Copyright by Nysha Chaderton 2009 - The University of Texas at ...

K feldspar preservation to slightly greater depths, perhaps, five kilometers (Wilkinson et
al., 2001). These well-established relationships taken in tandem with the field
observations suggest that the Scotland Formation exposed on the island of Barbados has
never been buried much more than five kilometers and possibly less than four kilometers
of burial.
Quartz overgrowths on detrital quartz grains are common in the Scotland
Formation sandstones. Studies of the Moogooloo Sandstone, in Western Australia
showed that these types of overgrowths increased with thermal maturity and less than 1%
of quartz cementation occurred at less than 60˚C (Baker et al., 2000). However, many
quartz overgrowths in this study are broken which suggests that the quartz grains are
recycled and thus the phase of quartz cementation is not related to the diagenesis of this
rock. The lack of quartz cementation that is local to the Scotland Formation suggests that
the rocks were not subject to temperatures < 60˚C.
Deformation bands are tabular structures of finite width that are the result of
strain localization. These features develop in sand and porous sandstone (Aydin, 1978;
Dragantis et al., 2005) and may form during soft sediment deformation or post burial
faulting (Fossen et al., 2007). Deformation bands are often classified based on the
amount of shear offset that they have undergone. In the thin sections from the Scotland
Formation no shear offset has been observed. The deformation features observed in these
samples include grain fracturing, a reduction in grain size and in porosity and an apparent
reduction of volume within the deformation band. Using the kinematic classification
system (Aydin et al., 2006; Fossen et al., 2007), these features would place the Scotland
Formation deformation bands within the class of compactional deformation bands.
Within the mechanical classification these features would be characterized as cataclastic
deformation bands. Cataclastic deformation bands have been found in unconsolidated
marine sand buried less than 50 m (Cashman and Cashman, 2000; Fossen et al., 2007).
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