Tuesday, July 6, 2010

Geology on the Road: Ely Limestone Panorama

Because I'll be away for a couple days, possibly without access to very usable wifi (I'll have a connection, but not a good blogging connection), I'm going to post this view of the Pennsylvanian Ely Limestone in the White Pine Range of White Pine County, NV, as seen from not far off Highway 50 near the dirt road turnoff to Illipah Reservoir. In fact, drive straight down this road (Google Maps Street View) and keep going straight a couple hundred yards past the left turn to Illipah Reservoir. That's the Ely Limestone in the middle ground ridge on the left, and Ely Limestone on the main ridge behind and to the right. (There could be some Riepe Springs Limestone capping the Ely, though it may not show in the photo.)
Alternately, park at the pullout on the east side of the paved highway right at the Illipah turnoff (at Nevada historic marker #53), and look around from there. The hills on the east side of the road, part of the Butte Mountains, show equally good examples of the Ely Limestone, which can be recognized miles away because of its typical cyclothemic appearance. I mentioned the cyclothemic aspect of the Ely Limestone in an earlier post, without showing good photos of it.

In northern Nevada, correlative formations from a similar depositional environment (though reportedly more clastic) are called the Moleen and Tomera Formations (the lower and upper Ely Limestone, respectively).

I won't get into the details of cyclothems and the cyclic depositional environments that were common during the Pennsylvanian of Nevada (and elsewhere through the Carboniferous and possibly into the Triassic), but this 1964 publication from The Symposium on cyclic sedimentation is a great place to start reading. There's even an article about the Pennsylvanian and Permian of eastern Nevada, including the Ely Limestone! H/T to Brian Romans @clasticdetritus and Clastic Detritus.

Bissell, H. J., 1964, Patterns of sedimentation in Pennsylvanian and Permian strata of part of the eastern Great Basin, in D.F. Merriam, ed., Symposium on cyclic sedimentation: Kansas Geological Survey, Bulletin 169, p. 43-56.

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