Crystal sizes in evolving silicic magma chambers

Bindeman, I. N.

doi:10.1130/0091-7613(2003)031<0367:csiesm>2.0.co;2

Cited by 80 publications

(40 citation statements)

References 23 publications

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“…Dissolution is taken to be limited by diffusion, and hence dependant on crystal size, whereas growth is considered to be independent of size. Cycles of a few degrees are sufficient to produce macroscopic coarsening and CSDs similar to that observed in natural systems (Higgins 1998;Bindeman 2003;Johnson and Glazner 2009). This process may well add onto coarsening produced by CN models and the two may not be easily distinguishable.…”

Section: Temperature Cycling Modelsmentioning

confidence: 80%

“…Another approach is to destroy the rock and separate the crystals (e.g. Kretz 1969;Bindeman 2003). Ideally size and shape are preserved, even if position, orientation, and context are lost.…”

Section: Textural Analytical Methodsmentioning

confidence: 98%

“…The most common mineral is sanidine, but it was intensely broken during the eruption process. However, zircon crystals are commonly intact and can be separated by gentle crushing and acid digestion (Bindeman 2003). Zircon CSDs are concave down on a classic CSD diagram (Figure 8).…”

Section: Example 1: Bishop Tuffmentioning

confidence: 99%

“…Zircon CSDs in the Bishop Tuff, USA (modified fromBindeman 2003). Zircons were separated mechanically, but the lower termination does not appear to be an artefact.…”

mentioning

confidence: 99%

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Textural coarsening in igneous rocks

Higgins

2010

International Geology Review

123

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Section: Temperature Cycling Modelsmentioning

confidence: 80%

Section: Textural Analytical Methodsmentioning

confidence: 98%

Section: Example 1: Bishop Tuffmentioning

confidence: 99%

“…Zircon CSDs in the Bishop Tuff, USA (modified fromBindeman 2003). Zircons were separated mechanically, but the lower termination does not appear to be an artefact.…”

mentioning

confidence: 99%

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Textural coarsening in igneous rocks

Higgins

2010

International Geology Review

123

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“…These datasets provide a statistical approximation of the occurrence frequencies of specific sizes of individual grains of the target mineral and are commonly used for describing or fingerprinting magmatic rocks. In addition, CSDs are useful for diverse petrogenetic applications, including assessing nucleation and growth rates of crystals [7,8,23], estimating residence times in magma chambers [2,16], identifying the effects of crystal-settling [5] or quantifying pyroclastic fragmentation intensity [1,4].…”

Section: Introductionmentioning

confidence: 99%

An image analysis method to determine crystal size distributions of olivine in kimberlite

et al. 2008

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Crystal size distributions (CSDs) are a standard method of describing populations of crystals within magmatic rocks. Olivine is the dominant phase in kimberlite (∼40-50% by volume) and features a diverse range of sizes, shapes and origins. CSDs of olivine provide a logical means of semi-quantitatively characterising kimberlite. The CSDs can then be used to distinguish or correlate between kimberlite bodies or to investigate processes related to ascent, emplacement and eruption. In this paper, we present an automatic image analysis technique that provides efficient quantification of olivine CSDs within digital images of polished slabs of kimberlite. This technique relies on a combination of algorithms for detecting regions of interest (ROI) and for segmentation of ROIs in order to identify individual olivine crystals that are used for size distribution datasets. The detection process identifies regions expected to be olivine using a modelbased colour detection technique using Mahalanobis distance combined with texture analysis based on local standard deviation and greyscale foreground enhancement techniques. The segmentation process separates adjacent domains to identify individual crystals using an iterative marker-based watershed algorithm to separate adjoined structures of varying sizes. We demonstrate the utility of automatic image analysis by comparing CSDs for olivine derived from this method versus results from manual digitisation of olivine grains. The automatic detection system correctly identified ∼86% of the manually detected olivine domains; ∼88% of the automatically detected regions correctly correlate to manually defined olivine grains. Discrepancies between the two methods are mostly the result of oversimplification of crystal margins (i.e. rounding) by manual tracing whereas automatic boundary recognition shows clear advantages in identifying irregularities in crystal edges. Closer examination of the results shows that both methods suffer from under-representation of smaller crystals due to: (1) human subjectivity and error in manual tracing and (2) noise removal processes in automatic detection. Automatic detection of olivine grains is much more efficient than conventional manual tracing; manual detection requires ∼6 h per sample versus ∼1 min for automatic analysis of the same sample.

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Zircon U‐Pb geochronology of the Mount Givens Granodiorite: Implications for the genesis of large volumes of eruptible magma

Frazer

Coleman

Mills³

2014

JGR Solid Earth

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The Mount Givens Granodiorite, a large pluton in the central Sierra Nevada batholith, California, is similar in area to zoned intrusive suites yet is comparatively chemically and texturally homogenous. New zircon U-Pb geochronology indicates that the pluton was constructed over at least 7 Ma from 97.92 ± 0.06 Ma to 90.87 ± 0.05 Ma. Combining the new geochronology with the exposed volume of the pluton yields an estimated magma flux of <0.001 km 3 /a. The geochronologic data are at odds with the previously speculated links between plutons such as the Mount Givens Granodiorite and large-volume homogeneous ignimbrites (often termed monotonous intermediates). Existing data indicate that large plutons accumulate at rates of ≤0.001 km 3 /a, 1-2 orders of magnitude less than fluxes calculated for dated monotonous intermediates. If monotonous intermediates are remobilized, erupted plutons accumulated at rates comparable to dated examples, they should preserve a record of zircon growth of up to 10 Ma. Alternatively, the long history of zircon growth recorded in plutons may be erased during the processes of reheating and remobilization that precede supervolcano eruption. However, zircon dissolution modeling, based on hypothetical temperature-time histories for preeruptive monotonous intermediates, indicates that rejuvenation events would not sufficiently dissolve zircon. We suggest that eruptions of monotonous intermediates occur during high magmatic flux events, leaving little behind in the intrusive rock record, whereas low fluxes favor pluton accumulation.

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Crystal sizes in evolving silicic magma chambers

Cited by 80 publications

References 23 publications

Textural coarsening in igneous rocks

Textural coarsening in igneous rocks

An image analysis method to determine crystal size distributions of olivine in kimberlite

Zircon U‐Pb geochronology of the Mount Givens Granodiorite: Implications for the genesis of large volumes of eruptible magma

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