Mineralogy of Massive Sulfides From the Ashadze Hydrothermal Field, 13 n, Mid-Atlantic Ridge

Sulfide mineralization in an ultramafic-rock hosted seafloor hydrothermal system: From serpentinization to the formation of Cu–Zn–(Co)-rich massive sulfides

“…The Lost City field records 30 000 years of hydrothermal activity driven by serpentinization reactions producing carbonate-brucite chimneys, low temperature venting (∼40-75°C) and high pH fluids (9-10) Früh-Green et al, 2003;Ludwig et al, 2006). The higher temperature ultramafic-rock hosted systems, Rainbow and Logatchev, exhibit mixed features between sediment-starved basalt-hosted systems with high bulk-rock Cu/Zn ratios, high Cu and Co and low Pb and Ni (Table 5), and ultramafic-hosted systems with high methane anomalies and ubiquitous serpentinization reactions within the host rocks (Batuyev et al, 1994;Bogdanov et al, 1995;Donval et al, 1997;Mozgova et al, 1999;Marques et al, 2006).…”

Minor and trace elements in bornite and associated Cu–(Fe)-sulfides: A LA-ICP-MS studyBornite mineral chemistry

“…In 'B' veins at Batu Hijau, mean Ag and Au concentrations were 3.83 and 306 ppm, respectively. An SEM-EPMA study of present-day seafloor sulfides (Mozgova et al, 2008) suggest up to thousands of ppm Ag and Au may enter both bornite and chacocite. In addition, there are data for bornite from several deposits in the Russian Urals, indicating enrichment in both Ag (e.g., Kuleshov andZaykov, 2005 cited by Novoselov et al, 2006) and Au (e.g., Vikentyev, 2006).…”

“Invisible” silver and gold in supergene digenite (Cu1.8S)

“…Among those studies, Hannington et al (1988) reported secondary enrichment of Au and Ag in recent submarine sulfides in the TAG hydrothermal field in the Mid-Atlantic Ridge, containing up to 16 ppm Au as free native Au and 116 ppm Ag in Cu-sulfides. In a more recent study, Mozgova et al (2008) documented up to 1200 ppm Ag and 1000 ppm Au in Cu-sulfides from the Ashadze hydrothermal field in the Mid-Atlantic.…”