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5
II
Objectives
and
methodology
The first step was to know the characteristics of
the subject to be studied. To do so a description
of the field aspects of the Banded Gneiss
formation was carried out, revising the details of
its cartography, the characteristics of the different
types of lithologies that form part of it, and its
distinctive internal structural features. This
preliminary approach to the studied object was
also applied to the formations that outline the
Banded Gneisses, which are the Eclogite Band
formation to the West and the Cariño Gneiss
formation to the East. This initial approach is
fundamental to deal with further investigations.
The next step was to have a better idea of the
studied objects, through the microscopic features
of the lithologies involved in the Banded Gneisses
(and also the Eclogite Band and the Cariño
Gneisses). To do so petrographic features were
described studying thin-sections of the selected
rock specimens. The first set of thin-sections was
prepared by the author to focus on the formative
aspect of the thesis. These observations allowed
to clarify the different deformative fabrics and the
temporal evolution of the mineral assemblages.
Some microprobe analyses were performed
to accurately identify some elusive-classifying
minerals.