A synthetic stratigraphic model of foreland basin development

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 wedgethickening model, erosion and deposition follow a diffusive process, and the lithosphere is compensated elastically. Erosion and deposition are controlled by the transport coefficients r of the diffusion equation. For a range of thrust velocities and lithospheric rigidities, transport coefficients are of order 102-103 m/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.

[1]  G. Karner,et al.  Gravity anomalies and flexure of the lithosphere at mountain ranges , 1983 .

[2]  C. Beaumont,et al.  Orogeny and stratigraphy: Numerical models of the Paleozoic in the eastern interior of North America , 1988 .

[3]  D. Snyder,et al.  Deep crustal structure and flexure of the Arabian Plate Beneath the Zagros collisional mountain belt as inferred from gravity observations , 1986 .

[4]  M. Kirkby,et al.  Hillslope Form and Process , 1972 .

[5]  F. Ahnert.  Functional relationships between denudation, relief, and uplift in large, mid-latitude drainage basins , 1970 .

[6]  J. Suppe,et al.  Mechanics, growth, and erosion of mountain belts , 1988 .

[7]  S. Schumm,et al.  Development of longitudinal profiles of alluvial channels in response to base‐level lowering , 1981 .

[8]  D. Wiltschko,et al.  Timing of Deformation in Overthrust Belt and Foreland of Idaho, Wyoming, and Utah , 1983 .

[9]  D. Nash.  Morphologic Dating of Degraded Normal Fault Scarps , 1980, The Journal of Geology.

[10]  I. Mcdougall,et al.  Denudation rates in northeast Papua from potassium-argon dating of lavas , 1967 .

[11]  James K. Mitchell,et al.  Fundamentals of soil behavior , 1976 .

[12]  Robert E. Wallace,et al.  Modification of wave-cut and faulting-controlled landforms , 1984 .

[13]  L. B. Leopold,et al.  River channel patterns: Braided, meandering, and straight , 1957 .

[14]  J. Suppe,et al.  Mechanics of fold-and-thrust belts and accretionary wedges , 1983 .

[15]  R. Tosdal,et al.  Cenozoic polyphase landscape and tectonic evolution of the Cordillera Occidental, southernmost Peru , 1984 .

[16]  P. Flemings,et al.  Dating Thrust-Fault Activity by Use of Foreland-Basin Strata , 1988 .

[17]  J. Suppe,et al.  Mechanics of fold‐and‐thrust belts and accretionary wedges: Cohesive Coulomb Theory , 1984 .

[18]  B. Isacks.  Uplift of the Central Andean Plateau and bending of the Bolivian orocline , 1988 .

[19]  S. Schumm,et al.  Experimental Study of Channel Patterns , 1972 .

[20]  Y. Jaluria,et al.  An Introduction to Heat Transfer , 1950 .

[21]  P. Heller,et al.  Time of initial thrusting in the Sevier orogenic belt, Idaho-Wyoming and Utah , 1986 .

[22]  D. Turcotte,et al.  A model for erosion, sedimentation, and flexure with application to New Caledonia , 1985 .

[23]  T. Jordan.  Thrust Loads and Foreland Basin Evolution, Cretaceous, Western United States , 1981 .

[24]  D. Nash,et al.  Forms of bluffs degraded for different lengths of time in emmet county, Michigan, U.S.A. , 1980 .

[25]  F. Armstrong,et al.  Tectonic Development of Idaho-Wyoming Thrust Belt , 1965 .

[26]  S. Colman,et al.  Ages Estimated from a Diffusion Equation Model for Scarp Degradation , 1983, Science.

[27]  P. Pinet,et al.  Continental erosion and large‐scale relief , 1988 .

[28]  D. L. Turcotte,et al.  Morphology of a delta prograding by bulk sediment transport , 1985 .

[29]  T. Jordan,et al.  Cenozoic stratigraphy and basin tectonics of the Andes Mountains , 1987 .

[30]  W. Culling,et al.  Analytical Theory of Erosion , 1960, The Journal of Geology.

[31]  J. Stix,et al.  Paleomagnetic Chronology, Fluvial Processes, and Tectonic Implications of the Siwalik Deposits near Chinji Village, Pakistan , 1985, The Journal of Geology.

[32]  W. Culling.  Soil Creep and the Development of Hillside Slopes , 1963, The Journal of Geology.

[33]  K. Furlong,et al.  Tectonic loading and subsidence of intermontane basins: Wyoming foreland province , 1985 .

[34]  C. Beaumont,et al.  Appalachian Thrusting, Lithospheric Flexure, and the Paleozoic Stratigraphy of the Eastern Interior of North-America , 1984 .

[35]  J. Thorne,et al.  Long-term thermo-mechanical properties of the continental lithosphere , 1983, Nature.

[36]  D. Roeder.  Andean-age structure of Eastern Cordillera (Province of La Paz, Bolivia) , 1988 .

[37]  P. Zeitler,et al.  History of Uplift and Relief of the Himalaya During the Past 18 Million Years: Evidence from Fission-Track Ages of Detrital Zircons from Sandstones of the Siwalik Group , 1988 .

[38]  P. Molnar,et al.  Gravity anomalies and flexure of the Brazilian Shield beneath the Bolivian Andes , 1985 .

[39]  J. Rundle,et al.  The Growth of Geological Structures by Repeated Earthquakes 2. Field Examples of Continental Dip‐Slip Faults , 1988 .

[40]  W. Culling.  Theory of Erosion on Soil-Covered Slopes , 1965, The Journal of Geology.

[41]  N. Kusznir,et al.  Dependence of the flexural rigidity of the continental lithosphere on rheology and temperature , 1985, Nature.

[42]  R. Allmendinger,et al.  Paleogeography and Andean structural geometry, northwest Argentina , 1983 .

[43]  L. B. Leopold,et al.  River Channel Patterns , 1970 .