This map emphasizes the igneous units of the quadrangle (mapped at 

 1:48000) and provides no real information on unconsolidated 

 deposits. All the unconsolidated deposits along the upper Little 

 Blackfoot are mapped as glacial undivided - seems questionable. 

 The exposed igneous units in the immediate vicinity of Blackfoot 

 Meadows are mapped as rhyolite flows, flow breccias and tuffs of 

 Tertiary age, with some underlying Cretaceous Elkhorn Volcanics 

 (welded tuff facies) also exposed. The basin above Blackfoot 

 Meadows is underlain dominantly by felsic volcanics, many 

 tufaceous. 



Blackfoot WPA 



Bibliographic source: U.S. Geological Survey bibliographic search 

 of the Blackfoot valley area. 



Author: Weber, M.W. and I.J. Witkind 



Title: Reconnaissance geologic map of the western half of the 

 Marcum Mountain quadrangle, Powell County, Montana 



Series: U.S. Geological Survey Open-file report 79-445 



Date: 1979 



Detailed surficial geologic mapping at 1:24,000 scale shows the 

 Blackfoot WPA site underlain by "Older Pinedale" outwash(?) of late 

 Pleistocene age. Outwash materials are described as moderately 

 well sorted in character. Outwash surface appears to merge into 

 the modern Blackfoot River floodplain just south of the WPA. 



Upland outcrops within the contributing drainage basin are mapped 

 as undifferentiated Proterozoic (Belt) formations. 



Bibliographic source: Geoindex lat-long search 



Author: Wallace, C.A. 



Title: Generalized geologic map of the Butte 1 degree X 2 degree 

 sheet, Montana 



Series: U.S. Geological Survey Miscellaneous Field Studies Map MF- 

 1925. 



Date: 1987 



Regional bedrock geologic compilation at 1:250,000 scale shows the 

 contributing surface-water basin underlain by undifferentiated 



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