This article analyzes the information provided by the sedimentary sequences of 29 lakes in central Mexico, 10 of which are currently paleolakes. During the Late Quaternary, the lakes of central Mexico experienced environmental changes driven by global and local climatic and geological processes, showing regional trends of wet and dry periods. Paleoenvironmental reconstructions are based on the use of 20 indicators, including diatoms, pollen, geochemistry, mineralogy, granulometry, magnetic susceptibility, and isotopes. Seven major episodes are recognized in the historical evolution of the lakes of central Mexico: i. Late Miocene–Pliocene: A period that includes the formation of large lakes in central Mexico by volcano tectonic activity under a regime of continuous humidity. ii. Pleistocene–Drought and climatic variability of the interglacial period. iii. Drying and successive lacustrine transgression during the Last Glacial Maximum. iv. Spatial climate variability in the Heinrich 1 period. v. Lake regression and expansion of terrestrial vegetation in the Bølling–Allerød period. vi. Transgression of lakes of central Mexico during the Younger Dryas and mid-Holocene periods. vii. Late Holocene: A period that includes lake desiccation influenced by the impact of human activities. The analysis of the data allows us to propose six challenges for the scientific community in future research of central Mexico.

The Pliocene (5.33-2.58 Ma) was comparatively warmer (+ 1.8-3.6 0C) than today and was characterized by elevated CO2 concentrations (400 ppmv). Thus, studying sedimentary sequences dated to this interval can serve as excellent analogues for comparing present conditions and provide tools for better modeling future trends. Yet, while most studies rely on marine archives, continental data dating back to this interval are scarce, particularly from boundary regions such as the Levantine Corridor. Sediments from the Erk-el-Ahmar Fm. (lacustrine, 3.9 Ma, Jordan Valley, Israel) and Bnot Lot member of the Sedom Fm. (lagoonal/lacustrine, 3.2-4.0 Ma, Dead Sea, Israel) highlight as one of the few well-exposed continental archives in the region that date back to that time.In the present contribution, we explore these two sedimentary archives and integrate in a multi-proxy fashion the physical, chemical, and biological properties of both outcrop and core sections (with the latter only retrieved from the Erk-el-Ahmar sequence). This study aims to reconstruct the paleoenvironmental setting and changing hydroclimatic conditions in the Levantine Corridor during these time intervals. By amalgamating the datasets, we show that while the region is characterized by increased warmth and augmentation in precipitation patterns, occasional cooling phases coupled with drought punctuate the Pliocene climatic history in the Levantine region.By synthesizing these diverse datasets into a consistent narrative, the project illuminates how precipitation, evaporation, and ecosystem processes interact under high-CO2 and high-temperature conditions. The outcomes provide the first robust benchmark of Pliocene hydroclimate evolution in the Levantine Corridor, offering critical insight into thresholds of lake resilience, feedback mechanisms, and the persistence of aquatic systems under sustained global warmth.

During the early Holocene, rapid sea- level rise led to the inundation of coastal areas, with shallow landscapes being the most affected. The Carmel coast, located in the Eastern Mediterranean, preserves a rich record of such a submerged landscape, hosting numerous archaeological sites, including the well-preserved Atlit-Yam Neolithic village. In order to reconstruct the geomorphological evolution of the submerged coastal landscape, 23 underwater sediment cores of variable length (ranging from 60 to 240 cm) were drilled both inside and outside the known extent of the Atlit-Yam village. A detailed stratigraphy of the submerged landscape was generated based on the analysis of 18 representative cores. The sedimentary sequences identified in the analyzed cores were defined by respective facies associations, and combined with physical (grain size, magnetic susceptibility), chemical (elemental geochemistry), and organic (total organic content) properties of the sediments. Moreover, the sediment cores were constrained by a radiocarbon chronology. Our analysis reveals the spatially heterogeneous stratification of submerged coastal sediments, influenced by sediment supply, stratigraphic dynamics, rising sea level and human activity. The stratigraphic framework presented here allows identification of sedimentary facies associated with the period of active human occupation. We identify ten sedimentary facies characterized by elevated total organic content, magnetic susceptibility, P/Al, Ti/Al ratios together with distinct grain sizes highlighting the complex interplay between sea-level rise, sedimentary processes, and landscape evolution from Late Pleistocene to the Early Holocene. This study provides stratigraphic and chronological evidence for sustained Neolithic occupation between ∼9600 and 8600 cal. Yrs BP, prior to the early stages of coastal inundation. These findings demonstrate the advantage of coring and sedimentological analysis for studying early human occupation of coastal areas in direct relations to landscape transformation due to rising sea levels.

We present the first subfossil chironomid record from the Arabian Peninsula from a sediment core from Lake Gayal el Bazal, southeastern Yemen, providing insights into hydrological changes over the last similar to 1100 years. Shallow-water chironomid morphotypes, Dicrotendipes nervosus-type and Polypedilum nubeculosum-type, indicating low lake levels and productive habitats with abundant macrophyte cover, suggest two dry intervals between ca. 1575 and 1670 CE and 1770-1930 CE. These periods fall within the Little Ice Age (LIA), suggesting a link between lower global temperatures and weakened monsoonal activity. Since ca. 1930 CE, Tanytarsus cf. formosanus-type Bazal is dominant, indicating higher lake levels and lower productivity. This is supported by rising Ti/Al values, suggesting enhanced runoff and increased precipitation. A rise in Ceratopogonidae Dasyhelea-type during the last three decades suggests a decrease in lake size, likely reflecting anthropogenic water withdrawal since ca. 1989. Our findings support the notion of a dry LIA, affecting parts of Eastern Africa, southwestern Saudi Arabia, and extending to other latitudes such as the Tibetan Plateau. This points to large-scale weakening of the boreal summer monsoons and latitudinal southwards shifts of the Intertropical Convergence Zone. A pluvial period during the 17th century could be connected to a positive Indian Ocean Dipole event. Reconstructed increasing moisture during the pre-industrial era, which contrasts modern-day precipitation measurements, could be explained by seasonal variability with moisture increase during the early summer and autumn. Overall, our record emphasizes the interplay of climate variability and anthropogenic activities in shaping water resources and their sustainability in extremely dry low-latitude regions such as the Arabian Peninsula.

High-resolution paleoclimate records from tropical continental settings are greatly needed to advance understanding of global climate dynamics. The International Continental Scientific Drilling Program (ICDP) project DeepCHALLA recovered a 214.8 m long sediment sequence from Lake Chala, a deep and permanently stratified (meromictic) crater lake in eastern equatorial Africa, covering the past ca. 250 000 years (250 kyr) of continuous lacustrine deposition since the earliest phase of lake-basin development. Lipid biomarker analyses on the sediments of Lake Chala can provide quantitative records of past variation in temperature and moisture balance from this poorly documented region. However, the degree to which climate proxies derived from aquatically produced biomarkers are affected by aspects of lake developmental history is rarely considered, even though it may critically influence their ability to consistently register a particular climate variable through time. Modern-system studies of Lake Chala revealed crucial information about the mechanisms underpinning relationships between proxies based on isoprenoid (iso-) and branched (br-) glycerol dialkyl glycerol tetraethers (GDGTs) and the targeted climate variables, but the persistence of these relationships in the past remains unclear. Here we assess the reliability of long-term climate signals registered in the sediments of Lake Chala by comparing downcore variations in GDGT distributions with major phases in lake-system evolution as reflected by independent proxies of lake depth, mixing regime and nutrient dynamics: seismic reflection data, lithology and fossil diatom assemblages. Together, these records suggest that during early lake history (before ca. 180–200 ka) the distinct mixing-related depth zones with which specific GDGT producers are associated in the modern-day lake were not yet formed, likely due to more open lake hydrology and absence of chemical water-column stratification. Consequently absolute GDGT concentrations dating to this period are relatively low, proxies sensitive to water-column stratification (e.g., branched versus isoprenoid tetraether (BIT) index) display highly irregular temporal variability, and correlations between proxies are dissimilar to expectations based on modern-system understanding. A sequence of lake-system changes between ca. 180–200 and ca. 80 ka first established and then strengthened the chemical density gradient, promoting meromictic conditions despite the overall decrease in lake depth due to the basin gradually being filled up with sediments. From ca. 180 ka onward some GDGTs and derived proxies (e.g., crenarchaeol concentration, BIT index and IR6Me) display strong ∼ 23 kyr periodicity, likely reflecting the predominantly precession-driven insolation forcing of Quaternary climate variability in low-latitude regions. Our results suggest that GDGT-based temperature and moisture-balance proxies in Lake Chala sediments reflect the climate history of eastern equatorial Africa from at least ca. 160 ka onwards, i.e., covering the complete last glacial–interglacial cycle and the penultimate glacial maximum. This work confirms the potential of lacustrine GDGTs for elucidating the climate history of tropical regions at Quaternary timescales, provided they are applied to suitably high-quality sediment archives. Additionally, their interpretation should incorporate a broader understanding of the extent to which lake-system evolution limits the extrapolation back in time of proxy-climate relationships established in the modern system.

For long time in the history of Earth, ferruginous conditions governed the oceans. With the rise of oxygen during the Proterozoic era and the subsequent evolution of living organisms, worldwide deposition of iron formations occurred. These sedimentary units reveal the transition into oxic oceans, passing by local and transitory euxinic conditions, especially in coastal shelves. Constraining the iron cycle and the biogeochemical processes occurring in present and past ferruginous basins helps answering some of the question regarding global oxygenation, the evolution of life and past climate changes. Therefore, Fe speciation and Fe isotopes in both Proterozoic and recent sedimentary records have been widely used to reconstruct past basin dynamics and redox conditions in the sediment–water interface. However, sedimentation and early diagenesis can alter paleoredox proxies and their primary climate signals. In this work, we disentangled alteration processes occurring at the redox front below the sediment–water interface of a ventilated deep-water lake (Lago Fagnano, Argentina/Chile). A sequential extraction protocol was applied to characterize two reactive Fe pools: Fe oxyhydroxides and reduced iron. Subsequently, Fe isotopes were constrained to determine the main processes mobilizing Fe. At the redox front, ferric minerals reach a δ56Fe value of − 1.3‰ resulting from oxidation of dissolved Fe likely following a Rayleigh distillation effect. Dissolved Fe is produced right below via Fe reduction, as shown by the low ferric Fe content. Our observations delineate a redox cycle and a redox horizon undergoing constant upward migration, initiated by regular sedimentation. However, during events of increased rapid sedimentation (e.g., seismites) this dynamic cycle is interrupted inducing full or partial preservation of the Fe-rich redox front. In such case, oxidation of dissolved Fe is interrupted and can be recycled in ferrous minerals, such as Fe monosulfides and amorphous phases with δ56Fe values down to − 1.7 ‰. These findings have significant implications for the recording of biogeochemical cycles in the geological past, the use of Fe isotopes in freshwater-lake sediments for paleoclimate studies, and the progress of our knowledge regarding the geochemistry of past oceans.

<p>During the early and middle Miocene, the Mediterranean became a restricted marginal sea with the contraction of the Mesopotamian Gateway and ultimate loss of connectivity to the Indian Ocean. Leading to the transformation of the Mediterranean into a restricted marginal marine sea . Low latitude circumglobal circulation through the basin characterized the basin for most of the Cretaceous and Paleogene. With the loss of this supply of surface and subsurface waters, dramatic changes occurred to the heat, energy, and nutrient budgets across the Mediterranean. The most affected area was the eastern basin. , As is well evidenced by the onset of sapropel formation, many other aspects of the sedimentary system changed in response to this ocean circulation rearrangement. Hemipelagic successions in southwestern Cyprus offer a window into the changes in the subsurface waters occurring in the Eastern Mediterranean through the closure of the gateway to the Indian Ocean. Dated to the late Aquitanian to the early Serravallian (22.5–14.5 Ma), this sequence is carbonate-dominated and overall continues. It exhibits sedimentation with mass transport contribution from shallow water carbonates to deeper facies. The succession exhibits fluctuation of bottom current activity, which was disrupted in the early Burdigalian by mass transports and temporarily halted during the Langhian. Phosphates are present through the entire succession, but most notably in the Langhian. Combined, these lithological characteristics indicate changes in bottom current energy and seafloor ventilation that point to two key intervals of connectivity restriction through the Mesopotamian gateway.</p>

Lake systems respond physically, chemically, and biologically to hydro-climatic change and variability, and these responses are documented in the sediments. Individual proxies and lacustrine environments may respond to climate variations in a nonlinear way, making it difficult to determine the direction and extent of a climatic shift. Here we investigate the response of lake ecosystem to climatic and environmental changes using a suite of paleo-proxies including ostracods, chironomids, and n-alkanes distribution from paleolake 'Gayal el Bazal (Yemen)'. A previous study from this site has provided a continuous, and high-resolution dataset providing an understanding of precipitation during the last ca 1200 years, particularly during Medieval Climate Anomaly (MCA) and Little Ice Age (LIA). However, the response of the lake ecosystem to these changing hydro-climate conditions, including water-level, salinity, and productivity, remains unknown. The n-alkanes dataset shows that during pluvial interval such as the MCA, the lake experienced an increase in nutrient input resulting in enhanced aquatic productivity. Concurrently, ostracods assemblage displays an increased abundance of swimmer species (like Bradleytriebella lineata and Fabaeomiscandona cf. breuili), suggesting an indirect response between ostracods and climate shifts. The chironomid community during the MCA interval is dominated by taxa belonging to the subfamilies of Chironomini, suggesting a warm, shallow, productive environment with macrophyte vegetation. The LIA interval is marked by increased abundance of higher-chain length n-alkanes, suggesting increased contribution from higher plants. Furthermore, ostracod distribution revealed increased abundance of non-swimmer species like Vestalenula cylindrica., which thrive under saline conditions in the lake. Changes in abundances of Tanytarsini during the LIA interval, which are associated with higher oxygen levels, suggest changes in lake productivity. As a result, the overall patterns in biological indicators reveal that their individual abundance and species/tribe distribution fluctuates in response to changes in the climate and hydrological conditions.

The lake level of the Dead Sea, Southern Levant, has fluctuated with an amplitude of-250 m in response to the last glacial-interglacial cycle. This exceptional sensitivity to climate change, and the availability of long sedimentary archives, make the Dead Sea a benchmark for long quantitative paleohydrological reconstructions. However, discontinuities and chronological uncertainties in the marginal sedimentary record have hampered the reconstruction of Dead Sea lake levels beyond the Last Glacial (70-14 ka before present, BP). Here, we apply a two-pronged methodology. First, we measure the lake water density along ICDP deep core 5017-1-A using a new method, Brillouin spectroscopy on two-phase halite fluid inclusions; we combine it with the composition of pore water and the thickness of halite layers in the core to reconstruct lake level, volume, mass balance and subsidence rate. Second, we tune the chronology of lake levels from outcrops by matching it to the chronology of the deep core. The resulting lake level reconstruction, spanning 237-70 ka BP, is validated by the excellent agreement between outcrop-and mass balance-based methodologies. It shows a long-term recession of the lake, its level decreasing from one interglacial to the other, down to a Holocene record low. There are two reasons for this lake level fall. First, with an average rate of 2.65 +/- 0.15 m/ka, subsidence has outpaced sedimentation at least over the last-130 ka. Second, by reducing the solute inventory of the lake, massive halite pre-cipitation events such as that of 131-116 ka BP have durably increased surface water activity and evaporation, and thus lowered the lake level, up to today. Conversely, our analysis suggests that, during 191-11 ka BP, the dissolution of Mount Sedom salt diapir and freshwater inflows provided to the lake about three times the mass of solute NaCl contained in the modern Dead Sea (in 1985). This massive solute influx, occurring mainly during glacial highstands, strongly contributed to lowering surface water activity and evaporation and, therefore, to increasing the lake volume. Our results suggest that Dead Sea lake levels are more accurately interpreted in terms of climatic change if surface water activity is taken into account.(c) 2023 Elsevier Ltd. All rights reserved.

This study addresses a specific component associated with mass transport complexes in marine systems: the role of hyperpycnal flows, dense shelf water cascading, submarine canyons, distributary channels, and other transport mechanisms in transferring organic matter from continental and shallow marine settings into deep-marine environments. We speculate that during the Eocene, allowing for only 0.1 parts per thousand of shelf carbon to be preserved through transport mechanisms would account for up to 13.7% of all organic carbon burial. As such, the potential to mobilize through this mechanism large quantities of organic carbon is significant. Our case study focuses on a 150 m Eocene sequence composed of organic-rich chalks interleaved with displaced neritic limestones. TOC values range between 1.5 and 14%, averaging 4.5%. Displaced limestones are composed of a variety of poorly cemented mud- and wackestones, with low-diversity assemblages of large benthic foraminifera associated with planktonic foraminifera, suggesting deposition under low-energy conditions within the oligophotic zone on the outer ramp. Transport overprints include soft-sediment deformation, partially lithified rip-ups, folds, small diapirs, bed-scale imbrication, brecciation and syn-sedimentary shear. These features indicate detachment, movement and emplacement following initial sedimentation, in some cases more than once. Emplacement occurs into a chalk facies that can vary in appearance from darker (higher TOC) and lighter (lower TOC) lithofacies. Combination between the sedimentological, petrophysical, and elemental analyses indicates shifts between autochthonous and allochthonous sedimentation, whereas the organic geochemical analysis reveals a correlation between modes of sedimentation and preservation/composition of organic matter. Organic richness seems to increase within intervals of allochthonous sedimentation, with lower TOC values within intervals of autochthonous sedimentation. Organic matter preservation is enhanced due to poor oxygenation of the sea floor, further depleted by rapid burial beneath mass-transport deposits, increasing sedimentation rates and thus organic matter preservation. Horizons rich in organic matter may be derived from three different sources: organic matter with a fingerprint of terrestrial sources (e.g., enhanced contribution of plant leaf waxes) transported from nearshore environments; an allochthonous marine fingerprint with sulfurized hopanoids, which seem to be reworked from pre-existing Cretaceous organic-rich carbonates entrained within fined-grained micro-turbidites in the paraautochthonous facies; and productivity-derived organic matter deposited on the seafloor of the deep marine environment. This study demonstrates how transport mechanisms allow for the long-term burial of organic carbon in marine systems. When taking into consideration similar processes reported to occur in the world oceans today, it is clear that sediment transport and long-term burial of organic carbon is a fundamental part of the global carbon cycle.

<p>Sediment density flows (<em>ρ</em><sub>flow</sub><<em>ρ</em><sub>water</sub>, overflows: flood plumes; <em>ρ</em><sub>flow</sub>><em>ρ</em><sub>water</sub>, underflows: including turbidity currents and debris flows) are major processes for transporting sediments and organic carbon from rivers, coasts or continental shelves into deep basins. These flows can also have serious socioeconomic consequences such as breaking seabed communications cables and pipelines. Given the potential impacts of climate change, it is important to quantify how sediment density flow processes are impacted by changing environmental conditions.</p> <p>Lab-simulations and/or field monitoring campaigns on the timescales of seconds to years are helpful for understanding specific triggers for sediment density flows and how their magnitude/frequency may change under different conditions. However, these methods cannot be applied to longer timescales, which are of great interest to geologists and palaeoclimatologists trying to understand the past. It is unclear whether, and if so how, long-term climate changes affect the magnitude/frequency or type of sediment density flows within a specific water body. One approach to answering this question is to analyze a comprehensive geological record that comprises deposits that can be reliably linked to modern sediment flow processes.</p> <p>To address this question, we analyzed the unique ICDP Core 5017-1 from the Dead Sea (the largest and deepest hypersaline lake on Earth -- <em>ρ</em><sub>water</sub>:1240 g/L) depocenter covering MIS 7-1. Based on an understanding of modern sediment density flow processes in the lake, we link homogeneous muds in the core to overflows (surface flood plumes, <em>ρ</em><sub>flow</sub><<em>ρ</em><sub>water</sub>), and link graded turbidites and debrites to underflows (<em>ρ</em><sub>flow</sub>><em>ρ</em><sub>water</sub>). Our dataset reveals (1) overflows are more prominent during interglacials, while underflows are more prominent during glacials; (2) orbital-scale climate changes affected the magnitude/frequency of the flows via changing salinity and density of lake brine and lake-level (<em>Lu et al., 2022</em>).</p> <p>The current research bridges the gap between our understanding of modern sediment density flow processes and deposits preserved in a long-term geological record in the Dead Sea, a tectonically active subaqueous environment (<em>Lu et al., 2020</em>). It has wider implications for turbidite paleoseismology and implies that to develop prehistoric turbidites as a reliable paleoearthquake indicator, comprehensive modern sediment flow monitoring is essential. It also has wider implications for paleoclimate research in a tectonically active subaqueous environment. A sedimentary archive is filtered to remove significant instantaneous event deposits such as turbidites and debrites could help paleoclimatologists to better reconstruct paleoclimate change.</p> <p> </p> <p>Refs.:</p> <p><em>Lu, Y., Wetzler, N., Waldmann, N.D., Agnon, A., Biasi, G.P., and Marco, S., 2020. A 220,000-year-long continuous large earthquake record on a slow-slipping plate boundary. Science Advances, 6 (48), doi: 10.1126/sciadv.aba4170</em></p> <p><em>Lu, Y., Pope E., Moernaut, J., Bookman, R., Waldmann, N., Agnon, A., Marco, S., Strasser, M., 2022. Stratigraphic record reveals contrasting roles of overflows and underflows over glacial cycles in a hypersaline lake (Dead Sea). Earth and Planetary Science Letters, 594, 117723, doi: 10.1016/j.epsl.2022.117723</em></p>

Mass transport complexes often form key elements of petroleum systems, affecting sedimentary structures, seepage pathways and biodiversity hotspots on the seafloor. Yet, the feedback and interaction between these elements is not well constrained. This study investigates the modes of gas accumulation, migration, and seepage at the toe of Palmahim Disturbance (PD), a major salt-rooted mass transport complex across the southeastern Mediterranean margin, and adjacent edge of the eastern deep-sea fan of the Nile. Interpretation of a 3D time migrated seismic reflection dataset was calibrated with visual seafloor observations of active seepage. The toe of PD, in the eastern part of the study area, comprises four km-scale NE-SW oriented bathymetric ridges. At the crests of the eastern three of these ridges are six, hundreds-of-meters wide pockmark systems, four of which host verified seeps. Multiple sub-circular tens-of-meters wide pockmarks are mapped in the Nile fan west of PD. Active seepage was also identified within two elongate pockmarks along the flanks of the bordering Levant Channel. The seismic data reveal that the PD toe pockmarks and ridges overlie anomalous high amplitude seismic re-flections (HASRs) from just beneath the surface to hundreds-of-meters deep intervals -below, at the base of and within a buried paleo mass transport deposit (MTD). These HASRs are interpreted to represent multiple gas-bearing intervals within thrust-faulted and folded blocks and their intermittent sealing, primarily at the base of the MTD. The Nile fan pockmarks overlie pervasive sub-seafloor HASRs that are overlain by low amplitude reflections, interpreted as gas-bearing channel-lobe sediments. Gas migration occurs via lateral to updip flow within depositional features and deeper folded sediments, and via sub-vertical flow, associated with the for-mation and leakage of transient reservoirs. Extension of fan sediments towards the PD pockmarks suggests additional updip focusing of gas, complementing sub-vertical gas flow to the PD pockmarks.

Submarine mass wasting processes in deepwater settings can incorporate large blocks, which may play a key role in deepwater geological processes and geohazard assessment. However, there is a limited understanding of the deformation style arising from the interaction between submarine blocks and structural/bathymetric barriers such as ramps. The deformation and kinematic history of several submarine blocks (with a thickness of up to 150 m) within a near seafloor mass transport complex in the Orange Basin are documented using seismic geo-morphic methods. The interpreted blocks are preserved in three discrete fault-bounded morphological terrains within a Neogene mass-transport complex. These terrains vary in lengths from 2 km to 6 km; they have heights of 60 m to 150 m and are characterized by discrete and localized structural highs on the present-day seafloor. Block sizes vary across terrains suggesting differences in the block evolution process. Blocks near the ramp appear in seismic profiles comprising (a) Chaotic and transparent seismic reflections and (b) parallel to sub-parallel, continuous, low to moderate amplitude reflections. This variability in seismic facies of the blocks reflects the de-gree of their interaction and translation over a ramp at the basal shear zone of the mass transport complex, ev-idenced by the difference in the block features on the upslope portion of the ramp versus the downslope part. Notably, the deformation styles recorded in the blocks show the impact of the ramp during mass flow, which has broader implications for understanding the internal mechanisms of blocky mass transport complexes in many continental margins.(C) 2022 Elsevier B.V. All rights reserved.

During the early and middle Miocene, the Mediterranean had become a restricted marginal marine sea with diminishing and ultimate loss of connectivity to the Indian Ocean. This dramatically changed the heat, energy, freshwater and nutrient budgets across the Mediterranean and most notably in its eastern basin. While one of the most prominent lines of evidence of this change in the Eastern Mediterranean is the onset of sapropel formation, many other aspects of the sedimentary system changed in response to this rearrangement. Here we present a detailed analysis of a hemipelagic succession from southeastern Cyprus dated to the late Aquitanian to the early Serravallian (22.5 – 14.5 Ma). This sequence is carbonate-dominated and formed during the decoupling of the Mediterranean Sea and the Indian Ocean. It exhibits sedimentation with mass transport contribution from shallow water carbonates to deeper facies with phosphatization and bottom current (at intermediate depth) interactions. This succession traces both local subsidence and loss of a local carbonate factory. Additionally, it records a shift in bottom current energy and seafloor ventilation, which are an expected outcome of connectivity loss with the Indian Ocean.

Gayal el Bazal is a karstic paleo-lake situated on the southern margin of the Arabian Desert, a climatic sensitive zone that responds to small-scale hydrological changes modulated by the Indian Ocean monsoon system. High-resolution biomarker and ostracods assemblages obtained from a 3.25 m composite core from the lake provides insight into past environmental changes for the last 1200 years. Moreover, variations in the sediment lithology and geochemical proxies from the lake core suggests fluctuations related to the dominating precipitation regime. Through data amalgamation, we identified two globally recognized events: the Medieval Climate Anomaly (MCA) and the Little Ice Age (LIA). The study shows that the n-alkane homologues exhibited different distribution modes during these different climatic stages, indicative of variation in the sources of organic matter in response to changes in the regional hydrological conditions. The climate reconstruction based on the n-alkane proxies (Paq, TAR) suggests a higher abundance of longer chain length carbons (C27-C35) derived from higher plants of the watershed during the MCA, indicating wetter conditions in the region. Furthermore, ostracods assemblage data also revealed Paracypretta amati abundance increases during the MCA and decreases during the LIA. The arid phase of LIA is also marked by gypsum formation and dust deposition and is consistent with evidence and theory for weakened summer monsoons during intervals of northern hemisphere cooling. Overall, this study aims to provide a better insight of the monsoon variability and to help to understand the role of northwards migrations of the Intertropical Convergence Zone (ITCZ) vis-à-vis monsoonal dynamics in the region.

<p>The continental shelf of Israel experienced major geomorphological changes during the past 250,000 years as a consequence of global sea level changes and oscillating sedimentation patterns of the Nile River. This study aims to provide insights into the geomorphological evolution of the Israeli continental shelf through time in relation to sea level oscillations. This research is based on geophysical interpretation of high resolution seismic surveys acquired along the Israeli continental shelf, complemented by statistical analysis of the interpretation picks. The main task included the identification of unconformities, erosional truncations and similar surfaces in the seismic profiles; and their chronological assemblage according to their stratigraphic order and ages obtained by previous studies. Seismic stratigraphy analysis of the geophysical dataset allowed dividing the shelf into four main seismic units (SU1 to SU4) bounded by distinctive four horizons. Two units (SU1 and SU3) represent transgression periods, probably during Marine Isotope Stages MIS1 and MIS5; and the two other units (SU2 and SU4) show morphologies suggesting marine regressive conditions, probably during MIS2 and MIS6. Overall the seismic units represent two major sedimentary cycles, which occurred presumably since MIS7 (ages according to previous studies) and correlate with the Hefer Formation stratigraphy (Tel Aviv and Ashdod members). Moreover, high resolution seismic interpretation reveals a distinctive morphology of some of the bounding surfaces in the form of depth-controlled terraces. Geomorphological and statistical analyses of these features, and their correlation with past sea level curves, suggest that their genesis is related to paleo-shoreline environments that probably occurred during MIS2 and MIS6. Particularly, the presumed MIS6 terrace serves as a prominent regional marker that was further used for estimating the average subsidence rates of the Israeli continental shelf to 0.18 mm/y since 136,000 ka. This study suggests the utilization of a novel statistical approach to unravel the mechanisms controlling the geomorphological evolution of the Israeli continental shelf, which can be applied to other shelf environments worldwide.</p>