Equation for compaction of paleosols due to burial

Abstract

Existing empirically derived compaction curves for marine sediments fail to estimate the compaction of paleosols, flood-plain sediments, and peats as indicated by deformation of clastic dikes, dinosaur footprints, and sandstone paleochannels. Yet compaction estimates are vital to reconstructing paleoclimate and geochemical profiles of paleosols, to modeling sediment accumulation rates of nonmarine rocks, and to tectonic flexural modeling of molasse facies. This paper presents a compaction equation and physically derived constants that make geologically realistic estimates of compaction of paleosols and other nonmarine sediments. A protocol for the application of the equation is suggested that would allow the following equation to solve for burial compaction ( C as a fraction of original thickness) given depth of burial ( D in km) as: > C = − S i/[( F / e D k) − 1]. This equation can be applied to nonmarine sedimentary rocks or paleosols given appropriate empirical data on the physical constants in the equation, such as initial solidity ( S i), initial porosity ( F ), and the corresponding curve-fitting constant (k). Data on physical constants useful for this equation are compiled here for a range of paleosol and nonmarine sediment types.