![]() ![]() 71), for example, mapped lava flows in the west-central Sierra Nevada noting contrasts in Neogene and modern canyon slopes, he suggested that “the elevation of the crest of the Sierra Nevada…has been…produced by a simple block-tilting without perceptible warping”-a view that has been subsequently accepted and quantified ( Huber, 1981 Wakabayashi and Sawyer, 2001). Perhaps less well known are 19th-century speculations on the nature of range uplift. Some aspects of this storied history are well known, such as John Muir's early work on Sierran glaciers and glacial erosion ( Muir, 1871, 1911 followed by Matthes, 1929, and Blackwelder, 1931), which initiated our current understanding of the forces that carve Sierran peaks and canyons. Pioneers of Sierran geology have provided a well-constructed platform on which later scientists could build, with the Range of Light illuminating processes as diverse as glaciation, structural geology, petrology, and tectonics. ![]() ![]() What makes the Sierra Nevada mountain range of particular interest is the rich history of geologic studies. Finally, the complete story of the Sierra also cannot be told without the tectonic forces that act on the Sierran crust, which involves the evolution of the San Andreas Fault system and the opening of the Gulf of California. The answers to these questions can be quite different, but are not necessarily independent, as insights from one may lend insight to another. One might also speak to the origin of canyons and peaks formed by erosion as much as uplift, or to the time at which the Sierra's varied present-day ecological zones were established. One might refer to the age and origin of the rocks that form the Sierra Nevada batholith, or instead to the time at which such rocks were uplifted to form the topographic crest of the eastern Sierra. A fundamental question for the conference and themed issue is “How did the Sierra Nevada form?” The question can mean many things to disparate disciplines. 1), since a large number of our Penrose abstracts were oriented to that topic, and because that region is no less a part of the Sierran story than the high peaks themselves. The theme is here expanded to include the Walker Lane ( Fig. This Geosphere themed issue is an outgrowth of our Penrose Conference: Origin and Uplift of the Sierra Nevada, California, which was held in Bridgeport, California, August 16–20, 2010. ![]()
0 Comments
Leave a Reply. |