Copyright by Nysha Chaderton 2009 - The University of Texas at ...
Copyright by Nysha Chaderton 2009 - The University of Texas at ...
Copyright by Nysha Chaderton 2009 - The University of Texas at ...
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Mineralogy<br />
This sample is domin<strong>at</strong>ed <strong>by</strong> common quartz and although K feldspar and<br />
plagioclase feldspar are present in small quantities, no accessory minerals are observed.<br />
Hem<strong>at</strong>ite cement is present in gre<strong>at</strong>er quantities than in WRA 16 (Figure 3.11). Quartz<br />
grains are extremely fractured and secondary intragranular porosity is a significant<br />
portion <strong>of</strong> overall porosity (Figure 3.14). As in the sample labeled WRA 16, fractured<br />
quartz is dominant. No quartz cement has formed on fresh, clean fractured surfaces.<br />
Sample: ITR 9<br />
This sample was taken from bed 9 in the measured section labeled ITR- Inner<br />
Turners Hall Ridge (Figure 3.15). <strong>The</strong> sample was taken from a bed th<strong>at</strong> has been<br />
interpreted to be a channel-mouth sand lobe. This measured section records 70 m <strong>of</strong><br />
continuous exposure. Sandstone beds vary from medium- to fine-grained and are thickest<br />
<strong>at</strong> the base <strong>of</strong> the section with a maximum thickness <strong>of</strong> 420 cm. Sand beds are capped<br />
with ripple-lamin<strong>at</strong>ed, fine-grained sands and silts. Minor loading structures and planar<br />
lamin<strong>at</strong>ion is present through out the section. No coarse-grained sand or conglomer<strong>at</strong>e<br />
component and no scoured bases were observed. This outcrop was interpreted to be a<br />
portion <strong>of</strong> a channel-mouth lobe.<br />
Mineralogy<br />
<strong>The</strong> quartz content <strong>of</strong> this sample is lower and K feldspar and plagioclase<br />
feldspar are more abundant (Figure 3.16). A small number <strong>of</strong> lithic fragments are present<br />
and they include altered volcanic rock fragments, argillaceous rock fragments, rare<br />
metamorphic rock fragments and chert. Minor amounts <strong>of</strong> biotite and white mica are<br />
present and the most abundant cement is hem<strong>at</strong>ite with minor amounts <strong>of</strong> pore-filling<br />
chlorite and kaolinite. Quartz overgrowths are present, but broken. No other quartz<br />
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