Issues

COVER: Aerial view looking northeast at Sunset Bay State Park (foreground) and Coos Bay (background) along the southwestern Oregon coast (USA). East-dipping sandstones and mudstones of the middle Eocene Coaledo Formation provide exceptional exposures of a prograding storm- and wave-dominated deltaic sequence adjacent to the inboard Coos Bay Coal Field, where lignitic coals accumulated under tropical conditions during the Eocene ‘Hothouse’ climate. These rocks and the underlying fluvio-deltaic Tyee Formation were deposited just prior to the onset of Ancestral Cascades arc magmatism; their widespread exposure across the southern Oregon Coast Range today is due to crustal thickening and exhumation since Oligocene time. See ‘Oligocene onset of uplift and inversion of the Cascadia forearc basin, southern Oregon Coast Range, USA’ by Darin et al., p. 603–609.