Compositions, growth mechanisms, and temporal relations of hydrothermal sulfide‐sulfate‐silica chimneys at the northern Cleft segment, Juan de Fuca Ridge

Journal of Geophysical Research B: Solid Earth
By: , and 

Links

Abstract

Three active hydrothermal vents forming sulfide mounds and chimneys (Monolith, Fountain, and Pipe Organ) and more widely distributed inactive chimneys are spatially related to a system of discontinuous fissures and young sheet flow lavas at the northern Cleft segment, Juan de Fuca Ridge. The formation of zoned tubular Curich chimneys (type I) on the Monolith sulfide mound is related to focused flow of high‐temperature (to 328°C) fluid. Bulbous chimneys (type II or “beehives”) at the Monolith and Fountain vents are products of diffuse high‐temperature (to 315°C) discharge. A broader zone of vigorous mixing between the hydrothermal fluid and seawater results in quench crystallization of anhydrite‐rich shells. Columnar Zn‐sulfide‐rich chimneys with narrow channelways (type III) are constructed where focused and relatively low‐temperature (261°C) fluid vents directly from the basalt substrate. The bulk chemistry (low Cu; high Pb, Ag, and SiO2 contents), mineralogy (pyrite‐marcasite‐wurtzite‐amorphous silica‐anglesite), colloform and filamentous textures, and oxygen isotope characteristics of inactive (type IV) chimneys indicate a low‐temperature (<250°C) origin involving diffuse and sluggish flow patterns and conductive cooling. Seafloor observations and 210Pb data indicate that (1) type IV chimneys are products of an earlier period of hydrothermal activity that ended no more than 60 years ago but prior to the sheet flow eruption, (2) the high‐temperature Monolith and Fountain vents are manifestations of the same heating event (shallow emplacement of magma) that led to the sheet flow eruption and recent megaplumes, and (3) the Pipe Organ Vent is in a very youthful stage of development and chimney deposition postdates the sheet flow eruption.

Study Area

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Compositions, growth mechanisms, and temporal relations of hydrothermal sulfide‐sulfate‐silica chimneys at the northern Cleft segment, Juan de Fuca Ridge
Series title Journal of Geophysical Research B: Solid Earth
DOI 10.1029/93JB02871
Volume 99
Issue B3
Year Published 1994
Publisher Wiley
Contributing office(s) Geology, Minerals, Energy, and Geophysics Science Center
Description 20 p.
First page 4813
Last page 4832
Other Geospatial Juan de Fuca Ridge
Google Analytic Metrics Metrics page
Additional metadata about this publication, not found in other parts of the page is in this table