Thursday, June 20, 2013

An Eight-Day Colorado River Trip Through Grand Canyon - Part 2

A continuation of the photo's from my recent rafting trip in Grand Canyon with Professional geologists.

Morning breakfast to fuel up for a hike in the summer heat.

Making lunches for the hike at 6 AM!

Approaching the confluence of the Little Colorado River at river mile 62. Cape Solitude towers over the confluence some 4,000 feet above our raft.

Dissolved calcium from the Redwall Limestone makes the Little Colorado River a turquoise blue color as light refracts off of the dissolved solutions. The water is warm and inviting for a swim.

At about 2 PM, our hike begins up Carbon Canyon. We have wet all of our clothes and hats and this helps to keep us cool. We have also put extra water in Ziplock bags so that when our shirts dry out, we can rewet them in the bags. Ingenious! After climbing around a huge rockfall in the canyon floor, we look back and see a thrust fault in the wall of the canyon. You will notice two thin beds just below the center of the photograph, then see them thrust over along a low angle line that run upwards from right to left. This is the thrust plane, which is likely an antethetic fault to the larger structure we still have yet to see.

Our group hiking in the slot canyon after the picnic lunch and approaching the Butte Fault.

Shown is the Tapeats Sandstone as the originally flat layers are dragged upwards along the trace of the Butte Fault (off the picture to the left). We had an interesting group discussion here about how some young earth creationists view this as evidence that the layers were soft (and thus young) and easily bent. Hmm? Is that the only possibility for how this formed? Or might there be a pre-determined outcome needed (and not related at all to geology) to fit another religious model? The answer is that when these rocks were deformed, they were at depth and ductile. Later erosion removed thousands of feet of overlying strata that then exposed what is seen here.

Geologist Lisa Greer looks at giant mud cracks in the Jupiter Member of the Galeros Formation. These rocks are part of a NeoProterozoic (about 800 million years old) package that is rare in the American Southwest.

The colorful beds of the Carbon Creek Member of the Galeros Formation.

At the end of the hike we retuned to the Colorado River at Lava Chuar Rapid.  Across the river are basalt rocks of the Cardenas Lavas, erupted about 1 billion years ago on a coastal floodplain.

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