Late Holocene Red Sea Coastal Evolution: Evidence from Shallow Subsurface Sedimentary Facies, North Al-Wajh, Saudi Arabia

• Published in: Thalassas : revista de ciencias del mar 2021-04, Vol.37 (1), p.1-12
• Main Authors: Ghandour, Ibrahim M., Majeed, Jawad, Al-Zubieri, Aaid G., Mannaa, Ammar A., Aljahdali, Mohammed H., Bantan, Rashad A.
• Format: Article
• Language: English
• Subjects: Amphiboles; Animal behavior; Aragonite; Calcite; Calcium carbonate; Clay minerals; Coastal Sciences; Cores; Dolomite; Dolostone; Earth and Environmental Science; Earth Sciences; Evolution; Feldspars; Fish & Wildlife Biology & Management; Freshwater & Marine Ecology; Grain size; Holocene; Lagoons; Marine & Freshwater Sciences; Marine molluscs; Mica; Mineralogy; Minerals; Mollusks; Oceanography; Plagioclase; Relative abundance; Sea level; Sea level changes; Sediment; Sedimentary facies; Sediments; Stratigraphy; Wadis
• ISSN: 0212-5919; 2366-1674
• DOI: 10.1007/s41208-020-00248-2

The stratigraphy of the late Holocene shallow subsurface coastal sediments, North Al-Wajh, Saudi Arabia was investigated to reconstruct the environmental evolution of the area in relation to sea-level changes. Five shallow cores (1.1 to 2.2 m long) were collected from the intertidal flat bordering the Dumaygh Lagoon, and the mouths of wadis Antar and Haramil. The cores exhibit siliciclastic-dominated sediments, in some parts containing reworked calcareous shell fragments of bivalves, gastropods and coral remains. The sediments were analyzed for grain size, loss on ignition (LOI), CaCO 3 content, and bulk mineralogy. Mineralogically, the sediments were dominated by siliciclastic minerals (quartz, plagioclase, feldspars, and hornblende) followed by low Mg-calcite (LMC), high Mg-calcite (HMC) and aragonite. In addition, traces of mica, amphiboles, clay minerals, and dolomite were recognized. There is a slight lateral variation in the relative abundance of aragonite and high Mg calcite (HMC), particularly at the base of cores. The results provide a simple scenario for the late Holocene Northern Red Sea coastal evolution. Two vertically stacked sedimentary facies were recognized from the cores; grey mud-dominated lagoonal/bayfill at the base and yellowish-brown sand-dominated intertidal flat at the top. The vertical facies stacking suggests a forestepping pattern or progradational sequence possibly attributed to the late Holocene relative sea-level fall.