Redistribution of Pb and other volatile trace metals during eruption, devitrification, and vapor-phase crystallization of the Bandelier Tuff, New Mexico

Stimac, James A.; Hickmott, D. D.; Abell, R.; Larocque, Adrienne C. L.; Broxton, D.E.; Gardner, Jamie N.; Chipera, S. J.; Wolff, J. A.; Gauerke, Eric

doi:10.1016/0377-0273(96)00024-8

Cited by 43 publications

(21 citation statements)

References 35 publications

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“…The ignimbrite sequence consists of the 1.6 Ma Otowi Member (Qbo) and the 1.2 Ma Tshirege Member (Qbt), which were deposited from pyroclastic eruptions of the Valles/Toledo caldera complex [ Smith and Bailey , 1966; Izett and Obradovich , 1994]. Both members are dominated by silicic ash, with subordinate pumice, lithic clasts, and phenocrysts of quartz, sanidine, and plagioclase feldspar [ Broxton et al , 1995; Stimac et al , 1996; Wilson et al , 2003].…”

Section: Geologic Settingmentioning

confidence: 99%

Diagenesis of deformation band faults: Record and mechanical consequences of vadose zone flow and transport in the Bandelier Tuff, Los Alamos, New Mexico

Wilson¹,

Goodwin²,

Lewis³

2006

J. Geophys. Res.

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[1] Deformation band faults in nonwelded ignimbrites of the Bandelier Tuff record unsaturated fluid flow and transport. More than two thirds of the faults studied display diagenetic minerals virtually absent from adjacent protolith. Stable isotope analyses indicate that smectite enrichment and calcite cementation result from low-temperature meteoric fluid-fault interaction. Fault zone microstructures, rare earth element signatures, and mineralogy indicate that smectite was introduced to deformation band fault zones by a combination of translocation from the surface and in situ alteration of fault gouge. Rod-shaped calcite microcrystallites and the close association of calcite with plant roots suggest a combination of pedogenic, biologically mediated, and physicochemical precipitation. Enrichment in smectite and calcite modified major oxide and trace element contents of deformation bands with respect to protolith. Collectively, these observations indicate that these faults have served as, and may still be, zones of preferential vadose zone fluid flow and transport. These processes alter fault rock permeability; affect the transport of solutes via processes such as dissolution, precipitation, and adsorption, and they change the mechanical properties of the fault zone. Smectite and calcite enrichment results in localization of deformation, effectively halting the further development of deformation bands. Vadose zone alteration therefore is one way to produce a clay-rich fault core at early stages in a fault's history, resulting in fault zone weakening and localization of slip. Progressive burial of growth faults can subsequently bring fault cores into the seismogenic zone.

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Section: Geologic Settingmentioning

confidence: 99%

Diagenesis of deformation band faults: Record and mechanical consequences of vadose zone flow and transport in the Bandelier Tuff, Los Alamos, New Mexico

Wilson¹,

Goodwin²,

Lewis³

2006

J. Geophys. Res.

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“…Augustine; Getahun et al 1996) and in ignimbrite and tuff deposits (e.g. Stimac et al 1996;Yurtmen and Rowbotham 1999) and is closely associated with K-feldspar within spherulites in devitrified obsidian domes and rhyolitic lavas (e.g. Swanson et al 1989;Dadd 1992).…”

Section: Introductionmentioning

confidence: 99%

The nature and formation of cristobalite at the Soufrière Hills volcano, Montserrat: implications for the petrology and stability of silicic lava domes

et al. 2013

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Cristobalite is commonly found in the dome lava of silicic volcanoes but is not a primary magmatic phase; its presence indicates that the composition and micro-structure of dome lavas evolve during, and after, emplacement. Nine temporally and mineralogically diverse dome samples from the Soufrière Hills volcano (SHV), Montserrat, are analysed to provide the first detailed assessment of the nature and mode of cristobalite formation in a volcanic dome. The dome rocks contain up to 11 wt.% cristobalite, as defined by X-ray diffraction. Prismatic and platy forms of cristobalite, identified by scanning electron microscopy (SEM), are commonly found in pores and fractures, suggesting that they have precipitated from a vapour phase. Feathery crystallites and micro-crystals of cristobalite and quartz associated with volcanic glass, identified using SEM-Raman, are interpreted to have formed by varying amounts of devitrification. We discuss mechanisms of silica transport and cristobalite formation, and their implications for petrological interpretations and dome stability. We conclude: (1) that silica may be transported in the vapour phase locally, or from one part of the magmatic system to another; (2) that the potential for transport of silica into the dome should not be neglected in petrological and geochemical studies because the addition of non-magmatic phases may affect whole rock composition; and (3) that the extent of cristobalite mineralisation in the dome at SHV is sufficient to reduce porosity-hence, permeability-and may impact on the mechanical strength of the dome rock, thereby potentially affecting dome stability.

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“…Cristobalite is a common high‐temperature alteration mineral found in silica‐rich tuffs [ Carlos et al , 1991; Caporuscio et al , 2012] and in basalts [ Naughton et al , 1976; Hamilton et al , 2008]. Occurrences of cristobalite in similar tuffs elsewhere have been attributed to hydrothermal or vapor‐phase alteration [ Naughton et al , 1976; Keith , 1991; Stimac et al , 1996; Shimizu and Aoki , 2011; Tempel et al , 2011; Wright et al , 2011; Caporuscio et al , 2012]. Previous studies have shown that percolation of meteoric water under ambient conditions is not a likely mechanism for cristobalite formation [ Matyskiela , 1997].…”

Section: Sage Flat Hollow Sitementioning

confidence: 99%

Spatial distribution of damage around faults in the Joe Lott Tuff Member of the Mount Belknap Volcanics, Utah: A mechanical analog for faulting in pyroclastic deposits on Mars

Okubo

2012

J. Geophys. Res.

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Volcanic ash is thought to comprise a large fraction of the Martian equatorial layered deposits and much new insight into the process of faulting and related fluid flow in these deposits can be gained through the study of analogous terrestrial tuffs. This study identifies a set of fault‐related processes that are pertinent to understanding the evolution of fault systems in fine‐grained, poorly indurated volcanic ash by investigating exposures of faults in the Miocene‐aged Joe Lott Tuff Member of the Mount Belknap Volcanics, Utah. The porosity and granularity of the host rock are found to control the style of localized strain that occurs prior to and contemporaneous with faulting. Deformation bands occur in tuff that was porous and granular at the time of deformation, while fractures formed where the tuff lost its porous and granular nature due to silicic alteration. Non‐localized deformation of the host rock is also prominent and occurs through compaction of void space, including crushing of pumice clasts. Significant off‐fault damage of the host rock, resembling fault pulverization, is recognized adjacent to one analog fault and may reflect the strain rate dependence of the resulting fault zone architecture. These findings provide important new guidelines for future structural analyses and numerical modeling of faulting and subsurface fluid flow through volcanic ash deposits on Mars.

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Redistribution of Pb and other volatile trace metals during eruption, devitrification, and vapor-phase crystallization of the Bandelier Tuff, New Mexico

Cited by 43 publications

References 35 publications

Diagenesis of deformation band faults: Record and mechanical consequences of vadose zone flow and transport in the Bandelier Tuff, Los Alamos, New Mexico

Diagenesis of deformation band faults: Record and mechanical consequences of vadose zone flow and transport in the Bandelier Tuff, Los Alamos, New Mexico

The nature and formation of cristobalite at the Soufrière Hills volcano, Montserrat: implications for the petrology and stability of silicic lava domes

Spatial distribution of damage around faults in the Joe Lott Tuff Member of the Mount Belknap Volcanics, Utah: A mechanical analog for faulting in pyroclastic deposits on Mars

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