Thursday, March 13, 2008

Death Valley Fans

I’m heading out to Death Valley over spring break, so I thought I’d post this neat LANDSAT image (from Looking forward to seeing some Pre-C and Paleozoic miogeoclinal strata, seeing some extensional tectonics and turtlebacks, and looking at some ALLUVIAL FANS (a particular favorite or mine).

The alluvial fan controversy is actually a pretty fun topic, you know. It has certainly got some personalities in it, and they have made for some fun literature. A classic in the alluvial fan literature is, of course, Blair and McPherson 1994 (in JSR), which first identified the debris-flow dominated versus sheetflood dominated depositional model. This is a pretty marked departure from the humid-fan/arid-fan or braid fan models, and really changes what we can get out of older alluvial fan deposits.

The LANDSAT image shows two distinct fan morphologies. The smaller, distinctly conical fans emanating from the Black Mountains are sourced from small drainages that have formed in crystalline basement, metamorphic and intrustive suites, and some volcanic intervals. Below is a NASA worldwind image looking obliquely to the east at these fans and their drainages.

The western fans are larger, more lobate features sourced from the Panamint Range. These have larger drainages, and are sourcing Precambrian and Paleozoic sedimentary rocks. The NASA worldwind picture below shows an oblique view looking west towards these fans.

Anyway, I hope to have some good pictures when I get back!


Ron Schott said...

Here's a photo of "Agnes" - the alluvial fan just south of Badwater, as seen from the peak just north of Dante's View. This is just one of the alluvial fan photos I've recently posted to my Flickr account dating from my Summer 2005 excursion through the region. You can also see Agnes in profile (including the recent fault scarps) in this cubic QTVR panorama taken at Badwater. Hope you enjoy your trip!

Eric said...

Jumpin' Cats! Nice pictures Ron (and nice panorama)!