TL;DR: A carbonate crust, with a principally digitate structure, caps the latest Permian reef complexes in east Sichuan, China as mentioned in this paper, confirming its age as earliest Triassic; it closely postdates the end-Permian mass extinction, and is related to associated palaeoenvironmental change.
Abstract: A carbonate crust, with a principally digitate structure, caps latest Permian reef complexes in east Sichuan, China. The crust contains the conodontHindeodus parvus, confirming its age as earliest Triassic; it therefore closely postdates the end-Permian mass extinction, and is related to associated palaeoenvironmental change. Although its branches have lobate margins, and internal structures of radial fabrics and lobate fabrics in different specimens, an organic origin cannot be confirmed, because crust fabric is largely recrystallised. Therefore we apply the term ?microbialite to reflect uncertainty of its nature. The crust is co-eval (within theparvus Zone) with confirmed microbial biostromes and mounds in Guizhou Province, south of Sichuan. The sum of evidence, assembled by workers in several sites worldwide, indicates a sea-level rise occurred in the boundary interval, and this is corroborated by facies of the Sichuan crust. Abrupt appearance and disappearance of the crust, formed by precipitated carbonates, in east Sichuan, represents short-lived unusual post-extinction marine conditions which were switched abruptly on, then off. Microbial deposits overlying the P/T boundary in other locations in the Tethys Ocean (Iran and Japan) support the view that the unusual oceanic conditions had at least a regional distribution. Because the crust abruptly terminates, and is not succeeded by fossil-rich deposits, application of the disaster biota concept is inappropriate; an environmentally-driven control on carbonate precipitation is better supported by the evidence, whether or not it was biotically-mediated.
TL;DR: In this paper, the depth distributions of larger foraminifera (27 species) were investigated along two transects in the fore reef areas of a NW Pacific fringing reef.
Abstract: The depth distributions of larger foraminifera (27 species) were investigated along two transects in the fore reef areas of a NW Pacific fringing reef. One transect is distinguished by a strong flattening below the steep reef slope (−30 m), whereas further steepening characterizes the equivalent part in the other transect. According to the different taphonomic processes affecting foraminiferal tests before final sedimentation, empty tests were classified into the three categories ‘optimally’, ‘well’ and ‘poorly’ preserved. The depth distribution of each preservation state was compared with living individuals. While distributions of optimally preserved tests almost coincide with living individuals, well-preserved tests are characterized by significant depth shifts that are stronger at the upper-most slope compared with the deeper parts. Since the time-averaged traction forces are similar in both investigated transects, differences between the distributions of living individuals and well-preserved tests are more intensive on steep versus flat slopes. Poorly preserved tests signalize allochthonous origin or reworking of relict sediments.
TL;DR: In this article, a rather diverse gastropod fauna from Sarmatian deposits of the Austrian/Hungarian Eisenstadt-Sopron Basin was studied and the fauna derives from two layers of clay and silt within a siliciclastic section at St. Margarethen in Burgenland (Austria).
Abstract: A rather diverse gastropod fauna from Sarmatian deposits of the Austrian/Hungarian Eisenstadt-Sopron Basin was studied. The fauna derives from two layers of clay and silt within a siliciclastic section at St. Margarethen in Burgenland (Austria). These layers are interpreted as littoral mudflats which formed during the Sarmatian (Late Middle Miocene) along the western coast of the Central Paratethys. Strong shifts in the composition of the gastropod fauna, dominated by Potamididae (Cenogastropoda: Cerithioidea), within each layer indicate successions of limnic-fluvial to oligohaline, brackish-littoral, and marine-littoral environments. These shifts in facies are reflected by an alternational of thePotamides hartbergensis assemblage,Granulolabium bicinctum assemblage, and thePotamides disjunctus assemblage.
TL;DR: The Java Sea is used as an analogue to examine oceanography, stratigraphy, and reefs of Devonian strata in the Appalachian and Michigan Basins as mentioned in this paper, where nearshore patch reefs and offshore “pinnacle” reefs occur in both the Java Sea and the Emsian-Eifelian Onondaga Formation.
Abstract: The Java Sea, one of the few modern tropical epeiric seas, is used as an analogue to examine oceanography, stratigraphy, and reefs of Devonian strata in the Appalachian and Michigan Basins. Nearshore patch reefs and offshore “pinnacle” reefs occur in both the Java Sea and the Emsian-Eifelian Onondaga Formation in the Appalachian Basin. Nearshore patch reefs also occur in the Eifelian Formosa Reef Limestone in the Michigan Basin.
TL;DR: In this paper, the facies architecture in the Jurassic succession of Monte Kumeta, coupled with a detailed biostratigraphy, allow to define dynamics and genetic factors controlling the conversion of a Bahamian-type carbonate platform to a pelagic escarpment.
Abstract: The accurate reconstruction of the facies architecture in the Jurassic succession of Monte Kumeta, coupled with a detailed biostratigraphy, allow to define dynamics and genetic factors controlling the conversion of a Bahamian-type carbonate platform to a pelagic escarpment. A change from tidalites to oolites i.e. from the restricted, interior lagoon to a more open-marine sandy depositional environment, records the establishment of a basin south of the Monte Kumeta sector in late Hettangian-Sinemurian times. The oolitic limestones are overlain by earliest Carixian bioclastic grainstones and packstones with micritized grains and by wackestones with radiolarians and sponge spicules, organized in thin sand prisms. The decrease of carbonate productivity indicated by these sediments records the dissection of the platform and the subsequent isolation of a submarine topographic high in the Monte Kumeta sector. Though based only on indirect evidence, it is suggested that a tectonically controlled scarp must have existed between the Monte Kumeta “high” and the basin. Progressive northward retreat of this scarp resulted in the conversion of a shallow platform sector into a gradually steepening slope, along which the distribution of sediments was controlled by repeated tectonic and gravity-induced modifications of the topography of the substrate. Vertical and lateral changes and geometrical relationships of the recognized lithofacies suggest that they were deposited on a stepped surface brought about mainly by, repeatedly reactivated basin ward dipping normal faults. This scenario is clearly reflected by the relationship of platform strata and the overlying encrinites of Carixian/Domerian age. The encrinite bodies show again a prismatic geometry, becoming thicker towards the south and filling the first generation of neptunian dykes. The top of the encrinites is marked by a peculiar jagged dissolution surface with dm-scale pinnacles capped by a thick ferromanganese crust. The formation of this peculiar surface could have been controlled by complex changes in water chemistry probably related to the Early Toarcian anoxic event. The crust itself is dissected by faults of decimetres to metres of throw, sometimes organized into small-scale positive flower structures. In the hollows/depressions of this highly articulated substrate pelagic sediments of Bajocian to Oxfordian age were deposited. They display a clearly onlapping relationship to the encrinites and to the carbonate platform beds. Their thickness rarely exceeds 4 to 5 meters and they are present also as neptunian dykes filling a dense network of fissures. During Late Callovian and Oxfordian times synsedimentary tectonics has intensified resulting in an increase of the inclination of the slope. This led to more and more abundant, gravitationally controlled deformations (slumping and sliding) of semi-lithified and unlithified sediments along the Monte Kumeta escarpment.
TL;DR: In this paper, the authors investigated the role of grain composition and depositional environments of upper Cenomanian-Santonian limestones of Sinai in a shallow-water, inner-platform setting.
Abstract: Factors controlling grain composition and depositional environments of upper Cenomanian—Santonian limestones of Sinai are discussed. The mainly shallow-water, inner-platform setting investigated is subdivided into five major facies belts, each represented by several microfacies types (MFTs). Their lateral distribution patterns and their composition underline aclear relation between depositional environment and platform position. The facies belts include sandstones and quartzose packstones of siliciclastic shorefaces, mudstones and bioclastic wackestones of restricted lagoons, shallow-subtidal packstones with diverse benthic foraminifera and calcareous algae, bioclastic and/or oolitic grainstones of inner-platform shoals, and wackestones of deep open-marine environments. The microfacies distribution patterns of the Cenomanian-Santonian strata are evaluated with respect to local and regional large-scale environmental changes. While protected shallow-subtidal environments with only subordinate ooids and oncoids prevail during the late Cenomanian, high-energy oolithic shoals and carbonate sands occur locally during the middle and late Turonian. They were probably related to a change of the platform morphology and a reorganisation of the platform after a late Cenomanian drowning. In the Coniacian-Santonian, the lack of ooids, oncoids, and the decrease of calcareous algae versus an increase in siliciclastics indicate a shift to lower water temperature and to a more humid climate. Especially in the Turonian, the interplay between sea-level changes, accommodation, hydrodynamics, and siliciclastic input is reflected by lithofacies and biofacies interrelation-ships that are elaborated within individual systems tracts. In particular, increasing accommodation intensified circulation and wave-agitation and controlled the distribution of high-energy environments of the middle and upper Turonian trans-gressive systems tracts. During highstands protected innerplatform environments prevailed.
TL;DR: In this article, a refined biostratigraphic subdivision and correlation of the Uppermost Carboniferous/Lower Permian deposits of the Southern Alps (Carnic Alps, Karavanke Mountains; Austria/Italy/Slovenia) were investigated within the same sample.
Abstract: In order to establish a refined biostratigraphic subdivision and correlation of the Uppermost Carboniferous/Lower Permian deposits of the Southern Alps (Carnic Alps, Karavanke Mountains; Austria/Italy/Slovenia), two major microfossil groups (fusulinoideans, conodonts) were investigated within the same sample. The fusulinoidean species diversity (71 species, including five new species and three new subspecies) and generic composition were reviewed and complemented. Additionally, the data on fusulinoidean assemblages were supplemented by co-occurring conodont faunas (seven species). Accompanying studies on material from the type sections of the Southern Urals (Russia) were made to improve the biostratigraphic correlation with the Russian standard zonation and to discuss paleobiogeographical aspects of the faunal associations. An integrated microfacies analysis of the sampled material in the Southern Alps serves to evaluate the relationships between certain genera and specific microfacies types.
TL;DR: In this paper, a sedimentological analysis based on classical petrology is proposed, which leads to the identification of 19 fourth order sequences, forming three third order system tracts, which are characterized by a particular evolution of the isotope and magnetic susceptibility curve.
Abstract: The Tailfer section (Belgium, northern border of the Dinant Synclinorium) exposes Middle Frasnian shallow-water limestones. This paper proposes a sedimentological analysis based on classical petrology, which leads to the identification of 19 fourth order sequences, forming three third order system tracts. This sedimentological analyses is complemented by carbon isotopic and magnetic susceptibility (MS) data (based on the relation between MS and lithogenic input). Each system tracts is characterised by a particular evolution of the isotope and MS curve:
--Biostromal Unit: the biostromes are built by lamellar and branching stromatoporoids and massive metazoans. MS values are weak, in relation with the important distance from landmasses and lesser amounts of lithogenic contribution. The carbon isotope values are close to Frasnian seawater values.
--Lagoonal Unit: it corresponds to a lagoonal facies succession, from inter- to supratidal zones, rich inAmphipora, paleosiphonocladalesUmbella, and pellets, alternating with paleosoils. MS values are high, related to landmass proximity and high lithogenic input. The carbon isotopic curve shows strongly negative values, close to −7%., resulting probably from a continental influence.
--Lagoonal and biostromal Unit: it consists of a lagoonal succession with some biostromal interruptions. MS values are lower than in the lagoonal unit and the isotopic values are higher (close to 0%.), related to an increase in distality.
TL;DR: In this article, a detailed analysis of parasequences of carbonate platform origin from the Calcari Grigi Formation (Rotzo Member, Lower Jurassic) in the Venetian Pre-Alps of Northern Italy reveals intense burrowing affecting warm lagoonal and protected shelf environments.
Abstract: Analysis of parasequences of carbonate platform origin from the Calcari Grigi Formation (Rotzo Member, Lower Jurassic) in the Venetian Pre-Alps of Northern Italy reveals intense burrowing affecting warm lagoonal and protected shelf environments of the Trento carbonate platform. The trace fossil pattern suggests a strong biogenic activity by many unknown organisms (episodic surficial bioturbation) and by decapod crustaceans (deep burrowing) during the Sinemurian—Pliensbachian. Burrow networks ofThalassinoides (T. suevicus, type I to IV) andOphiomorpha form three-dimensional systems (3DBS), up to 150 cm in thickness, that reveal well developed taphonomic characteristics. Occasionally, also rare body fossil remains (exuvia) ofPhlyctisoma (Erymidae) are preserved, although it is very difficult to attribute to this decapod crustacean a real tracemaker activity. In a total of 18 shallowing-upward taphosequences, each 2.3–2.6 m in thickness, the lower, subtidal part (BOP: base of parasequence), is invariably characterized by 3DBS. Three parts of a 3DBS are taphonomically relevant: a) the enlargement at bifurcation points (the so-called turning chambers) with related tunnel sections in horizontal networks; b) the distribution of vertical tunnels and their openings, locally associated with biogenic mounds; and c) the infilling with coarse-grained skeletal debris of abandoned burrows (tubular tempestites). Case (a), although well known in the literature, is nevertheless peculiar because of the exceptional diameter (up to 22 cm) and shape of bifurcations ofThalassinoides suevicus. Therefore their taphonomic analysis helps to refine shallowing-upward taphosequences. Case (b) and (c), instead, are exceptional because traces of the activity of decapod crustaceans at the sea-floor are very rare in the geologic record. The 3DBS involve taphofacies that are peculiar of the upper part of the Calcari Grigi across western Venetian Prealps. The analysis of 3DBS in all Lower Jurassic para-sequences will aid sequence stratigraphy and the paleoenvironmental reconstruction of the carbonate platform setting.
TL;DR: An integrated study of the early Messinian reef complex cropping out along the eastern coast of the Salento Peninsula (southern Italy), including stratigraphy, facies analysis and paleoecological aspects, is presented in this article.
Abstract: An integrated study of the early Messinian reef complex cropping out along the eastern coast of the Salento Peninsula (southern Italy), including stratigraphy, facies analysis and paleoecological aspects, is here presented. Fourteen facies types belonging to three main facies associations (back reef and shelf, shelf-edge, slope) have been recognized. They document a wide spectrum of depositional environments, reef building organisms and growth fabrics, in response to depth and other environmental factors in different parts of the reef complex.
TL;DR: The Carboniferous of Notsch (Austria) is composed of a thick sequence of dominantly siliciclastic deepsea sediments, which contain a diverse fossil assemblage of formainifers, algae and pseudo-algae as mentioned in this paper.
Abstract: The Carboniferous of Notsch (Austria), divided into Erlachgraben, Badstub and Notsch Formations, is composed of a thick sequence of dominantly siliciclastic deepsea sediments. Intercalated marly and silty limestones in the upper Erlachgraben Formation consist of bioclastic wackestones and algal wackestones/packstones which contain a diverse fossil assemblage of formainifers, algae and pseudo-algae. These microfossils are accurately described and documented, and three species of algae are established:Principia fluegeli n. sp.,Paraepimastopora noetschensis n. sp., andNanopora pseudofragilissima n. sp.
TL;DR: In this paper, the distribution of donezella across a carbonate platform (Sierra de Cuera) of Upper Carboniferous (lower Bashkirian-lower Moscovian) age located in the Cantabrian Mountains (Asturias, NW Spain) is investigated.
Abstract: Donezella is a problematic organism that during the mid-Carboniferous (latest Serpukhovian to Moscovian) characterized carbonate depositional systems in Europe, North Africa, Russia, Kazakhstan, and North America. ThoughDonezella is generally included in the green calcareous algae, it has been attributed to different systematic groups and its classification and paleoecology still remain controversial. This work focuses on the distribution ofDonezella across a carbonate platform (Sierra de Cuera) of Upper Carboniferous (lower Bashkirian-lower Moscovian) age located in the Cantabrian Mountains (Asturias, NW Spain). Sierra de Cuera exhibits a well-exposed cross-section from the horizontal platform through a steep slope (30°) to the basin floor. This unique feature allows reliable estimates of paleo-water depth and distance from the platform margin.Donezella specimens are interpreted asin situ when they form a network supporting cement-filled primary cavities and the ramified skeletons are surrounded by micrite coatings, often with a peloidal fabric, or by early marine cement. In the platform interior,Donezella is associated with phylloid algae and occurs in mud-rich low-relief bioherms. Towards the platform margin, massive units of boundstone are characterized by clotted peloidal micrite and radial fibrous cement-filled primary cavities. They containDonezella and a diverse fossil assemblage of calcareous algae, bryozoans, and foraminifers.Donezella's delicate network appears fortified by thein situ precipitation of peloidal micrite. On the upper slopein situ precipitated peloidal micrite, abundant radial fibrous cement, and fenestellid bryozoans are the major components of the boundstone facies, along withDonezella and a eskeletal community similar to the outer platform one. On the slope,in situ Donezella were observed down to paleowater depths up to 200 m. Sedimentologic, petrographic, and microfacies analysis ofDonezella accumulations in the different facies belts of Sierra de Cuera strongly suggest that this problematic organism was able to thrive over a large depth range, in low-energy but also in moderately agitated environments or in settings with temporary increase in current action, and in organic, physical-chemical and oceanographic conditions that enhanced the precipitation of peloidal micrite. The interval of water depth inferred from the well-exposed slope geometry of Sierra de Cuera suggests that eitherDonezella might not have belonged to the green calcareous algae or, alternatively, this depositional system was influenced by particular paleo-oceanographic conditions that extended the euphotic zone below the average depth. The morphology ofDonezella's skeleton and its sedimentological occurrences are not exclusively indicative of an affinity with Chlorophyta. Therefore, it is suggested thatDonezella should be considered as amicroproblematicum organism. The data presented in this study contribute to the inter-pretation of comparableDonezella accumulations in carbonate depositional systems where limited outcrop exposures do not allow correct evaluation of the geometry and facies distribution.
TL;DR: A stromatactis mud-mound has been found near Slavnicke Podhorie in the Czorsztyn Unit of the Pieniny Klippen Belt (Western Carpathians, Slovakia).
Abstract: A stromatactis mud-mound has been found near Slavnicke Podhorie in the Czorsztyn Unit of the Pieniny Klippen Belt (Western Carpathians, Slovakia). Its stratigraphic range is Bathonian to Callovian and it is one of the youngest known true stromatactis mud-mounds. The complete shape the mound is not visible since the klippe is a tectonic block encompassed by younger Cretaceous marls. The matrix is micritic to pelmicritic mudstone, wackestone to packstone with pelecypods, brachiopods, ammonites, and crinoids. An important component of the mound is stromatactis cavities that occur as low as the underlying Bajocian-Bathonian crinoidal limestones. The stromatactis cavities are filled by radiaxial fibrous calcite (RFC) as well as in some places by internal sediment and, finally, by clear blocky calcite. Some cavities remain open with empty voids in the centres. In some stromatactis cavities, tests of cavedwelling ostracodsPokornyopsis sp. were found, surrounded by the latest stages of the RFC. This indicates that stromatactis cavities formed an open network enabling migration of the ostracods and their larvae over a period of time. Except in the case of the stromatactis cavities, there are numerous examples of seeming recrystallizationsensu Black (1952) and Ross et al. (1975) and Bathurst (1977). The radiaxial fibrous calcite encloses patches of matrix and isolated allochems. The RFC crystals are oriented perpendicularly to the substrate whether it is a cavity wall or enclosed allochems. This means that the RFC crystals could not grow from the centre of the cavity outward as postulated by Ross et al. (1975). There are also numerous “floating” isolated allochems, which are much smaller than the surrounding RFC crystals. The explanation involving three-dimensional interconnection of allochems seems to be unlikely. In the discussed mud-mound there is a conflict between apparently empty cavities that had to exist in the sediment and seeming “recrystallization” related to the same RFC that forms the initial void filling. The authors favor an alternative explanation of the “recrystallization”. We presume that the allochems served as nucleation points on which the crystals started to grow. Obviously, the allochems and the micritic patches were different from the surrounding material. RFC crystals (either short-or long-bladed) of the “recrystallization” spar grew at the expense of decaying microbial mucillages. The mucus can enclose peloids, allochems, or whole micritic patches that “floated” in the cavity and served as nucleation sites for the RFC crystals. The entire mud-mound represents a microbially bound autochthonous micritic mass; the stromatactis and stromatactis-like cavities originated where purer mucillage patches occurred, giving rise to open spaces. Such features as the morphological variety of stromatactis fabrics, the pervasive penetration of the sparry calcite into matrix, and the enclosure of the “floated” allochems and mudstone patches by sparry calcite, seem to provide support for the presence of mucus aggregates within the mound body. The mucus might be related to protozoans rather than to sponges or other well organized metazoan organisms. Occurrence of the stromatactis cavities in the underlying Bajocian-Bathonian crinoidal limestones support the inference on biological origin of the stromatactis fabrics. The alternative inorganic models of stromatactis origin (e.g., internal erosion or water-escape) are hardly applicable to the sediment formed by crinoidal skeletal detritus.
TL;DR: In this paper, the authors studied the upper and lower slopes of the Forni Dolomite slope-basin complex, which can be interpreted as a slope apron that, as a model, can be extended to steeply inclined carbonate slopes.
Abstract: Upper Triassic (Middle-Upper Norian) shallow-water carbonates of the Dolomia Principale and its deep-water counterparts (Forni Dolomite) have been studied in the Carnian Prealps (northeastern Italy). The Dolomia Principale was a storm-dominated carbonate platform; in the Mt. Pramaggiore area, along a well-preserved 3.5 km-long platform-to-basin transition, the inner platform facies of the Dolomia Principale, characterized by m-scale shallowing upward cycles, give way seaward to open marine storm-dominated shallow subtidal lagoon deposits with frequent hardgrounds and evidence of microbial stabilization of the bottom sediment. The margin of the Dolomia Principale platform was colonized by meter-scale stromatolites and serpulid-microbial mounds that thrived due to the local highly stressed environment, characterized by drastic salinity fluctuations and turbid waters, that excluded the Upper Triassic coral-sponge communities. The Forni Dolomite slope-basin complex was characterized by an upper slope facies with debris flows, megabreccias, turbidites and serpulid-microbial mounds. The lower slope and basinal facies show thinning and fining trends. After restoring the original geometry of the slope, the depositional angles of the clinoforms range between 11 and 36 degrees, reflecting closely the coarse-grained character of the Forni Dolomite slope complex, which can be interpreted as a slope apron that, as a model, can be extended to steeply inclined carbonate slopes. The onset of synsedimentary extensional tectonics at the Middle-Late Norian boundary affected the platform-slope depositional system via: 1) localized inner platform collapses and the formation of an intraplatform anoxic depression at Mt. Valmenone, 2) a switch from platform lateral progradation during the Middle Norian to vertical aggradation in the Late Norian, reflected in an increase in platform relief, steeper foreslope angles and coarser-grained slope facies, and 3) controlling the spatial orientation of the margin of the Dolomia Principale.
TL;DR: In this paper, the Apulian shelf has been investigated with mound-shaped algal banks and associated bioclastic deposits, in a bathymetric range of 53-60m water depth.
Abstract: Mound-shaped algal banks and associated bioclastic deposits have been investigated on the Apulian shelf, SE Italy, off Capo d’Otranto and Santa Maria di Leuca within a bathymetric range of 53–60m water depth. The bioclastic deposits form different sand-gravel skeletal assemblages; each one characterised by different associations and occurrence of prevailing organisms in relation to substratum types. These deposits lie on a lee shore and form rhodalgal and bryomol relict-modern deposits which originate from the banks’ erosion by means of bottom currents and storms. These play a significant role in reworking bottom preventing colonization by a sessile stabilizing bottom community, and mobile deposits prevent large encrustations. Sediments are thus characterised by a variable taphonomical preservation state and time-averaging as shown by the occurrence of abraded bryozoan growth forms. The banks, sub-circular in shape, display a maximum diameter of 70 m and 1–2m relief. Their position on the shelf coincides with the present day 50 m isobath and it is assumed to correspond to a paleoshore such as that which formed in the Holocene during the transgression following the last ice age. Living counterparts of these banks occur today north of the study area at 10–30 m water depth.
TL;DR: The Calcare di Mendicino is a mixed carbonatesiliciclastic informal unit of Miocene (Late Tortonian-Early Messinian age) that crops out extensively in the northwestern part of the Calabria.
Abstract: The “Calcare di Mendicino” is a mixed carbonatesiliciclastic informal unit of Miocene (Late Tortonian-Early Messinian age), that crops out extensively in the northwestern part of the Calabria. In the Scannelle quarry near Belsito (Cosenza), four stratigraphic sections were studied to define the sedimentological and paleoecological setting. The carbonate body records the development of a deep-water coral bank characterized by a low-diverse community of azooxanthellate scleractinian (Oculina andDendrophyllia) and stylasterine hydrozoans colonies. Two main stages of bioconstruction development can be distinguished: a thicket and a bank stage. Among the biostromal dwellers the more common are bryozoans, echinoids, benthic foraminifers, gastropods, and bivalves. A higher content of planktonic foraminifers occur in the thicket stage. The coral bank flourished within the aphotic zone, with deep currents loaded with nutrients and siliciclastic sediments. The upper part of the “Calcare di Mendicino” carbonate body has been affected by a pervasive dolomitization destroying almost completely the sedimentary structures and the biofacies. The lower part, the main object of this paper, preserves the microfacies but it experienced a widespread recrystallization obliterating the primary geochemical characteristics. The diagenetic history, partly hidden, reveals three main stages: primary marine with isopachous fibrous cements, deep burial with cavities infilled by sparry calcite, and meteoric-phreatic with dog-tooth cements.
TL;DR: In this paper, an Upper Ladinian to Lower Carnian succession in the Idrija-Cerkno region (W Slovenia) is described and correlated with similar successions in the Dolomites.
Abstract: An Upper Ladinian to Lower Carnian succession in the Idrija-Cerkno region (W Slovenia) is described and correlated with similar successions in the Dolomites. Structurally, the area belongs to the Rodne unit (Trnovo nappe, NW Dinarides). The succession was reconstructed from three stratigraphically superimposed sections. The Orehovska Grapa section is characterised by finegrained turbidites composed of sandy mudstones with intercalations of lenses and beds of trachy-andesite tuff and resedimented tuffs. Beds of hemipelagic light grey wackestone are rarely interstratified. These rocks are correlative with the Upper Ladinian Wengen Group. The Police1 section is composed of black shaly marls and mudstones, hemipelagic wackestone, tuffaceous sand-stones, and in the upper part, of calciturbidites overlain by black laminated shales. The section is correlated with the lower part of the San Cassiano Formation. The Police 2 section consists mainly of wavy bedded peloidal and bioclastic limestone, alternating with thin interbeds of shaly mudstones and marls. The limestone and mudstones are interpreted as tempestites and gradually pass into bedded and massive dolomite of Early Carnian age. This succession is similar to the transition from the San Cassiano Formation to the Cassian Dolomite. The studied succession represents a shallowing upward basinal sequence capped by carbonate platform deposits. Palaeogeographically it is a Late Ladinian transition from the carbonate platform in the south to the typical basinal area in the north.
TL;DR: The authors examined the reality of this leagend from a comparison of the oolitic sand from Cleopatra's beach in Turkey with oolitics sand from the coast west of Alexandria in Egypt.
Abstract: Cleopatra’s beach is one of the most famous in Turkey for its distinctive white sand, composed largely of ooids. Legend has it that the Roman leader, Mark Antony, had this sand shipped from Alexandria in Egypt to create a beach for his lower Cleopatra, on Sedir Island in Gokova Bay, SE Aegean Sea. This study examines the reality of this leagend from a comparison of the oolitic sand from Cleopatra’s beach in Turkey with oolitic sand from the coast west of Alexandria in Egypt, the home city of Cleopatra, and only place in the Mediterranea where Holocene ooids occur in abundance.
TL;DR: In this article, textural features and trace element composition were used to determine the degree of meteoric diagenesis, and the insoluble residue (I.R.) is predominantly of primary origin and its amount ranges from 3% to 29%, averaging 13.75%.
Abstract: Holocene tufa deposits in the Northern Dalmatia region of Croatia occur along the banks and at present sites of waterfalls of the Zrmanja river and its tributary the Krupa river. Petrographic, geochemical and statistical analyses have been used to relate textural features and trace element composition to the degree of meteoric diagenesis. Trace metal concentrations associated with carbonate phase were determined by sequential extraction procedure. The insoluble residue (I.R.) is predominantly of primary origin and its amount ranges from 3% to 29%, averaging 13.75%, thus permitting variable water/rock ratios of the stabilazing meteoric system. All the evidence points to a scarcity of post-depositional recrystallization and cementation, but where present these features are accompanied by I.R., Mg, Sr and Zn depletion and Fe enrichment.
TL;DR: A unique small bioherm, called Placunopsis ostracina (Pectinacea), was described from the Lower Keuper in South Germany as discussed by the authors, which consists of the attached right valves of the tiny oyster-like lamellibranch.
Abstract: A unique small bioherm, 0.7 m in diameter and 0.25 m high, is described from the Lower Keuper in South Germany. Its core consists of the attached right valves of the tiny oyster-like lamellibranchPlacunopsis ostracina (Pectinacea). It is overgrown by a cm-thick laminated stromatolitic crust formed by microbial mats and sponges. The bioherm was dolomitized during early diagenesis and represents the temporary transition from restricted marine to more saline depositional environments. It is one of the stratigraphically youngestPlacunopsis bioherms found so far in the Germanic Triassic.
TL;DR: The Ningqiang Formation (late Telychian, Llandovery, Silurian) as mentioned in this paper is characterized by nearly 3000 m of shales in tercalated with carbonates.
Abstract: Ningqiang Formation (late Telychian, Llandovery, Silurian), characterized by nearly 3000 m of shales in tercalated with carbonates, is situated between Ningqiang (S. Shaanxi Province) to Guangyuan (N. Sichuan Province) adjacent to the northwest margin of the Yangtze Platform. The high diversity “Xiushan Fauna”, and abundant reef development, illustrate a relatively warm and persistent shallo marine environment in these early Silurian sediments. The sequence shows reef radiation after recovery from the end Ordovician mass extinction envents. Multiple horizons of reef-building occurred within a relatively short geological interval and resulted in more than 30patch reefs up to 200 m in diameter and 1–50 m vertically, composed of abundant fossils. Reef biota include frame-building corals, stromatoporoids, bryozoans, and microbialites, and reef-associated oranisms such as crinoids, brachiopods, trilobites, gastropods, nautiloids and ostracods. Three reefrelated biotic associations are recognised: a) reefs dominated by framework with crinoids and microbia; b) reefs dominated by only crinoids and microbia; and c) crinoiddomainated facies. Seven representative reef examples illustrate different morphologies and growth styles. A high terrigenous debris input and shallow epicontinental ramp, which lacked obvious topographic variation, were major controls which resulted in rather simple reefs; sedimentation was apparently the main constraint on lateral and vertical extension of reefs, and prevented large-scale reef complexes developing.
TL;DR: In this article, the authors provide a sedimentological description and genetic interpretation of a gas reservoir located in mud-dominated carbonates, which is part of the Lower Muschelkalk ramp system of Middle Triassic age.
Abstract: Carbonate ramps are prolific hydrocarbon reservoirs, usually associated with grain-rich facies types. The present paper provides a sedimentological description and genetic interpretation of a gas reservoir located in mud-dominated carbonates. These deposits are part of the Lower Muschelkalk ramp system of Middle Triassic age.
TL;DR: In this article, the authors show that the majority of these breccias are solution-collapse breccia, which are causally linked to paleokarstification.
Abstract: Carbonate breccias occur sporadically in the Lower-Middle Ordovician Maggol Limestone exposed in the Taebacksan Basin, South Korea These carbonate breccias have been previously interpreted as intraformational or fault breccias Thus, little attention has been focused on tectonic and stratigraphic significance of these breccias This study, however, indicates that the majority of these breccias are solution-collapse breccias, which are causally linked to paleokarstification Carbonate facies analysis in conjunction with conodont biostratigraphy suggests that an overall regression toward the top of the Maggol Limestone probably culminated in subaerial exposure of platform carbonates during the early Middle Ordovician Extensive subaerial exposure of platform carbonates resulted in paleokarst-related solution-collapse breccias in the upper maggol Limestone This subaerial exposure event is manifested as a major paleokarst unconformity elsewhere beneath the Middle Ordovician sequence, most notably North America and North China Due to its global extent, the early Middle ordovician paleokarst unconformity (‘the Sauk-Tippecanoe sequence boundary’) has been viewed as a product of second-order eustatic sea level drop during the early Middle Ordovician Although we recognizes a paleokarst breccia zone in the upper Maggol Limestone beneath the Middle Ordovician sequence, the early Middle Ordovician sequence boundary appears to be a conformable transgressive surface or a drowning unconformity, rather than a major paleokarst unconformity The paleokarst breccia zone in the upper Maggol Limestone is represented by a thinning-upward stack of exposure-capped tidal flat-dominated cycles that are closely associated with multiple occurrences of paleokarst-related solution-collapse breccias The paleokarst breccia zone in the upper Maggol Limestone was a likely consequence of repeated high-frequency sea level fluctuations of fourth- and fifth-order superimposed on a second-and third-order eustatic fall in sea level that was less than the rate of tectonic subsidence across the platform It suggests that second- and thirdorder eustatic sea level drop may have been significantly tempered by substantial tectonic subsidence near the end of maggol deposition The tectonic subsidence in the basin is also evidenced by the occurrence of coeval off-platform lowstand siliciclastic quarzite lenses as well as debris flow carbonate breccias With the continued tectonic subsidence, subsequent rise in the eustatic cycle caused drowning and deep flooding of carbonate platform, forming a conformable transgressive surface or a drowning unconformity on the top of the paleokarst breccia zone This tectonic implication contrasts notably with the slowly subsiding carbonate platform model for the Taebacksan Basin as previously intepreted Here we propose that the Taebacksan Basin evolved from a slowly subsiding carbonate platform to a rapidly subsiding intracontinental rift basin during the early Middle Ordovician This study also provides a good example that the falling part of the eustatic sea-level cycle may not produce a significant event at all in a rapidly subsiding basin where the rate of eustatic fall always remained lower than the rate of subsidence
TL;DR: In this paper, three trilobite biofacies are recognized in the Mungok Formation: i.e., Yosimuraspis, Kainella, and Shumardia in ascending order.
Abstract: The lithologic associations within the Lower Ordovician Mungok Formation in Korea define four depositional facies that formed across a continental margin fringing the Sino-Korean block: these facies represent lagoonal/restricted marine, shoal, inner shelf, and outer shelf environments. The stacking pattern of these facies reveals two systems tracts composed of five depositional sequences. The lower highstand systems tract consists of the lagoonal/restricted marine and shoal facies, whereas the upper lowstand systems tract comprises, in ascending order, inner shelf, outer shelf, and inner shelf facies. Three trilobite biofacies are recognized in the Mungok Formation: i.e.,Yosimuraspis, Kainella, andShumardia biofacies in ascending order. TheYosimuraspis Biofacies is dominated byYosimuraspis but also containsJujuyaspis andElkanaspis. The predominance of the endemic eponymous taxon suggests a lagoonal/restricted marine environment. The nearly monotaxicKainella Biofacies, which comprises pandemic genera such asKainella and occasionallyLeiostegium, may represent a less restricted environment than theYosimuraspis Biofacies. TheShumardia Biofacies occurs in the marlstone/shale lithofacies through relatively thick stratigraphic interval and is dominated by cosmopolitan trilobite taxa with some endemic species. The lithofacies and cosmopolitan trilobite assemblage of theShumardia Biofacies indicate that it occupied an outer shelf environment. The vertical succession of lithofacies and trilobite biofacies in the Mungok Formation records in general a shift from a restricted, shallow water environment to deeper-water environment.
TL;DR: In el presente trabajo se analizan las transformaciones de la politica social argentina en la decada del noventa, estudiando especificamente las transformaciónes en los sectores educativo, de cuidado de la salud and de prevision social as discussed by the authors.
Abstract: En el presente trabajo se analizan las transformaciones de la politica social argentina en la decada del noventa, estudiando especificamente las transformaciones en los sectores educativo, de cuidado de la salud y de prevision social Se propone que la transformacion fundamental experimentada por la politica social aqui analizada en la ultima decada fue la fragmentacion regresiva, proceso que, si bien registra antecedentes desde mediados de la decada del setenta, fue definitivamente consolidado en la decada del noventa mediante la tendencia a la privatizacion especialmente en los sectores previsional y de salud-, la descentralizacion especialmente en los sectores educativo y de salud-, y la particularizacion en los tres sectores sociales analizados- Estas transformaciones en la politica social se entienden como consecuencia de la adecuacion de la misma a las necesidades diferenciales del mercado laboral con relacion a la fuerza de trabajo durante el periodo, proceso que, a su vez, se considera resultado de las transformaciones experimentadas en la dinamica de acumulacion de capital en el ambito local, la cual estuvo caracterizada, en terminos generales, por la desindustrializacion, la reprimarizacion, la transnacionalizacion y la concentracion y centralizacion del capital
TL;DR: In this paper, the perfil del consumidor de alimentos organicos and evaluar the principales determinantes of sus decisiones of consumo e importancia relativa of the canales de compra.
Abstract: El proposito de este trabajo es analizar el mercado interno de alimentos organicos de nuestro pais, para ello se planteo como objetivo general definir el perfil del consumidor de alimentos organicos y evaluar los principales determinantes de sus decisiones de consumo e importancia relativa de los canales de compra. Se utilizaron dos fuentes de informacion: encuestas a consumidores y entrevistas a informantes calificados vinculados con la comercializacion de alimentos organicos. El periodo de recoleccion de datos fue entre junio y julio de 2002. Se concluyo que los consumidores destacan que el atributo mas importante de los alimentos organicos es que son sanos; la disponibilidad de informacion no resulta completa y no todos identifican el producto a traves de la marca, el sello de certificacion y/o la etiqueta de organico. Los principales canales utilizados son el negocio especializado en la venta de organicos, el supermercado y la venta directa de productores. Existen diferenciales de precios entre canales y sobreprecios respecto a los convencionales. Por otra parte los consumidores que eligen cada uno de estos, presentan caracteristicas diferenciales, en termin
TL;DR: In this paper, a trabajo centra en el analisis espacio-temporal de la actividad cotidiana de jovenes residentes de la ciudad de Mar del Plata.
Abstract: El proposito de este trabajo se centra en el analisis espacio-temporal de la actividad cotidiana de jovenes residentes de la ciudad de Mar del Plata. Mediante el estudio del uso del tiempo, se analiza la localizacion temporal, frecuencia y duracion de las actividades diarias y su distribucion espacial. La actividad diaria se estudia con el modelo espacio-temporal de la Geografia del Tiempo que aporta Torsten Hagerstrand. Como unidad de analisis, se toma al individuo concreto y se consideran las caracteristicas personales, el contexto organizativo, social y economico de la comunidad. Los resultados permiten interpretar y valorar el uso del tiempo de los jovenes, en funcion de las actividades cotidianas realizadas en dias laborables y no laborables. Se plantea una relacion entre espacios frecuentados, diversificacion de actividades, tiempo de duracion, distancia recorrida y medio de transporte, segun sexo, edad y nivel socioeconomico de los encuestados.
TL;DR: Gestion por procesos and actividades, una metodologia con enfasis en los proceso internos, has been investigated en el ambito publico de la Provincia de Buenos Aires as discussed by the authors.
Abstract: Los procesos internos de las organizaciones constituyen uno de los focos de atencion de los planteos estrategicos de la administracion ya que, a traves de su optimizacion, se intenta dar satisfaccion a las necesidades del usuario-ciudadano La "Gestion por procesos y actividades", una de las tecnologias con enfasis en los procesos internos, que ha tenido escasisima difusion en el ambito publico, es el objeto de estudio en el presente trabajo Se aborda la problematica de esta metodologia en el ambito de las organizaciones municipales, evitando un trasplante acritico desde la actividad privada, que es en la que tiene difusion Ademas, se la compara con otras dos metodologias que tambien enfatizan los procesos internos y luego se recorre el camino del analisis de la problematica de su aplicacion en un ente descentralizado de nivel comunal de la Provincia de Buenos Aires, con el proposito de identificar y caracterizar los elementos especificos de su funcionamiento El trabajo esta estructurado como sigue: presentacion de la cuestion sobre la que se indaga; recreacion del marco teorico de la Gestion por procesos y actividades; analisis de la realidad de los organismos municipales frente a esta nueva mirada; conclusiones
TL;DR: In this article, a compilation of side scan sonar, airgun and manned submersible surveys from several cruises to the mid-Norwegian Sula Reef Complex (SRC) is described in relation to the overall seabed topography.
Abstract: Cool-water carbonates in the aphotic zone of deep shelf and continental margin settings in the Northeast Atlantic are produced by the deep-water coral reefs withLophelia pertusa as the major framework builder. Through a compilation of side scan sonar, airgun and manned submersible surveys from several cruises to the mid-Norwegian Sula Reef Complex (SRC), the facies pattern and zonation of one of the largest deep-water reefs in the Northeast Atlantic is described in relation to the overall seabed topography. The late glacial to early postglacial iceberg scour on the crest and shoulder of the Sula Ridge provides settling ground for the scleractinian corals already in the early Holocene. Since then coral growth continues until today but was supposed to be disturbed by an environmental hazard, the so-called second Storegga event. The distinct distribution pattern of individualLophelia reefs on the Sula Ridge has stimulated a discussion on intrinsic environmental controls such as the bentho-pelagic coupling and the alternative hydrocarbon-based nutrition hypothesis.
TL;DR: A detailed interpretation of the Pleistocene shelf edge of the Florida Platform as found in various facies of the Key Largo Limestone beneath the Florida Keys is presented in this paper.
Abstract: New dates and analysis of 12 deep and 57 shallow cores allow a more detailed interpretation of the Pleistocene shelf edge of the Florida Platform as found in various facies of the Key Largo Limestone beneath the Florida Keys. In this study a three-phase evolution of the Quaternary units (Q1–Q5) of the Key Largo is presented with new subdivision of the Q5. (1) In the first phase, the Q1 and Q2 (perhaps deposited during oxygen-isotope stage 11) deep-water quartz-rich environment evolved into a shallow carbonate phase, (2) Subsequently, a Q3 (presumably corresponding to oxygen-isotope stage 9) flourishing reef and productive high-platform sediment phase developed. (3) Finally, a Q4 and Q5 (corresponding to oxygen-isotope stages 7 and 5) stabilization phase occurred with reefs and leeward productive lagoons, followed by lower sea levels presenting a sequence of younger (isotope substages 5c, 5a) shelf-margin wedges, sediment veneers and outlier reefs. The Key largo Limestone provides an accessible model of a carbonate shelf edge with fluctuating water depth, bordering a deep seaward basin for a period of at least 300 ka. During this time, at least four onlaps/offlaps, often separated by periods of karst development with associated diagenetic alterations, took place. The story presented by this limestone not only allows a better understanding of the history of south Florida but also aids in the interpretation of similar persistent shelf-edge sites bordering deep basins in other areas.