FIELD REPORT: stretching time and space in the Great Basin
06.03.2010, 12:24 pm
Filed under: Uncategorized

Sevier Lake, UT

We spent last weekend driving long stretches of dirt roads and the “loneliest highway in America” to the far reaches of Lake Bonneville. A southern lobe called Sevier Lake. Sevier is now a dry lake bed, though it was always a shallow section of the larger Lake Bonneville, with a maximum depth of only 15 ft.
from Major Levels of Great Salt Lake and Lake Bonneville, Utah DNR 1984

On this leg of the trip, we based ourselves in Baker, NV, conveniently located at the base of Wheeler Peak and the Great Basin National Park. Wheeler Peak is an anomalous mountain that boasts a remnant of a desert glacier dating to sometime in the Pleistocene. Nobody seems to know how old the ice is up there, but Rangers at the park told us it’s been there since the last ice age. It’s an odd and incredible arrangement to find a glacier in the high desert, but then again, perhaps not so strange as the the desert floor is so visibly and dramatically shaped by the Pleistocene. Why not 13,000 ft. up  as well?

Mt. Baker, site of a Pleistocene desert glacier

While in Baker, we found a great local bookstore tucked in the corner of the Electrolux Cafe.  We picked up a copy of John McPhee’s Basin and Range to have along with us for the drive back.

We came across this fantastic passage by McPhee, which resonated quite literally, on both the macro and micro scale, with the experiences we were having on our return drive to Wendover:

The whole Basin and Range, or most of it- is alive.  The earth is moving. The faults are moving…Fault scars everywhere. The world is splitting open and coming apart…It’s growing. The range is lifting up. This Nevada topography is what you see during mountain building. There are no foothills. It is all too young. It is live country. This is tectonic, active, spreading, mountain-building world…The crust- in this region between the Rockies and the Sierra- is spreading out, being stretched, being thinned, being literally pulled to pieces. The sites of Reno and Salt Lake City, on opposite sides of the province, have moved apart fifty miles.”  – John McPhee

polygon cracks fill the floor of dry Sevier Lake, a southern lobe of ancient Lake Bonneville

FOP’s roving studio on the Sevier Lake playa

As we shared in our last post, Salt Lake City and Reno are moving away from each other by 1″ a year, or a foot every 12 years. Since McPhee wrote the words above in 1980, the two cities, Reno in the west and Salt Lake City in the east, have moved apart by more than 2.5 additional feet. The stretching isn’t going to stop anytime soon.

This massive geologic force is happening fast enough for humans to actually grasp it. We can all imagine one foot and twelve years, but we can’t see the stretch literally unfold over hundreds of miles or hundreds of thousands of seconds in a year. FOP wondered just how far things will have stretched during our 15 day residency in the Basin.  When we arrived back in Wendover we looked to the playa floor for inspiration and to the micro-scale.

cracks in the mud playa at CLUI Wendover’s South Base

According to our calculations, over the 15 day duration of our time in the Great Basin, Salt Lake City and Reno grew by another monumental, and fully imaginable, 1mm.   We located a crack in the shrinking, drying mud of the Basin floor that illustrated just how far that is.

a 1mm crack in the Bonneville Basin’s mud floor

These calculations are based on an even distribution of stretch over the course of our time in the Basin, which we have no way of  actually knowing to be true, and of course the stretch occurs over hundreds of miles rather than in a condensed space.

While in the Basin, we did some rubbings of the mud cracks.  We were startled both by the texture that the rubbings revealed that was otherwise hidden from view in the blinding light … and by the remarkable similarity of forms across vast scales of space in the Great Basin.

Sevier Playa

FOP’s playa rubbings in situ

The rubbings of a few square feet of playa looked remarkably like aerial views or 3D relief maps of “stretch mark” ranges that flow north and south across the entire Great Basin.

detail of rubbing

As we read on in McPhee, we came upon a passage that we had forgotten since we last read the book:  The craziest part of the Basin and Range story is that, sometime in the geologic future, the crustal stretching in the Great Basin will likely open a passage to the Pacific, creating a vast inland sea that will flood deep into North America.  It’s just a matter of (geologic) time as they say.  Imagining this taking place all round us relocated our sense of Lake Bonneville in time–it moved our sense of its vanishing act from the now dry land much closer to the here and now. Our being here, in the temporarily dry basin of Lake Bonneville is one extremely recent chapter of an immensely larger and longer history of geologic change. In this history, and in the future, incomprehensibly vast quantities of water will continuously appear and disappear in this region.

Extension of the earth’s crust has been somewhat pronounced here, Deffeyes explains… He feels that when a seaway opens up, the spreading center will be somewhere nearby [the Nevada-California border].  Or possibly back in Utah, in the bed of Lake Bonneville...” – John McPhee

A relief map of the ever expanding Basin and Range installed at the Great Basin National Park visitor’s center

1 Comment so far
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fantastic. i’ve seen pictures of this lake in a strong melt season, and it does get a few inches. it’s breathtaking.

was the lake formed because the north american plate was spreading at one time? is a craton the same as a land mass plate, because i thought cratons could not spread.

-nick in slc, ut

Comment by Nick

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