Denudation, vertical crustal movements and sedimentary basin infill

Abstract

Zusammenfassung AbstractDenudation and vertical crustal movements are linked through the isostatic equation for conservation of lithospheric mass. Recent empirical results from a wide range of sources are presented on the rates of these processes. Denudation alone can cause non-tectonic (isostatic) surface uplift of the right magnitude predicted by theory. A case is made, following Ahnert, for a single linear relationship (although with much scatter) between denudation rate and mean drainage basin relief for large basins. Some recent determinations of denudational time constants have neglected to include tectonic and isostatic terms which oppose the reduction of relief by denudation. Application of diffusional transport models to determine the rate of sediment deposition are severely limited by inherent one-dimensionality and neglect of suspended and washload contributions. Basin infill sequences may be used to determine past sediment transfer coefficients from a hinterland, but problems arise in the apportionment of the various hinterland fluxes that occur in ~>real-worl&( three dimensional basins. Sediment yields in smaller half-gra-

The Los Llantenes Formation in the Precordillera of Jagüe (La Rioja Province) and the recognition of a rifting stage in the early evolution of the late Paleozoic basins in western Argentina.

“…Estas características sugieren un marco tectónico particionado, capaz de generar relieves importantes (Leeder, 1991(Leeder, , 1995, drenajes localizados (Leeder et al, 1988;Leeder y Jackson, 1993;Jackson y Leeder, 1994) y depocentros profundos a partir de sistemas con bloques rotados, como ocurre en ambientes extensionales (Schlische, 1993;Prosser, 1993;Gawthorpe y Leeder, 2000).…”

Three-Dimensional Growth of Flexural Slip Fault-Bend and Fault-Propagation Folds and Their Geomorphic Expression

“…The model is not appropriate for transport-limited fluvial systems that are an important component of many larger catchments. We consider that the underlying lithologies being deformed and eroded are uniform, rather than deal with the effects of progressive unroofing of a stratigraphic sequence, as such there are no temporal variations in K, m, or n. In order to model hillslope processes, a simple three-dimensional linear diffusion equation is used, where the sediment flux is assumed to be proportional to local slope and directed down slope [99,[101][102][103]. It has also been suggested that non-linear diffusion models are perhaps more appropriate for modelling hillslope evolution particularly when landsliding becomes an important process [104].…”

Tracing tectonic deformation using the sedimentary record: an overview

“…Hovius & Leeder (1998) and Leeder (1999) note that, more than any other issue in basin research, there is a need to explore the consequences of temporal and spatial changes in water and sediment supply and to intersect time series of these variables with other basin-defining variables such as basin subsidence rate, sea-and lakelevel change, catchment uplift rate and climate. Sediment budget or mass-balance methods aim at calculating the volumes of eroded sediment (Leeder 1991) and can be used, in conjunction with other information (for example, catchment area size), to calculate the average erosion (Einsele et al 1996) or discharge rates (Kuhlemann et al 2001). While there have been a number of studies done in this area (see Burbank & Pinter 1999 for details), there is still a lack of understanding of the controls on sediment budget within a basin.…”