USGS Visual Identifier

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Geologic Unit: Mesa Falls

Publication:
Christiansen, R.L., and Blank, H.R., Jr., 1972, Volcanic 
   stratigraphy of the Quaternary rhyolite plateau in Yellowstone 
   National Park, IN Geology of Yellowstone National Park: U.S. 
   Geological Survey Professional Paper, 729-B, p. B1-B18. 
   [Available online from the USGS PubsWarehouse:  http://
   pubs.er.usgs.gov/pubs/pp/pp729B]
Usage in Publication:
Mesa Falls Tuff*

Modifications: Geologic Province: Dominant Lithology:
 Named
 Isotopic dating
 Principal reference
 Snake River basin
 Montana folded belt province
 Tuff

Summary:
Named as the middle ash-flow sheet of the Yellowstone Group (raised in stratigraphic rank from formation) for Upper Mesa Falls, Henrys Fork of Snake River in the Island Park area, eastern ID, in Fremont Co. Type section designated as roadcut on U.S. Hwy 20 about 6.8 km north of Ashton, Fremont Co, ID, Snake River basin. Is present mainly at Island Park, lower slopes of Centennial Mountains, ID and southern Madison Range, MT, Montana folded belt province. Does not crop out in Yellowstone National Park. Varies in thickness; commonly more than 100 m thick. Consists of basal air-fall pumice and distal ash-flow tuff at type. The pumice is well-sorted and well-bedded air-fall deposit with crystals commonly several millimeters to a centimeter in grain size. The ash-flow tuff has conspicuously large feldspar phenocrysts. Top is eroded. Principal reference section designated on cliffs along gorge of Henrys Fork at Upper Mesa Falls. Overlies Huckleberry Ridge Tuff (new) of Yellowstone and other units. Is commonly overlain by Lava Creek Tuff (new) of Yellowstone. Is the only unit of the second volcanic cycle (of three) of the Quaternary Yellowstone Plateau. Sanidine date by K-Ar method 1.2 m.y. old.
Source: GNU records (USGS DDS-6; Denver GNULEX).


Publication:
Naeser, C.W., Izett, G.A., and Wilcox, R.E., 1973, Zircon 
   fission-track ages of Pearlette family ash beds in Meade 
   County, Kansas: Geological Society of America, Geology, v. 
   1, no. 2, p. 93-95.
Usage in Publication:
Mesa Falls Tuff*

Modifications: Geologic Province: Dominant Lithology:
 Overview
 Yellowstone province
 

Summary:
Recent petrographic and chemical studies of ash samples called Pearlette have shown that there are at least three different ash beds on the Great Plains and Rocky Mountain area of closely related petrographic and properties that are related to the Yellowstone Tuff. Pearlette type O identified at Onion Creek, SE1/4 NE1/4 sec 26, T24S, R24E, Grand Co, UT, Paradox basin, has 0.7 +/-0.2 m.y. age and at three localities in Meade Co, KS, Anadarko basin has 0.6 +/-0.07 to 0.9 +/-0.25 m.y. age. Type O correlates with Lava Creek Tuff of Yellowstone area WY. Pearlette type S is correlated with the Mesa Falls Tuff of Yellowstone area of 1.2 m.y. age. Zircons from type S not dated because of small size and paucity. Pearlette type B identified at Cudahy ash Mine, Meade Co, KS in the Anadarko basin has an age of 2.0 m.y. and is correlated with Huckleberry Ridge Tuff of Yellowstone National Park, WY in the Yellowstone province.
Source: GNU records (USGS DDS-6; Denver GNULEX).


Publication:
Love, J.D., and Christiansen, A.C., 1980, Chart showing rock 
   sequences and preliminary correlation of stratigraphic units 
   used on 10 x 20 geologic quadrangle maps of Wyoming: Wyoming 
   Geological Association Field Conference Guidebook, no. 32, 
   p. 279-282.
Usage in Publication:
Mesa Falls Tuff*

Modifications: Geologic Province: Dominant Lithology:
 Overview
 Greater Green River basin
 

Summary:
Does not crop out in WY, but Pearlette type S ash, its downwind equivalent has a K-Ar age on sanidine of 1.2 m.y. and is present in the Laramie and Hanna basins of the Greater Green River basin.
Source: GNU records (USGS DDS-6; Denver GNULEX).


Publication:
Izett, G.A., and Wilcox, R.E., 1982, Map showing localities and 
   inferred distributions of the Huckleberry Ridge, Mesa Falls, 
   and Lava Creek ash beds (Pearlette family ash beds) of 
   Pleistocene age in the western United States and southern 
   Canada: U.S. Geological Survey Miscellaneous Investigations 
   Series Map, I-1325, 1 sheet, scale 1:4,000,000
Usage in Publication:
Mesa Falls ash*

Modifications: Geologic Province: Dominant Lithology:
 Areal limits
 Greater Green River basin
 Paradox basin
 Salina basin
 

Summary:
Mesa Falls ash, an informal designation for an ash 1.27 m.y. old that is the downwind equivalent of the Mesa Falls Tuff of the area eastern Snake River basin, ID. Was formerly referred to as Pearlette type S. Ashes of Mesa Falls age have been found in Albany Co, WY in the Greater Green River basin, in Montrose Co, CO in the Paradox basin, and in Buttes and Cedar Cos, NE in the Salina basin. Inferred areal extent map postulates occurrence likely also in KS, OK, TX, and NM.
Source: GNU records (USGS DDS-6; Denver GNULEX).