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Probing deep weathering in the Shale Hills Critical Zone Observatory, Pennsylvania (USA) : the hypothesis of nested chemical reaction fronts in the subsurface

Auteur(s) et Affiliation(s)

BRANTLEY, S.L.
Earth and Environmental Systems Inst., Dept. of Geosciences, Pennsylvania State Univ., University Park, Etats-Unis
HOLLERAN, M.E.
Earth and Environmental Systems Inst., Dept. of Geosciences, Pennsylvania State Univ., University Park, Etats-Unis
JIN, L.
Earth and Environmental Systems Inst., Dept. of Geosciences, Pennsylvania State Univ., University Park, Etats-Unis
Dept. of Geological Sciences, Univ. of Texas, El Paso, Etats-Unis
Earth and Environmental Systems Inst., Dept. of Geosciences, Pennsylvania State Univ., University Park, Etats-Unis


Description :
To determine such depths, cuttings of Rose Hill shale were investigated from one borehole from the ridge and four boreholes from the valley at the Susquehanna Shale Hills Observatory (SSHO). It is shown that carbonate depletion coincides with the winter water table observed at ~20 m (ridge) and ~2 m depth (valley). Furthermore, pyrite and carbonate react quickly and many deep reaction fronts for these minerals are described in the literature. The AA. propose that deep transport of O2 initiates weathering at SSHO and many other localities because pyrite commonly oxidizes autocatalytically to acidify porewaters and open porosity. According to this hypothesis, the mineral distributions at SSHO are nested reaction fronts that overprint protolith stratigraphy. The fronts are hypothesized to lie subparallel to the land surface. To understand how reaction fronts record long-term coupling between erosion and weathering will require intensive mapping of the subsurface.


Type de document :
Article de périodique

Source :
Earth surface processes and landforms, issn : 0197-9337, 2013, vol. 38, n°. 11, p. 1280-1298, nombre de pages : 19, Références bibliographiques : 2 p.

Date :
2013

Editeur :
Pays édition : Royaume-Uni, Chichester, Wiley

Langue :
Anglais
Droits :
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