Modern salt-marsh foraminifera are widely used as indicators of past relative sea level, yet their distribution remains poorly documented in the microtidal back-barrier lagoons that characterize much of the Mediterranean coastline. This study investigates modern foraminiferal assemblages along elevational transects in two saltmarshes developing within two coastal lagoons in Sardinia (Central Mediterranean Sea) to determine whether elevation relative to mean sea level (MSL) controls assemblage composition and to evaluate their potential for high-resolution relative sea-level reconstruction. Despite ecological differences between the two sites, both transects exhibited a consistent vertical turnover from calcareous-rich assemblages at lower elevations to assemblages dominated by agglutinated taxa at higher elevations. Entzia macrescens provided the clearest indicator of upper marsh conditions, whereas Trochammina inflata showed a less consistent distribution. No foraminifera were recorded at the highest sampled station, located 0.6 m above MSL, suggesting that transitional assemblages in Mediterranean lagoons may extend only slightly above the tidal frame, Assemblage composition was significantly related to elevation when analyzed as a continuous variable, whereas no significant differences emerged among broad tidal-position categories. This contrast highlights the value of precise elevation measurements over simplified environmental zonation. Although the current dataset is insufficient to develop a robust regional transfer function, the consistency between the Sardinian sites and previous Adriatic studies confirms that elevation-dependent foraminiferal zonation also occurs in Mediterranean back-barrier lagoons. Larger modern training sets encompassing additional sites, sampling stations, and environmental variables are needed to quantify predictive uncertainty and assess the regional applicability of this relationship. Once validated, this approach could improve the indicative meaning and vertical precision of late-Holocene relative sea-level reconstructions while providing an independent geological framework for evaluating sea-level indicators derived from coastal archaeological structures.
This paper presents an analysis of micromammal assemblages from Kurtak-22-2025, a new section in the middle Yenisey River reaches in southern Middle Siberia. Correlations with the standard mammal biochronology of Russia based on faunal complexes, with the biochrons MQR of Eastern Europe based on key arvicoline lineages, and with the evolutionary stages of Myospalacinae in Northern Asia suggest a late Early Pleistocene age of the micromammal assemblages in Layers 7-10 at Kurtak 22-2025. The assemblages include typical Early Pleistocene forms (e.g., Beremendia fissidens, Sibirosiphneus razdoleanensis, Predicrostonyx sp., Clethrionomys hintonianus, Allophaiomys pliocaenicus) and also species of the latest Early – earliest Middle Pleistocene (early Microtus s.l.). A tentative fine-scale chronology of the sequence is hypothesized based on the evolutionary level of Microtus ex gr. hintoni nutiensis - thenii, Stenocranius hintoni and Alexandromys cf. protoeconomus identified using a comparative and linear morphometric approaches. The lower chronological limit of the faunal succession is hypothesized not older than the Jaramillo Subchron and the upper limit is around the boundary of the Razdolean and Vyatkino (= Tamanian and Tiraspolian) faunal complexes older than the Matuyama-Brunhes transition. Faunal associations reflect the existence of highly productive grasslands with steppe to meadow-steppe vegetation developed on loose nutrient-rich soils and a neighboring elevational gradient of habitats ranging from forests with C. hintonianus to alpine rocky (with Altaiomys, a rhizodont ancestral form of modern Alticola) and tundra-like habitats with Lemmus and Predicrostonyx. The presence of Microtus ex gr. hintoni nutiensis - thenii allows a correlation of Kurtak 22-2025 with the late Early Pleistocene European sites Les Valerots, Monte Peglia, Castagnone, Untermassfeld, Podumci 1. Kurtak-22-2025 represents the easternmost find of this taxon previously known only from Western and Central Europe and the Caucasus, thus, suggesting late Early Pleistocene faunal relationships between southern Middle Siberia and those regions.
Taphonomic models are largely derived from studies in temperate and semi-arid regions, whereas humid tropical environments remain underrepresented, particularly in South America. This study describes and interprets the taphonomic signatures of Quaternary megafauna preserved in active fluvial deposits in southwestern Mato Grosso do Sul State, Brazil, and establishes a chronological framework for these assemblages. The analyzed sites are distributed across the Apa, Miranda, and Formoso river basins, in the municipalities of Bela Vista, Bonito, and Miranda. The material comprises 142 fossil specimens housed at the Federal University of Mato Grosso do Sul in Mato Grosso do Sul State, with complementary material from the “Pedro Candolo” Museum of Paleontology in São Paulo State. Taxonomic identification was based on morphological criteria, and taphonomic analysis considered fracture patterns, abrasion, weathering, and bioerosion. Taxonomic composition includes Xenarthra, Proboscidea, Cingulata, Crocodylia, and Chelonia. Radiocarbon ages from the Apa River indicate an Early Holocene chronology. The fossil assemblages are composed of remains predominantly disarticulated and fragmented, with variable preservation and a high proportion of indeterminate remains. Differences in transportability indicate distinct hydrodynamic conditions, with a predominance of elements of intermediate transportability. Taphonomic features reflect deposition in open, dynamic systems, suggesting time-averaged assemblages that represent long-term depositional processes rather than synchronous ecological records.
Climate plays a significant role in sediment mobilization from continental interiors (hinterlands) to continental margins (depositional basins), and in regions dominated by the Indian Summer Monsoon (ISM), temporal changes in monsoon intensity significantly modulate the hydrological conditions and thus the exogenic sedimentation in distal continental margins. The Western Great Rann of Kachchh (WGRK), located on the Indian continental margin and lying barely above present sea level, preserves a sensitive archive of the interplay between hinterland climate and sea-level forcing on post-Last Glacial Maximum (LGM) sedimentation and landform evolution. We present chronological (AMS radiocarbon and OSL), sedimentological (grain size, n = 427), and geochemical (Chemical Index of Weathering, Plagioclase Index of Alteration, Ca/Ti, Ca/Σ(Ti,Fe,Al); n = 365; organic carbon, n = 55) analyses of the 46.5 m Allah Bund Sediment Core (ABSC), recovered proximal to the relict Nara River channel, spanning ∼19 ka to the Late Holocene. Downcore variability in these proxies, supported by statistical analysis identifies six phases of variable hydrological conditions: post-LGM strengthening during the deglacial transition (∼19–17 ka), moderate and weakened conditions during the late deglacial interval (∼17–12 ka), strengthened hydrological conditions during the Pleistocene–Holocene transition and Early Holocene (∼12–10 ka), progressive weakening during the early to mid-Holocene (∼10–7 ka), a brief strengthening during the mid-Holocene (∼7–6 ka), and fluctuating but overall weakened conditions after ∼6 ka. The relatively higher contribution of chemical weathered sediment between ∼19 and ∼11 ka indicates a relatively greater sediment contribution from the monsoon-exposed western Himalayan rivers which might be routed through the Nara channel, whereas a decrease in CIW and PIA after ∼11 ka reflects a relative increase in the contribution of physically weathered, Trans-Himalayan-influenced sediment from the upper Indus catchment (Ladakh–Karakoram). LGM sea-level lowering exposed much of the Gulf of Kachchh, driving delta progradation onto the currently submerged shelf; subsequent backfilling began in the early Holocene (∼11 ka) and continued through mid-Holocene (8–5 ka) sea-level rise, during which the WGRK transitioned to an intertidal regime. These findings demonstrate that continental-margin sedimentation in the WGRK is governed by the dynamic coupling of hinterland climate variability and sea-level change, providing a framework for interpreting allogenic controls on post-glacial sedimentary architecture in analogous low-relief, monsoon-influenced marginal settings.
