Anderson Ranch Dam and South Fork Boise River Field Trip Road Log

Regrouping stop at Pilot Travel Center Exit 95.

Stop 1: Milepost 102.8, pullout on Right. Discussion of Idavada rhyolite volcanics, Mount Bennett Hills and DanskinMountians.

We leave basalt flows and climb into IdavadaVolcanics - rhyolite. Note outcrop on Right at MP 103.2 - Vitrophere Rhyolite (no stop)

Stop 2: Milepost 7.4 large pullout on Right to look at rhyolitic tuff

Stop 3: Milepost 17.6 , on Right about 1.3 miles past Anderson Dam Road at Windy Gap. Granite of Batholith and Rhyolite of Mt. Bennett Hills.Introduce Dixie town site and mining district. Return to Anderson Dam Road, zero odometer.

Stop 4, Odo 1.9: Note King Mine dump to west, give data on mine output and structure of a mine workings. Relate to Daley Consolidated tunnel and Anderson Drain tunnel.

Stop 5, Odo 2.9: Note borrow pits for Anderson Ranch Dam; walk to canyon rim to admire canyon-filling basalts, point out landslides across canyon.

Stop 6, Odo 3.2 : Pullout on Left. Admire pegmatite dikes and aplites, andesitic dikes in granodiorite matrix.

Stop 7, Odo3.8 Pullout on Right, walk down around corner to flag to admire more dikes.

Stop 8, Odo 4.9 at Dam, toilet. Admire spillway. Give some data on ARD and problems in construction due to lousy rock and multiple dikes.

Stop 9, Odo 5.6: small pull-out on Left shoulder to look back across at left abutment and dikes. Note fire damage and osprey nest. Mention basalt dike at Odo 6.3 creating a small dam and slackwater and river cutting through contact between granite and basalt at Odo 7.3. Also at Odo 7.5 the Anderson's bridge and lower dump of Daley Consolidated Mine (no stops).

Stop 10, Odo 7.9: Reclamation Village, tell story of avalanches.

Stop 11, Odo 11.4: Introduce House Mountain MetasedimentaryOrthogneiss. Note Indian Point at Odo 11.7 (no stop). Mention turn at Cow Creek Bridge.

Odo 13.1 Cow Creek, turn Left.

Stop 12, Odo 14.1: Metasediments and pegmatites. Turn around after this stop.

Odo 15.1, turn Left back onto River Road.

Odo 18.2, Danskin Junction, turn Right.

Stop 13, Odo, 19.8: Pullout on Right. Many dikes here to top - pegmatite, aplite, basalt.

Stop 14, Odo 22.1: Pullout into track on Left to admire Steamboat Rock, which gave name to large basalt flows from Smith Prairie Steamboat shield volcano.

Stop 15, Odo 26.1: Junction with Triland Road. Point out Steamboat Volcano ahead.

Turn Left then Right on Prairie Road

Stop 16, Odo 27.9: Lava Tube from Smith Prairie Volcano to NE.

Turn Left at Long Gulch Road.

Stop 17, Odo 30.9; The Y Store, supplies and restroom.

Stop 18, Odo 36.4: Eroded area in Smith Prairie Basalt (same as Adair Stop 8)

Stop 19, odo 39.5: Admire inverted topography of Steamboat and Smith Prairie Basalts.

Stop 20, Odo 41.2: Overlook of Smith Prairie Basalts in lower canyon.

Stop 21, Odo 42.4: High overlook down SFBR canyon.

Odo 44.7 Willow Creek Trail Head and outhouse.

Stop 22, Odo 53.8: Faulted basalt dike. End of formal trip log.

Return to Interstate 84 via Blacks Creek Road. Optional stop at Bonneville Point for those interested.