Palaeoenvironmental Reconstruction Research Articles

Advances in giant clam (Tridacnidae spp.) sclerochronology and sclerochemistry

Understanding past environmental change through high-resolution palaeoenvironmental proxy reconstructions provides crucial baselines for understanding global environmental changes, particularly during the Quaternary Period. Such data are crucial for testing and refining climate models to enable better adaptations to current and future climate changes. Giant clams (Tridacnidae spp.), the largest bivalve mollusc in the Indo-Pacific region, possess distinctive features such as long lifespan, rapid growth, high-resolution growth patterns, wide distribution habitat, and stable shell geochemical composition. These attributes make giant clams a promising and dependable novel palaeoenvironmental archive, offering numerous available geochemical proxies. In this review, we examined preview studies on giant clams conducted for sclerochronology research, spanning publications from 1986 to 2023. The previous studies have proven that isotopic and trace elements proxies of the giant clam, including δ18O, δ13C, Sr/Ca, Mg/Ca, Ba/Ca, and Fe/Ca, can faithfully reconstruct palaeoclimate records including sea surface temperature, dissolved inorganic carbon, insolation, extreme weather events and primary productivity at ultra-high resolution. These proxies have been successfully employed for palaeoclimatic and palaeoenvironmental reconstructions from the Miocene to the present across a range of locations from South Japan to Northern Australia to the Red Sea. These studies have illuminated changes in interannual climate cycles, climate variation, and human migrations over thousands to millions of years. They have generated quantitative records that are valuable for testing and refining numerical climate models, understanding the relationship between past climate cycles and future climate variability, and providing insights into human-environment interactions over time. In the end, the review also addresses the challenges and provided recommendations for future research, highlighting persisting gaps in understanding the influence of microstructure on the shell, age dating of fossil samples, uncertainty in proxies, the need for tank experiments, and access to ultra-high resolution palaeoenvironmental records.

Stable isotope of Mesolithic remains of Pila wernei of the Nile area, Sudan: A tool for palaeoenvironment reconstruction

The article deals with stable isotopes of oxygen and carbon on current and archaeological semi-aquatic gastropod shell of the Pila wernei from Sudan and reports some new 14C analyses on archaeological Pila specimens. This, with the aim of obtaining new information on climatic and environmental changes in the al-Khiday area during the first phase of Holocene. The Pila shells come from a well-preserved shell midden present at al-Khiday and dated 8700-7000 cal yr BP. The area of al-Khiday was inhabited since at least 10 ka. Pila wernei species has never been studied in detail; this study demonstrates that the O and C isotope composition of aragonite shell is able to record the environmental and diet changes during the gastropod life. The comparison between the isotope data obtained on present-day and archaeological shells show a prevalence of C4 plants and higher rainfall during the Mesolithic. Two climatic fluctuations have been recognised: the first one indicating wetter conditions from 8650-8400 to 8500-8050 cal yr BP (decrease of the δ18O values), the second one pointing less wetter conditions from 8500-8050 to 7850-7600 cal yr BP (increase of δ18O values). Despite the difficulties in studying semi-aquatic gastropods due to their lifestyle habit, the identification of climatic fluctuations in the Early Holocene confirms the reliability of this proxy for climatic reconstructions. Despite the high number of isotopic analyses (1556) used in this work, they were not sufficient to mirror the fast climate changes characterising the studied period and finally obtain a detailed reconstruction for nearly the two millennia considered. Nonetheless, future projects may benefit greatly from unveiling the shell-environment relationship of the species.

The role of pollen and NPP research in palaeoenvironmental reconstruction of the Neolithic archaeological site “Gorjani-Topole” (Slavonia region, eastern Croatia)

The palynological study of eight samples from the Gorjani-Topole archaeological site was conducted with the aim of palaeoenvironmental reconstruction. In total, 44 different palynomorphs were recorded: 12 pollen taxa, 23 fungal spores/remains, four algal cysts, one amoebae and four palynomorphs of unknown origin. Among the non-pollen palynomorphs, Chomotriletes (previously Pseudoschizaea) occurred with the greatest frequency and abundance. The low pollen richness accompanied by the presence of only a few sporopolleninrich pollen types indicates unfavourable preservation conditions in the analysed core samples. The dominance of erosion/desiccation indicators supports the scenario of significant oscillations of the hydrological level in the sediments, with periodic drying of the substrate. Although the interpretation of changes in plant cover, due to the reduced pollen spectrum, is not feasible, it is still possible to indicate paleoecological trends and partially interpret them, considering the indicator value of the few preserved palynomorphs. The findings of cultivated grass pollen (Cerealia) and other anthropogenic indicators including weed pollen (Convolvulus arvensis) are of great importance. Moreover, Riccia moss spores or fungal Epicoccum spores could also indicate the anthropogenic impact on the study area.

The ostracod distribution in the Sea of Galilee (Levant): species distribution and post-mortem dispersal of valves and carapaces

The Sea of Galilee is a unique large freshwater or slightly oligohaline natural lake in the Levant. Therefore, it represents an important aquatic habitat in the region that also provides invaluable ecosystem services for the local communities. To improve our knowledge of the lake’s ecosystem and the use of disarticulated ostracod valves and preserved carapaces, micro-crustacean remains commonly used in palaeolimnology and palaeoceanography, as proxies for palaeoenvironmental reconstructions, and to examine the post-mortem dispersal of ostracod remains, 68 surface-sediment samples were collected from the lake bottom in 2012 and analysed for the ostracod assemblages. Both, the noded and smooth, forms of Cyprideis torosa dominate in the Sea of Galilee, with the former more abundant than the latter. Relatively abundant and found at half of the 68 sampling locations or more, are also Ilyocypris hartmanni, I. cf. nitida, Darwinula stevensoni and Neglecandona angulata. In addition, ten less abundant ostracod taxa were recorded in the lake. Of all 15 taxa recorded in our study, ten were also recorded in a study of the Sea of Galilee’s ostracod fauna conducted already in the 1960s. The newly recorded five taxa are relatively rare, and they were mostly found in the region of the Jordan River delta or near the southeastern shore of the lake which were not included in the survey of the 1960s. Thus, there is no evidence for a significant change in the ostracod fauna of the lake over the last half-century. In comparison to the ostracod assemblage from a late Pleistocene archaeological excavation site at the southwestern margin of the lake, the assemblage from the recent survey is slightly less diverse, probably because of the long duration of ca. 5000 years integrated by the sedimentary section of the archaeological site and also due to nearby freshwater inflows from which valves and carapaces were probably washed to the site’s location. Our study also shows that ostracod valves and carapaces are typically relatively abundant in most of the surface-sediment samples collected from locations at 18 m or shallower. In contrast, very few valves and carapaces were recorded at depths greater than 18 m, which is a zone affected by seasonal anoxia in the Sea of Galilee. These few ostracod remains were apparently transported by currents and waves to the central, deeper part of the lake, but their low number shows that such post-mortem dispersal of ostracod remains is insignificant in the deeper part of the lake. Thus, our study provides support for palaeoenvironmental and palaeoclimate reconstructions based on ostracod records from single sediment cores obtained from depths unaffected by post-mortem transport and seasonal or permanent anoxia.

The last 20,000 years of climate change in the Iberian Peninsula characterized by the small-mammal assemblages

Climate and environments have undergone significant changes throughout the Earth's history, which are reflected in the faunal record. In that sense, small mammals provide valuable palaeoecological insights due to their close relationship with their associated environments. Our research investigates the dynamics of small mammal communities in the Iberian Peninsula from the Late Pleistocene to the Holocene, comparing regional environmental variations as well as anthropogenic impacts. Our review of the small mammal assemblages from 26 archaeological sites across the Iberian Peninsula revealed a differential response of the small mammal communities between the northern and southern areas. The colder climatic conditions which characterized the Late Pleistocene favoured the presence of mid-European species (e.g., Alexandromys (Oecomicrotus) oeconomus, Chionomys (Chionomys) nivalis) in northern regions until the Mid Holocene, while other taxa today restricted to northern Iberia (e.g., Arvicola amphibius, Microtus gr. (Euarvicola) arvalis, Sorex araneus-coronatus) reached southern regions during the Last Glacial Maximum but disappeared at the beginning of the Holocene period. Palaeoenvironmental reconstructions indicate predominantly open landscapes and colder climates in the Late Pleistocene, with increased forest cover during the Early-Mid Holocene in northern areas. In contrast, the southern regions exhibited more stable environments compared to the northern ones. Our results underscore how the great environmental diversity and interactions between natural and anthropogenic factors affected the composition of Iberian small mammal communities during the last 20,000 years. Most specifically, during the Late Holocene, biogeographical patterns of the small mammals are mostly affected by anthropic activities, with changes in the distribution of some species (Microtus (Iberomys) cabrerae), and the entrance of new ones (synanthropic species).

Palaeoenvironmental Analysis of the Southern Part of the Danube–Tisza Interfluve (Hungary): The Northern Loess Wall of Katymár and the Hay Meadows and Loess Banks of Hajós

This study presents a comprehensive palaeoenvironmental reconstruction of the southern part of the Danube–Tisza interfluve in the Carpathian Basin from the Late Pleistocene to Early Holocene, addressing the region’s response to global climate forcings and local environmental factors based on multi-proxy analyses of two key protected areas: the Katymár brickyard and the hay meadows and loess banks of Hajós. By integrating radiocarbon-dated malacological, macrobotanical, pollen, phytolith, geochemical, and sedimentological analyses, it was possible to provide a picture of past climate–ecosystem interactions. The Katymár North sequence provides an extended chronology from Marine Isotope Stage 3 (MIS3, ca. 36,000 cal BP) through the Last Glacial Maximum (LGM) and into the Early Holocene, while the Hajós sequence offers high-resolution data for the LGM–Holocene transition. By the late Ice Age, humidity and surface moisture superseded temperature as primary palaeoecological limiting factors, promoting ecotone-like forest–steppe environments during cooling periods.

Melanoides tuberculata and Zootecus insularis gastropod shells provide a snapshot into past hydroclimatic conditions of arid environments: New perspectives from Oman

Shells of the aquatic gastropod Melanoides tuberculata and the terrestrial gastropod Zootecus insularis were analysed using high-resolution isotope sampling (up to 274 samples per shell) to assess their potential use as a proxy for hydroclimatic and palaeoenvironmental reconstruction in drylands. A total of 169 snails (fossil and modern) were collected from 37 sites in Northern Oman and Dhofar, with each site selected for its specific geomorphological, archaeological or ecological context. This included fluvial terraces, playa environments, modern oasis gardens, irrigation channels and Neolithic (6000–3200 BCE) and Early Bronze Age (3200–2000 BCE) archaeological sites. The δ18O data obtained from these gastropods could be classified into eight different patterns, three for the aquatic snails (Type 1 A–C) and five for the terrestrial snails (Type 2 A–E), which were linked to the environmental context of their habitat. Furthermore, the use of the aquatic snails enabled us to distinguish between groundwater and surface water signals, whereas the terrestrial snails were employed to reconstruct changes in rainfall origin, humidity, evaporation, regular wet-dry cycles, and/or the presence of meteorological events such as cyclones. According to the results, gastropods can be used to elucidate the long-term, local evolution of rain-fed floodplain ecosystems in drylands and to identify the hydrological resources present in the vicinity of archaeological sites, particularly with regard to type (e.g., surface water vs groundwater).

Small topographical variations controlling trace maker community: Combining palaeo- and neoichnological data at the Porcupine Abyssal Plain

Ichnological research has generally assumed that abyssal plains are dominated by quiescent, homogenous environmental conditions. Thus, deep-sea trace fossil assemblage changes have been usually linked to significant spatial and temporal environmental variations. Here, we conducted a comparative ichnological analysis between a small abyssal hill (50 m elevation) and the surrounding abyssal plain; this modest bathymetric variation is known to generate substantial environmental heterogeneity for the benthic fauna community of the Porcupine Abyssal Plain (c. 4850 m depth), Northeast Atlantic. Based on X-ray data from a 5 × 5 core grid emplaced in two box cores, we compared hill and plain bioturbational sedimentary structures, including trace fossil assemblages (e.g., ichnotaxonomy) and biodeformational structures (e.g., mixed-layer depth). We observed that topographically-enhanced near-bottom currents over the hill likely produce significant changes in depositional dynamics and sediment properties (e.g., grain size, organic matter content and degradation), and control specificities of bioturbational sedimentary structures (e.g., trace fossils, mixed layer attributes such as thickness, mottled background, discrete traces). Palaeoichnological data suggested that the abyssal plain had experienced consistent conditions during the last thousands of years while the abyssal hill recorded improving environmental conditions for the trace maker community. Our results highlight the complexity of the deep-sea environment, demonstrating that small changes in bioturbated sedimentary assemblages appear even within the same box core (m-scale), and that substantial changes can occur due to environmental heterogeneity (e.g., subtle topographic variations) at the local scale (km-scale). Considering the vast global extent of abyssal hill terrain, we suggest that their influence on the bioturbational sedimentary record may be significantly under-appreciated and require more attention in palaeoenvironmental reconstructions.

Correlation between dental microwear analysis and dietary habits of Neanderthal populations in the Iberian Peninsula

Abstract The dietary habits of Neanderthals are considered an issue of great interest in the literature and have opened an important number of fruitful debates. Indeed, understanding diets can provide important information regarding issues of palaeoenvironmental reconstructions and subsistence strategies. In this respect, dental remains can play a vital role in the conducted efforts to reconstruct the palaeoecological niches securely and accurately since dental microwear analyses have precisely detected dietary patterns of the populations in the past. In this context, the Iberian Peninsula forms an interesting model for examining Neanderthal populations, their subsistence strategies, and adaptive skills. This study aims the examination of already published data in order to provide a holistic approach regarding the dietary habits of H. neanderthalensis populations in the Iberian Peninsula, along with the importance of the utilization of dental microwear analysis in the archaeological record.

Modern pollen distribution along a Himalayan elevation gradient in Central Nepal

Modern pollen distribution and its relationship to environmental variables in tropical to alpine vegetation zones are investigated to provide a reference for palaeoenvironmental reconstructions and to improve the understanding of pollen dispersal patterns in Central Nepal. A total of 100 samples (from soil and moss) were collected from along an elevational gradient ranging from 173 to 4615 m above sea level. Results show that the alpine zone is dominated by arboreal pollen (AP) and the sub-alpine zone also shows good representation of coniferous taxa pollen such as Pinus, Abies, Tsuga, and Picea along with Ericaceae. The temperate zone has a good representation of Quercus (Evergreen) and Pinus pollen, whereas the sub-tropical zone is characterized by Alnus pollen and agricultural taxa such as Cerealia (planted Poaceae) and Brassicaceae. In the tropical zone, non-arboreal pollen (NAP), mainly Cerealia dominate, reflecting intensive agricultural practices. Shorea is completely silent in pollen representation. A redundancy analysis indicates that elevation is the primary factor influencing pollen distribution in this region. Overall, the pollen data reflect the vegetation distribution but Pinus is over-represented and Shorea is unrepresented, which should be taken into consideration when interpreting fossil pollen in Central Nepal.

Individual isotopic niche variation of herbivores and palaeoenvironmental reconstruction of the Mid-Pleistocene Site of Kathu Pan 1 (South Africa)

Individual niche variation occurs when individuals within a population adopt unique behavioural or ecological traits, giving the population a distinct niche structure. Although widespread amongst natural populations, most of niche theory and its applications in ecological and palaeoenvironmental contexts remains focused on species level patterns, treating variation within the population as noise. Using serial stable isotope profiles sampled along teeth of herbivore fossils recovered from the Mid-Pleistocene site of Kathu Pan 1, Northern Cape (South Africa), enabling partitioning of isotopic niche variation into between- and within-individual components. Stable carbon isotope data revealed significant dietary differences between-individuals within most of the taxa sampled, but no dietary differences between taxa. By contrast, stable oxygen isotope compositions were more consistent amongst individuals, but varied across taxa. In both isotope systems, as well as in bivariate space, most taxa comprised individuals with both narrow and broad isotope niches, indicating flexibility in dietary strategies. These results indicate sufficient opportunity for individual level specialization within the Kathu palaeocommunity, afforded by a palaeoenvironment that provided a consistent supply of resources year-round. Given the herbivore sample is strongly associated with fossil hominin activities, our results imply that hominins in these landscapes would have profited from year-round accessibility to resources, accounting for the record of occupancy of Kathu Pan I during the Mid-Pleistocene.

Lateglacial and Holocene palaeoenvironmental evolution of alkaline peatlands in the Somme valley (France): between climate and anthropogenic forcing

As in most chalk river valleys in NW Europe, the sedimentary fill of the Somme valley is mainly composed of fluviogenic alkaline peat. The site of Morcourt exhibits a thick and well‐preserved fluvial sequence (10 m, including 6 m of peat). This sequence provides the framework for reconstructing fluvial and palaeoenvironmental dynamics from the end of the Upper Weichselian Pleniglacial (~20 000 cal. a BP) to the High Middle Ages (~700 cal. a BP). The palaeoenvironmental reconstruction is based on a high‐resolution stratigraphic study of 60 transect cores, 36 radiocarbon dates and sedimentological, geochemical, pollen and plant macrofossil analyses. There are three main phases in the development of the valley floor: (i) after the incision of the abandoned Pleniglacial braided river channels, a first generation of localized peat developed during the Bølling and the Allerød interstadial (<1 m thick); (ii) at the beginning of the Holocene, a peat formation phase began in the deepest parts of the valley and then spread over the valley floor by the end of the Middle Holocene (~4700 cal. a BP), with the limited runoff shifting to a small lateral channel; and (iii) at the transition to the Late Holocene, environmental changes, driven by the intensification of human activities and perhaps accentuated by climatic modifications, caused the incision of the peat system as a result of the formation of a channel. This channel drained the valley, and then mixed a detrital load into the peat. By the Low Middle Ages, the system had been altered to such an extent that the peat was completely covered by organic silty alluvium. The water table was lower, which definitively inhibited peat formation. The Morcourt sedimentary record (thickness and continuity) and the resumption of turfigenesis during the Late Holocene are remarkable in NW Europe, making this site a model of continuous morpho‐fluvial evolution since the Lateglacial.

Pollen atlas and morphological analysis of the selected types from southeastern Tibet, China

The accuracy of fossil pollen identification is crucial for understanding past plant diversity, vegetation landscape and associated climate change, while dispersed/fossil pollen assignments heavily rely on how robust modern pollen reference is. There is high species richness in southeastern Tibet, China, however, pollen morphological studies in this area are still poorly documented. Here, we present pollen atlas of 57 species (40 genera, 22 families) collected from the Ranwu Lake Basin. Pollen grains were imaged with light microscope (LM, 100X oil-immersion objective lens) and scanning electron microscope (SEM). All pollen types are ordered and presented according to different aperture types and sculpture patterns, facilitating comparison with fossil pollen. Moreover, we selected some representative species mainly based on potential palaeoecological importance, including Sibiraea (Rosaceae), Koenigia cathayana (Polygonaceae), Stellera chamaejasme (Thymelaeaceae), Hordeum vulgare subsp. vulgare and Poa annua (Poaceae), to discuss their pollen identification characteristics for the first time and assess potential applications in Quaternary palaeoecological interpretation. This study enriches modern pollen atlas for Quaternary pollen analysis in the study area and the adjacent regions. Our results provide robust modern reference in pollen-based reconstruction of vegetation history, palaeoclimate and palaeoenvironment, and tracing pollen signal of local human activities as well.

Tectonically-controlled biofacies distribution in the Eocene Foraminiferal Limestone (Pag, Croatia): A quantitative-based palaeontological analysis

This paper analyses the lower to middle Eocene carbonate succession exposed at the Island of Pag (Croatia), in the External Dinarides, providing its palaeoenvironmental, palaeobathymetric, and stratigraphic reconstruction. A total of 125 samples have been collected within the Foraminiferal Limestone and the overlying Transitional Beds units cropping out in the sites of Vrčići and Pag for the quantitative analysis of the skeletal assemblage (point counting) and the foraminiferal association (area counting), including both large benthic and small benthic foraminifera. Further samples were collected from the overlying Dalmatian Flysch, to constrain the age of the top of the succession using calcareous nannofossil biostratigraphy. On these bases, the Foraminiferal Limestone has been dated from the Ypresian to the middle Eocene (late Lutetian/early Bartonian). Thanks to the analysis of the skeletal and foraminiferal assemblages, and the use of multivariate statistics, seven main biofacies were identified within the Foraminiferal Limestone and one biofacies within the Transitional Beds. The porcelaneous and agglutinated benthic foraminifera biofacies (BF1) indicates a well-illuminated, oligotrophic to mesotrophic, shallow water, lagoonal environment. The hyaline SBF and encrusting benthic foraminifera biofacies (BF2) developed in a shallow water, inner-ramp environment, and is related to a vegetated seafloor. The nummulitid biofacies (BF3) indicates a moderately high energy, shallow water environment, whereas the comminuted bioclasts and nummulitid biofacies (BF4) corresponds to a low-energy, shallow water environment, and both deposited in inner-to-middle ramp settings. The nummulitid and orthophragminid biofacies (BF5) indicates a moderate energy environment, deposited in middle ramp settings. The nummulitid and serpulid biofacies (BF6) consists of transported material from the inner ramp deposited in middle ramp settings. The orthophragminid and nummulitid biofacies (BF7) indicates a below-wave base, outer shelf setting and the planktic foraminifera biofacies (BF8), recorded in the Transitional Beds, indicates a hemipelagic environment. Based on the foraminiferal counting, quantitative parameters such as the orthophragminids/nummulitids ratio, the planktic/benthic foraminifera ratio, and the hyaline/porcelaneous foraminifera ratio were calculated. These parameters indicate that the succession formed along a distally steepened ramp profile, showing a progressively tectonically-controlled deepening of the depositional environment, culminating with the final drowning of the carbonate ramp. Quantification serves as a crucial instrument for a precise and reliable palaeoenvironmental reconstruction, allowing the comparison amongst different successions.

Application of herbivore ecometrics to reconstruct Neogene terrestrial palaeoenvironments in Falcón, Venezuela

Despite its important position close to the Isthmus of Panama, and abundance of fossil localities, the palaeoenvironment of the Falcón Basin in northwestern Venezuela has been understudied. The basin includes a sequence containing 6 terrestrial fossil assemblages, of which 5 are well-sampled enough for palaeoenvironmental reconstruction. Here we use these assemblages as a test case for taxon-free approaches in the Neotropics, that have been used in studies elsewhere, including dental functional traits, body mass and mesowear. Mesowear reveals browsing and grazing diets from the Late Miocene to the Late Pleistocene, and though the toxodontids (the most abundant mammalian herbivores) show a consistent browsing signal, other approaches support an environment which was largely more open than previously suggested. We find limited evidence for any dramatic climatic shift, instead finding more gradual changes in precipitation and tree cover. Ultimately, we find enough consistency in our results with those of other proxies to suggest that the methods employed here could potentially be applied to other localities in South America.

A new species of black drum (Acanthuriformes: Sciaenidae: Pogonias Lacépède, 1802) from the Upper Miocene of Argentina

Pogonias blettleri sp. nov., a new species of black drum (Acanthuriformes, Sciaenidae) from the marine Upper Miocene Paraná Formation, which crops out in the Province of Entre Ríos, Argentina, is described. The holotype specimen comprises a large and nearly complete skull articulated with the anterior vertebral column and associated with fragmentary remains of the pectoral and pelvic girdles, as well as a complete pectoral fin. Morphological and phylogenetic analyses including several Western Atlantic sciaenid taxa confirm the assignment of the fossil specimen to the genus Pogonias Lacépède, 1802, as the sister taxon to the clade of Pogonias cromis + Pogonias courbina. The erection of a new species is based on the presence of a combination of primitive and derived characters, such as: the sub-triangular dorsal outline of the anterior neurocranium, with the lateral borders of frontals delimiting an isosceles triangle; the cavernous frontals with wide bridge-like bony struts; a conspicuous dorsal protuberance of frontals; a crescent-shaped preoperculum, with a smooth posterior margin and a strongly thickened anteroventral edge; and a robust and craniocaudally wide hyomandibula, with a strongly ossified anterior expansion. The palaeoenvironmental reconstruction of the upper levels of the Paraná Formation suggests that P. blettleri sp. nov. inhabited brackish and shallow waters in estuarine environments, particularly in areas near large river run-offs. The known palaeontological content from this unit includes potential prey of the black drum, suggesting that P. blettleri sp. nov. likely fed on annelids, crabs, molluscs, and small fish, similar to its extant counterparts. https://zoobank.org/urn:lsid:zoobank.org:pub:3AA77DDD-4FDA-4CFD-AC7F-476F432B950B

Meandering streamflows across landscapes and scales: a review and discussion

The study of meandering patterns created by geophysical flows is important for a number of fundamental and applied research topics, including stream and wetland restoration, land management, infrastructure design, oil exploration and production, carbon sequestration, flood-hazard mitigation and planetary palaeoenvironmental reconstructions. This volume, Meandering Streamflows: Patterns and Processes across Landscapes and Scales , contains 13 papers that present field, laboratory and numerical investigations of meandering channels found in distinct environmental and geological contexts and focus on how the interactions of different autogenic and allogenic processes, both in the horizontal and the vertical dimension, affect meander kinematics and the resulting morphology, sedimentology and stratigraphic architecture. In this introductory chapter, we offer an overview of the evolution of scientific research on meandering streams over time, aiming to review and discuss meandering patterns in both fluvial and non-fluvial settings. Additionally, we present a new compilation of data on meander morphological features, drawn from both existing literature and novel sources, encompassing over 8000 meander bends discovered across a diverse array of environments.

The Lake Paravani archive – a contribution to the late Quaternary landscape evolution of the Lesser Caucasus (Georgia)

Lake Paravani, located on the volcanic Javakheti Plateau in the central part of the Lesser Caucasus at 2073 m a.s.l., forms a unique geo‐bio‐archive for palaeoenvironmental reconstructions in this remote region. Based on sediment cores from the southwestern part of the lake we expand the existing palynological and sedimentological records beyond the Last Glacial Maximum (LGM). For the first time, it is possible to reconstruct the palaeoenvironment in this part of the Lesser Caucasus back to c. 28 cal. ka BP. Our study shows that until 16 cal. ka BP glacial conditions dominated (Phase I) in the region; there is, however, proof that the lake already existed during the LGM. In the following transitional Phase II from 16 until 6 cal. ka BP, cold and arid conditions with sparse steppe vegetation and a lowered lake level prevailed. Around 10 cal. ka BP, tree pollen started to expand while herbaceous pollen, especially Chenopodiaceae, declined. In Phase III, since 6 cal. ka BP, mixed forest probably represented the Holocene climatic optimum. Fluctuating lake levels indicate shifting climatic conditions. The minor changes of arboreal pollen hin the uppermost part of Phase II may be an indication of human activity. The more humid, vegetation‐rich environment and mild climate around 4.5–2 cal. ka BP correlate with the expansion of the Late Bronze Age settlements in this area (from ~3.5 cal. ka BP/~1.5 ka BC). The proliferation of sites on the plateau, along with even higher‐altitude sites possibly dating to the same period, may indicate that this climate amelioration played an important role in enabling more sustained human occupation. The results extend the record on Lake Paravani by several millennia beyond the LGM and complement the palaeo‐lake reconstructions of the wider region, e.g. at Lake Van (Türkiye) or Lake Sevan (Armenia).

Palaeoenvironmental reconstruction of Holocene calcareous tufas distributed over a manganese deposit in Mexico

The Holocene calcareous tufa deposits are located in the north-central sector of the state of Hidalgo, Mexico. These deposits outcrop on the Upper Jurassic Chipoco Formation in the Molango Manganese District. Calcareous tufa deposits correspond to carbonate formations of inactive tufas disconnected from the current hydrological network. To better understand the textural, geochemical, and biological characteristics and environmental conditions during their formation, a detailed study involving field analysis, X-ray diffraction analysis, X-ray fluorescence analysis, and morphometric analysis with light microscopy, and scanning electron microscopy was carried out. Similarly, 14C analysis was undertaken to determine the age of the deposit. On this basis, two biofacies were defined, one with stem structures and the other with Phyto clasts, bryophytes (Plagiomnium cuspidatum), and copepods, limited both at the base and the top by lenticular-shaped erosive surfaces and sigmoidal clinoforms. These bio facies formed in lacustrine and paludal environments, and barrier waterfalls. From a geomorphological point of view, the accumulations of these calcareous tufas originated on slopes and/or at the foot of karstic springs, where the accumulation of material originated from the height of the spring with respect to the bottom of the valley, giving rise to a set of stepped tuffaceous plains with a wedge-shaped profile, colonized by important masses of bryophyte mounds, copepods, and vascular plants. This suggests a swampy environment where sedimentation took place in shallow water accumulations, where there is clear evidence of exposure and pedogenetic modification, indicating wet and dry episodes that translate into seasonal fluctuations in the water table. Six mineral phases were observed including silicates, carbonates and arsenates. The 14C analysis indicates that the plant found in the charcoal sample within the calcareous tufa deposit is of Holocene age.

Palaeontological and sedimentological studies of dated cores from the coast of Thyna (Sfax, Gulf of Gabes, Tunisia): multiproxy evidence for a high-energy extreme event and palaeoenvironmental reconstructions

Palaeontological and sedimentological studies of dated cores from the coast of Thyna (Sfax, Gulf of Gabes, Tunisia): multiproxy evidence for a high-energy extreme event and palaeoenvironmental reconstructions