Diffusion coupling between trace and major elements and a model for calculation of magma residence times using plagioclase

Costa, Fidel; Chakraborty, Sumit; Dohmen, Ralf

doi:10.1016/s0016-7037(02)01345-5

Cited by 240 publications

(132 citation statements)

References 46 publications

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“…Plagioclase, for example, can show sharp step-function-like gradients in Li (Charlier et al 2012) and Mg (Costa et al 2003) between anorthite-and albite-rich regions in partially equilibrated samples. If the different chemical potentials of the trace elements between the two chemically distinct domains are not considered, then estimated D·t values from Li and Mg concentration gradients would be incorrect (Costa et al 2003). However, these observations contain key differences to those made here for our zircon work.…”

Section: Discussion Of Experimental Resultsmentioning

confidence: 99%

“…However, these observations contain key differences to those made here for our zircon work. First, these studies identified Mg and Li compositional gradients correlating with anorthite mol% variations from 40 to 80, and 40 to 50 %, respectively (Costa et al 2003;Charlier et al 2012). In our zircon data, however, the minor element cation substitutions of REE for Zr and P for Si make up ~1 % or less of the cation sites in zircon.…”

Section: Discussion Of Experimental Resultsmentioning

confidence: 99%

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Li zoning in zircon as a potential geospeedometer and peak temperature indicator

Trail

Cherniak

Watson

et al. 2016

Contrib Mineral Petrol

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920 to 650 °C, calculated diffusivities are in agreement with a previously established Arrhenius relationship calibrated on trace-element-poor Mud Tank zircon. Our revised Arrhenius relationship that includes both datasets is:We also observed that synthetic sector-zoned zircon exhibits near-step-function Li concentration profiles across sectors that correlate with changes in the rare earth element (REE) and P concentrations. This allowed us to examine how Li diffusion might couple with REE diffusion in a manner different than that described above. In particular, re-heating these grains revealed significant Li migration, but no detectable migration of the rare earth elements. Thus, unlike most elements in zircon which are not mobile at the micrometer scale under most timetemperature paths in the crust, Li zoning, relaxation of zoning, or lack of zoning altogether could be used to reveal time-temperature information. Discrete ~10 μm concentration zones of Li within zircon may be partially preserved at 700 °C for tens to hundreds of years, and at 450 °C for millions of years. In this regard, Li zoning in zircon holds significant potential as a geospeedometer, and in some instances as a qualitative indicator of the maximum temperature experienced by the zircon.

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Section: Discussion Of Experimental Resultsmentioning

confidence: 99%

Section: Discussion Of Experimental Resultsmentioning

confidence: 99%

Li zoning in zircon as a potential geospeedometer and peak temperature indicator

Trail

Cherniak

Watson

et al. 2016

Contrib Mineral Petrol

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“…Geospeedometers have the ability to extract cooling information of natural rocks from mineral compositions using analytical or numerical models (e.g., Dodson, 1973;Eiler et al, 1992;Ganguly and Tirone, 1999;Costa et al, 2003;Müller et al, 2013;Watson and Cherniak, 2015;Liang, 2017). Applying the closure temperature equation of Dodson (1973) to Ca in olivine, two research groups estimated cooling rates of oceanic gabbros from the Faak et al (2013) as a function of silica activity and (b) the differences of two existing silica activity models for a basaltic system.…”

Section: Introductionmentioning

confidence: 99%

“…Because Faak et al's thermometer was calibrated only at 1100-1200 • C for plagioclase with 50-80 mol% anorthite, it is unclear how accurately their thermometer can be extrapolated to lower temperatures (e.g., 700-900 • C; Faak et al, 2015), at which Mg in gabbros has been extensively reset by diffusion. Although the 1-D plane sheet diffusion model is easy to implement, it is likely inadequate for 3-D shaped crystals with substantial diffusive resetting (e.g., Ganguly and Tirone, 1999;Costa et al, 2003).…”

Section: Introductionmentioning

confidence: 99%

Formation of fast-spreading lower oceanic crust as revealed by a new Mg–REE coupled geospeedometer

Sun

Lissenberg

2018

Earth and Planetary Science Letters

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A new geospeedometer is developed based on the differential closures of Mg and rare earth element (REE) bulk-diffusion between coexisting plagioclase and clinopyroxene. By coupling the two elements with distinct bulk closure temperatures, this speedometer can numerically solve the initial temperatures and cooling rates for individual rock samples. As the existing Mg-exchange thermometer was calibrated for a narrow temperature range and strongly relies on model-dependent silica activities, a new thermometer is developed using literature experimental data. When the bulk closure temperatures of Mg and REE are determined, respectively, using this new Mg-exchange thermometer and the existing REE-exchange thermometer, this speedometer can be implemented for a wide range of compositions, mineral modes, and grain sizes. Applications of this new geospeedometer to oceanic gabbros from the fast-spreading East Pacific Rise at Hess Deep reveal that the lower oceanic crust crystallized at temperatures of 998-1353 • C with cooling rates of 0.003-10.2 • C/yr. Stratigraphic variations of the cooling rates and crystallization temperatures support deep hydrothermal circulations and in situ solidification of various replenished magma bodies. Together with existing petrological, geochemical and geophysical evidence, results from this new speedometry suggest that the lower crust formation at fast-spreading mid-ocean ridges involves emplacement of primary mantle melts in the deep section of the crystal mush zone coupled with efficient heat removal by crustal-scale hydrothermal circulations. The replenished melts become chemically and thermally evolved, accumulate as small magma bodies at various depths, feed the shallow axial magma chamber, and may also escape from the mush zone to generate off-axial magma lenses.

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“…Olivine is one of the most useful minerals for such studies (e.g., Gerlach and Grove 1982;Nakamura 1995;Martin et al 2008) because it commonly occurs in mafic magma, and its rapid Mg-Fe interdiffusion enables timescales to be estimated at less than 1 month. Recently, Mg in plagioclase has been used to provide time scales of days to years (e.g., Costa et al 2003Costa et al , 2008Druitt et al 2012;Ruprecht and Cooper 2012). Magnetite phenocrysts are particularly useful in silicic magma systems for detecting the processes within days to months before eruption (e.g., Nakamura 1996; Devine et al 2003;Chertkoff and Gardner 2004;Tomiya and Takahashi 2005) because of their rapid diffusion (Van Orman and Crispin 2010) and common occurrence in various types of magma.…”

Section: Introductionmentioning

confidence: 99%

Short time scales of magma-mixing processes prior to the 2011 eruption of Shinmoedake volcano, Kirishima volcanic group, Japan

et al. 2013

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We estimated time scales of magma-mixing processes just prior to the 2011 sub-Plinian eruptions of Shinmoedake volcano to investigate the mechanisms of the triggering processes of these eruptions. The sequence of these eruptions serves as an ideal example to investigate eruption mechanisms because the available geophysical and petrological observations can be combined for interpretation of magmatic processes. The eruptive products were mainly phenocryst-rich (28 vol%) andesitic pumice (SiO 2 57 wt%) with a small amount of more silicic pumice (SiO 2 62-63 wt%) and banded pumice. These pumices were formed by mixing of low-temperature mushy silicic magma (dacite) and high-temperature mafic magma (basalt or basaltic andesite). We calculated the time scales on the basis of zoning analysis of magnetite phenocrysts and diffusion calculations, and we compared the derived time scales with those of volcanic inflation/deflation observations. The magnetite data revealed that a significant mixing process (mixing I) occurred 0.4 to 3 days before the eruptions (preeruptive mixing) and likely triggered the eruptions. This mixing process was not accompanied by significant crustal deformation, indicating that the process was not accompanied by a significant change in volume of the magma chamber. We propose magmatic overturn or melt accumulation within the magma chamber as a possible process. A subordinate mixing process (mixing II) also occurred only several hours before the eruptions, likely during magma ascent (syn-eruptive mixing). However, we interpret mafic injection to have begun more than several tens of days prior to mixing I, likely occurring with the beginning of the inflation (December 2009). The injection did not instantaneously cause an eruption but could have resulted in stable stratified magma layers to form a hybrid andesitic magma (mobile layer). This hybrid andesite then formed the main eruptive component of the 2011 eruptions of Shinmoedake.

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Diffusion coupling between trace and major elements and a model for calculation of magma residence times using plagioclase

Cited by 240 publications

References 46 publications

Li zoning in zircon as a potential geospeedometer and peak temperature indicator

Li zoning in zircon as a potential geospeedometer and peak temperature indicator

Formation of fast-spreading lower oceanic crust as revealed by a new Mg–REE coupled geospeedometer

Short time scales of magma-mixing processes prior to the 2011 eruption of Shinmoedake volcano, Kirishima volcanic group, Japan

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