Unformatted text preview: he Piedras-Girardot foldbelt has been a positive area since then, shedding clastic material into
these late Paleogene depocenters, that were being concurrently folded. Only the northern part of the study area
contains evidence for post-Miocene (Fig 2c.), and Quaternary deformation, which is at least partially related to the
latest movements along the Ibagué fault.
Microscopic and mesoscopic strain
Three fabric elements were investigated: 1) cleavage 2) deformed fossils; and 3) microscopic and mesoscopic veins.
Each element provides a partials, and sometimes local story. Together, these elements are used to get a general
picture of the contribution of early, nonrigid body deformation in the Piedras-Girardot foldbelt.
Cleavage is a pervasive, uniform, and prominent outcrop-scale element that trends ENE. Microscopically, cleavage
surfaces show a sutured morphology where thin films (approximately 0.1 mm) of insoluble material are
concentrated. The amount of shortening accommodated by a rock with a 2 cm domain spacing is less than 5 percent....
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- Winter '14
- Plate Tectonics, Northern Andes, Piedras-Girardot foldbelt