It's our tendency to view the Earth as unchanging and static. But here engraved upon the face of this mountain rock is a story of change. The dark mountain rock is Pinto gniess (pronounced nice). The lighter color rock is granite- monzogranite. The granite crystallized from magma deep within the Earth, which forced its way into the gneiss 85 million years ago. Here, where the two rocks touch, marks the edge of the magma chamber- the contact zone.
The granite, over millions of years, broke through the surface of the ground by mountain uplifting, underground chemical weathering, and finally, surface erosion. Now exposed, the granite reveals to us eons of geologic story.
Surface erosion exposed the already deeply weathered granite. During an earlier, wetter climate, the valley was cut by the action of flowing water. A stream knifed through the overlaying gniess, widening it and flushing the sediments away. Today, with a dryer climate and no stream to carry debris away, sediments are deposited and remain in the valley.
< Previous - Next >
The contact zone
|
Wrightwood Real Estate MOUNTAIN HOMES & CABINS Vacation Rentals & Homes for Sale |
Log Cabin Furnishings Lodgepole Pine Log Furniture Rustic Decor & Silhouette Metal Art |
HighDesertRED.com High Desert Real Estate Directory -- |
| Victorville - Hesperia - Apple Valley - *Adelanto - Baker - Barstow - *Lucerne Valley - Big Bear - Lake Arrowhead - Yucca Valley - Joshua Tree - Twentynine Palms - Palmdale - Lancaster - Mojave - Tehachapi - California City - *Boron - Ridgecrest - *Randsburg - Nipton - Shoshone - Tecopa - Death Valley Junction - Needles - Lone Pine - Big Pine - Bishop - Independence - Trona - |
|
Digital-Desert Abraxas Engineering privacy |
Copyright ©Walter Feller. All rights reserved. Respect U.S and international copyright statutes and our right to own and control our work - DO NOT LINK TO THESE IMAGES FROM WEB PAGES, FORUMS OR BLOGS - |
Desert Gazette |