Experimental constraints on rhyolite-MELTS and the Late Bishop Tuff magma body

Gardner, James E.; Befus, Kenneth S.; Gualda, G. A.; Ghiorso, Mark S.

doi:10.1007/s00410-014-1051-1

Cited by 45 publications

(35 citation statements)

References 34 publications

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“…It is important to note that rhyolite-MELTS is known to overestimate temperatures by ~40 °C Gardner et al 2014), and the similarly between rhyolite-MELTS and Zr-in-sphene and glass zircon saturation temperatures suggests the latter temperatures may be overestimates as well. Yet, even taking this potential overestimation into account, amphibole geothermometry gives temperatures that are generally inconsistent with these independent estimates.…”

Section: Discussionmentioning

confidence: 98%

Phase-equilibrium geobarometers for silicic rocks based on rhyolite-MELTS—Part 3: Application to the Peach Spring Tuff (Arizona–California–Nevada, USA)

Pamukcu

Gualda

Ghiorso

et al. 2015

Contrib Mineral Petrol

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250 ± 50 MPa) and on glass SiO 2 (255-275 MPa). Amphibole geothermobarometry gives much wider pressure ranges (temperature-independent: ~65-300 MPa; temperature-dependent: ~75-295 MPa; amphibole-only: ~80-950 MPa); average Anderson and Smith (Am Mineral 80:549-559, 1995) + Blundy and Holland (Contrib Miner Petrol 104:208-224, 1990) or Holland and Blundy (Contrib Miner Petrol 116:433-447, 1994-Thermometer A, B) pressures are most similar to phase-equilibria results (~220, 210, 190 MPa, respectively). Crystallization temperatures determined previously with rhyolite-MELTS (742 °C), Zr-in-sphene (769 ± 20 °C), and zircon saturation (770-780 °C) geothermometry are similar, but temperatures from amphibole geothermometry (~450-955 °C) are notably different; the average Anderson and Smith + Holland and Blundy (1994-Thermometer B; ~710 °C) temperature is most consistent with previous estimates. The rhyolite-MELTS geobarometer effectively culls glass compositions affected by alteration or analytical issues; Peach Spring glass compositions that yield pressure estimates reveal a tight range of plausible Na 2 O and K 2 O contents, suggesting that low Na 2 O and high K 2 O contents of many Peach Spring samples are due to alteration. Use of altered whole-pumice compositions in rhyolite-MELTS simulations is likely the cause of the incorrect crystallization sequence reported previously for Peach Spring compositions. Using the rhyolite-MELTS geobarometer, we estimate a more realistic composition for Peach Spring Tuff high-silica rhyolite, and the calculated composition finds close matches with some analyzed rocks and results in the expected sequence of crystallization.Abstract Establishing the depths of magma accumulation is critical to understanding how magmas evolve and erupt, but developing methods to constrain these pressures is challenging. We apply the new rhyolite-MELTS phase-equilibria geobarometer-based on the equilibrium between melt, quartz, and two feldspars-to matrix glass compositions from Peach Spring Tuff (Arizona-California-Nevada, USA) high-silica rhyolite. We compare the results to those from amphibole geothermobarometry, projection of glass compositions onto the haplogranitic ternary, and glass SiO 2 geobarometry. Quartz + 2 feldspar rhyolite-MELTS pressures span a relatively small range (185-230 MPa), consistent with nearly homogeneous crystal compositions, and are similar to estimates based on projection onto the haplogranitic ternary Communicated by Gordon Moore. Electronic supplementary materialThe online version of this article (

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Section: Discussionmentioning

confidence: 98%

Phase-equilibrium geobarometers for silicic rocks based on rhyolite-MELTS—Part 3: Application to the Peach Spring Tuff (Arizona–California–Nevada, USA)

Pamukcu

Gualda

Ghiorso

et al. 2015

Contrib Mineral Petrol

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“…Feldspar is the most typical solid-solution mineral on the Earth's crust. Figure 3 shows (Gardner et al, 2014). Figure 3 captures the general features of phase relations for ternary feldspar; however, the Or-rich side shows metastable relations, where leucite is of the liquidus phase (Waldbaum and Thompson, 1969).…”

Section: Phase Relations In the Ternary Feldspar Systemmentioning

confidence: 94%

Three–dimensional visualization of ternary prisms (T–prism): Development of a spreadsheet–based tool for Earth and material sciences

Kawabata

Shimura

2019

Journal of Mineralogical and Petrological Sciences

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T-prism is a Microsoft-Excel-based tool that visualizes ternary space diagrams (i.e., ternary prisms) in threedimensional (3D) space. This tool allows us to examine the overall features of a dataset in both three-and twodimensional spaces by altering the viewing angles. T-prism involves two algorithms that coordinate the transformation and rotation of diagrams in a virtual 3D space. This paper describes a new and simple coordinate transformation from a ternary space diagram (i.e., ternary prisms) to an XYZ orthogonal system. Coordinates of a point of interest in the ternary space diagram, expressed using the proportions of three components of a basal triangle (r, l, and t, where r + l + t = 100) and an additional variable (h), are converted into coordinates in the orthogonal system as follows: x = (r + 100 − l)/2, y = ffiffi ffi 3 p /2t, and z = fh. Here, f represents the correction factor used to appropriately express the length of an axis perpendicular to the basal ternary diagram. T-prism is particularly suitable for visualizing phase relations in multicomponent systems, the physical properties of materials, and compositional variations in solid solutions. Hence, the tool is applicable to a broad variety of research and teaching fields, including Earth science, material science, and physical chemistry.

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“…Several recent studies attest to renewed interest in the details of mineral and glass compositional variations in the Bishop magma (Chamberlain et al, 2014a,b;Evans and Bachmann, 2013;Gardner et al, 2014;Gualda and Ghiorso, 2013). Although differing in detail of interpretation, these studies concur that two (at least) rhyolite melts became juxtaposed shortly before or during eruption; however, much of the debate revolves around timing, attainment of thermodynamic equilibrium between phases, and whether or not the system was zoned prior to the mingling of the two magmas.…”

Section: Evidence For Cumulate Meltingmentioning

confidence: 97%

“…Much recent debate on the origins of zoning, especially in the case of the Bishop Tuff (Chamberlain et al, 2014a,b;Evans and Bachmann, 2013;Gardner et al, 2014;Gualda and Ghiorso, 2013), has focused on mineral phases and evidence for temperature and pressure gradients in the magmas prior to eruption. Here, we are more concerned with the chemical expression of zoning, largely seen in trace element abundances.…”

Section: Examples Of Zoned Systemsmentioning

confidence: 99%

Remelting of cumulates as a process for producing chemical zoning in silicic tuffs: A comparison of cool, wet and hot, dry rhyolitic magma systems

Wolff

Ellis

Ramos

et al. 2015

Lithos

121

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Experimental constraints on rhyolite-MELTS and the Late Bishop Tuff magma body

Cited by 45 publications

References 34 publications

Phase-equilibrium geobarometers for silicic rocks based on rhyolite-MELTS—Part 3: Application to the Peach Spring Tuff (Arizona–California–Nevada, USA)

Phase-equilibrium geobarometers for silicic rocks based on rhyolite-MELTS—Part 3: Application to the Peach Spring Tuff (Arizona–California–Nevada, USA)

Three–dimensional visualization of ternary prisms (T–prism): Development of a spreadsheet–based tool for Earth and material sciences

Remelting of cumulates as a process for producing chemical zoning in silicic tuffs: A comparison of cool, wet and hot, dry rhyolitic magma systems

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