Tag Archives: Sedimentary Rocks

Geopic of the week: well exposed fault


The picture above shows a normal fault exposed in an old railroad grade just north of Greers Ferry lake in the Ozark Mountains of central Arkansas.  Two different lithologies are juxtaposed against one another: siltstone on the left and sandstone on the right.   Exposures such as this one are relatively rare in the Ozarks where most of the bedrock is covered by loose sediment and vegetation.

This fault is extensive and roughly parallels the northern portion of Greers Ferry lake.  The fault gives the northern portion of the lake its linear shape (see below).

Greers Ferry lake