Thursday, February 14, 2008

Death Valley - A land of many treasures

And very few of the treasures are of the monetary kind. Mosaic Canyon, at the north end of the Panamint Mountains is a treasure trove of learning opportunities at all levels. In the picture above, students witnessed a rare sight of flowing water in a desert wash (after an overnight soaking in our campsite; no one really cared, it was the last day). We could watch the pebbles rolling down the channel, and it was easy to imagine one of the large flash floods that have carved the intricate narrows just upstream.

The canyon walls are adorned with the "mosaics", chunks of yellow dolomite marble that were once cobbles in the stream bed. They were later cemented, and then eroded by later floods. Understanding their origin was the goal of the student projects while they wandered up-canyon.

The canyon lies at the edge of a metamorphic core complex, Tucki Mountain, and numerous faults are visible on the walk up the canyon, including one of the sweetest pictures of a normal fault one could ask for.

The yellowish rock forming the canyon wall is the late Proterozoic Noonday Dolomite, a carbonate shelf deposit recording the subsidence of the recently rifted passive margin of the western edge of North America. At first glance, the rocks appear simply tilted, but closer observation reveals complex folding patterns.

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