Although the general concept of linear magnetic anomalies generated by seafloor spreading processes at the ridge crest is well established, the source of the magnetization within the ocean crest remains uncertain. Samples obtained during ALVIN dives in the Hess Deep comprise a range of differentiated tholeiitic extrusives, dikes and gabbros that represent a section through the upper gabbroic crustal layer, 700 m of sheeted dikes, and about 300 m of crustal pillow.lava sequence. The intention is to acquire a full suite of rock magnetic measurements on coarse and fine.grained rocks of different compositions, representing different levels of the upper ocean crust, and integrate these with the crystallization and alteration histories of the rocks, as well as the compositions of magnetic minerals.
