速堆积、缺氧程度和有机质埋藏量增加通常对应δ1 3C值增加。由于分子地层参数能提供生物与环境这两大直接影响碳同位素组成的量化信息 ,因此 ,碳同位素与分子地层的对比研究对正确解释碳同位素的特征和成因具有重要意义     

广西六景泥盆纪吉维阶-弗拉斯阶界线层牙形石生物地层

广西六景泥盆系剖面是我国泥盆系标准剖面之一 ,通过对其吉维阶 -弗拉斯阶界线上下地层进行详细的牙形石生物地层研究 ,自上而下识别出 12个牙形石带 :Palmatolepis jamieae带、Palmatolepis hassi带、Palmatolepispunctata带、Palmatolepistransitans带、上 Mesotaxisfalsiovalis带、下 Mesotaxisfalsiovalis带、Klapperina dispar-ilis带、上 Schmidtognathus hermanni- Polygnathus cristatus带、下 Schmidtognathus hermanni- Polygnathus cristatus带、上 Polygnathus varcus带、中 Polygnathus varcus带、下 Polygnathus varcus带。吉维阶 -弗拉斯阶界线 (即中 -上泥盆统界线 )由 Ancyrodella binodosa→ Ancyrodella rotundiloba early form→ Ancyrodella rotundiloba late form这一演化线系中的 Ancyrodella rotundiloba early form的首次出现确定 ,处于下 Mesotaxis falsiovalis带下部 ,在谷闭组底界之上 1.80 m处。     

桂林中、晚泥盆世环境旋回和生物事件

桂林地区中、晚泥盆世的沉积包含了两个主要的环境旋回,从艾菲尔到维特期为一个旋回,从费拉斯到法门早期为另一个旋回。生物事件主要发生在第一个旋回的海侵高峰时期,而生物事件的直接结果则在第二个旋回充分显示出。在吉维特期和费拉斯期曾一度兴旺的许多生物类群(其中以可造礁生物居多)在法门期开始时结束了生命活动。这种环境的变化与全球海平面升降相一致,绝灭事件在当时地处热带的地区显示更为明显。     

Lithofacies and sequence development on an Upper Devonian mixed carbonate-siliciclastic fore-reef slope, Canning Basin, Western Australia

Detailed sedimentological and stratigraphical analysis coupled with conodont biostratigraphy of a fore-reef slope succession in the Napier Range (Napier Formation) is used to develop a depositional model and relative sea-level history for late Frasnian to late Famennian reef evolution in the Canning Basin of north-western Australia. Changes in sedimentary style on the slope, reflecting differing rates of carbonate production on the platform, are linked to third- and higher order relative sea-level fluctuations. Overlapping slope aprons accumulated along the base of a steep-walled platform margin. Coarse carbonate debris was deposited adjacent to the margin as talus breccias (via rockfall) and debris-flow breccias. Depositional slopes up to 45°, and locally steeper, are demonstrated using rotated geopetal cavity fills. The predominance of channel-filling lithofacies throughout the slope succession indicates the highly channelized nature of the aprons. The middle slope is dominated by sandy oolitic-peloidal turbiditic grainstones interpreted as sediment exported from an active platform. The turbidites and associated debris-flow breccias contrast with condensed carbonate intervals and deep-water, non-fenestral stromatolites that record times of very low platform production. Lower slope turbidites and associated intraclastic breccias indicate widespread redeposition of sediment eroded from lithified and semi-lithified limestones higher up the slope. Several third-order sequences are recognized in the fore-reef succession and these are composed primarily of transgressive and highstand deposits. Carbonate production was severely restricted in the early Famennian coinciding with development of onlapping siliciclastic aprons during a relative sea-level lowstand. Evidence for a subaerial exposure event is also preserved within the siliciclastic strata. Controls on sequence development are difficult to constrain. Although two sequence boundaries can be correlated with falls on the global sea-level curve, the reef complexes evolved in an active extensional regime and it is highly likely that tectonism, in conjunction with eustasy, controlled accommodation on the platform and therefore carbonate productivity.