<Emphasis Type="Italic">Cyclopertorbitolites</Emphasis>, a new soritid (Foraminifera) from the Lower Eocene of the Eskişehir and Kastamonu regions (Turkey)

The Lower Eocene sediments in the southwestern Seyitgazi (Eskişehir) region include shallow-water rhythmic deposition of claystones, limestones, clayey limestones, and sandy limestones. The Lower Eocene unit in the northwestern Tosya (Kastamonu) region is composed of shallow-water limestones. Both units contain a new soritid foraminiferal genus, Cyclopertorbitolites (with the type species Cyclopertorbitolites tokerae sp. nov.). Cyclopertorbitolites tokerae gen. et sp. nov. is described in the Middle Ilerdian-Lower Cuisian sediments of Seyitgazi and in the Middle Ilerdian limestones of Tosya in this study. It is characterized by the presence of regular annular chambers with rectangular or subrectangular chamberlets at the juvenile stage and a porcellaneous lamina on either side of the test.     

Trace fossils of the Jurassic,blue Lias,Lyme Regis,Southern England

The Lower Jurassic, Blue Lias Formation at Lyme Regis, Dorset, England is rhythmically bedded with symmetrical rhythms consisting of laminated black shale followed by dark then pale marls (sometimes cemented into pale limestones) and back to laminated black shale. Its trace fossil fauna includes nine ichno‐genera and represents a shallow shelf paleoenviron‐ment. The ichnofauna occurs in three assemblages named after consistently occurring ichnogenera. A Chondrites assemblage (diversity = 1 ichnogenus) and a Chondrites‐Arenicolites assemblage (diversity = 2–3 ichnogenera) are typical of dark marls but may penetrate tops of laminated black shales. A thalassi‐noides‐Chondrites‐Arenicolites assemblage (diversity up to 7 ichnogenera) is typical of pale marls or limestones. Blue Lias limestones are diagenetic: dark laminated limestones and pale bioturbated limestones are cemented equivalents of laminated black shales and pale marls, respectively. However, pale burrow fills in darker sediments and vice versa confirm the rhythms are primary. Rhythms represent redox cycles, fluctuating from anoxic laminated black shales lacking mac‐robenthos or infauna (bioturbation index = 0) to oxic, bioturbated, pale marls or limestones with large mac‐robenthos such as Gryphaea or Plagiostoma and diverse infauna (bioturbation index = 5).     

Anthracoporella mounds in the Late Carboniferous Auernig Group,Carnic Alps (Austria)

Summary A heretofore undocumented example of skeletal mounds formed by the dasycladacean algaAnthracoporella spectabilis is described from mixed carbonate-clastic cycles (Auernig cyclothems) of the Late Carboniferous (Gzhelian) Auernig Group of the central Carnic Alps in southern Austria. The massive mound facies forms biostromal reef mounds that are up to several m thick and extend laterally over more than 100 m. The mound facies is developed in the middle of bedded limestones, which are up to 16 m thick. These limestones formed during relative sea-level highstands when clastic influx was near zero. The mound facies is characterized by well developed baffler and binder guilds and does not show any horizontal or vertical zonation. Within the massive mound faciesAnthracoporella is frequently found in growth position forming bafflestones and wackestones composed of abundantAnthracoporella skeletons which toppled in situ or drifted slightly.Anthracoporella grew in such profusion that it dominated the available sea bottom living space, forming ‘algal meadows’ which acted as efficient sediment producers and bafflers. BecauseAnthracoporella could not provide a substantial reef framework, and could not withstand high water turbulence, the biostromal skeletal mounds accumulated in shallow, quiet water below the active wave base in water depths less than 30 m. The massive mound facies is under- and overlain by, and laterally grades into bedded, fossiliferous limestones of the intermound facies, composed mainly of different types of wackestones and packstones. Individual beds containAnthracoporella andArchaeolithophyllum missouriense in growth position, forming “micromounds’. Two stages of mound formation are recognized: (1) the stabilization stage when bioclastic wackestones accumulated, and (2) the skeletal mound stage when the sea-bottom was colonized byAnthracoporella and other members of the baffler and binder guilds, formingAnthracoporella bafflestones and wackestones of the mound facies. A slight drop in sea-level led to the termination of the mound growth and accumulation of organic debris, particularly calcareous algae, fusulinids, crinoids and bryozoans, forming well bedded limestones, which overlie the mound facies     

Coral-rudist bioconstructions in the Upper Cretaceous Haidach section (Gosau Group; Northern Calcareous Alps, Austria)

Summary In the area of Haidach (Northern Calcareous Alps, Austria), coral-rudist mounds, rudist biostromes, and bioclastic limestones and marls constitute an Upper Cretaceous shelf succession approximately 100 meters thick. The succession is part of the mixed siliciclasticcarbonate Gosau Group that was deposited at the northern margin of the Austroalpine microplate. In its lower part, the carbonate succession at Haidach comprises two stratal packages that each consists, from bottom to top, of a coral-rudist mound capped by a rudist biostrome which, in turn, is overlain by bioclastic limestones and, locally, marls. The coral-rudist mounds consist mainly of floatstones. The coral assemblage is dominated by Fungiina, Astreoina, Heterocoeniina andAgathelia asperella (stylinina). From the rudists, elevators (Vaccinites spp., radiolitids) and recumbents (Plagioptychus) are present. Calcareous sponges, sclerosponges, and octocorals are subordinate. The elevator rudists commonly are small; they settled on branched corals, coral heads, on rudists, and on biolastic debris. The rudists, in turn, provided settlement sites for corals. Predominantly plocoid and thamnasteroid coral growth forms indicate soft substrata and high sedimentation rates. The mounds were episodically smothered by carbonate mud. Many corals and rudists are coated by thick and diverse encrustations that indicate high nutrient level and/or turbid waters. The coral-rudist mounds are capped byVaccinites biostromes up to 5 m thick. The establishment of these biostromes may result from unfavourable environmental conditions for corals, coupled with the potential of the elevator rudists for effective substrate colonization. TheVaccinites biostromes are locally topped by a thin radiolitid biostrome. The biostromes, in turn, are overlain by bioclastic limestones; these are arranged in stratal packages that were deposited from carbonate sand bodies. Approximately midsection, an interval of marls with abundantPhelopteria is present. These marls were deposited in a quiet lagoonal area where meadows of sea grass or algae, coupled with an elevated nutrient level, triggered the mass occurrence ofPhelopteria. The upper part of the Haidach section consists of stratal packages that each is composed of a rudist biostrome overlain by bioclastic wackestones to packstones with diverse smaller benthic foraminifera and calcareous green algae. The biostromes are either built by radiolitids,Vaccinites, andPleurocora, or consist exclusively of radiolitids (mainlyRadiolites). Both the biostromes and the bioclastic limestones were deposited in a low-energy lagoonal environment that was punctuated by high-energy events.In situ-rudist fabrics typically have a matrix of mudstone to rudistclastic wackestone; other biogens (incl. smaller benthic foraminifera) are absent or very rare. The matrix of rudist fabrics that indicate episodic destruction by high-energy events contain a fossil assemblage similar to the vertically associated bioclastic limestones. Substrata colonized by rudists thus were unfavourable at least for smaller benthic foraminifera. The described succession was deposited on a gently inclined shelf segment, where coral-rudist mounds and hippuritid biostromes were separated by a belt of bioclastic sand bodies from a lagoon with radiolitid biostromes. The mounds document that corals and Late Cretaceous elevator rudists may co-occur in close association. On the scale of the entire succession, however, mainly as a result of the wide ecologic range of the rudists relative to corals, the coral-dominated mounds and the rudist biostromes are vertically separated.     

The schulterkofel section in the Carnic Alps,Austria: Implications for the carboniferous-permian boundary

Summary The upper part of the LowerPseudoschwagerina Limestone (Rattendorf Group), outcropping on the northwestern flank of Schulterkofel Mountain, Carnic Alps (Austria) is described with special emphasis on fusulinid microfossils and facies. This fusulinid-rich section offers an ideal opportunity for biostratigraphy in defining the Permo-Carboniferous boundary in this region. The LowerPseudoschwagerina Limestone is composed of shallow-marine limestones with intercalated thin siltstone and sandstone beds. Fusulinid limestones are represented by two types of wackestones, both containing large quantities of smaller foraminifers. Fusulinid grainstones are rare. Limestones rich in fusulinids were found only within the bedded limestone facies in beds both below and especially above siliciclastic intercalations. This may indicate that the best living conditions for fusulinids existed immediately before and especially after the climax of a regressive phase (sea-level lowstand). The fusulinid limestones were deposited within a protected, shallow-marine shelf environment with normal salinity. Pseudoschwagerinid fusulinids appear in the upper part of the LowerPseudoschwagerina Limestone, in samples SK 107d (undeterminable species) and SK 108, i.e. between 92 m and 93 m above the base of the section within a bedded limestone immediately above the uppermost clastic intercalation. The fusulinid fauna is represented by about 30 species belonging to only a few genera. Species ofTriticites andRugosofusulina dominate, whereas those ofDaixina, Rugosochusenella andPseudofusulina are rare. A characteristic feature of the fauna is the strong similarity with fusulinid faunas described from Russia as well as from Middle and East Asia. Some of the described fusulinids are new for the Carnic Alps. The first appearance ofPseudoschwagerina andOccidentoschwagerina (Occidentoschwagerina alpina Zone) in the upper part of the LowerPseudoschwagerina Limestone in the Schulterkofel section defines the position of the Carboniferous-Permian boundary.     

Evolution of an isolated carbonate bank during Oligocene,Miocene and Pliocene times,Cayman Brac,British west Indies

Summary Modern carbonate sedimentation in the Caribbean Sea commonly occurs on banks that are surrounded and isolated by deep oceanic water. This depositional regime also occurred during the Tertiary, and many islands, such as Cayman Brac, have sequences that evolved in such settings. Cayman Brac is a small (about 39 km²) island, located on the Cayman Ridge, that has an exposed Oligocene to Pliocene succession which encompasses three unconformity-bounded formations. The upper Lower Oligocene Brac Formation is formed ofLepidocyclina limestones and sucrosis dolostones that locally contain numerous bivalves and gastropods. The overlying Lower to Middle Miocene Cayman Formation is formed of pervasively dolomitized mudstones to grainstones that contain an abundant, diverse biota of corals, gastropods, bivalves, foraminifera, and algae. Rhodolites are locally common. The Pliocene Pedro Castle Formation is formed of limestones, dolostones, and dolomitic limestones that contain a biota which is similar to that in the Cayman Formation. The unconformities between the formations represent substantial periods of time during which the previously deposited carbonates were lithified and eroded to produce karst terrains. All facies in the Brac, Cayman, and Pedro Castle formations on Cayman Brac developed on a bank that was no more than 20 km long and 3 km wide. There is no evidence of reef development other than isolated thickets ofStylophora and/orPorites and no systematic stratigraphic or geographic changes in the facies patterns of the formations. Comparison with modern Caribbean banks shows that the depositional regime was primarily controlled by water depth and energy levels. Limestones of the Brac Formation probably accumulated in low-energy conditions in water less than 10 m deep. The overlying Cayman Formation contains facies that formed in water 15 to 30 m deep with good cross-bank circulation. The Pedro Castle Formation formed in slightly shallower water (5–25 m) and lower energy conditions. The disconformities between the packages correlate with world wide eustatic drops in sea level.     

Favositidae (Tabulata) from Emsian to Middle Devonian limestones of the Tamworth Group (N.S.W., Australia)

Several different species and species groups of the familiy Favositidae from the Emsian and Middle Devonian limestones of the Tamworth Group (N.S.W., Australia) are described. The Emsian Sulcor Limestone Member yieldedFavosites sp. aff.F. basalticus (Goldfuss, 1826),Favosites sp. aff.F. salebrosus Etheridge, 1899,Favosites stellaris Chernyshev, 1937,Squameofavosites nitidus (Chapman, 1914),Sq. bryani (Jones, 1937),Pachyfavosites rariporosus Dubatolov, 1963, andP. tumulosus Yanet, 1965. The Middle Devonian Moore Creek Limestone Member yieldedFavosites ex gr.goldfussi D’Orbigny, 1850, exclusively. In the Emsian limestones occur favositids in a wide array of different facies, with most being found in stratified biostromes and in bedded nodular limestones. In the Middle Devonian most favositids are found in nodular and lumpy limestones which occur at the base and at the top of some successions      

Controls on Devonian hemi-pelagic limestone deposition analyzed on cephalopod ridge to slope sections,Eastern Anti-Atlas,Morocco

The hemi-pelagic Tafilalt Ridge separating the Maider Basin from the Tafilalt Basin developed progressively from an Early Devonian homoclinal ramp, through a Middle Devonian ramp-slope stage of moderate topography, to a mature cephalopod ridge during the Late Devonian and formed a spur-like element extending from the southern shallow-water Maider Platform to the broader northern hemi-pelagic Tafilalt Platform. During the Middle Devonian, thick lowstand aprons were shed onto the ridge-slope from an active mid-ramp carbonate factory in the south (Maider Platform). The shallow-water derived sediments first by-passed the central paleohigh, but then onlapped the ridge during start of sea-level rise. The allodapic limestones (storm-induced turbidites, tempestites, and debrites) of the aprons consist of large parts or entirely of reworked lithic peloids. The lithic peloids are interpreted as the main foundation of all micritic lithofacies types in the distal ramp locations, including those on the hemi-pelagic cephalopod ridge. Lateral facies transition of allodapic limestones into nodular cephalopod limestones on the ridge suggests the latter originate from allodapic beds and were subsequently transformed into nodular limestones by bioturbation, early diagenesis, and the faunal input from a hemi-pelagic community. Iron-rich hardgrounds formed on the ridge during major regressive phases as a result of increased winnowing by the wave-base and correlate with siliciclastic turbidite deposition on the slope. The hardgrounds can be correlated with hiatuses on the Tafilalt Platform, which formed a broader hemi-pelagic swell to the north. During the Late Devonian, the southern Maider Basin carbonate factory became unproductive or disappeared, and a ridge facies of truly hemi-pelagic autochthonous limestones developed. Allodapic deposits on the slope were shed from the ridge itself at this time but did not form well-defined aprons.     

An early cretaceous section in the Kircaova area (Berdiga Limestone,NE-Turkey) and its correlation with platform carbonates in W-Slovenia

Summary In the Kale (Gümüshane) area in the North Eastern Turkey, platform carbonates of the Berdiga Limestone were deposited during Late Jurassic-Early Cretaceous time in environments varying from intertidal to fore reef. The sequence shows extensive lateral and vertical alterations and interfingering of different facies types. In the upper part of the Berdiga Limestone in the Kircaova area a bituminous thin-bedded to platy limestone and shale 5 to 6 m thick occurs at the Early/Late Aptian boundary. It is underlain by limestones rich in silica nodules of up to 10 cm size. A facies analysis of a section about 70 m thick including the bituminous interval was carried out in 1994/95 at the SW border of the Kircaova area close to the road from L?rikas to Kale. The limestones consist mainly of packstones and grainstones locally rich in calcareaous algae and forminifera. Fragments of molluscs and echinoids as well as some ostracods and calcispheres occur. Some sponges, corals, and beds rich in molluscs occur in minor amounts in the middle part of the section which is characterized by intertidal to shallow subtidal facies. Algae and foraminifera indicate a Barremian-Early Aptian age of the lower part and Late Aptian age of the upper part of the section (e.g.Salpingoporellamuehlbergii, Salpingoporella aff.melitae, Clypeina solkani, Novalesia producta), divided by the bituminous limestones. In West Slovenia (close to the Italian border) a complete Cretaceous section occurs at Sabotin mountain containing Aptian beds with comparable faunal composition. In contrast to the Berdiga Limestone, in Slovenia at the rim of the dinaric platform a patch reef about 50 m in thickness is developed which is also covered by a bituminous limestones (black shale) marking the Early/Late Aptian boundary. Faunal elements in Slovenia arePalorbitolina lenticularis, Cuneolina laurentii, Orbitolina (Mesorbitolina) texana andSalpingopoprella dinarica. The bituminous limestone appears to be a marker horizon. At both locations it is locally rich in characeans probably indicating a regressive maximum before another transgression began in the Late Aptian/Albian as world-wide drowning event. Possibly the occurrence of the bituminous limestone (black shale) is associated with volcanic activity during the Aptian. If so it could be used as a chronostratigraphic marker horizon in both areas analyzed.     

Microbial impacts on the genesis of Lower Devonian reefal limestones, eastern Australia

Microbial contributions to reefal limestones are evident in eastern Australian Lower Devonian microbial frame/bindstones, red algal-microbial-stromatoporoid bindstones, and microbial-stromatoporoid bindstones. Varied microbialite textures, such as stromatolites, thrombolites, and leiolites, originated as accumulations and partial aggregations of calcimicrobes, peloids, and micrites, which also derived from microbial activities. In microbial frame/bindstones, calcimicrobes (e.g., Rothpletzella and Wetheredella) and dense micrite layers covered and bound underlying substrates. Stabilized substrates promoted the subsequent construction of layered, domal, and columnar frameworks, which were produced by combined accumulations and intermixed associations of calcimicrobes and micritic microbialites. Microbes flourished in the microbial-stromatoporoid bindstones and red algal-microbial-stromatoporoid bindstones during repeated growth interruptions of the framework-building skeletal organisms. Microbes bored into and eroded the skeletal frameworks to subsequently leave micritic envelopes, on which microbial and skeletal encrustations took place in turn. The importance of microbial colonization on the skeletal frameworks was first as subsidiary encrusters that helped to preserve them from erosion, and second as modifiers of the spaces suitable for succeeding encrusters. Partial aggregations of Renalcis filled in the interstices of the skeletal and microbial frameworks, thereby enhancing their rigidity.The microbial impacts on the genesis of reefal limestones are: (1) origination of components (calcimicrobes, peloids, and micrites); (2) formation of characteristic microbial textures; (3) main and subsidiary reef construction and encrustation; and (4) destruction of these components, textures, and structures, but also the protection of resultant constructions in turn. The Lower Devonian reefal limestones treated herein, surprisingly, preserve excellent records of a variety of microbial impacts. Similar effects may also have been common, although variable in preservation, in other ancient reefal deposits.     

Acicularia? weisswasserensis n. sp. and Terquemella? microsphaera n. sp., two new Dasycladales from the Upper Cretaceous (Late Turonian-Santonian) of the Northern Calcareous Alps (Gosau Group, Austria)

Two new dasycladalean algae are described from the Gosau Group of the Northern Calcareous Alps in Austria. The tiny spicules of Acicularia? weisswasserensis n. sp. were found in foraminiferal wacke- to packstones associated with rudist limestones of the Weisswasser locality (Middle Coniacian), Lower Austria. The small globulous Terquemella? microsphaera n. sp. occurs in marls to marly limestones of the Pletzachalm locality (Upper Turonian), Tyrol, and Russbach locality (Upper Santonian), Lower Austria. The Terquemella-Acicularia group requires taxonomic revision; the two forms described herein, however, are clearly distinct from other species, and belong to the smallest representatives of these genera. In addition, Acicularia? aff. magnapora Kuss and morphologically similar forms interpreted as gametophores of unknown larger dasycladales are described.     

Preliminary observations on plant-rock type relationships in the Shiraz-Dashte Arjan area,South-West Iran

Summary In the Dashte-Arjan area near Shiraz, rock formations appear to control the distribution of various plant species. The Fars formation (Miocene) and the Asmari-Jahrom formation (Eocene-Oligocen) sediments are characterized by distinet plant species and life forms. Among the characteristic calciphytes of Asmari-Jahrom limestones are Astragalus acutus, Amygdalus lyciodes, Cerasus microcarpa, and Fraxinus rotundifolia. The Fars formation limestones are characterized by Astragulus gossypinus, Acantholimon flexuosum, Noaea mucronata and Phlomis bruguieri, Except for Glycrrhiza glabra, white and red marls seem to have similar species, such as Alhagi maurorum and Carthamus oxyacantha. Gypsum of Fars formation has Berberis integerrima and Rosa beggeriana. Various life forms have been distinguished and were found to be confined to different rock types as well.Nomenclature of species is given in table 1.We are greately indebted to Dr. P.H. Davis and Prof. G. Pontecorvo F.R.S. for critically reading this paper and making some invaluable suggestions. We are grateful to the University Research Grant Commission for providing us a grant for this work. We are also indebted to the Dean, College of Arts & Sciences, Pahlavi University, Shiraz, Iran for providing us with a vehicle during this work.     

Pleistocene coral reefs associated with claystones, Southwestern Taiwan

 Scleractinian coral reefs, when coexistent with siliciclastic sediments, usually occur in association with deltaic or coastal sands. Nevertheless, Pleistocene reef limestones in southwestern Taiwan are developed in association with thick claystones that were deposited in a deeper-water environment. These reef limestones are characterized by: (1) rapid transition from underlying claystones upward to reefal limestones, (2) lateral interfingering with open-shelf claystones, (3) being overlain by terrestrial deposits or exposed with no covering strata, and (4) being located in close association with anticlines. The authors propose that these reef limestones developed on anticlinal ridges raised above the adjacent sea floor by thrust-front migration in a foreland setting. Accepted: 21 April 1998     

A close look at late carboniferous algal mounds: Schulterkofel,Carnic Alps,Austria

Summary During the uppermost Carboniferous and lowermost Permian algal mounds were formed in inner shelf settings of the Carnic Alps (Austria/Italy). A specific mound type, characterized by the dominance of the dasyclad green alga Anthracoporella was studied in detail with regard to geometry, relationship between mound and intermound rocks, composition of the sediment, biota and diagenetic criteria. The two meter-sized mounds studied, occur within depositional sequences of transgressive systems tracts in the Lower Pseudoschwagerina Limestones (uppermost Gzhelian) at the flank of the Schulterkofel. The mounds consist of an Anthracoporella core facies with a spongecrust boundstone facies at the base and at the top. The massive limestones of the Anthracoporella core facies exhibit abundant algal tufts and bushes, frequently in life position. The limestones of the intermound facies represented by thin-bedded bioclastic wackestones and packstones with abundant phylloid algae underlie and overlie the mounds. Intercalations of intermound beds within the mound facies indicate sporadic disruption of mound growth. Onlapping of intermound beds on steep mound flanks indicate rapid stabilization and lithification of mound flanks and the existence of a positive paleorelief. Asymmetrical shape of the mounds may be current controlled. Mound and intermound biota differ in the prevailing algae but are relatively similar with regard to associated foraminifera. Conspicuous differences concern bioerosion and biogenic encrustations. Bothare, high in intermound areas but low in the Anthracoporella core facies. The mounds show no ecological zonation. The mounds grew by in-place accumulation of disintegrated algal material and trapped bioclastic material between erect algal thalli. The comparison of the various Anthracoporella mounds demonstrates that almost each mound had ist own history. Establishing a general model for these mounds is a hazardous venture.     

Transitional reef-to-basin facies of Lower Frasnian limestones determined by microfacies analysis (Wietrznia,Holy Cross Mts,Poland)

Wietrznia section is situated between the shallow-water carbonate platform in the Kielce region and the Łysogóry basin. The transitional facies of the Wietrznia Frasnian includes two overlapping types of deposits: (1) thin-bedded dark-coloured limestone-marl alternations similar to the basin facies and (2) coarse-grained detrital limestones. Three lithotypes of limestones were identified: laminated or graded micritic, nodular, and detrital. The petrographic study makes it possible for the recognition of six major microfacies (MF 1 to MF 6). These lithotypes were formed by redeposition in a low- to high-energy environment. Their source material was the stromatoporoid-coral Dyminy reef in the central part of the Kielce region. Storms are considered to be the main agent, which causes in erosion and transport; micritic limestones and distal tempestites occur together, whereas detrital limestones are associated with proximal tempestites. Most probably, part of the detrital beds was formed as a result of grain-flow initiated under storm conditions.     

Microfacies and diagenesis of an upper oxfordian carbonate buildup in Mydlniki (Cracow Area,Southern Poland)

Summary A carbonate buildup near the top of the Upper Jurassic limestone sequence in the Cracow area with a rigid framework built ofTubiphytes and thrombolites, and some fragments of encrusted siliceous sponges and serpules is described. The limestones form a dome-like elevation at the eastern wall of a 15 m high quarry flanked on both sides by stratified limestones with cherts. Six microfacies have been distinguished within the buildup: (1)Tubiphytes/thrombolite boundstone and (2) bioclasticTubiphytes/thrombolite wackestone dominate in the central and bottom part of the buildup. They gradually replace the cyanobacterial crusts and siliceous sponges (3. sponge-algal boundstone), which are sporadically the rock-forming elements in the basal part of the buildup as well as the top. Serpules randomly distributed within the buildup also form small cm-sized structures with a rigid framework (4. serpula-peloid boundstone). (5) tuberoid-peloid wackestone/floatstone and (6) ooid intraclastic grainstone exhibit no significant distributional pattern. Bioclastic-peloidal packstone comprising material derived from the destruction of the buildup occurs in the highest part of the outcrop, overlying the buildup. The sediments of the buildup were subject to rapid lithification, evidence by borings and neptunian microdykes filled with internal sediments, as well as by fracturedTubiphytes. Numerous petrographic features indicate probable episodic emergence of the buildup during its growth; these include asymmetric dissolution textures, asymmetric cements, vadose crystal silt and calcite pseudomorphs after gypsum. Upper Oxfordian carbonate buildups in the Cracow area display various stages of evolution. The carbonate buildup in Mydlniki most closely resembles classical Upper Jurassic reefs.     

A basal Pachyrhizodontid fish (Actinopterygii, Teleostei) from the Lower Cretaceous of the Tlayúa Quarry, Central Mexico

Michin csernai gen. et sp. nov. from the Early Cretaceous (Albian) limestones of the Tlayúa Quarry, Puebla State, Central Mexico, is assigned to the Teleost clade Pachyrhizodontoidei as it possesses the enlarged inner premaxillary tooth, which is a unique synapomorphy of this clade. Additionally, the occurrence of relatively primitive characters (e.g., united parietals, angular and articular completely fused, caudal fin with five uroneurals) suggests that Michin csernai represents the most basal representative of the pachyrhizodontids.     

Spring-associated limestones of the Eastern Alps: overview of facies,deposystems, minerals,and biota

In the Eastern Alps, both fossil spring limestones and actively limestone-depositing springs are common. The geological context and a few radiometric age data of fossil spring-associated limestones (SAL) mentioned herein indicate that they accumulated subsequent to the Last Glacial Maximum in the Eastern Alps (24–21 ka BP). Prevalent facies of the SAL deposits, active and fossil, including phytoclastic tufa, microbialites s.l., springstone, and moss tufa form, or formed, from (a) waterfall/creek systems, (b) hillslope-paludal systems, (c) moss-tufa systems, and from (c) foreland-type systems. Precipitated minerals include calcite and, at springs of elevated Mg/Ca ratio, magnesian calcite and aragonite. In a few limestone-depositing, oxygen-deficient springs with dissolved Fe²⁺, downstream, iron oxide precipitates ahead of CaCO₃ (mineralogical zonation). Biota associated with calcium-carbonate deposition include cyanobacteria, green micro-algae, macro-algae, and mosses. Calcium-carbonate precipitation may be speeded by biological mediation, but mineralogy and polymorphy of precipitated CaCO₃ are not biotically controlled. In the Eastern Alps, SAL deposits in total range from 190 to 2,520 m a.s.l., corresponding to mean annual temperatures of 10°C to less than 0°C. In altitudes below the continuous permafrost line (about 2,600–3,000 m a.s.l., depending on location), SAL deposition is chiefly controlled by proper balance between water supply and sufficient supersaturation for CaCO₃, rather than by mean annual temperature.     

Microbial carbonates and corals on the marginal French Jura platform (Late Oxfordian,Molinges section)

Molinges was located on an Upper Jurassic ramp system of low-energy regime that developed at the southern margin of the French Jura platform. The sedimentary succession is characterized by the transition from a mixed siliciclastic-carbonate to a carbonate depositional setting that occurred during a long-term shallowing-upward trend. The disappearance of siliciclastics is explained by a climatic change, from humid and cold to drier and warmer conditions, previously identified in Late Oxfordian adjacent basins. The base of the section shows marl-limestone alternations of outer ramp. In its middle part, the section displays oncolitic marls, coral-microbialite beds and oncolitic limestones that deposited in a mid ramp position. Finally, the upper section part is made of oolitic limestones of inner ramp. In outer- to mid-ramp settings submitted to terrigenous inputs, the stacking pattern of deposits and facies evolution allow the identification of elementary, small-, medium-, and large-scale sequences. Small amplitudes of sea-level variations probably controlled rapid shifts of facies belts and reef window occurrences. In small-scale sequences, the coral beds developed during periods of sea-level rise. The decreasing rate of sea-level rise is marked by the downramp shift of the oncolitic limestone belt that led to the demise of coral-microbialite beds. These bioconstructions are mainly represented by thin biostromes in which corals never reach great sizes. The coral assemblages mainly include the genera Enallhelia, Dimorpharaea, Thamnasteria, and some solitary forms (Montlivaltia and Epistreptophyllum). They suggest relatively low-mesotrophic conditions in marine waters during the edification of the primary framework. Relatively cold water temperatures and periods of more elevated nutrient contents are probably responsible of the reduced coral development and the formation of a large amount of microbialites.