A synthetic stratigraphic model of foreland basin development

Abstract

The processes of erosion and deposition must be included in foreland basin models to predict correctly basin geometry and stratigraphy. We present a synthetic stratigraphic model of the development of nonmarine foreland basins that predicts progressive geometry, topography, and facies patterns. In the model, steady crustal shortening occurs according to a wedge‐thickening model, erosion and deposition follow a diffusive process, and the lithosphere is compensated elastically. Erosion and deposition are controlled by the transport coefficients κ of the diffusion equation. For a range of thrust velocities and lithospheric rigidities, transport coefficients are of order 102–103 m2/yr in the mountain belt; these values are much higher than those derived from the study of scarp degradation. In the sedimentary basin, transport coefficients of order 104 m2/yr are appropriate and are compatible with previous studies of fluvial and deltaic deposition. Rapid thrusting results in a narrow underfilled basin, while slow thrusting results in a wide overfilled basin. In addition, by varying the erosional and depositional transport coefficients while holding other parameters constant, we generate both overfilled and underfilled basins. These results suggest that changes in the rate of thrust loading, the climate, or the source rock lithology can create stratigraphic signatures that have been interpreted to record viscoelastic relaxation of the lithosphere. Clearly, to understand either the long‐term behavior of the lithosphere or to interpret orogenic history from preserved foreland strata, the manner in which a basin was filled must be considered. We apply the model to the evolution of the modern sub‐Andean foreland and find that an erosional transport coefficient of 3000 m2/yr and a depositional transport coefficient of 20,000 m2/yr successfully predict the observed basin geometry.

Clinoform development by advection‐diffusion of suspended sediment: Modeling and comparison to natural systems

“…Diffusion-based models of clinoform formation assume that sediment transport is a function of topographic slope [Kenyon and Turcotte, 1985;Flemings and Jordan, 1989;Jordan and Flemings, 1991;Thorne, 1995]. These models result in a clinoform geometry that resembles that in natural systems, but implicit in these models is the interpretation that sediment transport is a function of slope-driven processes, such as creep, sliding, and slumping [e.g., Kenyon and Turcotte, 1985].…”

“…In addition, slope-driven mass-transport processes, by removing sediment from the steeper foreset slopes, may act as a retreating agent, counteracting the effects of clinoform progradation [Ross et al, 1994;Pratson and Coakley, 1996;Pratson and Haxby, 1996]. Another shortcoming of slope-driven diffusion approaches is that only concave-up profiles are produced, which results in an active clinoform break that is coincident with the shoreline [Flemings and Jordan, 1989;Kenyon and Turcotte, 1985]. This shortcoming has been circumvented by introducing a water-depth dependent diffusion coefficient of Kaufman et al [ 1991].…”

The non-uniformity of fossil preservation

“…This history starts with rapid crustal thickening in the load and therefore rapid subsidence in the basin, followed by slower thickening and erosion of the load, leading to little or no subsidence and rapid sedimentation. This is followed finally by erosion of the load, with final uplift and filling of the basin [35]. As a result, foreland basins typically have two phases, an early phase of rapid deepening that records rapid crustal thickening and loading, and a later phase of net shallowing that records the erosion of the load and a decrease in the rate of subsidence [36].…”

Tectonic Implications of Stratigraphy Architecture in Distal Part of Foreland Basin, Southwestern Taiwan

“…Lately, time lag between erosion in the mountain side and deposition in the basin has been put into consideration when investigating and simulating a model of foreland basin sequences [38,39,40,41,42,43]. In response to each episode of active thrust faulting, newly formed foreland basin by rapid subsidence would not be filled up with sediments in the early time; therefore, according to the theoretical model [4], the sediment-starved basin would be deep and narrow and accumulate deep water sediments in an " underfilled" state [39,40,41]. In the following stage, the orogenic wedge began to uplift and the consequential erosion provided the sediments to fill up the basin when the large-scale thrust faulting wane.…”

“…From that moment, the basin gradually becomes widened and shallow and step into the " overfilled" state characterized by shallow water deposits [44]. Generally speaking, in response to each episode of large-scale thrust faulting in the orogenic belt, the subsidence rate in a basin, which is related to the rates of advancement of the front of orogenic belt and change of orogenic wedge morphology, the sediment supply rate and the global sea level change rate would all together affect the tectonostratigraphic architecture, time-spatial distribution of lithofacies and the superimposed unconformities in the basin [39,40,41,42,45,46,47,48,49]. Some models suggest that timing of rapid subsidence at different locations in a foreland basin has different tectonic implication [40,41,43].…”