wAbstract
@Chemical weathering was investigated by collecting samples from
five selected weathering profiles in a high elevation granitic
environment located in Seoul, Korea. The overall changes of chemistry
and mineralogical textures were examined reflecting weathering
degrees of the samples, using polarization microscopy, X-ray diffraction
(XRD), electron probe micro analysis (EPMA), X-ray fluorescence
spectroscopy (XRF), and inductively coupled plasma-mass spectroscopy
(ICP-MS). The chemical distribution in the weathering profiles
shows that few trace elements are slightly immobile, whereas most
major (particularly Ca and Na) and trace elements are mobile from
the beginning of the granite weathering. On the other hand, there
were mineralogical changes initiated from a plagioclase breakdown,
which shows a characteristic circular dissolved pattern caused
by a preferential leaching of Ca cation along grain boundaries
and zoning. The biotite in that region is also supposed to be
sensitive to exterior environmental condition and may be easily
dissolved by acidic percolated water. As a result, it seems that
some rock-forming minerals in the granitic rock located in Seoul
are significantly unstable due to the environmental condition
of acidic rainfall and steep slopes, where they are susceptible
to be dissolved incongruently leading some elements to be highly
depleted.
Keywords: Chemical weathering; Granitic environment; Mineralogical
textures; Trace elementsx
Introduction
Study area
Analytical methods
Results
@Microscopic features of weathered primary minerals
@Behavior of elements
@Behavior of major elements
@Behavior of trace elements
Discussion
Conclusions
Acknowledgments
References