Bathymetric data at a 200-m contour interval for the entire Mariana forearc, from south of 13°N to 25°N, permits the ®rst comprehensive overview of this feature. The Mariana forearc represents a sediment-starved end-member. The forearc in its southern and central sections is divisible into a structurally complex eastern province and a less-deformed western province. Despite the absence of an ac...

New geochronological data and published structural and stratigraphic data show that two distinctly different ophiolitic assemblages formed in general proximity to one another at nearly the same time and were subsequently imbricated along a regional thrust zone. The Josephine ophiolite constitutes a complete oceanic crust and upper mantle sequence which lies within the western Jurassic belt of t...

The geology of the Darien province of eastern Panama is presented through a new geologic map and detailed biostratigraphic and paleobathymetric analysis of its Upper Cretaceous to upper Miocene sediments. The sequence of events inferred from the stratigraphie record includes the collision of the Panama arc (the southwestern margin of the Caribbean plate) and South American continent. Three tect...

Hinterland plateaux and Mediterranean-style back-arc basins both form behind active subduction zones or collisional megathrusts, and share many characteristics: (1) early crustal thickening to about twice normal continental thickness; (2) thin lithospheric mantle; (3) mixed magmatism including asthenospheric, lithospheric, and crustal melts; (4) late-stage horizontal extension accompanied by ve...