Abstract
Different minerals characterize the three fractions in the different weathering zones. Halloysite in the clay fraction especially in the α and γ zones is due to a physical comminution of silt‐sized tubes. Strong peaks for halloysite (XRD) in the silt and sand fractions in these zones is shown (SEM) to be from partly altered feldspar fragments. Gibbsite is present mainly in the fine‐silt size and its presence in the sand in the α zone is due to cementation and aggregate formation. Aggregation of kaolinite also results in its being present in the silt and sand fractions.Estimates of the minerals in the three fractions are shown diagramatically as depth functions. XRD diffractograms of the three fractions and TEM micrographs of the clay fraction are also presented. It is concluded that the morphologically identified weathering zones also differ in their mineralogical properties.
Funding Information
  • National Science Foundation

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