An Integrated Approach to Seafloor Geologic Mapping on the Mid-Atlantic Ridge: ANGUS, ALVIN, and SONARRAY

Near-bottom acoustically navigated vehicles and a multi-narrow beam bathymetric charting system have been utilized for seafloor mapping in the FAMOUS rift valley of the Mid-Atlantic Ridge. A tethered device system (ANGUS) incorporating either a camera fish, rock dredge, corer, or heat probe is used for broad areal survey coverage. A manned submersible (ALVIN) is then deployed to investigate first hand specific sites of geologic interest. The vehicles can be tracked with a precision of 20 meters along a simultaneously collected high resolution bathymetric profile. Vehicle paths can be located relative to ultra-high resolution multi-beam bathymetric charts (SONARRAY) with a precision of 200 meters. Such precise integration has allowed meaningful extrapolation of observations between vehicle tracks useful for geologic mapping studies in the FAMOUS fracture zone B and other nearby areas.