HR: 1340h
AN: H43C-1506    [Abstracts]
TI: How can residence time control on weathering rates be distinguished from hydrologic control?
AU: * Mudd, S M
EM: simon.m.mudd@ed.ac.uk
AF: School Of GeoSciences, University of Edinburgh, Grant Institute, The King's Buildings, Edinburgh, EH9 3JW, United Kingdom
AU: Yoo, K
EM: kyoo@udel.ed
AF: University of Delaware Plant and Soil Sciences Department, 531 S. College Av., 152 Townsend Hall, Newark, DE 19716-2170, United States
AU: Sanderman, J
EM: jsandman@nature.berkeley.edu
AF: UC Berkeley, Ecosystem Sciences, 137 Mulford Hall - 3114, Berkeley, CA 94720, United States
AB: Based on laboratory studies, chemical weathering rates in the critical zone (CZ) have been considered to be a function of temperature and the chemistry of CZ pore waters. Because the rate of soil water flow through the critical zone determines, in part, the chemistry of the pore water, this control on chemical weathering rates could be considered hydrologic. More recently, however, several workers have discovered that the age (or residence time) of CZ materials also exerts a strong control on weathering rates. Here we demonstrate how the age of CZ materials varies in space on the catena scale (where erosion rates are changing in time, linking weathering to geomorphic processes) and on the soil profile scale (where weathering fronts propagate downward through CZ materials). We also show how hydrologic controls may be expected to lead to different spatial variations in chemical weathering rates than CZ material age controls, and how these differences can be harnessed to determine which of the two hypothesized controls dominate in eroding landscapes.
DE: 1625 Geomorphology and weathering (0790, 1824, 1825, 1826, 1886)
DE: 1826 Geomorphology: hillslope (1625)
DE: 1865 Soils (0486)
DE: 1886 Weathering (0790, 1625)
SC: Hydrology [H]
MN: 2007 Fall Meeting