thumbnail

Solute profiles in soils, weathering gradients and exchange equilibrium/disequilibrium

By:
, , , , , and
DOI: 10.1180/minmag.2008.072.1.149

Links

Abstract

The spatial and temporal changes in hydrology and pore water elemental and 87/86Sr compositions were used to determine contemporary weathering rates in a 65 to 226 ky old soil chronosequence formed from granitic sediments deposited on marine terraces along coastal California. Cl-corrected Na, K and Si increased with depth denoting inputs from the weathering of plagioclase and K-feldspar. Solute 87/86Sr exhibited progressive mixing of sea water-dominated precipitation with inputs from less radiogenic plagioclase. Linear approximations to these weathering gradients were used to determine plagioclase weathering rates of between 0.38 and 8.9 ?? 10-15 moles m-2 s-1. The lack of corresponding weathering gradients for Ca and Sr indicated short-term equilibrium with the clay ion exchange pool which requires periodic resetting by natural perturbations to maintain continuity, in spite of soil composition changes reflecting the effects of long-term weathering. ?? 2008 The Mineralogical Society.

Additional Publication Details

Publication type:
Conference Paper
Publication Subtype:
Conference Paper
Title:
Solute profiles in soils, weathering gradients and exchange equilibrium/disequilibrium
DOI:
10.1180/minmag.2008.072.1.149
Volume
72
Issue:
1
Year Published:
2008
Language:
English
Larger Work Title:
Mineralogical Magazine
First page:
149
Last page:
153