Pettigrew, R and Rogers, S ORCID: https://orcid.org/0000-0002-4920-5408 (2018) Carbonate Microfacies of the Cedar Mesa Sandstone: Examples from a Mixed Clastic/Evaporitic Continental Sabkha. In: The British Sedimentological Research Group AGM, 17 Dec 2018. (Unpublished)

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Abstract

Arid continental environments are typically dominated by aeolian, alluvial and fluvial deposits. Despite being commonly recognised, carbonate deposits within these environments are often overlooked, yet they can provide vital insight into the depositional history, climatic and tectonic controls of a basin. This work presents the first microfacies analysis of the carbonates found within the Cedar Mesa Sandstone Formation of the Western USA. The Cedar Mesa Sandstone Formation is a predominantly aeolian succession of early Permian age, exposed across much of the Colorado Plateau of southern Utah and northern Arizona. The formation is dominantly clastic erg deposits, which transition into a mixed sediment sequence, with carbonate and evaporitic horizons interspersed throughout which are interpreted as sabkha or sabkha-like deposits. Whilst many authors have worked within the aeolian dominant facies and proposed various facies schemes for the siliciclastic components, comparatively little attention has been paid to the mixed evaporitic/clastic/carbonate aeolian sabkha transition zone. This work details a microfacies analysis of the carbonates present within the Cedar Mesa Sandstone, in order to: (i) develop an appreciation of the carbonate components; (ii) suggest formational mechanisms and (iii) identify evolutionary trends within the environmental system, which stand alongside the formations clastic depositional story. Six microfacies are presented: MF1) Clastic Influenced Carbonate Wackestone; MF2) Carbonate Packstone; MF3) Microbial Bioclastic-Bindstone; MF4) Carbonate Mudstone; MF5) Bioclastic-Ostracod- Wackestone and MF6) Microcrystaline Chert. The microfacies have been interpreted to document the development of carbonate interdune and sabkha environments juxtaposed across a wetting and drying climatic cycle (which is also observed throughout the formations dominantly clastic sections). The carbonates exhibit excellent preservation and potentially some structures of additional interest, namely – wavey microbial laminations and stromatactis-like cavities.

Item Type: Conference or Workshop Item (Poster)
Divisions: Faculty of Natural Sciences > School of Geography, Geology and the Environment
Depositing User: Symplectic
Date Deposited: 04 Mar 2019 11:54
Last Modified: 04 Mar 2019 11:54
URI: http://eprints.keele.ac.uk/id/eprint/5967

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