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Rogue River


Natural History

Flora and Fauna of the Rogue Canyon

The ecosystem of the Klamath Mountains and the Rogue canyon is a complex mosaic of plant communities that provide homes for a wide variety of wildlife. Geologic complexity and a long history of relatively mild climate have created a haven for a diverse mix of plant and animal species, some of which represent prehistoric environments that have long since disappeared elsewhere.

Among the tree species found along the river are California black oak, canyon live oak, Oregon white oak, bay, big leaf maple, madrone, Douglas fir, and red alder. A wide variety of flowering plants bloom in the spring, including azalea, the fragrant white blooms for which the rapid Blossom Bar is named.

An abundance of birds and other wildlife make the Rogue canyon their home. Osprey, bald eagles, hawks, water ouzels, heron, and a variety of songbirds are seen. Raccoons, river otters, deer, mink, black bear, bobcat and other mammals are here, too.

Steelhead, Chinook and Coho salmon either live in the river year-round or migrate up-river to spawn. (Sadly, in recent years their numbers have been decreasing, due to the combined effects of overfishing, damming the river’s upstream reaches, and increased situation due to logging, farming, and urbanization.) Also found in the Rogue are sturgeon, bluegill, smallmouth bass, catfish, sculpin, and shad. Trout are native to the larger tributaries, such as Big Windy, Kelsey, and Missouri Creeks.

Geology of the Rogue River Region

The Rogue River country, which is a part of the larger Klamath Mountain Province, is one of the most structurally complex regions in Oregon. This complexity is due to the region’s position at the edge of the continent, and the role that plate tectonics played in the evolution of the area.

150 million years ago (during the Jurassic period) rocks were being deposited along an ancestral North American coastline. Simultaneously, movement of the Earth’s crust caused the floor of the Pacific ocean to begin to move towards the mainland. The Pacific and North American plates collided. Volcanoes generated by the collision developed into an offshore island chain. As this collision continued, pieces of the sea floor were pushed up against the mainland. The Klamath Mountains are built both of fire and water. Today we see evidence of volcanism, and one can find ancient sea floor, which once was hidden under three miles of water, now perched two to three thousand feet above sea level.

Oregon’s portion of the Klamath Mountains was originally situated 50 miles south of where they are now. About 100 million years ago they broke loose from the mainland along a fault which slowly moved them into their present position. Finally, beginning 50 million years ago, the area was uplifted and distorted, then eroded to create the rugged topography we see today.

Rogue Geology at River Level

In the vicinity of Galice the Galice formation is exposed in the river bed and along the banks. Elsewhere the Galice formation is in excess of 15,000 feet thick, but here we see only a thin slice of that. Rocks of the Galice include mudstones and some black shales. In addition to the mudstones, the Galice bears a thick section of volcanic rocks, some of which, unlike the mudstone and shale, are relatively coarse-grained and very resistant to erosion. In places the Galice mudstones and shales have been altered by heat and pressure to form hard slate.

As the river winds northward out of Galice we very quickly pass from the Galice Formation into the older rocks of the Rogue formation. These rocks originated as submarine lava and ash flows around a chain of volcanic islands. Most of these rocks have been altered by heat and pressure since their formation to create the hard, resistant rocks we see today. Rainie Falls exists because the extra-hard rock found there is resistant to the river’s erosion. Rainie is a good place to view banded metamorphic rock called gneiss, as well as veins of a pale, pea green mineral called epidote.

Landslides are common in the Rogue River canyon. One slide, which occurred near Whiskey Creek in the late 1800’s, dammed the river for a time and backed water 15 miles upstream to Hellgate.

Down river near Tyee Rapid the Rogue formation is replaced by the Dothan formation, which dominates the next 20 miles of river. This formation is composed mostly of sandstone, with some siltstone and mudstone also present. In places along the river these rocks have been warped into tightly bunched folds by the forces that created the Klamath Mountains.

At Horseshoe Bend the river begins a dramatic detour around a hard, quartz-rich wall of rock that temporarily deflects the river from its course.

The change from Dothan back to the Rogue Formation rocks occurs just below China Bar. Less than a mile downstream the river bends sharply to the left and follows an ancient fault line through Mule Creek Canyon. Here Dothan formation rocks comprise the left (east) wall and Rogue formation rocks the right. During the 1964 flood the river level was 80 feet higher here than it is at normal summer flows.

At Blossom Bar, the river’s most legendary rapid, evidence of the power of flowing water is a dramatic sight. The boulders — which create the rapid’s channels, waves and obstacles — were carried down tiny Blossom Bar Creek, from a mile or more upstream, during a flood on that creek.

Below Tate Creek the Rogue formation gives way to the Flournoy formation. These marine rocks are evenly bedded layers of sandstone and siltstone, as well as conglomerates, which create the unusual and striking formations seen near Flora Dell Creek. At 50 million years old this is the youngest geologic formation along the river.

 

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