ABSTRACT: Synthetic Foreland Basin Stratigraphy

JOHNSON, DAVID D., and CHRISTOPHER BEAUMONT, Dalhousie University, Halifax, Nova Scotia, Canada

Foreland basin stratigraphy is determined by a competition among the rates of basin controlling processes: the rate of mass accretion to an orogen by thrust tectonics, the rate of mass redistribution by surface processes, the rate of flexural isostatic compensation, and the rate of absolute sea level change. We have constructed a kinematic plan-form foreland basin model to look for stratigraphic signatures that reflect either the dominant influence of one of these basin-controlling processes or the combined effect of several processes.

The foreland basin model links thin-skinned tectonic development of an orogen, lithospheric flexure, mass redistribution by surface processes, and eustasy. The tectonic model uses critical wedge principles to construct a two-sided wedge-shaped orogen. The flexural isostasy model uses either an elastic or a thermally activated linear visco-elastic lithosphere rheology. The surface processes model couples hillslope (mass diffusion) and climate mediated fluvial (mass advection) processes to erode, redistribute, and deposit mass across the orogen, its foreland basin, and peripheral bulge.

Synthetic stratigraphic assemblages are presented that contrast the effects of eustasy, tectonism, and climate on foreland basin stratigraphy. Basin stratigraphy is characterized by sedimentary units bounded by chronostratigraphic horizons, disconformities, and/or unconformities. Sedimentary facies are classified in terms of characteristic model properties of the depositional environment: slopes, river power, and dimensionless numbers (Peclet or Damkohler).

AAPG Search and Discovery Article #91012©1992 AAPG Annual Meeting, Calgary, Alberta, Canada, June 22-25, 1992 (2009)