Petrographic Compositional Assessment of Eolianites of the Ghayathi Formation (Late Quaternary, United Arab Emirates) in Relation to Their Depositional Age

Abstract

Calcareous eolianites of the Ghayathi Formation are highly responsive paleoclimate indicators owing to their brief reconstitution times and high cementation rates. A detailed study of this formation, specifically on the carbonate composition, is expected to provide a more comprehensive interpretation of the paleoenvironment and paleoclimate. Another aspect of this thesis is to obtain highly precise elevation data of the transgression surface to link with various highstand events that have different elevations. Field examination was first carried out to collect nine samples of the Ghayathi Formation from age-dated locations and the transgressive surface elevation data from four locations: Nouf, Futaisi, Bil Ghaylam, and Ghantoot. Petrographic analysis was carried out using the point-counting approach. Correlation analyses were carried out from the point-counting results, including correlations between components, age vs. composition, and elevation vs. composition. All significant intercomponent correlations are then interpreted to explain the sedimentological and diagenetic processes experienced by the formation. On the correlation of depositional age against composition, only the percentage of peloids is correlated with age, with a negative correlation. This is interpreted to be related to marine diagenesis processes in the source area. The correlations of the eolianite sample elevations with intragranular pore space, intergranular cement, and bioclast compositions can successfully explain the diagenetic processes occurring in the eolian deposits in terrestrial environments. Measurements of transgressive surface elevation on Futaisi Island and the Nouf area provide an interpretation that not all transgressive surfaces are formed by the same event. Elevation measurements on Bil Ghaylam Island further strengthen the understanding of the relationship between elevation and diagenesis. Meanwhile, measurements in the Ghantoot area found a discrepancy in the results of OSL age dating carried out by previous researchers on eolianite, which appeared to be younger than the possible age of the transgressive surface above it obtained from the widely accepted sea-level curve. To provide a valid justification, it is necessary to conduct further research, particularly in the geochronology of the Fuwayrit Formation.

Date of Award	17 Dec 2023
Original language	American English
Supervisor	Thomas Steuber (Supervisor)