PEARCE FERRY RAPID

[kayakbird]

This station

GQ0073

 

has been my ultimate snowbird destination all winter.

I have visited the area several times in the last few years to observe and measure the very new Pearce Ferry Rapid

FROM THE STATION

 

CLOSEUP

 

that is being formed as the Colorado River cuts a new channel through 70 years of Lake Mead sediments.

A good discussion of the instantaneous geology taking place can be found at

Super Imposition Rapids

 

Long term geology is also very visible here. Just to the east the Grand Wash Cliffs show the horizontal strata of the Colorado Plateau

 

and just to the west the Wheeler Ridge fault

 

begins the Basin and Range province that runs across Nevada to southeastern Oregon.

A 106 is set on several thousand feet of recent fill.

 

Another attraction is watching the play of late afternoon sunlight on the Grand Wash Cliffs.

GQ0226

 

Looking past A 115 from the primitive Pearce Ferry campground.

 

And there are a lot of benchmarks in the immediate area. There was concern as Lake Mead first filled that the mass

of water would set off earthquakes. A seismograph station was built and became the setting for SEISMOGRAPH

GR0407

 

Note: post has been recently broken off, but the base remains in the sand mound.

 

The mesa where the seismograph is located may have been a training ground for NPS surveyors because there are a bunch of these

GR0408

 

scattered around; and from the numbering system, maybe others that do not have a PID.

 

I'm guessing that for earthquake monitoring there are several level runs that have two or more benchmarks per mile.

Along Hualapai Wash 17 miles to the southwest I found three in a 1315 ft stretch: FS0424, FS0423, and FS0422.

 

In 1948 the USGS had a boat outing and circled the reservoir with triangulation stations,

many of which have been or are being, washed out.

GR1549

 

Several slump cracks are showing at, above and below the station.

 

Wish that I could go back for another week. With all the winter moisture the desert wild flowers should be just about ready to put on a spectacular show. MEL

[foxtrot_xray]

Thanks for the links and all - interesting to read about the river and changing routes of it after the lake! Fascinating!