Thursday, October 4, 2012

Highlights – Quartz Sand Cementation

Cementation in sandstone is spatially variable.  McBride documents cementation patterns in the Eureka Sandstone, a classic early Paleozoic quartz arenite sand sheet that was deposited across much of the western United States, and investigates why in some places it is friable and others is referred to as a “quartzite,” even in the same outcrop.  The results of the study illustrate how heterogeneous early quartz cementation leads to heterogeneous compaction; the culprit is interpreted to be related to the distribution of an authigenic illite coating on some grains that acted to retard quartz cementation.  The data indicate how cementation by quartz is not always a homogeneous process and quartzite and friable sandstones can exist in close proximity.

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