Abstract: The biostalactites from the Kakoskali cave in Cyprus represent a new example of the complex biotic relationships between skeletal organisms and microbial communities in building bioconstructions of cryptic marine environments. Biostalactites are mainly constituted of polychaetes of the family Serpulidae and, to a lesser degree, foraminifers and bryozoans. Within the skeletal framework of these organisms, two types of microcrystalline calcite (micrite) have been recognized: autochthonous and detrital micrite. The autochthonous fraction is syndepositionally lithified and occurs as clotted peloidal and, subordinately, aphanitic (structureless) textures, suggesting the presence of heterotrophic microbial activities thriving on decaying metazoan organic matter. This fraction is limited to the protected portions of the bioconstructions, especially in the inner and lower parts. The presence of iron and manganesiferous oxidizing bacteria is suggested by the deposition of ferromanganesiferous crusts and Frutexites-like structures. These microbial-induced biomineralizations are the main evidence of carbonatogenetic and Fe–Mn, autotrophic and chemoheterotrophic, bacterial activities. The Kakoskali cave is frequently visited by divers who, during their immersions, resuspend the fine bottom sediment, which later covers the surface of the bioconstructions, disturbing the delicate equilibrium of the biotic association. This perturbation, which is also caused by strong waves and currents, during winter months, reflects on the bioconstruction morphologies, community composition, and colonization pattern. Bioconstructions exhibit an upper smooth surface, produced by few taxa (e.g., polychaetes, foraminifers), hosting a low number of living individuals, and a lower comparably rough surface, colonized by a more abundant community showing a higher species richness. The ratio surface roughness/smoothness is related to micrite sediment type: the upper part is mainly characterized by loose detrital micrite while the internal and lower parts by syndepositional cemented autochthonous micrite.

Abstract: Ikaite (CaCO3·6H2O) forms at near-freezing temperatures and its precipitation is favored by high alkalinity and high concentrations of dissolved phosphate. With increasing temperatures during early burial, ikaite transforms into its calcite pseudomorph referred to as glendonite. To further constrain the biogeochemical processes that impact the transformation of ikaite to glendonite, glendonites from Cenozoic strata of western Washington State, USA, were analyzed for their petrographic characteristics, stable isotope (C, O, S) patterns, and lipid biomarker inventories. Glendonites from the Humptulips, Pysht, Lincoln Creek, and Astoria Formations occur in strata that enclose abundant methane-seep deposits. Despite robust evidence for the anaerobic oxidation of methane (AOM) at these ancient seep sites, molecular signatures of this biogeochemical process were not found within glendonite. Glendonite was found to contain abundant, moderately 13C-depleted iso- and anteiso-fatty acids, compounds interpreted as biomarkers of sulfate-reducing bacteria in marine settings. The 34S-enrichment in carbonate-associated sulfate (δ34SCAS = 54.1 ‰) and the 34S-depletion of pyrite (δ34SCRS = 6.8–12.5 ‰) in glendonite samples confirm that bacterial sulfate reduction was a prominent process in the sedimentary environment during the transformation of ikaite to glendonite. Low δ13Cglendonite values, such as those of the Washington State glendonites (as low as −21‰), have previously been interpreted as signatures of methane-derived carbon; however, the admittedly small data set obtained from the Washington State glendonites is best explained with organoclastic sulfate reduction as the alkalinity engine driving carbonate precipitation. This surprising finding reveals that more comprehensive work is needed to decipher the biogeochemical processes that governed the transformation of ikaite to glendonite in ancient marine settings, including the relative contribution of organoclastic sulfate reduction and AOM.

Abstract: An uppermost Triassic–lowermost Jurassic carbonate platform succession, which is 430 m thick, in northwestern Sicily is described with the aim to provide new data on the sedimentological and biological variations across the Triassic–Jurassic boundary in peritidal environments. The studied succession belonged to the rimmed carbonate shelf that developed during the Late Triassic along the margins of the Ionian Tethys. The peritidal sediments consist of meter-scale shallowing-upward cycles formed by subtidal, intertidal, and supratidal facies. Three main informal units are differentiated along the section on the basis of the variations recorded by the subtidal facies. The lower and middle units are attributed to the Rhaetian, on the basis of the common presence of the foraminifer Triasina hantkeni, associated with several benthic foraminifers, such as Aulotortus sinuosus and Auloconus permodiscoides. Megalodontids are particularly abundant and large in the lower unit, whereas they become rare in the middle unit and disappear in the upper unit. The last occurrence of T. hantkeni, along with the disappearance of the benthic foraminifer fauna, and the bloom of the calcareous alga Thaumatoporella parvovesiculifera is assumed as a proxy of the Rhaetian–Hettangian boundary. Recovery biota during the early Jurassic occurs about 20 m upward of the boundary zone, marked by the appearance of benthic foraminifers, such as Siphovalvulina sp. The observed biostratigraphic signature in the studied section is easily comparable to similar Tethyan sections already described from Italy, Greece, and Turkey; thus, it is believed that the faunistic turnover does not reflect local facies variations, in response to changes in the accommodation space of the platform, but regional changes in a more wide area of ocean Tethys.

Abstract: The palynological study and palynofacies analysis supported by size analysis of opaque phytoclasts and diversity indexes for particulate organic matter in stratigraphically well-constrained (inoceramid biostratigraphy) sections is applied in monotonous Upper Cretaceous carbonate-siliciclastic sediments of southern Poland. Integrated data allow for the estimation of the proximity of an uplifted area from the studied sections. For the first time in palynofacies analysis, both Simpson’s Index of Diversity (1 − D) and Shannon’s index are used for organic matter distribution providing a comprehensive understanding of a proximal–distal trend in a sedimentary basin. Cluster analysis allowed grouping the samples within proximal to distal shelf zones. The size analysis of opaque woody phytoclasts is used to extrapolate the distance from the source area. Palynofacies analysis indicates the existence of an uplifted area (probably connected with “Kukernitz Island”) in the Holy Cross part of the Danish-Polish Trough during the Maastrichtian. The presented results improve contemporary paleogeographical interpretations for this part of the Late Cretaceous central European Basin. The youngest Maastrichtian deposits of the Miechow Synclinorium are described, based on inoceramids which are of early Late Maastrichtian age.

Abstract: Cold-water corals of the Late Pleistocene (21,400–22,500 BP) are recorded from the sea-bottom of two inter-atoll channels (Kardiva Channel at 457-m depth and Male Vaadhoo Channel at 443-m depth) of the eastern row of the Maldives archipelago. Coral assemblages are composed mainly by Lophelia pertusa and secondarily by Madrepora oculata and Enallopsammia rostrata. These cold-water coral patches are places where the benthic life, mainly sessile, is concentrated, which is clearly absent off-rubble patches. The main epibionts are tube-dwelling polychaetes (mainly Spirorbis and Serpula), bryozoans, siliceous sponges, barnacles, gorgonids, solitary corals, encrusting foraminifera, and microbial mats. The analysis of epibionts assemblages shows different biocoenoses between both studied sites as well as a dependency of the epibiont coverage with regard to the coral genus. Some living benthic organisms such as brachiopods, bivalves, gastropods, barnacles, and ophiuroids find refuge among coral branches. The common record of juvenile specimens of vagile organisms such as small ophiuroids, is probably related to the nursery function of the cold-water corals in spite they are fossils. Environmental requirements of Recent cold-water corals (Lophelia, Madrepora and Enallopsammia) differ of conditions at both sampling sites with sensibly lower oxygenation degree and density of waters than needed for cold-water corals. Therefore, it is proposed that the present-day oxygen and density conditions are the factors which inhibit modern cold-water coral growth in the inter-atoll channels.

Abstract: The kilometer-sized and 100-meter-thick carbonate platforms of the Escalada Fm. I and II (Middle Pennsylvanian) accumulated in the foredeep of a marine foreland basin during the transgressive phases of 3rd-order sequences and were buried by prograding siliciclastic deltaic systems in the course of the subsequent highstand. The carbonate successions show a general upward trend from grain- to mud-supported carbonates, interfingering landwards with siliciclastic deposits of a mixed siliciclastic-carbonate shelf (Fito Fm.) adjacent to deltaic systems. The spatial variability of the carbonate facies and the high-frequency (4th–5th order) cycles, from the platform margin-outer platform to the deltaic systems, has been interpreted from basin reconstruction. Carbonate facies include skeletal grainstone to packstone, ooidal grainstone, burrowed skeletal wackestone, microbial and algal boundstone to wackestone forming mounds, various algal bafflestone and coral biostromes in areas with siliciclastic input. These high-frequency transgressive–regressive cycles are interpreted to record allocyclic forcing of high-amplitude glacioeustasy because they show characteristic features of icehouse cycles: thickness >5 m, absence of peritidal facies, and in some cases, subaerial exposure surfaces capping the cycles. In the mixed cycles, siliciclastics are interpreted as late highstand to lowstand regressive deposits, whereas carbonates as transgressive-early highstand deposition. The lateral and vertical variability of the facies in the glacioeustatic cycles was a response to deposition in a rapidly subsiding, active foreland basin subjected to siliciclastic input, conditions that might be detrimental to the growth of high-relief carbonate systems.

Abstract: Sedimentary facies of seven Posidonia oceanica meadows of western Mediterranean Sea were investigated. Five meadows are located in the Tyrrhenian coast, two are placed in the western coast of Sardinia and Corsica. These meadows develop on soft and hard substrates, often forming “mattes”, in areas characterized by different oceanography, morphology, and terrigenous inputs produced by coastal erosion and fluvial runoff. A total of five sedimentary facies have been recognized ranging from pure terrigenous to bioclastic: terrigenous sand to gravelly sand, bioclastic sands, skeletal gravelly sands, mixed siliciclastic–carbonate sands, well to moderately sorted skeletal siliciclastic sands. All of the sedimentary facies associated with P. oceanica are in the sand grain size. The gravelly fraction is generally subordinated and variable, whereas the muddy fraction is generally low. The very low frequencies of the muddy fraction can be attributed to re-suspension processes and to the lack of carbonate mud production. The rate of epiphytic carbonate production obtained by two of the investigated meadows averages 400 g m−2 year−1. This value is in the range of temperate Mediterranean as well as of tropical and subtropical seagrasses. The epiphytic carbonate production plus the calcareous biota living on seagrass substrate contributes to form mixed siliciclastic–carbonate sediments of the nearshore environment of the Mediterranean. Lastly, the carbonate production associated with seagrass was derived by biota belonging to the heterozoan assemblage, where aphotic organisms are dominant, together with oligophotic biota such as coralline algae and symbiont-bearing foraminifera. Consequently, in the well-illuminated seagrass settings, the prevalent skeletal assemblages is represented by the heterozoan association while the components of the photozoan assemblages are absent or subordinate. This a key point for the paleoenvironmental reconstruction of the photic zone in the fossil record. Because the skeletal components of many seagrass dwellers greatly contribute to the carbonate sediment production of photic shallow-water environments, the seagrass meadows became substantial places of carbonate production and C (organic and inorganic) sequestration during the Cenozoic.

Abstract: The lowermost carbonate beds of the Cerro San Pedro (San Pedro de la Cueva, Sonora State, Mexico) previously assigned to the Mississippian, belong in fact to the lower Ordovician. The limestone of this succession is often dolomitized and chertified, and displays gastropods, pelmatozoans, sponges, and trilobites as major bioclastic components. The different microfacies show that high-energy grainstones, proximal tempestites, and distal tempestites dominated the sedimentation. The paleoenvironments of deposition correspond to an inner ramp, a mid-ramp, and perhaps the upper part of an outer ramp. The strata are characterized by the incertae sedis cyanobacteria Nuia sibirica. A taxonomic revision and discussion of these cyanobacteria, often confused with ooidic grains, is emphasized. Some data are presented on other microfossils, such as primitive, monothalamous foraminifers: Rauserina sp., Vicinesphaera sp., and Neoarchaesphaera sp., leperditicopida and their endolithic microperforations, and primitive chaetetids. Compared to the contemporaneous deposits of the USA, some paleobiological components, e.g., the lithistid siliceous sponges Archaeoscyphia, stromatoporoids? Pulchrilamina, and receptaculacean algae Calathium, are quite rare in the studied section of Sonora, but the predominance of tempestites in the carbonate succession shows that boundstones formed before were systematically eroded and resedimented. The paleogeographic implications are the following: (1) a lower Ordovician intertropical Nuia Province is newly defined in the western part of the lower Ordovician intertropical belt; (2) San Pedro de la Cueva constitutes one of the westernmost outcrops of this new Nuia Province; (3) from Sonora, Nuia extends eastward as far as South China; (4) due to its westernmost paleoposition, San Pedro de la Cueva was frequently affected by tropical storms; and (5) northern lower Ordovician terranes of Mexico (Sonora, Chihuahua, and Baja California) are entirely distinct from the southern ones (Oaxaca). The paleopositions and paleogeographic connections of these northern Mexican terranes with Laurentia, Avalonia, and peri-Gondwanan parts of South America, through the Iapetus and Rheic oceans, still remain disputable or unknown.

Abstract: Varied west-transported and far-traveled Jurassic melanges in southwestern Serbia represent a key to understand the geodynamic history and to solve paleogeographic questions and reconstructions in the Triassic–Jurassic passive and active margin arrangement of the Inner Dinarides. Of special interest are the carbonate-clastic radiolaritic melange areas in the Zlatar Mountain below the Dinaridic Ophiolite nappe. The present study reports from a Middle Jurassic sedimentary melange in the area of Vodena Poljana. Carbonate components and blocks of the mass-flow deposits consist exclusively of a reworked Middle/Late Anisian to Early Jurassic distal shelf succession. Ophiolite components from the Dinaridic Ophiolite nappe stack are missing in the spectrum. The underlying series of the Zlatar Melange belong to Early/Middle Anisian shallow-water carbonates and to Late Anisian to Middle Jurassic deep-water sedimentary rocks of the Hallstatt facies zone. South of Vodena Poljana in the overlying ophiolitic melange occur Late Triassic radiolaritic components from the sedimentary cover of the Late Triassic ocean floor, beside ophiolite clasts and limestone components from the continental slope. A comparison with preserved Hallstatt Limestone successions and Jurassic melange complexes from the Eastern Alps, Western Carpathians, and Albanides strengthen the interpretation of a provenance of the Zlatar melange from the distal passive margin facing the Neotethys Ocean to the east. An autochthonous Dinaridic Ocean west of the Drina-Ivanjica Unit cannot be confirmed.

Abstract: A core recovered in the North German Basin at the locality of Eulenflucht in the Suntel Mountains, 30 km SE of Hannover, Germany, is interpreted in terms of Oxfordian to Kimmeridgian sequence stratigraphy of this basin. Thirteen different facies are recognized which record the evolution of an outer ramp into a restricted hypersaline lagoon. Changes in grain size, variations in the amount of components, fluctuations of the matrix content and of the microscopic texture, as well as vertical lithofacies stacking patterns, were integrated to define small-scale sequences. Medium-scale sequences were identified by changes in facies combinations of the constituent small-scale sequences. Large-scale sequences were differentiated by facies proportion statistics in the distinct medium-scale sequences. This allows the complete sequence stratigraphic subdivision of the Oxfordian and Kimmeridgian succession to be interpreted. The stable carbon isotopic composition of bulk samples enables a correlation with chemostratigraphic records found elsewhere. This result is supported by an ostracod biostratigraphy that allows a chronostratigraphic assignment of the succession. The large-scale sequences were controlled by climate and local tectonic movements. It is proposed that a long-term shallowing trend during the Kimmeridgian time was induced by regional uplift.

Abstract: The sedimentary succession in central Poland records significant changes in facies at the turn of the Planula and Platynota zones in the Upper Jurassic, expressed by the drowning of the ramp-type platform and development of an extensive isochronous marl horizon. The topmost level of the marl horizon is a regional hardground, which is interpreted as the third-order sequence boundary Kim 1. In some areas, the hardground was eroded and is only preserved as bored and encrusted clasts. The composition of the borings may indicate that colonization and recolonization of the clasts took place in an extremely shallow water environment. The overall low level diversity of clast-encrusting organisms and their occurrence on both sides of clasts indicates frequent overturning and high current activity. However, other extrinsic factors, such as salinity fluctuations, may have been involved. The final redeposition and burial of the clasts were related to subsidence through widespread reactivation of Paleozoic faults. Comparison with Middle Oxfordian–Lower Kimmeridgian sequences of central and southern Poland indicates that the carbonate ramp morphology and paleoenvironmental conditions were periodically subjected to significant modification during phases of extensional tectonics, with the development of fault-controlled intra-platform ridges and basins. These features may have been the NE continuation of parallel swells and basins developed in the southern part of the carbonate platform adjacent to the Tethys.

Abstract: Anachronistic and unusual carbonate facies (AUCFs) are identified in four localities with exposed Spathian strata in the western Balkanides. These include thin-bedded micritic limestone, flat-pebble breccia/conglomerate, mud-chip conglomerate, limestone-marl ribbon rock, vermicular limestone, and microbial oolite. Their depositional and/or early diagenetic origin is interpreted on the basis of petrographic characteristics, results from previous studies, and comparison with analogues from the geological record. Various controlling factors are distinguished in the context of their relative influence on global, regional, or local scale, i.e., environmental conditions (high degree of CaCO3 supersaturation, fluctuations in oxygen levels and salinity), biological controls (bioturbation, microbial blooms, scarcity or abundance of metazoans), and uniformitarian sedimentary processes (wave agitation, storm action, terrigenous input, seismic shocks). Most of the AUCFs are assigned to features associated with enhanced CaCO3 precipitation, while the vermicular limestones belong to fabrics that formed due to limited biologic activity. The thin-bedded micritic limestones, flat-pebble breccias/conglomerates, and limestone-marl ribbon rocks represent anachronistic facies, while the remaining AUCFs are regarded as unusual sedimentary features and fabrics. This study reports a new occurrence of diverse Spathian AUCFs formed in subtidal settings besides those described from the southwestern USA and south China. The results show that anomalous paleoceanographic conditions for carbonate sedimentation persisted locally in the shallow Western Tethys until late Early Triassic time.

Abstract: In the Middle Anisian, extensional tectonic movements led to the development of a small isolated carbonate platform in the middle part of the Balaton Highland, Transdanubian Range, Hungary. In the Late Illyrian, a condensed pelagic carbonate succession with phosphorite horizons was formed on the top of the already drowned platform. These strata contain an extraordinarily diverse ammonite fauna. This unit is overlain by radiolarian-rich carbonates, locally with radiolarite interbeds. We suggest that the drowning process and the post-drowning sediment deposition were controlled partly by regional factors, i.e., the onset of opening of the Neotethys Ocean, and partly by local factors such as the bottom topography and related current activity, which may also be connected with the opening of the ocean. The predominance of the radiolarian-rich sediments suggests eutrophic surface water, which may be explained by a monsoon-driven upwelling model. The segmented sea-floor topography together with the high-fertility surface water conditions may have provided favorable habitats for the ammonites, which may have adapted to various ecological conditions, leading to extreme diversification of this group. Since similar Middle to Late Anisian evolution was reported from many other units of the western Neotethys margin, regional factors such as the establishment of an extensional tectonic regime and related marginal basin formation, monsoon-driven upwelling, and related high surface water productivity seem to be of critical importance in controlling the depositional conditions.

Abstract: Fil: Beresi, Matilde Sylvia. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - Mendoza. Instituto Argentino de Nivologia, Glaciologia y Ciencias Ambientales. Provincia de Mendoza. Instituto Argentino de Nivologia, Glaciologia y Ciencias Ambientales. Universidad Nacional de Cuyo. Instituto Argentino de Nivologia, Glaciologia y Ciencias Ambientales; Argentina

Abstract: Ocean acidification is widely accepted as a primary threat to coral reef populations. Negative physiological effects include decreased calcification rates, heightened metabolic energy expenditure, and increased dissolution of coral skeletons. However, studies on the dissolution of coral skeletons structures under ocean acidification conditions and their implications on sediments remain scarce. In this work, we examined skeletal dissolution kinetics from four of the most representative hermatypic corals of the Eastern Pacific coasts (Pocillopora, Porites, Pavona, and Psammocora). Samples were treated with a highly acidic solution for defined periods of time, and measurements of dissolved calcium ([Ca+2]) were used to evaluate the kinetics of coral skeleton dissolution. All genera tests except Porites showed a zero reaction rate. Porites exhibited a first-order reaction and a faster reaction rate than other genera. Compression strength tests and skeletal density did not correlate with reaction rate. Pavona showed greater structural strength. Porites were the most susceptible to acidic dissolution compared to other genera tested due to their morphology, i.e., possession of the largest surface area, suggesting a high vulnerability under low-pH conditions. The hierarchical response in dissolution kinetics among coral genera tested suggests that the most soluble coral might act as a buffer under ocean acidification conditions.

Abstract: The study of conglomerate-type deposits represents a valuable tool that may be used on a large scale to reconstruct the stratigraphic record of the adjacent regions. In order to identify the source area, the first step is to analyze the lithology of the pebbles. The Gura Râului Aptian conglomerates and the Upper Albian–Cenomanian conglomerates are forming the siliciclastic infill of the Piatra Craiului Syncline unit. This study aims to identify the source area by using various analytical techniques such as lithological description, morphometric measurements, and determination of paleocurrents. The carbonate pebbles from these deposits contain various types of microfacies and microfossils, which indicate a Middle Jurassic to Early Cretaceous (Barremian–Early Aptian) age. Other clasts include Callovian–Oxfordian siliceous pebbles and metamorphic fragments from the Cumpana and Leaota groups. The analysis suggests that the Aptian conglomerates were sourced from the adjacent units located in the northern–northwestern part of the Piatra Craiului Massif. They consist of autochthonous carbonate sediments, which are surrounded by metamorphic rocks. A possible scenario is that the erosion of the carbonate succession from the surrounding areas continued until the end of the Early Cretaceous. The source area of the uppermost Albian–Cenomanian conglomerates also coincides with the carbonate succession from the Piatra Craiului Massif. A first argument in favor of this hypothesis is represented by the microfacies and microfossil associations hosted within the carbonate pebbles of this siliciclastic unit. They show similarities with assemblages described by different authors from the Kimmeridgian–Lower Valanginian succession of the Piatra Craiului Massif.

Abstract: The early–late Serravallian boundary (Badenian–Sarmatian) is a key interval for understanding Central Paratethys evolution. Environmental changes resulted in a great regional faunal turnover known as the Badenian-Sarmatian extinction event (BSEE). Here, we present a high-resolution sedimentological and biostratigraphical study from a rare site located on the Vienna and Danube basin junction (Slovakia). Four Middle Miocene depositional cycles/episodes ranked between 13.1 and 12.6 Ma are described in detail: (1) early Serravallian (13.1 Ma or older) shallow-marine episode; (2) early Serravallian (Badenian; Bulimina–Bolivina biozone; ~13.1 Ma or younger) outer shelf cycle; (3) late Serravallian (Sarmatian; large Elphidia biozone; ~12.6 Ma or younger) inner shelf cycle; (4) late Serravallian? A sedimentary episode represented by a scour filled with a reworked Serravallian (Upper Badenian and Sarmatian) material. The middle Miocene strata are overlaying and discordantly separated by Quaternary fluvial (floodplain) sediments (2.58 Ma or younger). These episodes reflect the early–late Serravallian turnover documented in the bioevents and in the sedimentological record.

Abstract: The horizontal and vertical transitions of a wide range of bioconstructions are documented from the shallow domains of a Kimmeridgian carbonate ramp (Upper Jurassic) in the Jabaloyas area of NE Spain. The bioconstructions include microbial buildups, coral-bearing thrombolite buildups, coral-microbial buildups, branching coral patches, oyster patches, and stromatoporoid carpets. Buildups form stacked pinnacles up to 19 m thick, within a broad spectrum of coeval inter-buildup carbonate facies. Coral-bearing thrombolites are coincident with shallow-marine oolitic sands, indicating development during the initial platform flooding (unit 1). During the continued sea-level rise (units 2 and 3), coral-microbial buildups [encrusted by Crescentiella (Tubiphytes) and serpulids] were established from proximal to distal mid-ramp domains, and these showed an increasing proportion of microbial crust in distal domains. Inter-buildup oolitic facies sharply grade down-dip to hummocky cross-stratified intraclastic, peloidal, and skeletal deposits, mostly sourced from the coral-microbial buildups. The lower part of unit 4 was dominated by microbialites in the proximal areas, related to local fresh-water input causing seawater stratification and oxygen depletion. The upper part of unit 4 indicates an initial recovery of metazoan frame builders, with abundant branching corals. During the late regression (units 5 and 6), Marinella lugeoni red algae, oyster patches, and stromatoporoid boulders developed close to the shoreline in well-oxygenated waters with high nutrient content. The reported data contribute to the discussion of the optimal environmental conditions for each “bioconstruction window” in Jabaloyas, namely sediment and nutrient supply, water depth, water oxygenation, wave energy and light availability.

Abstract: This project was developed to investigate systematically patterns of recent sedimentary facies around one of the rare Caribbean examples of an oceanic barrier reef system. Seventeen sediment samples collected around Roatan (Bay Islands, Honduras) range from fine to very coarse bioclastic sand. Sorting is either moderate or poor, which suggests a weak influence of transport processes. Occurrence and abundance of major grain types are principally comparable to other modern reefal systems; however, there are some differences in terms of absolute grain abundance. Corals and calcareous algae are very abundant in marginal reefal sediments where they reach average amounts of 24% and 32%, respectively. Lagoonal sediments contain on average 14% foraminifera, 15% molluscs, 16% Halimeda, and 31% fine material (<125 µm). Statistical analyses revealed five sedimentary facies including algal-rich rudstone, coralgal grainstone, mixed skeletal pack-floatstone and foraminiferal-molluscan wackestone. The facies distribution pattern results from the interplay of the ecology of carbonate-producers, carbonate production and destruction, sediment stability, depositional energy, and reef morphology. Roatan is a mixed carbonate-siliciclastic system, although despite the proximity to a metamorphic island, the average content of siliciclastics in reefal (2%) and lagoonal (17%) sediments is not very high. The lack of higher amounts of siliciclastic material is attributed to the absence of permanent river systems and a high carbonate production rate. Non-skeletal grains (peloids) are common in protected areas of the Roatan marginal reefs, although ooids are rare in the system as a whole. Reduced skeletal grain formation and decreased sedimentation rate seem to be responsible for the peloid enrichment in areas near the reef-lagoon transition zone.

Abstract: The Upper Cretaceous-Paleogene genus Trinocladus that is based on T. tripolitanus Raineri, 1922, originally described from Libyan material, is morphologically well constrained. Its species are commonly distinguished on the basis of their biometrics. However, the narrow Gaussian distribution reported for some measurements may result from post-mortem dynamic sorting as suggested by a review of the surrounding microfacies. An examination of Brazilian material of the type-species suggests a slightly club-shaped thallus morphology. Two “false Permocalculus” species originally described by Johnson and the type-material of which has been reexamined are formally reascribed to the genus Trinocladus. T. budaensis, the smallest one, has slightly club-shaped thallus, too. T. elliotti is poorly mineralized and insufficiently documented. In addition to T. tripolitanus, Raineri described a tiny species which was later revised by Pia, i.e., Dissocladella ondulata. D. bonardii, a name recently introduced by Radoicic et al. and which is based on Raineri’s original material, is considered here as an objective junior synonym of D. ondulata.

Abstract: Zoophycos is a well-known trace fossil common throughout the Phanerozoic. Paleozoic forms show important differences in morphology and habitat distribution with respect to the Jurassic, Cretaceous, and Cenozoic ones. Therefore, Early–Middle Triassic is considered a crucial time-span for the understanding of the evolution of this trace fossil. So far, Early Triassic Zoophycos is unknown and Middle Triassic forms were recorded only in deposits from Thuringia. The morphology and paleoenvironment of Zoophycos from the middle–upper Muschelkalk of the Iberian Range is herein described. The best-preserved trace fossils occur in a dolomicritic bed Ladinian in age, and are represented by small forms with a subcircular, slightly lobed outline and very little penetration depth. They were deposited in a very shallow, quiet-water environment with transition to supratidal/emerged areas. The low diversity of both trace fossils and skeletal remains point to stressful conditions related to strong salinity variations and/or poor water circulation. A comparison was made with Zoophycos from Anisian deposits of the Muschelkalk in Germany. This showed that both forms are quite simple and penetrate only the shallowest tiers, although they are different in whorl outline and lobe shape. This confirms that, notwithstanding the morphological variability of this group, Zoophycos still maintained a quite simple structure in the Triassic. A shallow-water environment was deduced for both localities, confirming that at least until the Early Jurassic Zoophycos had not definitively migrated toward deep-water areas.

Abstract: Tectonic uplift on the shores of Bahia San Rafael in Mexico’s upper Gulf of California exposed a Pliocene delta system that covers a map area of 4 km2. Subaerial dissection by arroyos entrenched during Pleistocene and post-Pleistocene time carved cross-sectional slices through the delta, showing its dominant construction resulting from massive transfers of siliciclastic sand derived from the breakdown of igneous rocks (tonolite) in a well-defined terrestrial basin. Restoration of the sedimentary structure by elimination of Pleistocene arroyos and linkage of former topographic lines reveals a triangular shape recognizable as a classic fan delta. The complex includes an alluvial fan that emerges from a small opening in the landscape connected to a semi-circular, high-walled basin with a map area of 2.6 km2. Through a strictly longitudinal sequence, estimates of the excavated basin’s volume and the delta’s sedimentary volume were conducted as a mass-balance exercise that yielded a strong match. The lower central part of the delta features dense concentrations of sand dollars (Dendraster granti) that form a distinct limestone coquina not previously recognized elsewhere in Baja California. Through the regional biostratigraphy of concurrent range zones supplemented by absolute age dates from inter-bedded volcanics in other places, a later Pliocene age around 3–2 Ma is suggested for the sand dollars and the delta complex in which they are buried. Such timing corresponds to the close of the Pliocene Warm Period, during which a persistent El Nino climate brought tropical storms and excessive rainfall to the upper Gulf of California. Comparisons with other Pliocene deltas throughout the Gulf of California underscore the unique status of the complex named the Ballena fan delta.

Abstract: Miocene tropical carbonate platform slopes in southern Spain contain classical reef-slope facies distribution but also an unexpected abundance of serpulid-rich facies, locally forming build-ups. Two sections from the Miocene Sorbas and Nijar Basins were mapped and analyzed petrographically in order to identify the factors determining this facies variability. Reef-slope facies is intercalated with serpulid-rich facies and siliciclastic bodies. Serpulids are the pioneers colonizing the substrate in zones of quiet hydrodynamic conditions after hydrographical changes such as eventual river discharge. The interplay of sea-level changes and hydrographical conditions, together with episodic terrestrial influx, control lateral and along-slope facies variability as well as the facies distribution across the carbonate platform. Neither a deterministic distribution of facies belts nor a stochastic partitioning of facies in mosaics can accurately explain the facies distribution. A new model is proposed to explain facies variability in the context of intrinsic and extrinsic factors.

Abstract: La formacion de los licenciados en turismo en Argentina incluye asignaturas de economia porque se coincide en reconocer su importancia para el ejercicio profesional. El peso de estas materias en la curricula difiere segun la insercion institucional de la carrera y su vinculacion con un area de investigacion todavia en consolidacion: la economia del turismo. Ante la diversidad de situaciones observadas, surge el interrogante sobre la posibilidad de integrar diferentes corrientes de pensamiento en una asignatura y se propone una discusion teorica en base a tres ejes epistemologicos: el turismo como campo de conocimiento abierto e interdisciplinario; la economia como ciencia social en la que se superponen teorias y paradigmas; y el pensamiento complejo. A partir de la revision de contenidos minimos y programas que se dictan en las universidades publicas del pais, se propone un conjunto de temas economicos para la formacion de los profesionales en turismo.

Abstract: La diversificacion de la produccion es parte importante del proceso de desarrollo economico, dados sus efectos positivos sobre el crecimiento de largo plazo, la creacion de empleo y la disminucion de la desigualdad, particularmente en paises menos desarrollados. Este articulo presenta los resultados de una investigacion sobre diversificacion productiva a nivel de la firma en la industria del Partido de General Pueyrredon (PGP). Los mismos muestran evidencia de asociacion positiva entre la diversificacion de las empresas y su tamano y entre diversificacion e intensidad tecnologica sectorial. Tambien, se observa que las firmas surgidas en periodos favorables al crecimiento industrial estan mas especializadas, mientras que las creadas en periodos desfavorables estan mas diversificadas. Ademas de estos resultados, un aporte importante del trabajo es su abordaje metodologico, ya que la medicion de la diversificacion se realiza a partir de informacion sobre productos y no sobre actividades. Las tecnicas estadisticas utilizadas son el coeficiente de correlacion de Pearson, el test ANOVA de comparacion de medias y la prueba de Bonferroni.

Abstract: Este articulo indaga sobre como la convergencia a Normas Internacionales de Informacion Financiera (NIIF) podria producir una disminucion en la asimetria de la informacion para los stakeholders. Para esto se analizaron seis PyMEs, asociadas a la produccion de alimentos y agropecuaria, a la comercializacion de articulos de ferreteria y a la prestacion de servicios de consultoria, seguros y salud. A cada una de las organizaciones se les elaboro el manual de politicas contables, ajuste a los sistemas de informacion, manual de revelaciones, procedimientos contables y conversion, lo que permitio la elaboracion del estado financiero de apertura. Por medio de la comparacion de la informacion financiera presentada bajo los Principios de Contabilidad Generalmente Aceptados (Decreto 2.649 de 1990) y la NIIF se deduce que las PyMEs en el corto y mediano plazo deberan realizar ajustes en su operacion porque la convergencia impactara su capacidad de endeudamiento, la disminucion en su patrimonio y alteraciones en el ciclo operativo.

Abstract: En diciembre de 2016 entraron en vigencia en el ambito internacional, modificaciones a las normas relacionadas con el Informe de Auditoria. El objetivo del presente trabajo es realizar una revision de las nuevas normas, analizando el grado en el que las mismas contribuyen a la consecucion de los propositos de claridad y transparencia pretendidos y las posibilidades de su aplicacion en Argentina. Las modificaciones introducidas en las Normas Internacionales de Auditoria (NIA) requieren cambios sustanciales en la estructura del Informe. Incorporan nuevas secciones: "Asuntos clave de Auditoria" y "Otra informacion"; modificaciones en su distribucion y variaciones sobre la empresa en marcha. A pesar de los objetivos pretendidos, quedan dudas sobre la posibilidad de que todos los usuarios de los estados contables puedan comprender el informe. Parece dificultosa su aplicacion en entes y estudios de auditoria de pequenas estructuras, significando una carga adicional de dudosas ventajas.

Abstract: El objetivo general de la presente investigacion es determinar los factores asociados al exito en la innovacion en productos y procesos en firmas industriales argentinas. La presente investigacion es de tipo explicativo, por lo que se propone un modelo lineal generalizado de interceptos aleatorios para captar el efecto de las variables explicativas a nivel de la firma, controlando por sector y region. El tratamiento simultaneo de efectos microeconomicos, sectoriales y mesoeconomicos permite aislar la contribucion de cada uno de dichos efectos sobre la probabilidad de innovar exitosamente, principal aporte de la presente investigacion.

Abstract: Luego del 2005 -y a instancia del Estado- el protagonismo sindical en la determinacion de la masa salarial de una organizacion ha vulnerado la equidad compensatoria, desde la percepcion de alguno de los miembros de la organizacion. De este hecho intenta dar cuenta este trabajo, al resenar la experiencia de nuestro pais en los ultimos seis anos. Experiencia de la que no resulta ajena el Estado en sus tres poderes. Aqui se relevan una serie de practicas a las que los sindicatos recurren en defensa de la preservacion del poder adquisitivo: el accionar de "terceros" que es tenido en cuenta por los actores de cada negociacion. Y por ultimo, pero no menos importante para el quehacer competitivo de las organizaciones, se advierte sobre las consecuencias (y consiguiente desafio gerencial) de dicho accionar para aquellos trabajadores no representados en este proceso.