Microbial and aeolian influences on coniatolite development near Jebel Dhanna, Abu Dhabi

• Autores: Anthony Kirkham, Bryan N. Twombley
• Localización: Carbonates and Evaporites, ISSN 0891-2556, Vol. 35, Nº. 3, 2020
• Idioma: inglés
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• Resumen

  • Coniatoids and the more extensive coniatolites were originally described, respectively, as rough surfaced, aragonite coated grains and rough surfaced, aragonite encrusted beachrocks near Jebel Dhanna, Abu Dhabi. At that time, a microbial involvement in their origins was rejected in favour of supratidal physico-chemical precipitation and this study investigates the validity of those conclusions. Vadose aragonite cementation has certainly occurred but new evidence of microbial involvement is presented and an intertidal influence is suggested with due consideration given to Holocene eustatic sea levels. The surface roughness of particularly the coniatolites is largely due to wick-like movement of surface marine waters under the influence of prevailing northwesterly winds, including the Shamal. Leewards growth extensions of the microbial communities in the direction of aeolian-driven, marine surface water drainage were rapidly cemented by micritic aragonite which also engulfed carbonate grains. A similar aeolian wick-like precipitation process is illustrated in a halite deposit of an Abu Dhabi sabkha salina.