Stop
#4
---Inclusions---
This stop is located southwest of the
volcanic dome. (Google Earth)
An inclusion of the coarse-grained Cretaceous Green Valley Tonalite enclosed within a matrix of the gray fine-grained volcanic unit. The surfaces of the fine-grained volcanics are gray when fresher and orange-brown when weathered. What does the inclusion data tell us about the relative age of the rocks?
Inclusion
of the coarse-grained tonalite enclosed within the gray fine-grained andesite
volcanic unit. Note: This outcrop
slumped off the hillside in about 2008 and is no longer there.
Going from Stop 4 to the top of the volcanic dome at Stop 5.
There are small exposures of tonalite near the bottom of the hill, as
you progress further towards the top, there is a contact between the tonalite
(redish orange) and the volcanic unit (gray with green lichen), then it’s the
volcanic unit all the way to the top.
Contact between tonalite and the volcanic
unit, notice the green lichen, they like to grow on the volcanics and not on the
tonalite.
The volcanic unit along the trail