Models of hydrothermal circulation within 106 Ma seafloor : constraints on the vigor of fluid circulation and crustal properties, below the Madeira Abyssal Plain
MetadataShow full item record
Heat flow measurements colocated with seismic data across 106 Ma seafloor of the Madeira Abyssal Plain (MAP) reveal variations in seafloor heat flow of ±10–20% that are positively correlated with basement relief buried below thick sediments. Conductive finite element models of sediments and upper basement using reasonable thermal properties are capable of generating the observed positive correlation between basement relief and seafloor heat flow, but with variability of just ±4–8%. Conductive simulations using a high Nusselt number (Nu) proxy for vigorous local convection suggest that Nu = 2–10 within the upper 600–100 m of basement, respectively, is sufficient to achieve a reasonable match to observations. These Nu values are much lower than those inferred on younger ridge flanks where greater thermal homogeneity is achieved in upper basement. Fully coupled simulations suggest that permeability below the MAP is on the order of 10−12–10−10 m2 within the upper 300–600 m of basement. This permeability range is broadly consistent with values determined by single-hole experiments and from modeling studies at other (mostly younger) sites. We infer that the reduction in basement permeability with age that is thought to occur within younger seafloor may slow considerably within older seafloor, helping hydrothermal convection to continue as plates age.
Author Posting. © American Geophysical Union, 2005. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geochemistry Geophysics Geosystems 6 (2005): Q11001, doi:10.1029/2005GC001013.
Showing items related by title, author, creator and subject.
Crustal structure of the Trans-Atlantic Geotraverse (TAG) segment (Mid-Atlantic Ridge, 26°10′N) : implications for the nature of hydrothermal circulation and detachment faulting at slow spreading ridges Canales, J. Pablo; Sohn, Robert A.; deMartin, Brian J. (American Geophysical Union, 2007-08-09)New seismic refraction data reveal that hydrothermal circulation at the Trans-Atlantic Geotraverse (TAG) hydrothermal field on the Mid-Atlantic Ridge at 26°10′N is not driven by energy extracted from shallow or mid-crustal ...
Crustal magnetization and the subseafloor structure of the ASHES vent field, Axial Seamount, Juan de Fuca Ridge : implications for the investigation of hydrothermal sites Tontini, F. Caratori; Crone, Timothy J.; de Ronde, Cornel E. J.; Fornari, Daniel J.; Kinsey, James C.; Mittelstaedt, Eric; Tivey, Maurice A. (John Wiley & Sons, 2016-06-24)High-resolution geophysical data have been collected using the Autonomous Underwater Vehicle (AUV) Sentry over the ASHES (Axial Seamount Hydrothermal Emission Study) high-temperature (~348°C) vent field at Axial Seamount, ...
A reduced crustal magnetization zone near the first observed active hydrothermal vent field on the Southwest Indian Ridge Zhu, Jian; Lin, Jian; Chen, Yongshun J.; Tao, Chunhui; German, Christopher R.; Yoerger, Dana R.; Tivey, Maurice A. (American Geophysical Union, 2010-09-21)Inversion of near-bottom magnetic data reveals a well-defined low crustal magnetization zone (LMZ) near a local topographic high (37°47′S, 49°39′E) on the ultraslow-spreading Southwest Indian Ridge (SWIR). The magnetic ...