Grain Orientation of Massive Sandstones

Abstract

<p> This study describes the analysis of orientation of elongate quartz grains in massive turbidite sandstones from the Chetco Formation (Jurassic) of southwestern Oregon. Inferences on depositional fabric of this resedimented facies are made.</p> <p> Grain orientation in the plane parallel to bedding is generally not highly significant statistically, and current direction, supplied by imbrication, is not persistent vertically through the beds. However, a rotation pattern of current direction in each bed is detected.</p> <p> Variations in orientation distribution could represent variations in sediment concentration of the flow and in the rate of deposition.</p>