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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cement<strong>at</strong>ion is observed. A number <strong>of</strong> quartz grains are fractured to produce secondary<br />
intragranular porosity.<br />
Sample: ITR 14<br />
This sample was taken from the bed 14 in the measured section labeled ITR-<br />
Inner Turners Hall Ridge (Figure 3.15). Bed 14 has been interpreted to be a channel-<br />
mouth sand lobe. This measured section records 70 m <strong>of</strong> continuous exposure. Sandstone<br />
beds vary from medium- to fine-grained and are thickest <strong>at</strong> the base <strong>of</strong> the section with a<br />
maximum thickness <strong>of</strong> 420 cm.<br />
Mineralogy<br />
<strong>The</strong> quartz content <strong>of</strong> this sample is lower and K feldspar and plagioclase feldspar<br />
are more abundant. A small number <strong>of</strong> lithic fragments are present and they include<br />
altered volcanic rock fragments, argillaceous rock fragments, rare metamorphic rock<br />
fragments and chert. Minor amounts <strong>of</strong> white mica are present and there are minor<br />
amounts <strong>of</strong> pore-filling chlorite and kaolinite. Hem<strong>at</strong>ite cement<strong>at</strong>ion has completely<br />
occluded porosity in some cases and blocked pore thro<strong>at</strong>s in others (Figure 3.17). Quartz<br />
overgrowths are present, but broken. No other quartz cement<strong>at</strong>ion is observed. Some<br />
organic m<strong>at</strong>ter is present in this sample.<br />
Sample: CMRA<br />
This sample was taken from the first bed in the measured section labeled CMR-<br />
Chalky Mount Ridge section A (Figure 3.18). This measured section records almost 60 m<br />
<strong>of</strong> a stacked channel-levee sequence. <strong>The</strong> sample was taken from the upper portion <strong>of</strong> a 3<br />
m thick bed th<strong>at</strong> ranges from gravel overlying an erosive base and fines upward to a<br />
medium-grained sand. <strong>The</strong> sample was taken from the middle <strong>of</strong> a bed th<strong>at</strong> was<br />
interpreted to be a channel-fill deposit<br />
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