1. Priest River Metamorphic Core Complex Field Trip
Geology Spring 2009

2. Quartz-feldspar boudin in Hauser Lake Gneiss

3. Strongly foliated & lineated, and mylonitized Hauser Lake the Newman Lake “Y”. West is to the left.

4. Folded Hauser Lake Gneiss, Hauser Lake, Idaho

5. Dipslope (foreground) on strongly lineated and mylonitized granite, Round Mountain, ID. View is to the NE and the Purcell Trench. Here the Purcell Trench detachment fault dips to the NE under the Purcell Trench valley. Mountains to the east across the valley are weakly metamorphosed Belt Supergroup.

6. S-C mylonites in the granite at Round Mtn.; top is to the east (right).

7. Checking out the Hauser Lk
Checking out the Hauser Lk. Gneiss below the Spokane Dome mylonite zone; Spirit Lk., ID.

8. Garnet amphibolite in Hauser Lk. Gneiss, Priest River, ID
Garnet amphibolite in Hauser Lk. Gneiss, Priest River, ID. This amphibolite is interpreted as a metamorphosed mafic sill in the Hauser Lk. Gneiss (formerly Prichard Fm.).

9. Archean-aged (2.651 BY) migmatitic orthogneiss, Pend Oreille Gneiss, is the pre-Belt basement and the oldest rocks in ID north of the Snake River Plain.

10. Laclede Augen Gneiss (1. 576 BY) along Hwy. 2, Laclede, ID
Laclede Augen Gneiss (1.576 BY) along Hwy. 2, Laclede, ID. This beautiful orthogneiss occurs as a tectonic “sliver” within the Hauser Lake gneiss.

11. Folded, sheared, and boudinage-like structure to amphibolite (mafic dikes) in the Laclede Augen Gneiss, Hwy. 2, ID. Pull-apart & rotation of amphibolite blocks above, folding at ground level.