The area studied in detail, known as the Antone District,
is located in the southeast corner of Wheeler County, Oregon, ,
between longitude 119 37. and 119°54 east, and latitude 44°23
and 44°3O' north.
Surface elevations range from 3050 feet above sea level in
the northeast corner of the district,...
Pre-Tertiary metamorphic rocks, Jurassic granitic intrusions,
and Eocene basalts are exposed along the North Fork of the John Day
River at its confluence with Granite Creek. Geochemical and textural
evidence suggest greenschist-metamorphosed, strongly sheared,
volcanogenic rocks originated in an island-arc environment. These
greenstones were apparently intruded during the Late Permian...
Pluvial Lake Chewaucan was a late Pleistocene lake, as much as 375 feet deep, covering 480 square miles in the northwestern part of the Great Basin in southern Oregon. The lake basin, now occupied by Summer Lake, Upper and Lower Chewaucan Marshes, and Lake
Abert, was formed by down-dropped fault...