Paleosols in sedimentary rocks and their application in sequence stratigraphy
Speaker: Tsun You Pan
Abstract
A paleosols, which exposed most commonly in alluvial strata, is a soil that formed on a landscape of the past. Paleosols can be classified according to deposition, and erosion rate of pedogenesis: if erosion was insignificant and sedimentation was rapid and unsteady, weakly-developed paleosol formed. In contrast, if sedimentation was steady, well-developed paleosol formed. Both autogenic and allogenic processes can
influence the forming of paleosols.
Paleosols are also helpful in stratigraphic studies. In the paleosol-bearing alluvial strata exposed along Dawson Creek, U.S.A., the section can be divided into 49 fining-upward fluvial aggradaional cycles (FACs), 6 fluvial aggradaional cycles sets (FAC sets), and 4 sequences. The least mature and most poorly-drain paleosols were found in transgressive-equivalent (TE) strata, whereas the mature and well-drain paleosols were found in highstand- to falling-stage-equivalent (HFE) strata. Sequence boundaries are placed at the sharp inflection between thining and thickening FACs.
Reference
Atchley, S. C., Nordt, L. C., and Dworkin, S. I., 2004, Eustatic control on alluvial sequence stratigraphy: a possible example from the Cretaceous-Tertiary transition of the Tornillo basin, Big Bend National Park, west Taxas, U.S.A. Journal of Sedimentary Research, v. 74, No. 3, p. 391-404
Kraus, M. J., 1999, Paleosols in clastic sedimentary rocks: their geologic applications. Earth-Science Reviews, v. 47, p. 41-70