Weathering of Devonian monzogranites as recorded in the geochemistry of saprolites from the South Mountain Batholith, Nova Scotia, Canada

Authors

  • Ann Marie O'Beirne-Ryan Department of Earth Sciences, Dalhousie University, Halifax, Nova Scotia B3H 3J5 Canada; *Correspnding Author
  • Marcos Zentilli Department of Earth Sciences, Dalhousie University, Halifax, Nova Scotia B3H 3J5 Canada

DOI:

https://doi.org/10.4138/2785

Abstract

Parent mineralogy, paleoenvironment, and subsequent diagenetic and erosional history contribute to the nature of the paleoweathering profiles (saprolites) developed on the South Mountain Batholith. Saprolites of three different ages (pre-Carboniferous, pre-Triassic, and pre-Pleistocene) developed on Devonian monzogranite and exhibit increases in oxidation and hydration and decreases in rare earth elements with increasing weathering. In addition, changes in Ca, Ba, Rb, Zn, Pb, Co, and other elements in the oldest saprolite indicate element mobility during weathering. Re-exposure of these partially weathered profiles at surface in today's acidic and oxygen-rich environment may result in further migration of elements from these saprolites. RÉSUMÉ La minéralogie originelle, le paléoenvironnement, et les antécédents diagénétiques et d'érosion subséquents sont autant de facteurs qui déterminent les profils de paléométéorisation (saprolithes) observés dans le batholithe de South Mountain. Des saprolithes de trois époques différentes (antérieures au Carbonifère, à l'ère triasique, et au Pléistocène) se sont formées sur du monzogranite. On observe une oxydation et une hydratation accrues, une diminution de la présence des éléments du groupe des terres rares, et une météorisation plus grande. De plus, des altérations de Ca, Ba, Rb, Zn, Pb, Co et d'autres éléments dans les saprolithes plus anciens indiquent le caractère meuble des éléments pendant la météorisation. Une nouvelle exposition de ces profils en partie météorisés dans le milieu acide et riche en oxygène d'aujourd'hui pourrait entraîner une autre migration des éléments contenus dans ces saprolithes. [Traduit par la rédaction]

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Published

2006-12-12

How to Cite

O’Beirne-Ryan, A. M., & Zentilli, M. (2006). Weathering of Devonian monzogranites as recorded in the geochemistry of saprolites from the South Mountain Batholith, Nova Scotia, Canada. Atlantic Geoscience, 42(2/3). https://doi.org/10.4138/2785

Issue

Vol. 42 No. 2/3 (2006)

Section

Articles

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