|
|
click photo for larger file
Bishop Tuff and Sherwin Till
|
Photographer: Ron Wolf
ID: 0000 0000 1010 1996 (2010-10-21)Copyright © 2010 Ron Wolf
|
|
INFORMATION PROVIDED WITH THE PHOTO
|
date of photo Sep 26, 2010
location
Along Hwy 395, 10 miles north of Bishop (Mono County, California, US)notes This roadcut along U.S. 395 about 10 miles north of Bishop clarified a small geological question - the age of the Sherwin Till. It is almost always difficult to establish the age of glacial events with precision because they don't produce material amenable to radiometric dating. At this site the Bishop Tuff unconformably sits atop a layer of till from Sherwin Stage glaciation. The tuff is a massive unit produced by ash falls and ash flows during a volcanic eruption 760,000 years ago. This contact places an upper boundary on the age of the Sherwin till. Note how the decomposed till supports more vegetation than the tuff. The crest of the hill is covered with a thin layer of gravel from Tahoe Stage glaciation about 50,000 to 100,000 year ago. The vertical structures are clastic dikes, formed when the Tahoe gravel filled extension fractures in the tuff.keywords: geology, earth science, stratigraphy, Pleistocene, Quaternary, Cenozoic, till, tuff, volcanism, glaciation, clastic dike
camera Canon 40D, 24mm, f/14, 1/80 sec.
photo category: Misc. - geology
|
| |
|
Using this photo The thumbnail photo (128x192 pixels) on this page may be freely used for personal or academic purposes without prior permission under the Fair Use provisions of US copyright law as long as the photo is clearly credited with © 2010 Ron Wolf.
For other uses, or if you have questions, contact Ron Wolf RonWolf[AT]EyeOnNature.com. (Replace the [AT] with the @ symbol before sending an email.) |
|
|