Paleoenvironments of the Albian Glen Rose Carbonate System in the Gulf of Mexico: USA and Mexico

Abstract

Abstract

The Gulf of Mexico (GoM) in the Early Cretaceous (Barremian-Albian) was characterized by the widespread deposition of shallow water carbonates. These carbonates formed a large platform with barrier reef systems which extended from Florida across to central Texas and as far west as Arizona, with additional isolated platforms extending south through Mexico and the Yucatan Peninsula. These carbonate systems flourished for about 25 myr before being drowned by hemipelagic sedimentation in the middle Cenomanian, and can be divided into three supersequences: the Aptian Sligo-Hosston (SH), the Early-middle Albian Glen Rose (GR), and the Late Albian-Early Cenomanian Paluxy-Washita (PW). Using a combination of seismic data, well penetrations, and published outcrop studies, we present the first basin-scale paleogeographic and thickness maps of the GR Supersequence, including remarkably thick evaporite deposits (e.g. Ferry Lake of the northern GOM) that are unique to this carbonate-dominated succession.

In Mexico, Glen Rose carbonates (including the Aurora, Acatita, and Tamaulipas Formations) formed large, isolated carbonate platforms with interior evaporitic lagoons, rising above a deep carbonate shelf. Seismic facies analysis indicates that the Glen Rose is characterized by an aggrading barrier reef along the shelf edge in the northern GoM. This barrier reef was fairly continuous and provided a barrier between shelf sediments and the deep basin; intermittent inter-reef passages provided local pathways for sediments to exit the shelf. The number of these passages varied from east to west, and their absence likely played an important role in the development of restricted, evaporitic environments. The shelf itself is mainly characterized by carbonate mud, drifts of carbonate debris, patch reefs, and anhydrite deposits. Sediment drifts/patch reefs sometimes form low-relief hydrocarbon reservoirs in the eastern GoM (e.g., Sunniland Trend in Florida). Widespread anhydrite deposition is a distinct feature of the Glen Rose shelf, with net thicknesses of anhydrite >2000′ in some Florida wells. The main area of siliciclastic deposition identified in the GR is a wave-dominated delta in southern Mississippi and Louisiana associated with a gap in the barrier reef margin (possibly caused by turbid water inhibiting carbonate growth); no data is available south of the shelf margin here, but it is possible that this system is a source of sand in the basin.

AAPG Datapages/Search and Discovery Article #90260 © 2016 AAPG/SEG International Conference & Exhibition, Cancun, Mexico, September 6-9, 2016