A NEW TYPE OF CARBONATE ROCKS ON THE OCEAN FLOOR (MID-ATLANTIC RIDGE, 30°07′ N)

Abstract

The Mid-Atlantic Ridge (MAR) is crosscut by a complicated system of transform faults. Intersection of these structures is marked by tectonically weakened zones, which serve as conduits for the exhumation of products of hydrothermal alteration of deep-seated rocks to the ocean floor surface if physicochemical conditions are favorable for the process. In 2000, the first active hydrothermal field (Lost City) with brucite–carbonate mineralization and an anomalous fluid composition was revealed at the intersection of the MAR and the Atlantis Fracture Zone. At the same time, an inference was made on the possible wide distribution of such hydrothermal mineral associations on the ocean floor. Currently, active investigations of the field are still in progress.