Roadside Geology of Northern and Central California (Roadside Geology Series)
Format: PDF / Kindle (mobi) / ePub
California s geology makes headlines when faults shift, volcanoes puff steam, and coastal bluffs fall into the sea. The latest edition of this popular book explores the state s recent rumblings and tremulous past with the aid of full color illustrations. Spectacular photographs showcase multihued rock, from red chert and green serpentinite to blue schist and gray granite. The color geologic road maps, based on the 2010 Geologic Map of California, are detailed and easy to read. The geologic information, particularly for the Klamath Mountains, Modoc Plateau, and northern Sierra Nevada, has been updated to reflect the more recent geologic understanding of these complex areas. For your next road trip, replace your tattered, dog-eared copy of the old edition with this gorgeous new volume.
much snow out of the clouds that little remains for the Carson Range. That rain shadow developed before the ice ages because the Carson Range shows no sign of glaciation. Its peaks are full and rounded, not craggy and jagged like those of the heavily glaciated high Sierra. Glaciation Imagine huge glaciers glittering in the summer sun all along the west side of the lake and rising as a nearly continuous wall of white to the high crest of the Sierra Nevada. Glacial moraines faithfully record the
more dramatic. The difference is in the fractures. All rocks of any kind contain fractures, which typically come in several parallel sets. The granite in Yosemite Park contains strongly developed sets of vertical fractures. Glaciers erode bedrock mostly by freezing fast to it, then plucking out the blocks between the fractures as the ice moves downslope. That explains why so much of the Yosemite valleyscape follows vertical fracture sets in the granite. The straight valleys follow them, as do
the oceanic trench into the earth's mantle. A small proportion, generally just a few percent, of the oceanic crust shears off the descending slab and into the mass of sediments accumu lating in the trench to become ophiolites. The Coast Range is full of them. Watch for their darkly greenish or black pillow basalts and occasional outcrops of dark peridotite, more or less altered to greenish serpentinites. Watch as you drive through the Coast Range for those strange patches of ground where the
ocean floor that were stuffed into the Franciscan trench. The Coast Range ophiolite is the oceanic crust that was on the east side of the trench, not sinking. Some of the Franciscan rocks were jammed against it, some dragged under it. The base of the serpentinite that sepa rates the Coast Range ophiolite from the Franciscan complex is the surface along which the sinking ocean floor sank, the former plate boundary. Most of the rocks between the Coast Range ophiolite and the coast belong to the
the south. The bounding faults bend around to the south at the east end of the basin to become parallel to the San Andreas fault. (gQ) COAST RANGE Any thick accumulation of muddy sediments deposited in seawater is a likely source of crude oil. The Eel River basin looks especially tempting because apparently similar basins in the southern California Coast Range have produced enormous quantities of oil. Drilling in the Eel River basin has revealed precious little petroleum in any form, and hope