Source Rocks and Sediments in Drainage Area of North Eden Creek, Bear Lake Plateau, Utah-Idaho
Abstract
The Bear Lake Plateau extends north-south across the north central corner of Utah and the southeastern corner of Idaho. North Eden Creek drains westward through part of the plateau and is cross-axial across both strikes of beds and other structures in the area. The formations in the area mapped are of Triassic, Jurassic, and Tertiary age, although only Jurassic and Tertiary rocks contribute sediments to North Eden Creek. The formations consist of sandstones (Nugget) limestones (Twin Creek) and conglomerates (Wasatch). A local extrusion of basalt occurs in the southwestern part of the drainage area. Particle-size analyses of 15 samples from pits dug along North Eden Creek and its tributaries and North Eden Delta show that mean and maximum particle sizes increase downstream due to additions by tributaries and mass-wasting from the coarse-grained, highly jointed Nugget Formation flanking lower parts of the stream. Mineralogic analyses of these samples show that quartzite and chert predomi