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The Indo-Pacific gastropod Terebralia palustris is particularly suitable for comparing natural and anthropogenic induced taphonomic pathways due to its wide geographic distribution and common presence within archeological context. The present study aims to (1) correlate shell architecture and morphology with fragmentation pattern and preservation, (2) quantify taphonomic changes to differentiate between natural vs. anthropogenic preservation features, (3) provide a guideline for analyzing fragmented shell remains in archeological material. Shells and taphonomic features were studied from both recent mangrove environments from the Emirate of Sharjah, United Arab Emirates as well as archeological material within the Iron age II site (1000–600 BC) of Muweilah near the City of Sharjah. Techniques utilized include morphometry, thin sectioning, scanning electron microscopy (SEM) of recent specimens and a semi—quantitative taphonomic analysis of anthropogenic material. Thin sectioning shows a complex internal shell morphology with a tripartite subdivision of shell layers. The recent material shows better preserved features on both the exterior and internal shell surfaces than the highly fragmented material recovered from the archeological context, which shows a distinct size distribution as well as showing higher levels of surface abrasion, surface cracks and color alterations. These features are correlated to extraction techniques, cooking methods and waste disposal handling.

Hard substrate communities can impact coral reef growth by adding or removing calcium carbonate when they act as encrusters or bioeroders, respectively. Although such sclerobiont communities are known across the Phanerozoic, the Triassic saw a substantial increase in reef macrobioerosion. This study provides the first quantitative assessment of sclerobionts in a Late Triassic (Norian) reef coral community (from the Nayband Formation in central Iran) and establishes some post-Paleozoic trends in reef bioerosion. Sclerobionts were common on the dominant coral Pamiroseris rectilamellosa and covered between 0 and 26.4% of total coral surface area among the 145 colonies investigated. Encrustation was significantly more prevalent (1.78% of total area) than bioerosion (0.36% of total area). The underside of corals was 3.5 times more affected by sclerobionts than the upper surfaces. This suggests that the sclerobionts preferentially colonized dead parts of the corals. The main encrusting taxa were polychaete worms (76.2%), followed by bivalves (11.9%). The main bioeroders were Polychaeta (51.4%), Porifera (22.2%), and Bivalvia (20.7%). The lack of a correlation between encrustation and bioerosion intensity suggests that the number of sclerobionts is not simply a function of exposure time before final burial. Our review of the published literature suggests a declining trend in the relative importance of bivalves, polychaetes and cirripeds in reefs, whereas sponges increased in importance from the Triassic until today.

Palaeoclimatic and palaeoenvironmental proxy data are presented for the Late Quaternary based on mineralogical, geochemical and palynological analysis of a palaeosoil-sediment section in the lower Kürtün Valley (Samsun region, Northern Türkiye). The geochronology along the section is established based on OSL and radiocarbon dating. The base of the palaeosoil-sediment section consists of a palaeo-terrace fill of the Kürtün Creek dated to 108 ± 9 ka, corresponding to the last interglacial period (MIS5c). After this warm and humid period, the last ice age began. Sea level dropped and the Kürtün Stream deepened its bed. Fluvial terrace deposits were covered with colluvial materials and a palaeosoil sequence formed. The bottommost part of the palaeosoil formation carries the fingerprints of a dry climate of 68 ± 9 ka ago (MIS4). The middle part of the section coincides with MIS2 (28,959 cal BP) and is characterized by humid conditions with arid pulses accompanied by the occurrences of calcrete nodules. The palaeosoil-sediment section ends with the records of MIS1 (8381 cal BP), corresponding to warmer and more humid conditions. This study emphasizes the importance of palaeosoil-calcrete formation in the lower Kürtün Valley for explaining climate changes from MIS5c to MIS1. The results are compatible with studies conducted in the Eastern Mediterranean. High-resolution multi-proxy studies are recommended to better understand the connection between local climates and global climate phenomena in the Late Quaternary.

New biostratigraphic and microfacies data from the Durmitor Mt. in northern Montenegro result in a detailed reconstruction of the Middle Triassic depositional history with special emphasis on the Middle-Late Anisian stepwise deepening related to the opening of the Neo-Tethys Ocean and the intense Illyrian volcanism in the Dinarides. The continental break-up and early opening history of the Neo-Tethys Ocean is recorded in the Middle-Late Anisian drowning sequence of the Pelsonian shallow-water Ravni Carbonate Ramp. The first pulse in the late Pelsonian creates a horst-and-graben topography forming a classical break-up unconformity. In addition, shallow-water carbonate production decreased significantly, and deep-marine red nodular limestones (Bulog Formation) and related sedimentary deep-water successions deposited throughout the late Pelsonian – early/middle Illyrian, in cases up to the Ladinian, as proven by ammonoids and conodonts. In the Durmitor Mt., intense volcanism in the middle Illyrian created short-living islands surrounded by atolls with shallow-water carbonate production up to the late Illyrian, as proven by conodonts. The older break-up and volcanism related topography get destructed around the middle/late Illyrian boundary by a second pulse of extensional tectonics, and resulted in deposition of Mass Transport Deposits (MTDs) with reworked middle Anisian (Pelsonian) shallow- and deep-water limestones (Komarani Formation). The shallow-water limestones are dated by dasycladalean algae and foraminifera, while the deep-water limestones are dated by ammonoids and conodonts. From the late Illyrian onwards deposition is characterized first by red condensed limestones with ammonoid-rich Fossillagerstätten beds subsequently overlain by Ladinian condensed grey siliceous deep-marine limestones. In the Early Carnian first turbidites with shallow-water grains overlain by reefal float- and rudstones indicate the onset and progradation of the Wetterstein Carbonate Platforms. In contrast to the well-known Middle Anisian (late Pelsonian) drowning event in the Western Tethys Realm the middle-late Illyrian depositional history associated with the intense volcanism and extensional tectonics is not well understood. This knowledge gap is filled by precisely dated sedimentary successions in the Durmitor Mt. in northern Montenegro.

The effect of microbial binding for the stabilization of steep carbonate slopes is well documented in Cenozoic examples but its significance and relationship with abiotic marine cements in Paleozoic reef systems and steep slopes is not clearly established. Here, samples from a Late Silurian (Ludlovian) reef complex are evaluated by using an integrated approach that involves petrographic and isotope analyses, cathodoluminescence microscopy, and environmental scanning electron microscopy. This study reveals the in situ production of mineral fabrics of microbial origins, including micrite, peloidal micrite with dendritic fabrics, meniscus, and bridge-like cements. This study stresses the leading role of microbes in the early lithification stages that led to the stabilization of Silurian steep carbonate slopes. These findings are further supported by the occurrence of fossilized microbes and extracellular polymeric substance. The micritic cements are the first step in the diagenetic paragenesis followed by abiotic fibrous and equant calcite cements whose stable isotope values are in concert with estimated values of calcite precipitated in equilibrium with Silurian seawater. Results from this project provide insights into the relationship between microbial binding and early abiotic marine cements in ancient reef systems and, further, provide evidence for a consortia of microbes that existed 440 Ma ago.

Crustose coralline algae (CCA) are important ecosystem engineers and carbonate producers today and in the geological past. While there is an increasing number of publications on CCA every year, it is evident that there are many misunderstandings and inconsistencies in the assignment of CCA to taxonomic and functional groups. This is partly because CCA are treated by biologists, ecologists and palaeontologists as well as covered by studies published in journals ranging from geo- to biosciences, so that there is often a mixture of terminology used and differing scientific focus. In this review, a comprehensive overview is given on what is known about CCA, their functional traits and their roles in environments from the present and the past. In this context, some bridges are built between the commonly different viewpoints of ecologists and palaeontologists, including suggesting a common and straightforward terminology, highlighting and partially merging different taxonomic viewpoints as well as summarizing the most important functional traits of CCA. Ideally, future studies should seek to quantitatively analyse potential implications for CCA and their associated organisms under ongoing global change.

Lower Devonian (Pragian-Emsian) reefal deposits of Sierra Morena (SW Spain) contain locally abundant calcified cyanobacteria, calcareous algae, and various microfossils including foraminifers. Calcified cyanobacteria are represented by Girvanella spp. A–C, which form crusts and clumps of various shapes. Supposed green algae (?Dasycladales) are represented by a new genus with one new species, Bediaella hispanica gen. et sp. nov. Algospongia include Vasicekia margaritula (Saltovskaya, 1986) n. comb. Microproblematica are represented by Rothpletzella sp. The studied assemblages indicate photic and warm conditions in a shallow and well-agitated environment with normal salinity, and probably mirror episodes of shallowing due to eustatic sea level fluctuations.

This study provides a comprehensive examination of algal bioherm structures, including reefs and carpets that contain nannoplankton and foraminifera, originating from the upper Badenian (middle Miocene) strata of the Vienna Basin in the Central Paratethys. These lithofacies primarily consist of the carbonate red algal genus Lithothamnion. Through an integrated approach that combines calcareous nannoplankton, foraminifera, sedimentology, and palynology, the study explores the Serravallian (upper Badenian) sediments from the Vienna Basin. The biostratigraphic age, consistent with the NN6 and CPN9 zones, is further corroborated by ⁸⁷Sr/⁸⁶Sr dating. This research highlights the importance of taphonomic processes and paleoecological proxies in small-scale characterization and detecting short-term shifts within paleoenvironmental conditions. These unique bioherm structures enable a novel description of a limestone formation within the Vienna Basin (Sandberg Formation), which seems pervasive across the Central Paratethys region. The findings uphold the hypothesis of a profound connection between the Mediterranean and Central Paratethys via the Trans-Tethyan Trench Corridor, bolstered by upwelling conditions observed in the eastern perimeter of the Vienna Basin. Two main inhibitory mechanisms for carbonate growth in the Upper Badenian within the Central Paratethys area are confirmed: the first is a substantial siliciclastic influx from the Alps and Carpathians, supported by the ongoing rifting of the Vienna and Danube Basins; the second is the propagation of evaporites in the Transcarpathian and Transylvanian Basins leading to precipitation, which disrupts carbonate growth. This investigation underlines the intertwined relationship between regional geodynamics and carbonate sedimentation processes during the Miocene.

This study focuses on the paleontological content of the middle Eocene (Bartonian) carbonate–siliciclastic sediments of the Capo Mortola Calcarenite Formation from Olivetta San Michele (Liguria, Italy). Along the succession, there are significant paleoecological changes triggered by the variation in neritic input as a consequence of tectonic and climatic instability. Among microfossils, nummulitids prevail, followed by orthophragmines, smaller benthic, and planktonic foraminifera, whereas mollusks and ichnofossils are the most abundant macrofossils. The sudden changes in the benthic communities due to the progressive increase in fluvial input are recorded throughout the sedimentary succession. An increase in water turbidity caused stressful conditions for autotrophic taxa, reducing their size and abundance. In contrast, filter feeders became dominant, suggesting an increase in dissolved and suspended nutrients. Ichnological analysis shows environmental fluctuations controlled by the transport of neritic material offshore, thus confirming the general deepening trend of the studied succession. In the upper part of the succession, we recorded an alternation between gravity flows and marly sediments that are interpreted as short-term alternations between low and intense precipitations. The gravity flows yield taxa such as larger benthic foraminifera (LBF), smaller benthic and planktonic foraminifera, mollusks, and corals. In turn, marls display only a few LBF and abundant smaller benthic and planktonic foraminifera. In these intervals, the increase in planktonic foraminifera also suggests a deepening of the carbonate ramp coinciding with a reduction of light that did not favor the development of LBF. These changes are probably related to the climatic dynamics that occurred in the Bartonian in the western Tethys.

Microbial carbonates are common components of Quaternary tropical coral reefs. Previous studies revealed that sulfate-reducing bacteria trigger microbial carbonate precipitation in supposedly cryptic reef environments. Here, using petrography, lipid biomarker analysis, and stable isotope data, we aim to understand the formation mechanism of microbial carbonate enclosed in deep fore reef limestones from Mayotte and Mohéli, Comoro Islands, which differ from other reefal microbial carbonates in that they contain less microbial carbonate and are dominated by numerous sponges. To discern sponge-derived lipids from lipids enclosed in microbial carbonate, lipid biomarker inventories of diverse sponges from the Mayotte and Mohéli reef systems were examined. Abundant peloidal, laminated, and clotted textures point to a microbial origin of the authigenic carbonates, which is supported by ample amounts of mono-O-alkyl glycerol monoethers (MAGEs) and terminally branched fatty acids; both groups of compounds are attributed to sulfate-reducing bacteria. Sponges revealed a greater variety of alkyl chains in MAGEs, including new, previously unknown, mid-chain monomethyl- and dimethyl-branched MAGEs, suggesting a diverse community of sulfate reducers different from the sulfate-reducers favoring microbialite formation. Aside from biomarkers specific for sulfate-reducing bacteria, lipids attributed to demosponges (i.e., demospongic acids) are also present in some of the sponges and the reefal carbonates. Fatty acids attributed to demosponges show a higher diversity and a higher proportion in microbial carbonate compared to sponge tissue. Such pattern reflects significant taphonomic bias associated with the preservation of demospongic acids, with preservation apparently favored by carbonate authigenesis.