Annotated record of the detailed examination of Mn deposits from DSDP Leg 76 (Hole 534A)

The continental edge of eastern North America is the passive margin with the oldest geological history available in the modern oceans. Rifting and seafloor spreading between the North American and African continents began in the late Triassic to Early Jurassic. A possible spreading-center jump and reorganization in spreading at the time of the Blake Spur Magnetic Anomaly (?Bathonian ) left some of the oldest crust on the western margin of the North Atlantic. Penetration and sampling of such old ocean crust and the immediately overlying pelagic sedimentary cover, consisting of Middle Jurassic and younger strata, has long been a key objective in oceanographic research. This objective was accomplished at Site 534.