Eocene and Miocene extension, meteoric fluid infiltration, and core complex formation in the Great Basin (Raft River Mountains, Utah)

Methner, Katharina; Mulch, Andreas; Teyssier, Christian; Wells, Michael L.; Gottardi, Raphaël; Gébelin, Aude; Chamberlain, C. Page

doi:10.1002/2014tc003766

Cited by 24 publications

(26 citation statements)

References 73 publications

(259 reference statements)

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“…This places the Pioneer metamorphic core complex in an important geographic and temporal position at the junction of the northern and central belts of metamorphic core complexes. The central belt of metamorphic core complexes includes the Raft River-Albion-Grouse Creek metamorphic core complex (Utah), located just south of the Snake River Plain, and the Ruby Mountain-East Humboldt and Snake Range metamorphic core complexes farther south in Nevada; these metamorphic core complexes display Eocene to Miocene extension (e.g., McGrew and Snee, 1994;MacCready et al, 1997;Miller et al, 1999;Sullivan and Snoke, 2007;Wells et al, 2000;Colgan et al, 2010;Gans et al, 2011;Konstantinou et al, 2012Konstantinou et al, , 2013Methner et al, 2015). The southern belt of metamorphic core complexes, from Arizona to Mexico, records significant Miocene extension, lower magnitudes of exhumation, and small amounts of partially molten crust (e.g., Foster et al, 1993;Scott et al, 1998).…”

Section: Regional Geologymentioning

confidence: 99%

Eocene extension and meteoric fluid flow in the Wildhorse detachment, Pioneer metamorphic core complex, Idaho

et al. 2015

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The relationship between microstructure and fluid flow traced by hydrogen isotope ratios (dD) is examined within the Wildhorse detachment system of the Pioneer metamorphic core complex in south-central Idaho. Within the detachment footwall, 100-m-thick mylonitic quartzite containing minor white mica and K-feldspar displays a NW-trending stretching lineation and consistent top-to-the-NW sense of shear criteria. Microstructures within the detachment footwall comprise two groups: quartz ribbons and relict quartz grains flattened within the foliation, with porphyroclastic white mica fish; and intensely deformed and recrystallized quartz with high-aspect-ratio white mica arranged within C′ shear bands. White mica dD values are highly negative and cluster around-145‰ in high-aspect-ratio white mica and around-120‰ in porphyroclastic white mica fish. The most negative values are interpreted to reflect interaction with meteoric fluids from a high-elevation catchment (3000-4000 m), and the less negative values are interpreted to represent incomplete hydrogen isotope exchange between the meteoric fluid and the pre-extensional metamorphic fluid dD values in the white mica porphyroclasts. A suite of tightly clustered 40 Ar/ 39 Ar ages from synkinematic white mica in the detachment footwall dates deformation, recrystallization, fluid-rock interaction, and therefore the presence of high topography at 38-37 Ma; these ages are consistent with the cooling/exhumation history of the high-grade core of the Pioneer metamorphic core complex in the late Eocene. The 38-37 Ma 40 Ar/ 39 Ar ages are substantially younger than previously published ages of high topography in British Columbia to the north (49-47 Ma), in line with the hypothesis that high topography propagated from north to south in the northern segment of the North American Cordillera through Eocene time.

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Section: Regional Geologymentioning

confidence: 99%

Eocene extension and meteoric fluid flow in the Wildhorse detachment, Pioneer metamorphic core complex, Idaho

et al. 2015

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“…Infiltration of meteoric fluids has been documented in the footwall of detachment zones that bound the metamorphic core complexes of the North American Cordillera, based mainly on the low hydrogen (δD) and oxygen (δ 18 O) isotope values of synkinematic hydrous minerals [e.g., Fricke et al ., ; Losh , ; Mulch et al ., , ; Holk and Taylor , ; Gottardi et al ., ; Gébelin et al ., , , ; Methner et al ., ; Quilichini et al ., , ], the Menderes Massif of Turkey [ Hetzel et al ., ], and extensional detachments in the European Central Alps [ Campani et al ., ]. Surface fluids penetrated the deforming crust down to the brittle‐ductile transition in these orogens by means of normal faults and fractures that dissected the brittle upper crust, while at the same time movement within the detachment zone induced advection of hot footwall material that promoted buoyancy‐driven fluid convection [e.g., Person et al ., ].…”

Section: Introductionmentioning

confidence: 99%

Infiltration of meteoric water in the South Tibetan Detachment (Mount Everest, Himalaya): When and why?

et al. 2017

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The South Tibetan Detachment (STD) in the Himalayan orogen juxtaposes low‐grade Tethyan Himalayan sequence sedimentary rocks over high‐grade metamorphic rocks of the Himalayan crystalline core. We document infiltration of meteoric fluids into the STD footwall at ~17–15 Ma, when recrystallized hydrous minerals equilibrated with low‐δD (meteoric) water. Synkinematic biotite collected over 200 m of structural section in the STD mylonitic footwall (Rongbuk Valley, near Mount Everest) record high‐temperature isotopic exchange with D‐depleted water (δDwater = −150 ± 5‰) that infiltrated the ductile segment of the detachment most likely during mylonitic deformation, although later isotopic exchange cannot be definitively excluded. These minerals also reveal a uniform pattern of middle Miocene (15 Ma) 40Ar/39Ar plateau ages. The presence of low‐δD meteoric water in the STD mylonitic footwall is further supported by hornblende and chlorite with very low δD values of −183‰ and −162‰, respectively. The δD values in the STD footwall suggest that surface‐derived fluids were channeled down to the brittle‐ductile transition. Migration of fluids from the Earth's surface to the active mylonitic detachment footwall may have been achieved by fluid flow along steep normal faults that developed during synconvergent extension of the upper Tethyan Himalayan plate. High heat flow helped sustain buoyancy‐driven fluid convection over the timescale of detachment tectonics. Low δD values in synkinematic fluids are indicative of precipitation‐derived fluids sourced at high elevation and document that the ground surface above this section of the STD had already attained similar‐to‐modern topographic elevations in the middle Miocene.

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“…The presence of fluids during deformation in midcrustal shear zones associated with MCCs has long been recognized (Fricke et al, 1992;Gébelin et al, 2011Gébelin et al, , 2014Gottardi et al, 2011Gottardi et al, , 2015Kerrich & Rehrig, 1987;Methner et al, 2015;Mulch et al, 2004Mulch et al, , 2007Quilichini et al, 2015Quilichini et al, , 2016Wickham et al, 1993). Some isotopic studies have identified the source of synkinematic fluids as basinal brines (Roddy et al, 1988;Spencer & Welty, 1986), magmatic or metamorphic in origin (Axen, 1992;Kerrich & Rehrig, 1987;Smith et al, 1991Smith et al, , 2008, or mixing of multiple sources (Nesbitt & Muehlenbachs, 1995;Spencer & Welty, 1986).…”

mentioning

confidence: 99%

“…Some isotopic studies have identified the source of synkinematic fluids as basinal brines (Roddy et al, 1988;Spencer & Welty, 1986), magmatic or metamorphic in origin (Axen, 1992;Kerrich & Rehrig, 1987;Smith et al, 1991Smith et al, , 2008, or mixing of multiple sources (Nesbitt & Muehlenbachs, 1995;Spencer & Welty, 1986). Other isotopic and field-based studies suggest circulation of surface-derived fluids that penetrate to 10-15-km depths (Fricke et al, 1992;Gébelin et al, 2011Gébelin et al, , 2014Gottardi et al, 2011Gottardi et al, , 2015Kerrich & Rehrig, 1987;Methner et al, 2015;Mulch et al, 2004Mulch et al, , 2007Quilichini et al, 2015Quilichini et al, , 2016Wickham et al, 1993). The mechanism by which surface-derived water is pumped beyond the brittle-ductile transition is conceptually challenged by physiomechanical process (e.g., Connolly & Podladchikov, 2004;Fusseis et al, 2009;Lyubetskaya & Ague, 2009;Menegon et al, 2015;Yardley, 2009).…”

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confidence: 99%

Fluid–Rock Interaction and Strain Localization in the Picacho Mountains Detachment Shear Zone, Arizona, USA

et al. 2018

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The Picacho Mountains (SE Arizona, USA) are composed of a variety of Paleogene, Late Cretaceous, and Proterozoic granite and gneisses that were deformed and exhumed along the gently south to southwest dipping detachment shear zone associated with the Picacho metamorphic core complex. The detachment shear zone is divided into three sections that record a progressive deformation gradient, from protomylonites to ultramylonites, and breccia. New thermochronological data from mylonite across the footwall of the detachment shear zone associated with the Picacho metamorphic core complex suggest that the footwall was exhumed through about ~300°C between 22 and 18 Ma by progressive incisement of the footwall of the detachment shear zone. Combined geochronological and oxygen and hydrogen stable isotope data of metamorphic silicate minerals reveal that mylonite recrystallization occurred in the presence of a deep‐seated metamorphic/magmatic fluid, and experienced a late stage meteoric overprint during the development and exhumation of the detachment shear zone. Quartz‐biotite and quartz‐hornblende geothermometry from the base to the top of the detachment shear zone yield equilibrium temperatures ranging from 630 to 415°C, respectively. This temperature trend is attributed to an insulating effect caused by rapid slip and juxtaposition of cool hanging wall on top of a hot footwall. It is suggested that rapid cooling of the top of the detachment shear zone caused strain to migrate toward lower structural level by incisement of the footwall of the shear zone. Progressive strain front migration into the ductile footwall produced hydromechanical anisotropies parallel to the detachment shear zone, effectively saturating the footwall with magmatic/metamorphic fluids and preventing downward flow of meteoric fluids. The combined microstructural, geochronological, and stable isotope results presented in this study provide insight on the dynamic feedback between deformation and fluid flow during the evolution of a detachment shear zone.

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Eocene and Miocene extension, meteoric fluid infiltration, and core complex formation in the Great Basin (Raft River Mountains, Utah)

Cited by 24 publications

References 73 publications

Eocene extension and meteoric fluid flow in the Wildhorse detachment, Pioneer metamorphic core complex, Idaho

Eocene extension and meteoric fluid flow in the Wildhorse detachment, Pioneer metamorphic core complex, Idaho

Infiltration of meteoric water in the South Tibetan Detachment (Mount Everest, Himalaya): When and why?

Fluid–Rock Interaction and Strain Localization in the Picacho Mountains Detachment Shear Zone, Arizona, USA

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