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

COMPARISON WITH PREVIOUS WORK
Punch (2004) and Kasper (1985) classified the Scotland Formation sandstones as
moderately-to-poorly sorted. In this study, however, grains that had been completely
fractured apart, but appeared to have been part of a single, larger grain were counted as
one grain. This approach possibly explains why only two of the samples in my study
exhibit poor sorting. Samples WRA 16 and WRB 8 (Figures 12 and 14) have a large
number of fractured grains and it is unclear how many grains produced the fragments.
Punch’s (2004) samples when plotted on a QFL diagram range from quartz
arenites to subarkoses (Figure 3.21). Kasper and Larue’s (1986) samples ranged from
quartz arenites, to sublitharenites with some sub arkoses (Figure 3.22).
Punch (2004) concluded that formation fluids caused the dissolution of some
feldspars in the samples. She determined that burial had not been deep or long enough for
dissolution of all of the feldspars to occur. Quartz overgrowths found on clean surfaces
void of clay rims were recorded as quartz cement.
Kasper and Larue (1986) noted the abraded quartz overgrowths that are indicative
of reworked sedimentary source rocks and recorded that feldspars were rare in the
samples they examined. Both Punch’s 2004 work and this study (Figure 2.23) observed
feldspar in greater amounts.
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