We examine the hydrothermal structure of the lava-dike transition zone in oceanic crust of Integrated Ocean Drilling Program (IODP) Hole 1256D using detailed sample measurements of permeability, porosity, metamorphic minerals, and structures. The transition zone consists of basaltic sheet and massive flows, a cataclastic unit, and hyaloclastitic breccias. Structural investigations show that this transition occurs through a larger depth interval than that previously defined, extending 254 m upward from the top of the Sheeted Dike Complex (811.4 to 1065.7 meters below seafloor (mbsf)). Through the transition zone, models predict a general decrease in permeability, based on a corresponding decrease in porosity with depth. Laboratory measurements of physical properties show porosity decreases drastically, as does permeability. Thin sections reveal no open pore space, and all structures are filled: veins (mm- to cm-thick) or sets of parallel veins or vein networks, Riedel-deformation bands, cataclasites (

Dike intrusion controls on permeability and hydrothermal circulation of oceanic crust at IODP Hole 1256D / L. Gilbert, P. Tartarotti, E. Fontana, M.L. Bona, D. Gross, G. Lapier, C. Dempsey - In: AGU Fall Meeting Abstract Volume[s.l] : American Geophysical Union, 2012. (( convegno AGU Fall Meeting tenutosi a San Francisco nel 2012.

Dike intrusion controls on permeability and hydrothermal circulation of oceanic crust at IODP Hole 1256D

TARTAROTTI, PAOLA;E. Fontana;
2012

Abstract

We examine the hydrothermal structure of the lava-dike transition zone in oceanic crust of Integrated Ocean Drilling Program (IODP) Hole 1256D using detailed sample measurements of permeability, porosity, metamorphic minerals, and structures. The transition zone consists of basaltic sheet and massive flows, a cataclastic unit, and hyaloclastitic breccias. Structural investigations show that this transition occurs through a larger depth interval than that previously defined, extending 254 m upward from the top of the Sheeted Dike Complex (811.4 to 1065.7 meters below seafloor (mbsf)). Through the transition zone, models predict a general decrease in permeability, based on a corresponding decrease in porosity with depth. Laboratory measurements of physical properties show porosity decreases drastically, as does permeability. Thin sections reveal no open pore space, and all structures are filled: veins (mm- to cm-thick) or sets of parallel veins or vein networks, Riedel-deformation bands, cataclasites (
Settore GEO/03 - Geologia Strutturale
Settore GEO/10 - Geofisica della Terra Solida
https://abstractsearch.agu.org/meetings/2012/FM/OS13A-1695.html
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/2434/451745
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