Tucked away in a small nook of an unheralded canyon of the Sierra Nevada is an actual gem of a geological locality. It’s a marvelous instance of columnar jointing that has been modified by glacial scouring, and it is NOT referred to as Satan’s Postpile. Welcome to the Columns of the Giants.

The Stanislaus River does not fairly have the panache of the Merced River, which flows by means of Yosemite Valley, or the Tuolumne River, the architect of Hetch Hetchy Valley. It is not protected as a nationwide park like Kings Canyon. It had glaciers in the course of the ice ages, however they did not have the volumes of ice essential to carve stunningly deep gorges just like the beforehand talked about river valleys. However it does have a grandeur all its personal.

The headwaters of the Stanislaus expose rocks which can be fairly distinct from these of the opposite extra well-known rivers. The rocks have a darker side, on account of being composed of comparatively younger volcanic rocks, moderately than the granite that makes up three-quarters of the Sierra Nevada. Freeway 108 crosses one of many uppermost tributaries at Sonora Go (9,624 toes/2,933 meters), and vacationers can get a spectacular view of those former volcanoes that have been energetic about 10 million years in the past. They erupted onto a muted panorama of eroded granitic rocks. Among the eruptions produced flows that traveled greater than fifty miles downstream by means of the canyons of the Ancestral Stanislaus River. Later erosion appearing on these flows produced the well-known Stanislaus Desk Mountain within the neighborhood of the Gold Rush Cities of Jamestown and Sonora.

Starting round 2 million years in the past, glaciers started tearing away on the larger components of the Sierra Nevada, eradicating lots of the volcanic flows and carving U-shaped gorges just like the one above, seen only a few miles downstream of Sonora Go at Chipmunk Flat. The ice age was not a single occasion. The ice superior and retreated greater than a dozen instances, with hotter intervals in between that lasted for 1000’s of years. It was throughout considered one of these interglacial intervals that one thing extraordinary occurred within the higher reaches of the Stanislaus River drainage. Roughly 150,000 years in the past there was a volcanic eruption down within the canyon.

It wasn’t a big eruption, actually not on the dimensions of a few of the rhyolite cataclysms that devastated the areas east of the Sierra crest 767,000 years in the past. It was extra of a gentle cinder cone eruption that may have flooded a portion of the canyon, flowing only a few miles downstream earlier than the lava flows ceased. Subsequent glaciations scoured away a lot of the remaining lavas, and river erosion eliminated nonetheless extra. Hidden in a cleft, a basalt dike simply upstream of the columns could also be all that continues to be of the volcano answerable for the eruption. It is not a lot, simply the fracture within the granite that stuffed with basalt that fed the eruptions above. 

The stays of the lava circulate, although? Spectacular! The lava circulate (or flows; there have been probably two of them) was ponded by some obstruction downstream, most probably a glacial moraine, and a modest lava lake developed, a number of tens of meters deep. Because the lava cooled, it shrank and the rock fractured in typically hexagonal columns roughly perpendicular to the floor towards which the lava flowed. For the reason that lava flows have been erupted onto a canyon backside with slopes on both facet, not the entire columns are vertical (that is additionally true of the better-known Satan’s Postpile). 

Subsequent glaciations (primarily the Tahoe and Tioga phases for individuals who need to know) tore away on the lava circulate, exposing the columns. Over the past 10,000 years or so because the final Tioga glaciers melted away, frost wedging has pried lots of the columns free, dumping them into an unlimited talus slope that covers the bottom of the lava circulate. Chilly air emanating from the bottom of the talus suggests {that a} mass of ice may truly stay deep throughout the rockpile. 

Columns of the Giants will be simply visited by following Freeway 108 about 25 miles east of the Pinecrest Lake Resort space or 13 miles west of Sonora Go. In a single day lodging will be discovered at close by Kennedy Meadows and plenty of Nationwide Forest campgrounds. Instructional teams might be able to make preparations to remain the Excessive Sierra Institute at Baker Station only a few miles away (contact the Yosemite Neighborhood School District for extra data).

Stanislaus Nationwide Forest has supplied a parking space and easy bogs for guests, and a paved ADA-compliant path and bridge gives entry. The path is just a few hundred yards lengthy, and the visible rewards are nice. 

Cannot get there in particular person? My good friend and colleague Ryan Hollister put collectively a fabulous digital area train that gives an expertise that’s the subsequent neatest thing to being there. It was featured on NPR’s Science Friday a couple of years in the past.