Geologic Evolution of Atlantic Continental Rises

Continental rises comprise approximately 10% of sedimentary processes by which modern and sub- the earth's surface and contain 20% of its total sedi- modern submarine fans and related features are ment volume ( ~ 100 million cubic kilometers). How- constructed. To provide a broader perspective of conti- ever, their great depth (2,000-6,000 m) below the sea nental-rise evolution, we have organized this volume surface and distance from shore-based population cen- into four parts: ters, have kept them relatively insulated from man's geological explorations. During the last 10-15 years, 1. Part I addresses prerift and synrift tectonic and however, driven by an ever-increasing thirst for knowl- depositional aspects that account for the location, edge of our planet's nature and origin, by a rising geometry, and thickness of subsequent continental imperative to find new reserves of fossil fuels, and by a rises. demand to find safe haven for hazardous wastes, ma- 2. Part II embraces early postrift aspects, such as rine scientists have intensified their surveys of this vast subsurface structure, stratigraphy, and accumula- province. tion rates; relationships to continental slope and Voluminous geological and geophysical data from shelf deposition and to continental source terrains; multichannel and single-channel seismic-reflection and the relative effects of local and global reg- profiles, high-resolution seafloor images (SEABEAM, ulating agents, such as tectonism, eustacy, and pa- Sea MARC, GLORIA), and various gravity, piston, leoclimate. This accounts for most of the ~ 187 and rotary cores (Deep Sea Drilling Project, Ocean million-year evolution of Atlantic continental rises.