April 2, 2012

Monday Geology Picture: Ferromanganese-Encrusted Boulder from the Ninetyeast Ridge, Indian Ocean

Posted by Evelyn Mervine

Boulder with ferromanganese crust, Ninetyeast Ridge, Indian Ocean, 2007.

Two weeks ago I posted a picture of a fragment of boytroidal ferromanganese crust that was dredged from the Ninetyeast Ridge in the Indian Ocean. Today I thought I would share a few pictures of a ferromanganese-encrusted boulder that was recovered from the Ninetyeast Ridge during the same 2007 expedition.

Ferromanganese crusts actually caused some trouble for our rock descriptions. Before we could identify many rocks, we had to chip or saw off the ferromanganese crusts. Actually, due to alteration we had to break or saw apart many rocks in order to expose fresher surfaces that were easier to identify.

A closer view of the boulder and crust, Ninetyeast Ridge, Indian Ocean, 2007.

I’m afraid that rock-breaking became somewhat of a competitive sport on the expedition. Well, I guess there isn’t much else to do (other than describe and sort rocks) on a two month expedition in the middle of the Indian Ocean.

My husband-to-be (on right) and our friend James... trying to impress me with their rock breaking skills. Ninetyeast Ridge, Indian Ocean, 2007.