MINERALOGY AND CRYSTALLOCHEMISTRY OF LOW- TEMPERATURE FERROMANGANESE DEPOSITS OF THE RELICT HYDROTHERMAL MOUND FROM THE TAG HYDROTHERMAL FIELD, MID-ATLANTIC RIDGE

Citation
Ai. Gorshkov et al., MINERALOGY AND CRYSTALLOCHEMISTRY OF LOW- TEMPERATURE FERROMANGANESE DEPOSITS OF THE RELICT HYDROTHERMAL MOUND FROM THE TAG HYDROTHERMAL FIELD, MID-ATLANTIC RIDGE, Okeanologia, 37(3), 1997, pp. 448-456
Citations number
25
Categorie Soggetti
Oceanografhy
Journal title
ISSN journal
00301574
Volume
37
Issue
3
Year of publication
1997
Pages
448 - 456
Database
ISI
SICI code
0030-1574(1997)37:3<448:MACOLT>2.0.ZU;2-H
Abstract
Low-temperature Fe-Mn deposits from the TAG hydrothermal field are com posed of bacteria-like particles of protoferrihydrite, nontronite, goe thite, and thin plated aggregates of birnessite. Particles of prototof errihydrite (mineral formed at lower Eh than other iron oxides) contai ning much silica were replaced in situ by nontronite or goethite durin g alteration. Birnessite precipitation at the final stages of the hydr othermal process was partly replaced by vernadite due to bacterial act ivity. Protoferrihydrite together with silica precipitated within the whole hydrothermal field. As to birnessite, it precipitated locally. T hin films composed of Fe-vernadite and Mn-ferroxygite were found on th e surfaces of hydrothermal deposits. They indicate the cessation of hy drothermal activity.