G. M. D. Warrlich, D. A. Waltham, and D. W. J. Bosence

Department of Geology, Royal Holloway University of London, Egham, Surrey, TW20 0EX, UK

ABSTRACT: Quantitative 3D Facies and Sealevel History Prediction from Computer Modelling

A 3D stratigraphic forward modelling computer program, CARBONATE 3D, has been developed (Warrlich, 2001). It simulates the evolution of carbonate platform and mixed carbonate-siliciclastic environments by modelling sedimentary processes. The program outputs 3D and map views as well as cross sections.

CARBONATE 3D models the development of carbonate and mixed carbonatesiliciclastic stratigraphies by simulating the following sedimentary processes:

- Carbonate platform margin production dependent on water depth, restriction and sedimentation
- Carbonate platform interior production dependent on water restriction
- Pelagic sediment production and deposition
- Erosion, transport and redeposition of sediment dependent on currents, slope, depth and restriction.
- Subaerial dissolution

The rates of these processes, as well as runtime and sealevel curve, can be altered by the user. In many stratigraphies, however, the available data is insufficient to define these parameters. A way of bracketing them is to obtain a quantitative goodness of fit between simulated stratigraphy and real data and then to vary the parameters to optimise this (inversion).

Inversion was carried out for a depositional sequence from the Late Miocene fringing reef platform at Níjar, Almería Province, SE Spain. Here Middle and Late Miocene strata are deposited on an irregularly eroded Permo-Triassic basement of the Sierra Alhamilla (Betic Internal Zone) and around the dacite dome of El Joyazo. The Middle Miocene sediments are unconformably overlain by several Late Miocene carbonate-clastic depositional sequences that prograde basinward. The last of these sequences is a Messinian Porites Reef Complex that prograded over the dacite dome of El Joyazo, that developed into an atoll. Separated by a major erosional unconformity are deposits of the Terminal Carbonate Complex (TCC), recognised throughout the western Mediterranean. The reef complex and the TCC are not tilted by later tectonic events and hence the original depositional slopes are preserved.

AAPG Search and Discovery Article #90906©2001 AAPG Annual Convention, Denver, Colorado