Studies on the evolution of characteristics and dynamic mechanisms of dry/wet status in global arid regions are contradictory. We systematically assessed the evolution and drivers of dry/wet status in global arid regions from a paleoclimate perspective using observational datasets, paleoclimate records, and climate model simulations from Paleoclimate Model Intercomparison Project Phase 4 (PMIP4)-Coupled Model Intercomparison Project Phase 6 (CMIP6) and PMIP3-CMIP5. Our results show that climate change during the last glacial maximum (LGM) provides a reverse analog for the near-future climate in global arid regions. The notable migration of the subtropical high during the LGM profoundly altered the atmospheric circulation and influenced dry/wet status in global arid regions. The multimodel ensembles project that under the shared socioeconomic pathway (SSP) 8.5 scenario, nonuniform heating induced by polar-amplified warming will introduce northward migration of the subtropical high. The resulting reduction in subtropical precipitation will lead to expansion of global arid regions under global warming, which is consistent with previous studies based on atmospheric aridity.

The region encompassing the Sahara and the Arabian Peninsula has seen dramatic changes in Holocene moisture availability. While the highlands of Yemen are sensitive to moisture dynamics, their history remains poorly known. This study provides new information on Holocene environmental change in the Yemeni highlands through analyses of the lithostratigraphy and ostracod stratigraphy of two localities. The diversity and abundance of ostracod populations serve as key environmental indicators, reflecting stability and change in aquatic habitats. Six time periods are identified, each representing distinct phases of environmental and climatic change. Undated gravelly fine sands, possibly of late-glacial or Early Holocene age, indicate dry conditions. Subsequent stages indicate a progression of moister conditions and warmer climates characterized by the formation of ponds and lakes and fluctuations in water availability. Shifts occurred between oligotrophic and eutrophic conditions, and between desiccation trends and wetter conditions. We found the taxonomic composition of ostracod populations in Yemen’s highlands to include species from mountainous regions of Africa and the broader Palaearctic. This research aligns with previously reported data and expands our understanding of past ecosystems and climatic conditions in highland Yemen.

A model for groundwater silicification within the Sables de Fontainebleau in sub-contemporary landscapes in the Paris Basin proposed 35 years ago has since been continuously and substantially updated, particularly with reference to new studies that relate silica precipitation to periglacial climate conditions. Herein we link the various distinctive morphologies of silicified sandstone bodies to the flow paths of groundwaters that imported the silica, the conditions under which it was precipitated, and the patterns of iced ground. The silicified masses are, in a way, fossil groundwater flow paths. The spatial arrangements of these paleo-groundwater flow paths suggest that permafrost developed to significant depth in parts of the Paris Basin. Our model visualizes a gradual settlement of periglacial conditions in the landscape starting with (1) cooling of the near-surface regolith and development of horizontal silicified pans; (2) progressive descent of impermeable permafrost as glacial conditions persisted, leading to non-horizontal flows ‘forced’ beneath the frozen layer; (3) thickening of the permafrost and consequent pressurization of groundwater in the phreatic zone when groundwater outflows to the valleys froze and closed, and convoluted silicified masses and possibly vertical dikes were formed; (4) followed by later thawing of the permafrost and a reduction in hydrostatic level due to climate warming leading to growth of geotropic silicified bodies when residual permafrost remained at depth. In this context, the distinctive morphologies of the silicified sand masses are proxies for the paleohydrology that prevailed during silicification and constitute a new toolbox for determining the depths reached by permafrost at time of silicification.

We examined a zooarchaeological assemblage from Badger Island, a 12.4 km2 landbridge island in the Furneaux Group, Bass Strait, south-eastern Australia. The accumulation consisted of Pleistocene and Holocene strata that were rich in mammal remains. Small mammal remains were accumulated by owls, whereas large mammal remains were accumulated by people and/or autochthonous mortality. The Pleistocene fauna was dominated by grassland mammals, particularly Mastacomys fuscus (Broad-toothed Rat), but these gradually declined and were largely replaced by forest–woodland dwelling mammals in the Holocene. The same pattern of faunal change has been observed on the large main island of Tasmania (∼65,000 km2), suggesting changes observed at Beeton Rockshelter are representative of the region. Because all of the Furneaux Group Islands were united as one landmass in the past, the fossil fauna observed in Beeton Rockshelter is relevant to conservation-oriented mammal-restoration initiatives, which are being considered throughout the entire Furneaux Group.

This paper addresses the taxonomic status of the extinct large-bodied sea mink Neogale macrodon. Since the early twentieth century, bones of this mink have been found commingled with those of the extant mink, Neogale vison, in Maine’s prehistoric archaeological sites. These two size classes of mink have been described as separate species and as sexually dimorphic size variants of N. vison. A century later, researchers revisited this dispute using data from North American modern and archaeological mink skulls, along with limited postcranial bones, and decided in favor of two species. However, this conclusion was challenged.

We return to the discussion by focusing on postcranial bones, which have advantages over skulls for metric analyses. We considered historical evidence for mink morphology and behavior and determined that, although the two forms shared the same habitat, our large number of identified specimens (NISP) of mink (NISP > 1200) contained no detectable evidence for interbreeding. We conclude that the sea mink was an emerging marine fissiped, transitioning from an undetermined N. vison ancestor in a manner analogous to the polar bear (Ursus maritimus) and the sea otter (Enhydra lutris). Lastly, we suggest N. macrodon became extinct during the nineteenth century under heavy pressure from market hunting.

The hypothesis of Paleolithic rock art in Siberia remains neither proven nor disproven. This research provides key evidence for a later age of the earliest known images in the Minusinsk Depression. A set of geological, geomorphological, and absolute-dating methods was utilized to reconstruct the geological history of the Maydashy rock art site (Minusinsk Depression, Southern Siberia). This research for the first time has allowed us to date the lower chronological boundary of the period when the earliest images known in Southern Siberia as “Minusinsk Style” were created. In the Late Pleistocene, the cliff area of the site was buried under alluvial deposits of the first floodplain terrace of the Yenisei River that formed in the second half of MIS 2. At the beginning of the Holocene, before its optimal onset, Yenisei eroded the terrace and exposed the rock surface to mark the potential lower boundary (< 11 ka) when the Maydashy site images were carved. This approach can be useful in rock art research for dating carvings from open-air sites; it is applicable for the rock art sites of other regions where ravine formation affected their natural context.

Geochemical and 40Ar/39Ar age analyses of a new exposure of a previously destroyed volcanic ash locality within the Airport Terrace above the Middle Popo Agie River in Lander, Wyoming, allows us to re-establish it as Lava Creek A from the last major eruption of the Yellowstone caldera, with a weighted mean age of 628.2 ± 4.1 ka. Confirmation of the ash as Lava Creek more firmly establishes correlation of the terrace with the WR-7 terraces along the Wind River that contain Lava Creek ash and with outwash correlated to the Sacagawea Ridge type moraine at Dinwoody Lakes. By projecting the Airport Terrace gradient upstream, we show that it grades to the previously mapped terminus of the Sacagawea Ridge valley glacier. Additionally, 10Be boulder-exposure ages of ca. 521, ca. 554, and ca. 556 ka from Sacagawea Ridge moraines in nearby canyons support more closely constraining the Sacagawea Ridge glaciation here to Marine Oxygen Isotope Stage 16, which corresponds with recent evidence for an advance of the Laurentide Ice Sheet at this time in the U.S. midcontinent.