Mid-Late Holocene Paleoenvironmental and Sea Level Reconstruction on the Al Lith Red Sea Coast, Saudi Arabia

Abstract

Late Quaternary paleoenvironments are of particular interest to understand how the Earth System’s climate will respond to the undramatic changes during this period, compared with the broader glacial-interglacial variations. In this study, a shallow sediment core (2.84 m long) retrieved from the Red Sea coastal zone in northern Ghubbat al Mahasin, south of Al-Lith, Saudi Arabia, is used to reconstruct the mid-Late Holocene paleoenvironments and sea level based on a multiproxy approach. Remote sensing data, sedimentary facies, benthic foraminiferal assemblages, δ18O and δ13C stable isotopes, elemental composition and 14C dating were utilized. The stratigraphy of the core shows three distinctive depositional units. The basal pre 6000 year BP unit consists of unfossiliferous fine to medium sand sharply overlain by black carbonaceous mud and peat, suggesting deposition in a coastal/flood plain under a warm and humid climate. The middle unit (6000-3700 year BP) records the start and end of the marine transgression in this area. It consists of gray argillaceous sand containing bivalve and gastropod shell fragments and a benthic foraminiferal assemblage attesting a lagoonal or quiet shallow marine environment. The upper unit (<3700 year BP) consists of unfossiliferous yellowish-brown argillaceous fine-grained sands deposited on an intertidal flat. Both middle-and upper-units stack in a regressive shallowing upward pattern although they may be separated by a hiatus. The overall regressive facies and the stable isotopic data are consistent with a late Holocene sea-level fall and a change to a more arid climate.

Depositional Setting and Cementation Pattern of Al-Mejarma Beachrocks, Saudi Arabia: A Proxy for the Late Quaternary Red Sea Coastal Evolution

“…In an ongoing research, a short (2.5 m long) core collected from the intertidal flat shows stacking of two facies; lagoonal gray mud containing skeletal remains of bivalves, gastropods and corals, sharply overlain by intertidal flat yellowish-brown medium-grained sand. This facies organization is consistent with the shallow subsurface coastal facies organization at Al-Shuaiba [67], Al-Kharrar [63,64,68], north Al-Wajh [65], and Al Lith [66].…”

“…Following the last post-glacial sea-level rise, sea-level fluctuations during the Holocene have had a profound influence on the Red Sea's coastal evolution. Evidence for the highstand along the Red Sea and the Gulf of Aqaba coasts is well documented by coral terraces, palaeoshoreline notches, and erosional benches [60][61][62], shallow subsurface coastal sedimentary facies [63][64][65][66] and upcore change in benthic foraminiferal distribution [67,68]. Ghandour and Haredy [64] recognized transgressive-regressive successions from the Red Sea coastal plain of Al-Kharrar Lagoon, Saudi Arabia.…”

Beachrock as a Paleoshoreline Indicator: Example from Wadi Al-Hamd, South Al-Wajh, Saudi Arabia

“…This humid interval possibly coincides with the middle Holocene pluvial period [45]. Several examples have been reported from inland basins and Red Sea coastal zones in western Saudi Arabia, suggesting a middle Holocene long-term climatic humid climate ( [6,9,45,48]. The carbon and oxygen isotopic data of the Gulf of Aqaba fossil corals suggest that the climate of the area was humid prior to 4.9 ka ago, and that after that, the climate turned extremely arid [49].…”

“…Several proxies have been utilized worldwide to infer Holocene climate and sea level changes. These proxies include shoreline shifts and subsequent vertical variations in sedimentary facies [4][5][6][7], temporal variations of microfossils [8,9], beachrocks, marine notches and raised coral reefs [10][11][12][13][14]. Recent descriptions of coastal sedimentology of the tropics and warm temperate zones render beachrocks as potentially useful indicators of sea level and climatic changes and former paleoshoreline positions [13,15,16].…”

Facies variations in response to tectonic evolution, climate and sea-level changes since the Late Cretaceous in Wuhu region, Eastern China

“…The river-ocean interaction area is a strong ocean-landatmosphere interaction zone. Under the impacts on extreme climate events, sea-level fluctuation and regional crustal movements, sediments record a vast amount of information on natural environmental evolution and are therefore very sensitive to global climate and paleo-environmental changes (Wang et al, 2007;Wang and Ji, 2011;Yao, 2014;Liu et al, 2010;Ghandour et al, 2021). The study of climate-sea level change and local sedimentary response of land-ocean systems has become a crucial issue in the evolution of the global environment, and is vital to address current changes in anthropogenic climate and geospatial patterns (Feist et al, 2019;Singh and Sinha, 2019;Yang et al, 2022).…”