Red Bluff Granite
* Age: 14 to 16 million years old.
* Formation: Intrusive igneous rock formed from the cooling and solidification of magma deep underground.
* Composition: Primarily composed of quartz, feldspar, and biotite.
* Location: Found in the Red Bluff area near Bend, Oregon.
Thunderbird Rhyolite
* Age: 15 to 20 million years old.
* Formation: Extrusive igneous rock formed from volcanic eruptions.
* Composition: Predominantly rhyolite, a type of volcanic rock with a high silica content.
* Location: Found in the central Oregon Cascades, including the Thunderbird Mountain area.
Relationship:
While they are both igneous rocks in the same geographic region and have similar ages, they have different origins and compositions. Red Bluff granite is an intrusive rock that solidified underground, while Thunderbird Rhyolite is an extrusive rock that erupted onto the surface.
In summary:
* Red Bluff granite and Thunderbird Rhyolite are separate geological formations.
* They are both igneous rocks found in the Cascade Range, but they have different origins, ages, and compositions.
* Red Bluff granite is an intrusive rock, while Thunderbird Rhyolite is an extrusive rock.
