Controls on Carbonate Factory Distribution in a Restricted Intraplatform Basin: Upper Jurassic Smackover, Southwest Alabama
type: CreativeWork
description: This study documents the stratigraphy and depositional facies of the Upper Jurassic Smackover Formation in the Manila Basin, southwest Alabama, and examines the carbonate factories responsible for sediment production. Four wells with associated cores and log data were analyzed, alongside geochemical proxy concentrations measured via X-ray Fluorescence (XRF) and Laser Induced Breakdown Spectroscopy (LIBS). These proxies were grouped into redox, terrestrial, and nutrient to assess how oceanographic conditions influence carbonate sediment production and accumulation.The transgressive Lower Smackover is dominated by microbially produced lime mudstone, with minor microbialite and peloidal packstone. A restricted marine environment led to low oxygen conditions, with high nutrient levels due to internal waves or regional upwelling. Although the contribution of terrestrial nutrients was likely minimal, nutrients transported via fluvial systems accumulated over time within a geographically-restricted basin.The regressive Upper Smackover documents the progradation of a deltaic system and oolitic shoals into the basin. The distal slope of the prograding system is primarily composed of microbialite while the shallower, mid slope is dominated by peloidal packstone, recording the transition from a microbial carbonate factory at depth to a skeletal carbonate factory. The shallowest part of the system consists of oolitic grainstone and mature sandstone, recording high saturation in the photic zone. Effective wave agitation and current flushing of nutrients contributed to supersaturation and the abiotic precipitation of oolites in shallow, near-shore environments. Alternating wet and dry climates resulted in high variability, albeit with low averages, of both nutrients and terrestrial inputs. This study reveals a strong correlation between water chemistry and carbonate factory types. Microbial factories operated in dysoxic, nutrient-rich environments, while skeletal factories thrive…
abstract: This study documents the stratigraphy and depositional facies of the Upper Jurassic Smackover Formation in the Manila Basin, southwest Alabama, and examines the carbonate factories responsible for sediment production. Four wells with associated cores and log data were analyzed, alongside geochemical proxy concentrations measured via X-ray Fluorescence (XRF) and Laser Induced Breakdown Spectroscopy (LIBS). These proxies were grouped into redox, terrestrial, and nutrient to assess how oceanographic conditions influence carbonate sediment production and accumulation.The transgressive Lower Smackover is dominated by microbially produced lime mudstone, with minor microbialite and peloidal packstone. A restricted marine environment led to low oxygen conditions, with high nutrient levels due to internal waves or regional upwelling. Although the contribution of terrestrial nutrients was likely minimal, nutrients transported via fluvial systems accumulated over time within a geographically-restricted basin.The regressive Upper Smackover documents the progradation of a deltaic system and oolitic shoals into the basin. The distal slope of the prograding system is primarily composed of microbialite while the shallower, mid slope is dominated by peloidal packstone, recording the transition from a microbial carbonate factory at depth to a skeletal carbonate factory. The shallowest part of the system consists of oolitic grainstone and mature sandstone, recording high saturation in the photic zone. Effective wave agitation and current flushing of nutrients contributed to supersaturation and the abiotic precipitation of oolites in shallow, near-shore environments. Alternating wet and dry climates resulted in high variability, albeit with low averages, of both nutrients and terrestrial inputs. This study reveals a strong correlation between water chemistry and carbonate factory types. Microbial factories operated in dysoxic, nutrient-rich environments, while skeletal factories thrive…
author: Oppedisano, Marisa J.
language: en_US
language: English
date published: 2024
date modified: 2026-07-27T18:44:03Z
provider: University of Alabama
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: University of Alabama Libraries