Tuesday, January 24, 2012

Concentric thinolite layers at Winnemucca Lake

Winnemucca Lake in Nevada is like Pyramid Lake a remnant of the Pleistocene Lake Lahontan. Winnemucca Lake is separated from Pyramid Lake by the Lake Range, but almost meets it at Dago Bay, north of where the Truckee River flows into Pyramid Lake. Winnemucca Lake is mainly a dry lake now: the top picture shows its playa at New Year's Eve 2011. Depending on the day light, it may look like salt or snow. But a hike into the playa confirms that it is sand and soil (which may be covered by snow on some rare, snowy winter days). 

The Pyramid-Winnemucca landscape is rich in natural tufa sculptures including Popcorn Rock, Indian Head Rock and the towers and deposits at The Needles. Spectacular tufa formations can be explored at the south end of Winnemucca Lake. There, assemblies of thinolite rolls are scattered along the side of a gentle slope. Getting close to these unusual rocks, one can see crystalline tufa forming concentric layers, as seen in the picture above. How did calcium carbonate deposit and align into these mysterious, round-shaped megaliths?

Getting there
From I-80 at Wadsworth near Fernley take Route 447 north. This route enters the Pyramid Lake Indian Reservation along the Truckee River and leads to Nixon. From there, Route 447 continues north to Gerlach and the Black Rock Desert. The site of interest is about five miles north, just past the left-side intersection with the dirt road going to the east shore of Pyramid Lake, the Great Stone Mother & Basket and the scenic Pyramid rock (currently closed).  The thinolite tufas are on the right side, off Route 447, which leaves and reenters the Reservation there.

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