Carbonate rock-water diagenesis lower cretaceous, Stuart City Trend, South Texas
type: CreativeWork
description: The Stuart City Trend in south Texas is a Lower Cretaceous shelf-edge buildup of bioclastic and reefal carbonates. This carbonate system is currently buried to depths of between 3,300 and 5,000 meters. Combined with the equivalent updip shallow water, shelf carbonates of the Edwards and Glen Rose Formations, these carbonates form an extensive Gulfward dipping carbonate wedge. The whole-rock chemical and isotopic characteristics of the limestones of the Stuart City are the product of their initial composition and early surface and near-surface diagenetic history. Burial diagenesis has not significantly altered the chemical and isotopic character of these limestones. Marine diagenesis was volumetrically important and consisted of micritization and the precipitation of fine to very coarsely crystalline, fibrous to bladed, isopachous, Mg-calcite cements. These cements have been neomorphically altered to calcite, while still retaining a Mg⁺⁺ memory and a marine-like isotopic character. Diagenesis by meteoric water was volumetrically important in altering the depositional character of the carbonate sediments associated with the topographic highs along the Stuart City Trend. Secondary porosity formation, Mg-calcite and aragonite stabilization and equant spar calcite cementation are important products of this diagenesis. The equant spar calcite cements are poor in iron and manganese. They make up approximately 16 percent by volume of the limestones studied. The majority of these cements have δ¹³C compositions which fall in the range of modern marine carbonates [...]. Oxygen isotopic variability of the equant spar calcites is controlled by the δ¹⁸O composition of the diagenetic fluids and the degree of openness of the carbonate sediments to these fluids. Thermally induced ¹⁸O depletion in the equant spar calcites was of secondary importance. Pyrobitumen pore fillings and inclusions in the outer one millimeter rims of the very coarsely crystalline, equant spar calcite cements…
abstract: The Stuart City Trend in south Texas is a Lower Cretaceous shelf-edge buildup of bioclastic and reefal carbonates. This carbonate system is currently buried to depths of between 3,300 and 5,000 meters. Combined with the equivalent updip shallow water, shelf carbonates of the Edwards and Glen Rose Formations, these carbonates form an extensive Gulfward dipping carbonate wedge. The whole-rock chemical and isotopic characteristics of the limestones of the Stuart City are the product of their initial composition and early surface and near-surface diagenetic history. Burial diagenesis has not significantly altered the chemical and isotopic character of these limestones. Marine diagenesis was volumetrically important and consisted of micritization and the precipitation of fine to very coarsely crystalline, fibrous to bladed, isopachous, Mg-calcite cements. These cements have been neomorphically altered to calcite, while still retaining a Mg⁺⁺ memory and a marine-like isotopic character. Diagenesis by meteoric water was volumetrically important in altering the depositional character of the carbonate sediments associated with the topographic highs along the Stuart City Trend. Secondary porosity formation, Mg-calcite and aragonite stabilization and equant spar calcite cementation are important products of this diagenesis. The equant spar calcite cements are poor in iron and manganese. They make up approximately 16 percent by volume of the limestones studied. The majority of these cements have δ¹³C compositions which fall in the range of modern marine carbonates [...]. Oxygen isotopic variability of the equant spar calcites is controlled by the δ¹⁸O composition of the diagenetic fluids and the degree of openness of the carbonate sediments to these fluids. Thermally induced ¹⁸O depletion in the equant spar calcites was of secondary importance. Pyrobitumen pore fillings and inclusions in the outer one millimeter rims of the very coarsely crystalline, equant spar calcite cements…
author: Prezbindowski, Dennis Robert
language: eng
keywords: Diagenesis, Texas, Gulf Region, Petrology, Groundwater, Geology, Stuart City Trend, Carbonate systems, Limestones
date published: 1981
date modified: 2026-07-24T05:01:22Z
provider: University of Texas
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: University of Texas at Austin

PropertyValue
property ID: Handle
value: https://hdl.handle.net/2152/117585

PropertyValue
property ID: DOI
value: 10.26153/tsw/44465