Mineralization in the
Eastern Kumaon Himalaya appears to have made no distinction with regard to the
stratigraphic horizon, lithology, mineralogy or age of the host rocks. It
occurs in virtually all rock formations throughout the district.
is, however, a significant association of known mineral deposits in space. They
occur in clusters and are confined to known fracture systems, or lineaments
identified on the basis of various criteria and through processing of
multispectral satellite data.
appears to be a tectonic and structural control on the main elements of
metallogeny. Linear zones of wallrock alteration were developed by hot fluids
ascending and reacting with hostrocks along deep fracture systems.
is a conspicuous zone of altered wallrock overlying the sulfide orebody at
Barigaon near Askot. The alteration mineral assemblages in the sheared, fine
grained, schistose host rocks consist predominantly of sericite, chlorite,
feldspars and clays.
spectral signatures of the altered zone of Askot were characterized by a
statistical analysis of hyperspectral data provided by the Advanced Spaceborne
Thermal Emission and Reflection Radiometer on board the TERRA satellite launched
in December 1999 as part of NASA's Earth Observing System
on this characterization, zones of similarly altered wallrock were identified
throughout the district by a supervised classification of Landsat ETM+ data.
About one hundred localities, where similar alteration is prevalent, have been
identified. Many of these are small occurrences, but at least thirty of them
are sizeable and therefore merit further exploration.
rock formations throughout the district are marked by a high density of
lineaments. These have been identified, mapped and analyzed by processing of
Landsat ETM+ data. The rocks are dislocated by a high density, but just a few
sets of fractures. The dominant lineament trends are WNW-ESE and NNE-SSW.
mineral occurrences and wallrock alteration zones identified through satellite
data processing trend in a WNW-ESE to NW-SE direction. Orebodies, viz., the
ones at Askot and Rain Agar, also trend in this direction, suggesting a strong
analysis of lineaments, altered zones and known mineral occurrence in the
Eastern Kumaon region suggests a strong lineament control over metallogeny.
Digital terrain modeling of the region suggests that lineaments have played a
significant role in the geomorphic evolution of the area.
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