Geoscience Reference
In-Depth Information
Box 14.1
Death Valley alluvial fans
The Death Valley fans are the archetype fans in much of the literature, which deals with three main themes:
tectonic control, climatic control and modern fan processes. Tectonic control includes both passive control of
fan geometry and style, and active tectonics (minor faults across the west-side fans; major faults bounding the
mountain front of east-side fans; tectonic subsidence creating accommodation space, the result being burial of
older fan sediments by modern aggrading east-side fans). Quaternary climatic control expressed in alternating fan
(a) Summary map showing the main tectonic units and schematic cross-section across Death Valley; (b) composite
satellite image of the central part of Death Valley (taken from Google Earth); (c) west-side fans: Hanaupah fan seen
from Dante's View above Death Valley. Note the large backfilled fans on flanks of the uplifted Panamint Mountains, with
Telescope Peak on the skyline, and composite telescopic fan surfaces with well-developed fanhead trenches; different
surface ages are picked out by surface texture and varnish colour, with the basal zone trimmed by the Lake Manley Late
Pleistocene pluvial lake shoreline. (d) East-side fans, Badwater fan, on the downthrown side of Badwater fault: small
sheetflood dominated aggrading fan; little or no fanhead trench; near-uniform modern fan surface age. (e) Small (fre-
quently photographed) east-side debris cone, near Mormon Point. Note the multiple ages of debris flows picked out by varnish
development.
