The origin of the Neihart Quartzite, a basal deposit of the Mid-Proterozoic Belt Supergroup, Montana, U.S.A

J. Schieber
1989 Geological Magazine  
The Neihart Quartzite is the basal quartz arenite unit (,: 270 m thick) of the MidProterozoic Belt Supergroup of western North America. Petrographic studies indicate a source area with plutonic granitic, metamorphic and felsic volcanic rocks. Extreme textural maturity and bimodality indicate an episode of aeolian transport for the detrital quartz grains. The lower 80 % of the Neihart Quartzite were probably deposited by braided streams, whereas the upper 20 % were deposited in shoreline environments.
more » ... n shoreline environments.
doi:10.1017/s0016756800022366 fatcat:h4cic5xtezfmzeo25sef3ehvvm