Tuesday, October 9, 2012

A little juniper, and a bit of sage ...

Evelyn Mervyn at Georneys is hosting this month’s Accretionary Wedge -- the topic is Field Trip/Camp Moments:
“Share a fun moment from geology field camp or a geology field trip ...”
Having just returned from a road trip, it’s not surprising that the memorable moment that comes to mind is a recent one -- a night last week in the White Mountains of eastern California.  Amazingly, there was no fire ban in effect, and I foresaw an evening around the campfire, with dancing flashing light and comforting warmth.

Wandering up the slope behind camp, I picked up small juniper branches and a bit of sagebrush too.  Juniper burns hot and flashy, and both are sweetly aromatic.  Just a small fire is enough to keep the dark and cold away, to provide an added measure of security.  The sweet smoke seems to free deep memories ... maybe even hard-wired instincts of ancestors long ago for whom fire was so important, far more than just a pleasant addition to an evening in the mountains.
Stack twigs, then small branches.  Set a match to the wood.  Feed the little fire occasionally.  In the safety of its bright crackling warmth, let the mind drift.

After an afternoon communing with ancient bristlecone pines on really ancient dolomite, I had much to contemplate.  Some of the bristlecones have been growing for over 4000 years.  The dead go back even further, to almost 10,000 years ago.  Who was wandering through these mountains and building evening fires when these trees were young?  Surely people were gathering piñon nuts -- cones were abundant where I camped.  But would they have continued on up to 10,000 feet elevation, to where there were only stunted trees with tiny seeds?  I’m guessing not.  Contemplation of nature for its beauty and amazing stories must be a modern luxury.  We had to wait -- for both leisure time and the insights of science.
Two dead bristlecone pines on slope in mid-distance.  Dense bristlecone wood decomposes very slowly in this cold dry environment.  The dead may stand for thousands of years.
Of course, lifespans of even the oldest bristlecones are but the most fleeting of moments compared with the ages of the rocks around them.  The sandstones and quartzites of the Deep Springs Formation are ca 550 million years old.  The calcareous muds that became the Reed dolomite accumulated even earlier ... maybe 570 million years ago.
Quartzite of the Cambrian Deep Springs Formation.
Bristlecone pine on Proterozoic - early Cambrian Reed dolomite.
These rocks aren’t just old.  They’re special in that they were deposited at a time not well-represented in the rock record -- late Proterozoic and early Cambrian.  This is the gap that we in the western USA know as the Great Unconformity.  Seas had retreated westward, leaving much of western North America exposed to the elements.  Nothing was deposited, and erosion wore away at the landscapes, sometimes all the way down to Archean basement rocks.  But not here.  Today’s eastern California remained inundated in early Cambrian time, being west of the shoreline.  In fact, one of the most complete early Cambrian sequences in the world is found here in the White and nearby Inyo Mountains -- on the order of 20,000 feet thick.
Crest of the White Mountains -- high, dry and with lots of early Cambrian rocks.
Why are Paleozoic rocks so often described as “drab”?  They’re not as colorful as the sandstones of the Colorado Plateau, it's true, but the patterns and arrangements are quite striking.  I was easily lost in shooting them.

Back to the fire -- I occasionally added more wood, and let my mind drift.  Just imagine a sparkling shallow ocean in eastern California, with low hills barely visible on the horizon to the east in Nevada.  Strange little creatures wriggle in sand and mud that will become rocks of the Reed and Deep Springs formations in 550 million years or so ... wow, what a view!  As always, I was struck by the adventures that our minds can create for us.  We may not have complete stories of how these landscapes came to be, but take the information we do have, add a bit of human imagination and ... voilá! ... such wonderful experiences materialize!  I’m grateful to all the botanists and geologists who have helped tell these stories.

I am indebted to two authors in particular for making my recent trip so enjoyable.  Frank DeCourten’s Broken Land, about the Great Basin, is packed with pleasure for both the mind and the spirit (or soul, as DeCourten says).  Ronald Lanner also conveys a strong sense of love and amazement, as well as knowledge, in his wonderful Bristlecone Book.

For more on the ancient bristlecone pines of the White Mountains, see but there s life in the old dame yet, a post I put together after a visit there last spring.

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