Clays and Clay Minerals, Vol. 54, No. 6, 721–736, 2006.
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Authors
Simas, Felipe N. B.
Schaefer, Carlos Ernesto G. R.
Melo, Vander F.
Guerra, Marcelo B. B.
Saunders, Martin
Gilkes, Robert J.
Issue Date
2006-11
Type
Article
Language
en_US
Keywords
Periodicals , Geology , Allophane , Clay Minerals , Cryosols , Maritime Antarctica , Ornithogenesis , Phosphate , Soils , X-ray Amorphous Phases
Alternative Title
Clay-Sized Minerals in Permafrost-affected Soils (Cryosols) from King George Island, Antarctica
Abstract
Cryosols from Maritime Antarctica have been less studied than soils from continental areas of Antarctica. In this work X-ray diffraction, difference X-ray diffraction, differential thermal analysis, thermogravimetry, transmission electron microscopy/energy dispersive spectroscopy and selective chemical dissolution were used to characterize the clay fraction of basaltic, acid sulfate and ornithogenic Cryosols from ice-free areas of Admiralty Bay, King George Island. Non-crystalline phases are important soil components and reach >75% of the clay fraction for some ornithogenic soils. Randomly interstratified smectite-hydroxy-Al-interlayered smectite is the main clay mineral of basaltic soils. Kaolinite, chlorite and regularly interstratified illite-smectite predominate in acid sulfate soils. Jarosite is also an important component of the clay fraction in these soils. Crystalline Al and Fe phosphates occur in the clay at sites directly affected by penguin activity and the chemical characteristics of these ornithogenic sites are controlled by highly reactive, non-crystalline Al, Si, Fe and P phases. Chemical weathering is an active process in Cryosols in Maritime Antarctica and is enhanced by the presence of sulfides for some parent materials, and faunal activity.
Description
Citation
Clays and Clay Minerals, Vol. 54, No. 6, 721–736, 2006.
Publisher
The Clay Minerals Society
License
Copyright © 2006-2018.