Mineral Resources On-Line Spatial Data
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|Name||Cretaceous volcanic rocks|
|Geologic age||Phanerozoic | Mesozoic Cenozoic | Cretaceous-Late Tertiary|
|Original map label||Kv|
|Primary rock type||volcanic rock (aphanitic)|
|Secondary rock type||fine-grained mixed clastic|
|Other rock types|
Igneous > VolcanicMany types of volcanic and hypabyssal forms are represented by this map unit, such as lava flows, tuffs, lahars, stocks, dikes, and sills. Likewise, a wide variety of igneous lithologies are included; most are intermediate in composition, but mafic to felsic compositions are included. Also, volcaniclastic and clastic sedimentary rocks are interlayered with the volcanics.
Sedimentary > Clastic > Mixed-clastic > Sandstone-Mudstone (Bed)
Ross, P.R., Andrews, D.A., and Witkind, I.J., 1955, Geologic map of Montana: U.S. Geological Survey, 2 sheets, scale 1:500,000.
Roberts, A.E., 1972, Cretaceous and early Tertiary depositional and tectonic history of the Livingston area, southwestern Montana, in Geology of the Livingston area, southwestern Montana: U.S. Geological Survey Professional Paper 526-C, p. C1
|Geographic coverage||Broadwater - Cascade - Deer Lodge - Jefferson - Lewis and Clark - Madison - Meagher - Park - Powell - Stillwater - Sweet Grass|
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