Nature of co-bearing ferromanganese crusts of the Magellan Seamounts (Pacific Ocean): Communication 1. Geology, mineralogy, and geochemistry

作者：Novikov G V^*; Mel'nikov M E; Bogdanova O Yu; Vikent'ev I V

来源：Lithology and Mineral Resources, 2014, 49(1): 1-22.

DOI：10.1134/S0024490213060072

Communication 1 of the present paper is devoted to various aspects of the hydrogenic ferromanganese crusts in the western and eastern clusters of the Magellan Seamounts in the Pacific. It was revealed that crusts are developed on guyots as a continuous sheet of Fe-Mn minerals on exposures of primary rocks. They commonly make up ring-shaped deposits along the periphery of the summit surface and in the upper sectors of slopes. Thickness of the crust varies from n to similar to 18 cm and shows irregular variations in separate layers. Irrespective of the geographic position, crusts are composed of four layers-two lower phosphatized (I-1 and I-2) and two upper nonphosphatized (II and III) layers. The crusts differ in terms of structure and texture, but they are sufficiently similar within separate layers (I-1, I-2, and others). The major ore minerals in crusts are commonly represented by poorly crystallized and low-ordered minerals (Fe-vernadite and Mn-feroxyhyte); the subordinate mineral, by the well-crystallized and ordered vernadite. It has been established that heavy and rare metal cations are concentrated extremely irregularly in ore minerals of the crusts, suggesting a pulsating mode of their input during different geological epochs.

• 出版日期2014-1