Abstract

Shatter cones that point steeply upward are present in abundance over an area >100 km2 in Belt Supergroup sandstone outcrops in Beaverhead County, southwestern Montana. Crushed sandstone with fragments dispersed in a fluidal textured, cryptocrystalline matrix of similar chemical composition has also been found. Absence of cones in adjacent units of Mississippian and younger age suggests a late Precambrian-early Paleozoic age for the formation of this newly discovered impact structure, only a small part of which is preserved in the complexly faulted terrain.

This content is PDF only. Please click on the PDF icon to access.

First Page Preview

First page PDF preview
You do not currently have access to this article.