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Dramatic climatic and environmental changes over the last 12,000 years have significantly impacted Arabian coastal stratigraphy and human populations. The Bar Al Hikman peninsula (BAH), the largest low-lying area (1000 km2) along the Arabian Sea coast of Oman is a monsoon storm-dominated carbonate-evaporite system, where late Neolithic artifacts suggest human presence from at least 5.75–5.05 ka before the present (BP). Despite its archaeological significance at the crossroads of important Neolithic coastal sites in Dhofar, Masirah, and Ja'alan coast, paleoenvironmental interpretation, timing, and expression of relative sea level (RSL) changes in this coastal area remain poorly understood. Fortunately, the extensive size and arid climate of the area have preserved carbonate-dominated Mid-Late Holocene coastal geomorphologies exceptionally well, making this area an excellent geological archive to study past coastal environments, thereby understanding how environmental changes at BAH influenced Neolithic human mobility and settlement patterns. This study reconstructs the paleoenvironment of BAH over the last 12,000 years using a combination of field and remote sensing techniques, including satellite imagery, digital elevation models, bathymetric data, GIA modeling, and Sea Level Index Points to trace RSL history. The Holocene transgression began flooding the extensive continental shelf offshore BAH around 10 ka BP, progressively separating Masirah from the mainland through channel formation between 9.5 and 8.0 ka BP. It then inundated the present-day BAH peninsula around 7.7 ka BP, reaching a highstand of 2.5–3.2 m above present sea level by 6.0 ka BP (Mid-Holocene Highstand; MHHS), before gradually declining to the current level. Human presence documented at BAH (5.75–5.05 ka BP) coincides with the end of the mid-Holocene highstand, and the onset of the regression. This relative sea level history is contemporaneous to the aridification of Arabia, a period of transition from mangrove-dominated intertidal settings to coral reef and carbonate coastal barriers. The disappearance of mangrove-like gastropods around 5.4 cal ka BP and the subsequent appearance of significant coral fragments in the sediment indicates a critical change in terms of environmental settings with less nutrients and a warmer sea surface temperature). Comparing the findings at BAH to well-established nearby Neolithic sites on Masirah Island, the scarcity of prehistoric remains at BAH suggests that during the Mid-Holocene Highstand (MHHS), the small, rocky, paleo-low-lying islands at BAH may have served as waypoints and shelters between Masirah and the mainland. [Display omitted] • Holocene relative sea-level history and paleo-environmental reconstruction of the Peninsula of Bar Al Hikman, Arabian Sea coast, Oman. • Human presence in the area (5750–5050 cal BP) coincides with the end of the Mid-Holocene Highstand and the onset of Arabian Aridification. • Late Neolithic populations used small, rocky paleo-low-lying islands as waypoints and shelters between Masirah and the mainland. [ABSTRACT FROM AUTHOR]

Numerous palaeoenvironmental and archaeological studies from southern Arabia (Yemen and Oman) have revealed strong relations between phases of human settlements and climate change linked to the Indian monsoon system. Analyses on speleothems, cave fills, lacustrine deposits and palaeo-mangroves have shown that during the Early to Mid-Holocene, a humid Optimum culminated around 9000–8000 cal BP. New results on inland speleothems and cave sediments from the Jebel Qara (southern Oman) are crucial in our depiction of Early and Mid-Holocene climatic evolution and cultural dynamics of the region. These aspects are discussed here, based on new archaeological surveys, excavations, geoarchaeological and micromorphological studies, aiming to better understand connections with Terminal Pleistocene and Early Holocene autochthonous cultures of southern Arabia. Our results suggest that the final Pleistocene was marked by strong aridity, which promoted a widespread thermoclastism within rock shelter and deposition of aeolian sand; in contrast, the transition towards the Holocene is marked (since c. 12,000 cal BP) by a progressive increasing in environmental humidity, which permitted the formation of thick strata of peridesert loess. After this phase, the environmental humidity of the Jebel increased and permitted the existence of a large community of land snails; the latter were exploited by Early Holocene hunter–gatherers who lived in the rock shelters between c. 10,500–9500 cal BP and left consistent accumulations of land shells ( escargotières ). The maximum of Holocene humidity was reached between 9000 and 8000 cal BP; regional aquifer were recharged and the deposition of calcareous tufa at the entrance of caves started, lasting up to c. 4500 cal BP. C and O stable isotopes from calcareous tufa highlights, in accordance with several regional records, the progressive decline of the intensity of the Indian Ocean monsoon and the transition towards arid conditions. In this phase, the area was abandoned and archaeological communities possibly relocated along the coast of central and southern Oman, where they exploited the mangrove environment. [ABSTRACT FROM AUTHOR]

An early-to mid-Holocene humid phase has been identified in various Arabian geo-archives, although significant regional heterogeneity has been reported in the onset, duration and stability of this period. A multi-proxy lake and dune record from Wahalah in the United Arab Emirates (UAE) documents significant variations in hydrology, biological productivity and landscape stability during the first half of the Holocene. These data reveal that post-Last Glacial Maximum dune emplacement continued into the earliest part of the Holocene, with the onset of permanent lacustrine sedimentation at the site commencing ∼8.5 ka cal. BP. A long-term shift towards more arid conditions is inferred between ∼7.8 and 5.9 ka cal. BP, with intermittent flooding of the basin and distinct phases of instability throughout the catchment area. This transition is linked to the southwards migration of the Intertropical Convergence Zone (ITCZ) and associated weakening of monsoon rains. A peak in landscape instability is recorded between ∼5.9 and 5.3 ka cal. BP and is marked by a pronounced increase in regional dune emplacement. These variations are considered alongside the record of human settlement raising important questions about the interactions between population demographics, climate and environment in southeast Arabia during the Neolithic. [ABSTRACT FROM AUTHOR]