Other ID: none
Organization(s): USGS, Woods Hole Coastal and Marine Science Center
Location: Atlantis Fracture Zone, Hayes Fracture Zone, Mid-Atlantic Ridge axis, North Atlantic;
Principal Investigator(s): Kim D. Klitgord
Affiliate Investigator(s): Leonid V. Dmitriev - Vernadsky Institute of Geochemistry
Data Type(s): Sonar: Multibeam, Electro-Magnetic: Magnetics, Electro-Magnetic: Gravity, Sampling: Biology, Sampling: Geology
Scientific Purpose/Goals: The overall objective of the 12th cruise leg 1 of the R/V PETROV was to initiate an integrated geological sampling and geophysical surveying program of the Mid-Atlantic Ridge between the Atlantis Fracture Zone and the Hayes Fracture Zone, from 30 degrees N to 34 degrees N. The sampling and survey program was designed to address specific scientific objectives related to understanding the geological, geochemical, and geodynamic processes that help to control the generation and subsequent deformation of oceanic lithosphere. These scientific objectives are summarized as follows: 1) Establishing the morphotectonic framework of the axial Mid-Atlantic Ridge by: a. identifying and mapping the large-offset and the "zero-offset transform/fracture zones and the variability in their fault systems; b. identifying and mapping the axial bathymetric high, rift-valley graben, and flanking fault blocks including the segmentation characteristics of the ridge; and c. identifying and mapping magnetic lineations that provide age-isochron information and other magnetic signatures that reflect magmatic processes at the ridge. 2) Establishing the magmatic contribution to oceanic crustal generation by: a. determining the geochemical variations along the ridge axis in young oceanic crust; b. examining the relationships between these variations and ridge segmentation; and c. examining of small-scale variations at large-offset, small-offset, and zero-offset transform zones. 3) Investigating the deformation of oceanic crust within transform/fracture zones by: establishing the metamorphic character of mafic and ultramafic rocks, including microfabric, fluid-inclusion, and geochemical evidence.
Start Date: 1989-02-02
Start Port/Location: Rotterdam, Netherlands
End Date: 1989-02-28
End Port/Location: Bridgetown, Barbados
Equipment Used: Multibeam swath bathymetry, Marine magnetometer, Gravity meter (wh), Seismic reflection, Dredge
Information to be Derived:
Summary of Activity and Data Gathered:
Staff: Kim D. Klitgord
Klitgord, K.D., Dmitriev, Leonid V., Casey, John F., Silantiev, Sergei, and Johnson, Kevin, 1993, U.S.-Soviet collaborative geological and geophysical survey of the Mid-Atlantic Ridge near 31 degrees N, the Petrov Fracture Zone: U.S. Geological Survey Open-File Report 94-007, 23 p., download PDF.