Mountney, Nigel P.1
(1) Keele University, Keele, United Kingdom
ABSTRACT: Eolian Facies Models
Although eolian facies models have been developed since the 1970's, only recently have they become sufficiently sophisticated to enable the effects of external climatic and tectonic controls to be expressed in terms of resultant facies architecture. By adopting a joint conceptual and process-based approach, the response of eolian systems to changes in controlling parameters such as sediment supply, sediment availability, water table and wind regime is now well understood. Dynamic models are able to account for spatial and temporal variations in these controlling parameters and predict likely stratigraphic responses. Large-scale, quantitative stratigraphic data sets from outcrop are being applied to unequivocally demonstrate relationships between preserved eolian architecture and original bedform morphology and migratory behavior.
In dry eolian systems, the key to developing predictive models has been an appreciation of the paleoenvironmental significance of the 3D geometry and hierarchical nature of bounding surfaces, which has enabled the products of allocyclic control be discerned from the complex mechanics of autocyclic bedform behavior. In wet eolian systems, subtle variations in interdune architecture provide the basis for a spectrum of predictive models that explain preserved eolian architecture in terms of interactions between water table level, sediment availability, dune size and dune migration rate, parameters which in turn are a function of sediment distribution pathways, climate and basin setting.
The development of eolian facies models remains important for hydrocarbon exploration, particularly in mature provinces, where good well control allows the employment of sophisticated models in the search for small plays based on subtle stratigraphic traps.
AAPG Search and Discovery Article #90026©2004 AAPG Annual Meeting, Dallas, Texas, April 18-21, 2004.