Friday, October 21, 2011

Trilobites before lunch

The last time I tried this blogger decided to stop working.

Earlier this month I had the opportunity to hike across the Grand Canyon from rim to rim. Wow! what a trip. I went with a group from the Grand Canyon Field Institute taking a geology class (of course) The trip met all of my expectations both as a backpack trip and as getting to know the geology of a part of the Colorado Plateau I am not familiar with. Most of my time is spent around Canyon lands where I am quite familiar with the Mesozoic sedimentary sequence. This Paleozoic stuff was all new to me. Hence the title of this post. We started with the Kaibab limestone and ended in the Cambrian Tapeats sandstone where we spent some quality time during lunch looking for trilobites. This is just the trip down. It gets better!

Looking over the edge the night before our descent into the canyon.
The Coconino sandstone. A layer that scares the hikers traveling back up to the rim. This Permian aged sandstone creates a 300 foot cliff with some great cross bedding showing the "petrified" sand dunes .
Lots of chert nodules throughout the Redwall limestone, another formidable cliff former!
Ribbon falls, notice the travertine dome at the base of the falls. Calcium carbonate rich water has created a fantastic dome similar to a stalagmite in a cave.
Next will be about time spent at the bottom of the canyon.