δ18O values in speleothems have been utilized to document past changes in South American monsoon intensity. However, changes in regional vegetation and ecosystems have not been part of this ...discussion, and other cave proxies such as speleothem δ13C values, a useful proxy for vegetation reconstruction, have been neglected due to interpretive complexities. Here we report δ13C values and 87Sr/86Sr ratios in stalagmites, together with XRF-derived elemental chemistry, δ13Corg values and carbon content from a sedimentary profile from the same cave where the stalagmites were collected. In combination with a previously published δ18O record, this enables us to clarify climate and environmental shifts that occurred between the Last Glacial Maximum and the Holocene in central South America. We show that vegetation was sparse during the last glacial period in spite of a previously inferred strong monsoon, and that changes in atmospheric pCO2 combined with local hydrological and temperature feedbacks may have determined vegetation development during this time.
•Multiple cave sediment proxies for vegetation and environmental reconstructions.•Vegetation was sparse during the last glacial period in Southern Amazon.•Climate and environmental transformation occurred between the LGM and the Holocene.•Atmospheric CO2 have determined vegetation evolution.
Northern Vietnam is situated on a major route of Pleistocene hominin dispersal in East Asia, and the area's karstic caves preserve many prehistoric shell middens. Fossil and genomic evidence suggest ...a complex human history in this region and more widely across Southeast Asia and southern China, but related archaeological investigations are hampered by challenging site stratigraphies. Recent investigations of shell middens in other geographical settings have revealed the microstratigraphic complexity of these anthropogenic deposits. But caves promote distinctive site formation processes, while tropical climates may catalyse geomorphic and diagenetic changes. These environmental factors complicate the interpretation of northern Vietnam's shell middens and constraining their effects upon the formation, preservation and destruction of these sites is critical to understanding the archaeology of this region. We examine two archaeological cave sites, dated to the Late Pleistocene and located in the limestone uplands surrounding the Hanoi Basin. Each contains multiple shell midden layers associated with prehistoric occupation and burials. Using thin-section micromorphology (microstratigraphy), we reconstruct the depositional and post-depositional histories of these sites, presenting a geoarchaeological framework of interpretation that is applicable to shell middens in mainland Southeast Asia and tropical zones more widely. This work represents a further step towards improving our understanding of prehistoric human dispersals and adaptations in this region.
This article is part of the theme issue ‘Tropical forests in the deep human past’.
Current knowledge about Paleolithic human plant use is limited by the rare survival of identifiable plant remains as well as the availability of methods for plant detection and identification. By ...analyzing DNA preserved in cave sediments, we can identify organisms in the absence of any visible remains, opening up new ways to study details of past human behavior, including plant use. Aghitu-3 Cave contains a 15,000-yearlong record (from ∼39,000 to 24,000 cal BP) of Upper Paleolithic human settlement and environmental variability in the Armenian Highlands. Finds from this cave include stone artifacts, faunal remains, bone tools, shell beads, charcoal, and pollen, among others. We applied sedimentary ancient DNA (sedaDNA) metabarcoding to the Aghitu-3 sedimentary sequence and combined this with pollen data to obtain a temporal reconstruction of plant assemblages. Our results reveal a stratification of plant abundance and diversity where sedaDNA reflects periods of human occupation, showing higher diversity in layers with increased human activity. Low pollen concentrations combined with high sedaDNA abundance indicate plant remains may have been brought into the cave by animals or humans during the deposition of the lower two archaeological horizons. Most of the recovered plants are reported to be useful for food, flavor, medicine, and/or technical purposes, demonstrating the potential of the environment around Aghitu-3 Cave to support humans during the Upper Paleolithic. Moreover, we identified several specific plant taxa that strengthen previous findings about Upper Paleolithic plant use in this region (i.e., for medicine and the manufacturing and dyeing of textiles). This study represents the first application of plant sedaDNA analysis of cave sediments for the investigation of potential plant use by prehistoric humans.
•We successfully recovered plant DNA from Upper Paleolithic layers at Aghitu-3 Cave.•Detailed assessment of pollen and plant DNA shows a diverse array of plant uses.•Plant DNA reflects periods of human occupation and provides evidence for plant use.•Detected taxa support earlier reports of prehistoric plant use as medicine and dye.
The Bàsura Cave (Toirano, Savona, NW Italy) hosts important cave bear bone assemblages and a numerous and varied, tracks and traces record left by humans and other producers. An outstanding element ...of the analysed material is represented by fossil bear fur fragments, which were found in the inner deposits of the cave, and that, to date, are virtually unknown in the cave global record. After analysing and discussing micromorphological features of the inedited material, we integrate and interpret new radiocarbon data, along with taphonomic, sedimentological, geochemical and mineralogical evidences, with the aim of improving our understanding about the nature and chronology of the bear fur-bearing deposit. The bear fur fragments are included in a stratigraphic succession corresponding to a secondary deposit, formed after the dismantling, reworking and redeposition of a former bear-bearing deposit, as a result of short but intensive flooding events that most probably took place at the end of the Last Glacial Maximum. After sediments redeposition, important diagenetic changes have occurred and probably driven by guano deposits, whose pre-existence, in absence of record, is inferred from corrosion features, nutrient concentrations, mineral species identified (REE bearing hydroxyapatite), and claw traces left by bats on the cave ceiling and walls. Diagenetic imprint derived by guano deposits caused mineralization of bear fur fragments by replacement with apatite, which faithfully copied the form and structure of hairs but also of vegetal tissues, phytoliths and pollen found within them. Our study demonstrates for the first time that the bear fur is one of the main vectors in introducing botanical microremains into the interior of the “Old World” caves.
•Periods of wet paleoclimate were recorded in cave sediments.•Five phases of latosolization were recorded in the last 100 kyr.•Intense weathering and gibbsite were synchronous with carbonate ...crusts.•Global scale events (e.g., Heinrich) triggered latosolization periods.
The present-day semiarid region of NE Brazil experienced multiple periods of increased precipitation during the Quaternary. They were likely linked to global-scale events (e.g., Heinrich Events) and drove changes in vegetation dynamics, leading to the expansion of rainforest vegetation. Here, we hypothesize that soil features preserved in cave sediments records paleoenvironmental changes induced by global-scale events that affected NE Brazil during the Late Pleistocene - Early Holocene. To test this hypothesis, we analyzed the elemental and isotopic geochemistry composition, bulk sediment mineralogy, soil micromorphological features, and fauna fossil type and content of a well-preserved 6 m cave sediment profile spanning 103 kyr – 8 kyr in Toca de Cima do Pilão at the Serra da Capivara National Park. Our approach provides new information on the history of soil formation, vegetation, and climate of NE Brazil during the Late Pleistocene - Early Holocene. The results demonstrated that severe weathering and dense vegetation was the dominant paleoenvironmental conditions during wet periods, when latosolization was the main soil forming process. The evidence for wet and intense weathering periods was the co-existence of speleothems layers with Ferralsol features, such as runiquartz, granular microstructure, Fe nodules and gibbsite formation. Some of these features were found in layers deposited in synchrony with Heinrich Stadial and Younger Dryas periods, suggesting that past soil processes in NE Brazil were affected by those global-scale events. We propose five phases of latosolization in our study area during the last 100 kyr. The first was identified around 80 kyr, the second occurred around 29 kyr. The third coincided with Heinrich Stadial 1 (16 kyr) and the fourth likely occur during the Younger Dryas, and the fifth phase occurred during the middle Holocene.
Newly discovered paleokarst sediments with an abundant Miocene palynological record in the Eastern Sudetes bridge the gap in reconstructing the landscape and tectonic history of the NE Bohemian ...Massif during the Neogene. Palynological analysis performed for seven samples derived from the karst fissure allowed the examination of the sporomorph distribution (pollen grains and spores of plants) and nonpollen palynomorph content (algal and fungal microremains) in each layer. The results revealed the presence of numerous pre-Quaternary taxa, including “paleotropical” species, within the analyzed sediments. The pollen analysis results indicate a warm-temperate and humid climate during sedimentation of the Nowy Waliszów karst infill, along with the development of wetland vegetation (swamp forests, riparian forests, and shrub bogs) and mesophytic forests. Recorded taxa are typical for flat and hilly landscapes, predating growth of the present >1000-m relief mountainous topography and formation of the primary European triple drainage divide in the Śnieżnik Massif area. Paleokarst palynology strongly supports a mid-Miocene (∼15 ± 1.5 Ma) onset of environmental change in the Sudetes due to accelerated tectonic uplift of the Eastern Boundary Fault bounding the Upper Nysa Kłodzka Graben and Orlica–Śnieżnik Dome tectonic block. The data presented enhance our understanding of the pre-Pleistocene development of the NE Bohemian Massif, with a particular focus on the orogen-scale landscape evolution from flat, inland wetlands to hilly, mountainous topography.
•Sudetes landscape evolution re-anchored with the new Miocene paleokarst site.•Post mid-Miocene (∼15 ± 1.5 Ma) onset of the NE Bohemian Massif accelerated uplift.•Pollen data indicates a warm temperate and humid climate during the sedimentation.•Neogene vegetation typical for flat and hilly landscapes.
This paper describes a set of paleokarst caves at Torricelle Hills near Verona (Southern Alps, Italy.) At this locality, erosional surfaces and paleokarst cavities show that sedimentation of late ...Paleogene neritic limestones was interrupted by subaerial exposure. Karst features developed during a phase of marine regression that started after the early Oligocene and ended in the mid Miocene. These caves were originally completely filled by iron oxides- and hydrated oxides-rich paleosol sediments (ochre) that, for centuries, have been mined for pigments. Mining activity emptied the caves, leaving the voids and related shapes mostly intact; as a result, the original morphologies have been exhumed, making these caves a rare example of explorable paleokarst. These “ochre caves” were mapped in a series of surveys over a few years. The exploration of overall 4.5 km of accessible passages in four caves yielded a wealth of information on speleological features, stratigraphy, paleontology, and paleogeography, and here we exploit this information to infer the genesis of these unusual caves. Their evolution started in phreatic conditions, characterized by very slowly moving or still waters that led to the formation of solution facets. A vadose phase of development ensued, followed by infilling by reworked soil-derived sediment and associated paragenetic modifications. Sediment accumulation ended with the complete fossilization of the caves under epiphreatic conditions. Siliciclastic and carbonate sediments containing littoral fossils indicate that the caves developed in the vicinity of a coast, and that they were subject to marine ingression. Overall, these paleokarst coastal caves seem to be a fossilized example, well preserved and explorable, of the Carbonate Island Karst Model on larger islands. We interpret these caves as conduits that drained the freshwater lens in a spatially limited carbonate peninsula that existed in this part of the Lessini paleocoastline between the Oligocene and the Miocene.
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