Abstract Jara‐Muñoz et al. (2024), https://doi.org/10.1029/2024gc011541, presented a new reconstruction of the lake level for the transition between paleolake Lisan and the Dead Sea, which prompted further discussion by Torfstein et al. (2025), https://doi.org/10.1029/2024gc011972. We appreciate their interest in our work, although their critique partly relies on inaccurate statements and methodological misconceptions regarding our approach. Our study reconstructs past lake levels using lake‐level index points derived from dated stromatolites and surveyed paleoshorelines corrected for ground deformation. It thus appears that these methodological details may not have been fully considered in their evaluation. Contrary to their claim, earlier data sets were not ignored by us but compared based on a critical assessment. Our systematic approach requires index points with well‐constrained vertical and temporal uncertainties, a condition often not achieved in earlier data sets of lake level histories. While facies data remain important for interpreting lake dynamics, these cannot serve as index points in our reconstruction framework. Based on 89 radiocarbon and U‐series ages, our reconstruction constrains the Lisan highstand to 30–28.5 ka, approximately 5 ka earlier than previously estimated. This discrepancy does not arise from omission but from improved handling of uncertainties and tectonic corrections. The U‐Th dating bias alleged by Torfstein et al. (2025), https://doi.org/10.1029/2024gc011972, to be caused by acid leaching seems to stem from a misunderstanding of our methods. In light of the careful data collection and analysis, our reconstruction remains internally consistent, statistically robust, and fully reproducible, qualities we hope will guide future discussions toward data‐based observations.

The Middle Miocene Birsa Formation in the Gulf of Hammamet, northeastern Tunisia, records the evolution of a tectonically influenced deltaic system controlled by variations in accommodation space, sediment supply and relative sea-level changes. This study presents an integrated sedimentological, petrophysical and sequence stratigraphic characterization of the Birsa Formation based on well-log analysis from a concession in the Gulf of Hammamet. The investigated interval consists of interbedded sandstones and shales organized into eight reservoir subzones that exhibit significant lateral and vertical heterogeneity. Gamma-Ray, resistivity density and neutron log responses were used to identify depositional facies ranging from distributary channels and mouth-bar deposits to distal delta-front and prodelta shales reflecting successive lowstand, transgressive and highstand depositional phases. Structural analysis indicates that tectonic inversion reactivated pre-existing extensional faults forming elevated fault-bounded blocks that acted as favorable hydrocarbon traps whereas structurally lower areas are predominantly water-bearing. Petrophysical evaluation reveals that reservoir quality is primarily controlled by effective porosity, clay volume and water saturation. Among the identified depositional sequences, the most favorable reservoir intervals occur within the lowstand systems tract (LST) where sand bodies exhibit higher effective porosity, lower clay content and improved hydrocarbon saturation compared to transgressive and highstand deposits. This case study illustrates the value of integrating sequence stratigraphic interpretation with petrophysical and structural analyses to improve the understanding of reservoir distribution and quality variations within inverted graben settings. The results provide new insights into the combined influence of depositional architecture and tectonic evolution on hydrocarbon accumulation in the Birsa Formation and offer a robust framework for improving reservoir characterization in the Gulf of Hammamet.

The Egyptian Red Sea region offers a unique and spatially extensive record of relative sea-level (RSL) proxies from the last interglacial durig Marine Isotopes Stage 5 e (MIS 5e; 129 to 116 ka), making it an ideal location for reconstructing past sea levels. In this study, we compiled 24 U-series dated RSL data points across a stretch of more than 450 km of coastline, focusing on three main sedimentological sea-level indicators: coral reefs, beach deposits and lagoon deposits. Using the standardized framework of the World Atlas of Last Interglacial Shoreline (WALIS), we ensured consistent data comparison and interpretation. Our analysis reveals that MIS 5e sea levels, based on refined proxies and accounting for uncertainties, ranged between approximately 3 m and 12 m above present sea level. Our investigation highlights key interpretive challenges when comparing the Egyptian Red Sea record with regional and global counterparts, particularly regarding the timing, magnitude and potential existence of suborbital sea-level peaks under current coarse chronological resolutions. We also evaluate errors associated with different coral zonation models and address contrasting sea level scenarios, including relatively stable sea level, multiple transgression/oscillation scenarios and earlier MIS 5e highstand. These findings underscore the need to refine the chronological framework to better constrain the MIS 5e sea-level fluctuations along the Egyptian Red Sea coast at a sub-millennial scale. The database is available at https://doi.org/10.5281/zenodo.13951411 (Altyeb et al., 2025).

Miocene siliciclastic reservoirs of northeastern Tunisia provide key analogues for Mediterranean hydrocarbon systems, yet pore architecture and flow behaviour remain insufficiently constrained. In the Eljabouza area (Cap Bon), the Fortuna (Chattian-Aquitanian) and upper Beglia (Serravallian) formations were evaluated by coupling rock fabric with directional petrophysical measurements on 132 oriented cubes from 18 outcrop samples. Facies and rock-fabric analysis enable the identification of nine facies and six rock types in the Fortuna and eight facies and three rock types in the Beglia deposits. Quartz dominates with accessory feldspar, iron(hydr)oxides and clays. Localised feldspar dissolution generates secondary porosity. Petrophysical properties range from tight sands (Phi < 2%, K < 15 mD) to highly permeable units (Phi > 20%, K > 1 D) in the Fortuna deposits, while the Beglia Formation shows more uniform and generally favourable quality (Phi up to similar to 26%, K to similar to 3 D). Permeability is strongly anisotropic with consistently higher values along the X and Z axis reflecting directional grain scale fabric characterised by aligned grain contacts and preferentially oriented intergranular pore throats parallel to bedding and cross- lamination at plug scale. Pore type control is decisive as primary intergranular pores provide storage and effective flow paths, whereas dissolution-related secondary porosity markedly enhances connectivity and offsets low to medium porosity, quantified through Digital Image Analysis (DIA). Pore geometry (shape factor gamma approximate to 1.1-2.4) displays weak correlation with K and sub-resolution microporosity contributes appreciably to flow capacity. Overall, reservoir performance across the Fortuna-Beglia system is governed by the interplay of rock fabric, directional permeability and pore type partitioning. The Beglia Formation generally outperforms the Fortuna Formation, whose heterogeneity implies potential compartmentalization. These results underscore the importance of accounting for measurement orientation and pore type distinctions across different resolutions when upscaling to predict flow in similar siliciclastic reservoirs.

In the Gulf of Hammamet, the Serravallian Birsa Formation is considered a major target for hydrocarbon accumulations associated with folded and faulted structures. The study herein deals with a petrophysical assessment using the IP software and electrical logs analysis of drilled boreholes spanning the Serravallian reservoirs. The Birsa Formation comprises stacked sand reservoirs divided into three sub-units: the lower sub-unit is referred to as the Lower Birsa, the middle sub-unit is attributed to the Intra-Birsa Carbonate, also called IBC, and the upper sub-unit is particularized as the Upper Birsa. The layering of each sub-unit was achieved based on distinctive trends in the GR, sonic, resistivity, density, and neutron curves. These layers are identified between wells with eight sand bodies laterally correlated following a southwest (SW) to northeast (NE) trend. Proven hydrocarbons are encountered, especially in the IBC and lower sub-units of 0.5 to 11 m in pay thickness within a gross reservoir package of 100 m. The present petrophysical assessment shows that the Birsa sandstones are mineralized oil and gas and exhibit excellent reservoir quality, reaching 35

Along the Egyptian and Saudi Arabian rifted margins of the northern Red Sea, the near-absence of a continental shelf forces photozoan-dominated carbonate-producing ecosystems to develop directly along siliciclastic shoreline. These coastlines are dissected by ephemeral desert stream networks (wadis), which episodically deliver high volumes of siliciclastic sediment during rare but intense flash flood events. These floods form coastal-fan deltas that episodically prograde into the shallow marine zone. Over centennial to millennial time scales, these intermittent pulses of siliciclastic sedimentation create new shallow-water substrate, which forms essential real estate for colonization by photozoan carbonate ecosystems. Crucially, the intervals between flash flood events, which may span decades or longer, provide prolonged periods of reduced turbidity and sedimentation and are necessary for recovery, growth, and lateral expansion of carbonate ecosystems. Paradoxically, the same siliciclastic inputs that are often viewed as disruptive to carbonate production can, over the long term and at the basin scale, facilitate the growth of carbonate shelves in steep, narrow-margin settings in arid environments. The broadest areas of carbonate shelf sedimentation in fact, occur on the subaqueous parts of fan deltas adjacent to the largest wadi catchments. This dynamic is most pronounced where large wadi catchments generate extensive subaqueous fan deltas-zones where carbonate sedimentation can occur at scales more than three orders of magnitude greater than the regional shelf average. Traditional paradigms that portray siliciclastic influx as uniformly suppressive to carbonate accumulation fail to capture the nuanced relationships and complex sedimentary dynamics inherent in mixed depositional systems. In arid settings characterized by episodic but intense siliciclastic input delivered through high-magnitude, low-frequency flash flood events, separated by protracted intervals of reduced or negligible terrigenous sedimentation, the periodicity and magnitude of sediment supply become fundamental controls on carbonate-platform evolution. These discrete pulses of sedimentation promote progradation of fan deltas and create transient accommodation in proximal shallow-marine settings, which, during inter-flood intervals, are exploited by photozoan carbonate-producing communities. Consequently, the temporal distribution of siliciclastic delivery exerts a first-order influence on carbonate-shelf expansion in steep and narrow-margin settings, constituting a previously underappreciated control on the spatial and temporal development of carbonate systems.

Key Messages: (1) Outcrops of the Yacoraite Formation in the Salta Basin provide a unique high-resolution analogue for understanding sedimentary dynamics and controls over reservoir quality in a lacustrine system. (2) A shift from a stable, perennial lake to an ephemeral, fluctuating system drove facies variability and diagenetic overprinting, impacting heterogeneity in petrophysical properties, reservoir continuity, and flow unit compartmentalization.

Key Messages: (1) Phase of rifting determines unique structural footprints that control siliciclastic source terrains, sediment pathways, and linked location and type of carbonate platform development. (2) Facies distribution within the rift basin is strongly influenced by accommodation and hydrodynamics controlled by tilted fault blocks. Fault-bounded escarpments on nascent passive margins form narrow facies belts that tightly hug the shoreline and are bisected by shelf-incised canyons. Relatively broad delta-top platforms support a variety of shallow marine environments that develop over low-gradient areas and play a key role in controlling the transfer of siliciclastic sediments across the shelf. (3) Carbonate production and siliciclastic sediment routing systems operate largely through mutual processes, with feedbacks that either drive facies partitioning and/or mixing.

Source-to-sink studies commonly assume independent sediment routing systems for siliciclastics and carbonates. This study integrates satellite-derived topography, imagery, swath multibeam bathymetry, and field observations to characterize a mixed carbonate-siliciclastic routing system from source to sink in the Gulf of Aqaba, northern Red Sea. The study area is lined by ephemeral desert streams (wadis) that deliver pulses of sediment to the shelf and basin during flash floods. We find that where wadis are distributary at the coast, they deposit amalgamated fan deltas associated with a continuous fringing reef, a narrow continental shelf, and a smooth line-fed slope system devoid of major submarine canyons or fans. Where knickpoints have migrated to the shoreline or into active wadi channels, the fringing reef is bisected by reentrants (sharms), there is no continental shelf, and the slope is composed of a rugged assortment of canyons and ridges. Development of sharms is the net effect of erosion by headward knickpoint migration and construction by differential aggradation on the shelf. Submarine fans linked to shelf-incising canyons are generally larger than those associated with slope-confined canyons. Fan size strongly correlates with the catchment area of the affiliated wadi networks, linking terrigenous and marine sedimentary systems. Our study offers a window into coupled terrigenous, coastal, shelf, slope, and basinal processes that have produced a steep, narrow, mixed carbonate-siliciclastic margin. The findings presented herein build on traditional depositional models and demonstrate feedbacks between integrated carbonate and siliciclastic sediment routing systems, especially in an arid climate.

Key Messages: (1) In steep, narrow, arid margins siliciclastic sedimentation is critical for building a shallow water substrate that enables subsequent proliferation of photozoan carbonates. (2) Intervals between pulsed, often catastrophic siliciclastic influx, driven by flash floods in ephemeral desert streams (wadis), provide recovery windows during which resilient coral communities can colonize the newly formed shallow shelf area. (3) Rather than impeding carbonate growth, periodic siliciclastic input under clear, oligotrophic water conditions can actively support, rather than simply alternate with carbonate platform development or inhibit it.

Key Messages: (1) Longshore sediment transport is a critical mechanism for mixing siliciclastic and carbonate sediments in arid shelf environments. (2) Shelf-produced carbonates and point-sourced siliciclastics are blended in littoral cells. (3) Shore-attached submarine canyons act as key sediment-routing features, linking shelf processes to deep-basin deposition.

Key Messages: (1) The Red Sea shoreline is shaped by dry climate, tectonic activity, geological, and biological processes, and sea level fluctuations. (2) In the northern Red Sea's mixed carbonate-siliciclastic system tectonic activity and flash-floods often overprint sea level signals, by controlling accommodation partitioning and disrupting lateral facies continuity. (3) A quality-filtered meta-analysis of MIS 5e shoreline proxies, reveals inconsistencies in previous interpretations and emphasizes the need for additional field sedimentological and geochemical constraints for accurate Pleistocene sea level reconstruction.

Abstract To date, the most complete paleolake‐level reconstructions for the late Pleistocene water bodies that once occupied the Dead Sea depression have been based on the combination of dating of lake sediments and terrestrial materials. However, despite these major accomplishments, there is still limited spatial control regarding the water levels, suggesting some degree of uncertainty concerning the magnitude and rate of lake‐level changes. Here, we re‐examine the late Pleistocene lake‐level changes in the Dead Sea during the transition from paleolake Lisan to the present‐day Dead Sea. We rely on systematic dating of fossil stromatolites including 84 radiocarbon and 15 U‐series ages, stable‐isotope measurements, paleobiology, high‐resolution topography, and numerical modeling to assess lake‐level changes. Our results indicate that the highstand of paleolake Lisan was of shorter duration and the transition between Lake Lisan and the Dead Sea occurred at least 5 Kyrs earlier than previously indicated. By refining the timeline and accuracy of lake‐level positions during the transition paleolake Lisan—Dead Sea, our study offers new insights into the regional and local paleo‐climatic conditions during the last glacial period in this region.

Integrating geological and 2D basin modeling of the East Beni Suef Basin, located in north-central Egypt, allows extending burial and thermal history modeling into the deeper parts of the basin, which are not explored by drilling activities thereby evaluating the hydrocarbon potential of the actual kitchen areas. In addition, this regional approach allows us not only to study the hydrocarbon generation potential of the deeper kitchen area but also the migration and accumulation history of the basin. The East Beni Suef Basin (EBSB) is an extensional rift basin, which was initiated following the opening of the NeoTethys and Atlantic oceans and the associated tectonic motion of Africa with respect to Eurasia during the Early Cretaceous. Its stratigraphy comprises five main rock units of mixed siliciclastic-carbonates ranging from the Albian to the Eocene from base to top as follows: Kharita Formation, Bahariya Formation, Abu Roash Formation, Khoman Formation, and Apollonia Formation. The Upper Cretaceous Abu Roash Formation is divided into seven members based on the siliciclastic to non-clastic ratio and includes the main petroleum system elements of the basin, where the carbonate “F” Member is the source rock, while the siliciclastic portions of the “E” and “G” members constitute the reservoir rocks. This study aims to gain insight into the geological evolution of the EBSB and to improve our understanding of its Upper Cretaceous petroleum system, in terms of burial and thermal histories, source rock maturity, and hydrocarbon generation, migration, and accumulation. Thus, an integrated geological and basin modeling workflow was employed, making use of two basin-wide seismic sections, crossing the EBSB in SW-NE and NW-SE directions, and three boreholes with well data. The interpreted 2D seismic lines served as the basis to define the geometrical and structural framework and the development of the subsequent 2D basin modeling of the basin. Modeling results indicate that the Abu Roash “F” source rock maturity ranges from the early oil window at the basin margins to the main oil window in the center. The main phase of hydrocarbon generation occurred during the Eocene after trap formation in the Late Cretaceous. Generated hydrocarbons have migrated both laterally and vertically, most likely from the central part of the basin toward the basin margins, particularly eastward to the structural traps. The model predicts low accumulation rates for the EBSB, which are caused by the ineffective sealing capacity of the overburden rocks and normal faults. In addition to the proven kitchen for the charging of the Abu Roash “E” reservoirs, an additional kitchen to the west of the basin is suggested for the Abu Roash “G” reservoirs. The results of this work can better elucidate the present-day distribution of the Upper Cretaceous accumulations in the EBSB for further successful exploration activities.

We integrated geological and 2D basin modelling to investigate the tectonostratigraphic evolution of the East Beni Suef Basin (EBSB) of north central Egypt and its implications for the Upper Cretaceous petroleum system. Two intersecting seismic sections and three exploration wells were used for this study. The geological model defines the structural and geometrical framework of the basin, which formed the basis for subsequent 2D basin modelling. The developed basin models were calibrated and fine-tuned using vitrinite reflectance and corrected temperature data. Modelling results indicate that the Abu Roash ‘F’ source-rock maturity ranges from the early oil window at the basin margins to the main oil window in the centre. The main phase of hydrocarbon generation occurred during the Eocene after trap formation in the Late Cretaceous. Generated hydrocarbons have migrated both laterally and vertically, most likely from the central part of the basin towards the basin margins, particularly eastwards to the structural traps. The model predicts low accumulation rates for the EBSB, which are caused by the ineffective sealing capacity of the overburden rocks and normal faults. In addition to the proven kitchen for the charging of the Abu Roash ‘E’ reservoirs, an additional kitchen area to the NW of the basin is suggested for the Abu Roash ‘G’ reservoirs.

The mixed carbonate-siliciclastic Yacoraite Formation, Salta Group in northern Argentina has been interest of recent studies searching for potential analogues for the South Atlantic pre-sal carbonates. Microbial lacustrine carbonates are important reservoir systems and their characteristics and stratigraphic packaging are a major factor impacting compartmentalization. This study provides sedimentological and facies analyses combined with petrographical, isotope geochemical and petrophysical analyses of lacustrine clastics and carbonates using an example from the Yacoraite Formation (Salta Group) in northern Argentina (Tres Cruces sub-basin). The Yacoraite Formation records the evolution of a lacustrine system responding to basin scale tectonic processes and climatic conditions and is interpreted as a microbially-related mixed carbonate clastic lacustrine system comprising 8 main Facies types, deposited in either a perennial or an ephemeral system. The most dominant architectural elements are: Sandstones with interbedded shales (F1), Shales with interbedded sandstones and siltstones (F2), Thick-bedded oolitic grainstone (F5), Thin-bedded oolitic grainstone-packstone (F6) and Stromatolite boundstone (F8). These facies types allow to differentiate two types of lacustrine environments: Perennial (Stage I) vs Ephemeral (Stage II) intercalated with episodes of continental plains deposition, arranged in three depositional sequences (Yacoraite I, II and III), each recording either transgressive or a regressive-transgressive trend. Carbonate and clastics are arranged in cycles during the Perennial l Stage suggesting that the depositional system responded in patterns attributable to reciprocal sedimentation, whereas, during the Ephemeral Stage 2, spatial coexistence of clastic and carbonate seem to be the case rather that cyclic vertical superposition. Thick-bedded oolitic grainstone and Stromatolites (F5 and F8 respectively) of the perennial lacustrine system show laterally continuous and thick beds with the best reservoir properties. Furthermore, the Sandstones with interbedded shales (F1) are characterized by intermediate values of porosity and permeability, which would not result in permeability barriers. On the other hand, Thin-bedded oolitic grainstone-packstone (F6) of the ephemeral lacustrine system are characterized by a high degree of heterogeneity due to their limited areal distribution and their complex spatial variability with Shales with interbedded sandstones and siltstones (F2).

The Yacoraite Formation (Cretaceous–Paleogene) is a mixed carbonate–siliciclastic microbialite-bearing lacustrine succession deposited in the intra-continental Salta rift basin (Argentina). In the northern sub-basin of Tres Cruces, the spectacular exposures and high lateral continuity of the outcrops provide a suitable setting to investigate and reconstruct the paleoenvironments of deposition and the resulting facies architecture of this closed, saline lake system. The Yacoraite Formation deposited in a predominantly shallow-water ramp-like lake system, characterized by eighteen main facies, classified within four main facies associations, each defining a particular depositional environment along the lake profile. From proximal (shallow) to distal: i) Palustrine Facies Association; ii) Littoral Facies Association; iii) Sub-littoral Facies Association; and lastly iv) Profundal Facies Association. In the Yacoraite paleo-lake extensive fringing mud-flat environments surrounded the lake margins, while the littoral marginal areas hosted extensive wave-dominated oolitic–bioclastic grainstones forming shoals and bars parallel to the lake margins and provided a sheltered environment in the back-shoals that allowed prolific microbialite development. In proximity to river inputs, shallow-water deltas and shoreline sandstones accumulated in the littoral margins. In the sub-littoral zone, mud-supported carbonates such as ostracod wackestones and mudstones deposited below the fair-weather wave base, and in the profundal settings deep-water organic-rich shales deposited. The Yacoraite paleo-lake evolved from a relatively stable and perennial lake system (lake stage 1) into a rapidly fluctuating ephemeral lake system (stage 2), as a result of progressively changing environmental and climatic conditions toward more arid settings. Climate control is also critical in the facies architecture, with the development of short-term cyclicity, represented by meter-scale transgressive–regressive (T–R) cycles being the result of lacustrine expansion–contraction cycles. The regressive hemicycles represent shallowing-upward succession of sub-littoral and littoral carbonate-dominated facies, whereas the transgressive hemicycles are mostly represented by sub-littoral and profundal mudstones and shales. Stacking of short-term cycles resulted in the development of medium- and long-term cyclicity at the scale of tens of meters, which represent the long-term evolution of the lake system. Lastly, a comparison with two well-documented closed lake systems highlights the role of allogenic factors acting at a regional scale (e.g., climate and tectonics) in controlling the lake-basin type, facies association and the resulting architecture. Factors at the lake-basin scale (e.g., lake margin profile, bathymetry) modulate the expression of facies and cyclicity. Ultimately, the characterization of the kilometer-scale outcrops of the Yacoraite paleo-lake provides a reference analog study to support the characterization of similar depositional systems and reservoirs of other ancient, closed lake systems, including the Pre-Salt Carbonates of the South Atlantic.

The geometry of carbonate platforms reflects the interaction of several factors. However, the impact of carbonate-producing organisms has been poorly investigated so far. This study applies stratigraphic forward modelling (SFM) and sensitivity analysis to examine, referenced to the Miocene Llucmajor Platform, the effect of changes of dominant biotic production in the oligophotic and euphotic zones on platform geometry. Our results show that the complex interplay of carbonate production rates, bathymetry and variations in accommodation space control the platform geometry. The main driver of progradation is the oligophotic production of rhodalgal sediments during the lowstands. This study demonstrates that platform geometry and internal architecture varies significantly according to the interaction of the predominant carbonate-producing biotas. The input parameters for this study are based on well-understood Miocene carbonate biotas with characteristic euphotic, oligophotic and photo-independent carbonate production in which it is crucial that each carbonate-producing class is modelled explicitly within the simulation run and not averaged with a single carbonate production–depth profile. This is important in subsurface exploration studies based on stratigraphic forward models where the overall platform geometry may be approximated through calibration runs, and constrained by seismic surveys and wellbores. However, the internal architecture is likely to be oversimplified without an in-depth understanding of the target carbonate system and a transfer to forward modelling parameters.

Forward stratigraphic modelling is a fast-developing modelling approach, used to test conceptual models, and predict stratigraphic architecture and depositional facies from basin to reservoir scales. Published subsurface applications demonstrate its added value by integrating multidisciplinary data as well as geological concepts into its constraints. When applied to carbonate depositional systems, composed of multiple sediment factories, the co-operating and interdependent production mechanisms remain poorly studied. By applying the technique to a well-studied section of the Maldives carbonate platform, a specific model design—adapted to the geological age and setting, and constrained by available data—sheds light on the interaction of its carbonate producers. The results yield a naturalistic depositional facies distribution and offer insight in the changing relationship between biotic communities during the platform evolution. After calibration, the reference model unequivocally links the formerly proposed genetic model to the seismostratigraphic architecture. Furthermore, the results show how environmental changes (seemingly of secondary impact compared to changes in physical accommodation in the stratigraphic record) can induce substantial fluctuations in carbonate production rates of biotic communities, affect the ecological accommodation, and thus impact the platform architecture. Therefore, it is crucial to treat carbonate production rates during periods of environmental change as variables with associated uncertainties in a forward stratigraphic model setup.

Stromatolites form by the close interaction between the microbial activity and the environment in a great range of depositional settings resulting in heterogeneous growth morphologies and fabrics. The link between morphological diversity and internal structure of stromatolites to environments is not straightforward due to the dual influence at all scales of biological and physico-chemical factors. Specifically, in low energy settings biological controls are the dominant in influencing stromatolites, as suggested from modern analogues. In this study we examine geometries and fabrics of stromatolites from the mixed carbonate-siliciclastic marginal lacustrine succession of the Yacoraite Formation (Cretaceous-Paleogene) in Tres Cruces (Salta Basin). The outcrops that extend along a W-E transect of 10 kilometres, provide exceptional exposure allowing to analyse the geometries and lateral continuity of the stromatolite beds. Current stratigraphic research interprets the Yacoraite succession as a closed, saline lake with two evolutionary stages. The first stage, dominated by carbonate production, represents a shallow-water perennial lake with moderate wave energy. The second stage corresponds to a rapidly fluctuating, low-water energy ephemeral lake with abundant fine-grained siliciclastics and frequent subaerial events. This change is related to climatically driven lake-level fluctuations. Marked differences in the lateral continuity of the stromatolite beds and their associated facies have been observed along the Yacoraite succession. In the perennial lake, the stromatolite beds overlie oolitic facies and can be traced laterally for several kilometres whereas in the ephemeral lake the stromatolites grow on both oolitic and siliciclastic facies and form discontinuous levels along hundreds of meters that pass laterally into the oolitic facies. Stromatolite growth morphologies, however, show a more homogeneous distribution that does not clearly reflect the evolutionary changes of the Yacoraite paleolake. Generally, the stromatolites of the perennial lake exhibit planar morphologies that pass upwards into coalescent domes forming structures that range in height from few decimetres up to 1 m. The stromatolites of the ephemeral lake are mainly planar, wavy (dm-scale) or domes that are coalescent and form tabular decimetric structures. Morphological vertical zonation is rare. The change in stromatolite morphology can be tentatively attributed to decreased accommodation and water energy conditions. However, this interpretation needs to be taken carefully considering that all these types of stromatolite morphologies have been observed along the Yacoraite succession, regardless of the lake stage. Stromatolites show mainly well-developed internal lamination. Their microfabrics are either fine-grained (micritic, clotted and/or filamentous) or formed by combinations of fine-grained and sparry layers composed of fibrous calcite crusts, calcite spherulites and/or shrubs. Further work will intend to better understand the spatial and temporal distribution of the stromatolite geometries and fabrics along the Yacoraite Formation to shed light on the influence that environmental and biotic factors exert in stromatolite macro, meso and microscale in low-energy lacustrine settings.