Contribution of Oceanic Gabbros to Sea-Floor Spreading Magnetic Anomalies

See allHide authors and affiliations

Science  30 Oct 1992:
Vol. 258, Issue 5083, pp. 796-799
DOI: 10.1126/science.258.5083.796


The contribution of oceanic gabbros, representative rocks for layer 3 of the oceanic crust, to sea-floor spreading magnetic anomalies has been controversial because of the large variation in magnetic properties. Ocean Drilling Program (ODP) Leg 118 contains a continuous 500.7-meter section of oceanic gabbro that allows the relations between magnetization and petrologic characteristics, such as the degree of metamorphism and the magmatic evolution, to be clarified. The data suggest that oceanic gabbros, together with the effects of metamorphism and of magmatic evolution, account for a significant part of the marine magnetic anomalies.