1 March 2010
So, those sediments we saw yesterday? They’re faulted in the area around the Crucifix Site.
In normal faults, the upper block moves downward with respect to the lower block. They are typical of extensional tectonic settings.
The normal faults exposed at the Crucifix Site are a lot like those we observe a kilometer to the north, up on the Volcanic Tableland. The difference is that the Volcanic Tableland faults disrupt the stiff upper layer of the Bishop Tuff (“Ig2”), while these Crucifix faults are smaller and more subtle — cutting through weaker stuff.