The origins of red beds have fascinated geoscientists for generations. In this contribution, Picard examined the Red Peak Member of the Chugwater Formation (Triassic) in west-central Wyoming, a thick succession of red sandstone and siltstone. Coupling field sedimentologic observations, petrography, X-ray diffraction, and well log analysis, the study focuses on the ubiquitous siltstone, rather than the sandstone units. The data led Picard to suggest that the climate was warm to hot and semi-arid to arid, but he ended with the penetrative suggestion that “Further study of [redbed] siltstones is urged.” Many geologists who favor gingers have gladly followed his advice.
Petrography of Red Peak Member, Chugwater Formation (Triassic), west-central Wyoming by M. Dane Picard