New evidence supporting the Silgara formation' split-off and proposal of a new stratigraphic framework for the metamorphic basement of the Santander Massif (Colombian Eastern Cordillera)

Abstract

The latest geochronological studies carried out in the Silgara Formation (an original name given to a group of schist and phyllites outcropping southwestern Santander Massif), has provided the basis for proposing this formation's split-off in the following units: Silgara Schist s.s., Chicamocha Schist and San Pedro Phyllites. These units are characterized by its different metamorphic lithologies and by its different protolith deposition' ages. In the context of the aforementioned ideas, the current work aims to provide new evidences supporting the referred proposal concerning the Silgara Formation' split-off, based on detrital zircons isotopic analysis from the already mentioned new three metamorphic units and on some whole rock geochemistry analysis as well. Likewise, based on the accumulated geological information, a new stratigraphic framework for the Santander Massif' metamorphic basement is here proposed.