The volcanic zone

On the 10 of August, dive 1975 crossed a portion of the northern mid ocean ridge segment of the Mid Atlantic Ridge before abutting against the Romanche Fracture zone. Target structures to observe during the dive were a thin ridge segment and a rounded volcanic edifice.

We started the working profile at a depth of 3927 meters below sea level in a field of fairly fresh pillow basalts. We then climbed, all the way up, the westward facing wall of the ridge between recent debris and some pillow outcrops, to finally find beautiful pillow basalts outcropping at the very top at a depth of 3590 m!  We descended the ridge on the other side where more debris and some outcrops of pillow where still in place to find at the very bottom another field of pillow basalts. The volcano was totally built with pillow lavas and strongly sedimented at the very top but a beautiful sight nonetheless!

By A. Cipriani