Magma Solidification Processes beneath Kilauea Volcano, Hawaii: a Quantitative Textural and Geochemical Study of the 1969-1974 Mauna Ulu Lavas

Vinet, Nicolas; Higgins, Michael D.

doi:10.1093/petrology/egq020

Cited by 67 publications

(42 citation statements)

References 92 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Comparison of CSD curves of the mircomonzogabbros from Qisir Dagh (Fig. 11) with the standard CSD models of Vinet & Higgins (2010) (Fig. 12) suggests the similarity of CSD curves of this study to the curve presented in Fig.…”

Section: Discussionsupporting

confidence: 66%

Crystal size and shape distribution systematics of plagioclase and the determination of crystal residence times in the micromonzogabbros of Qisir Dagh, SE of Sabalan volcano (NW Iran)

Pourkhorsandi¹,

Mirnejad²,

Raiesi³

et al. 2015

Geologica Carpathica

View full text Add to dashboard Cite

Abstract:The Qisir Dagh igneous complex occurs as a combination of volcanic and intrusive rocks to the south-east of the Sabalan volcano, north-western Iran. Micromonzogabbroic rocks in the region consist of plagioclase, alkaline feldspar and clinopyroxene as the major mineral phases and orthopyroxene, olivine, apatite and opaque minerals as the accessory minerals. Microgranular and microporphyritic textures are well developed in these rocks. Considering the importance of plagioclase in reconstructing magma cooling processes, the size and shape distribution and chemical composition of this mineral were investigated. Based on microscopic studies, it is shown that the 2-dimensional size average of plagioclase in the micromonzogabbros is 538 micrometers and its 3-dimensional shape varies between tabular to prolate. Crystal size distribution diagrams point to the presence of at least two populations of plagioclase, indicating the occurrence of magma mixing and/or fractional crystallization during magma cooling. The chemical composition of plagioclase shows a wide variation in abundances of Anorthite-Albite-Orthoclase (An = 0.31-64.58, Ab =29.26-72.13, Or = 0.9-66.97), suggesting a complex process during the crystal growth. This is also supported by the formation of antiperthite lamellae, which formed as the result of alkali feldspar exsolution in plagioclase. The calculated residence time of magma in Qisir Dagh, based on 3D crystal size distribution data, and using growth rate G = 10 -10 mm/s, varies between 457 and 685 years, which indicates a shallow depth (near surface) magma crystallization and subvolcanic nature of the studied samples.

show abstract

Section: Discussionsupporting

confidence: 66%

Crystal size and shape distribution systematics of plagioclase and the determination of crystal residence times in the micromonzogabbros of Qisir Dagh, SE of Sabalan volcano (NW Iran)

Pourkhorsandi¹,

Mirnejad²,

Raiesi³

et al. 2015

Geologica Carpathica

View full text Add to dashboard Cite

show abstract

“…Synneusis is perhaps most likely to occur if the system contains sufficient melt for the crystals to move relative to each other (Schwindinger and Anderson 1989) and is typically manifest in volcanic and plutonic rocks by grain clusters (e.g. Schwindinger 1999;Jerram et al 2003;Vinet and Higgins 2010). Another possible mechanism for creating aggregates is the disintegration of a mushy layer forming within the magma chamber (Passmore et al 2012).…”

Section: Crystal-poor Systems: Grain Aggregations In the Early Stagesmentioning

confidence: 99%

“…Access to this stage of the solidification history is via crystal-rich glassy enclaves entrained in erupted lavas (Holness et al 2007a), or via the crystal load of volcanic rocks (e.g. Vinet and Higgins 2010), although these sources provide no spatial information. Rapidly-cooled versions of this stage are also available from the drilled crust of lava lakes.…”

Section: Crystal-rich Mush: the Final Stages Of Solidificationmentioning

confidence: 99%

See 1 more Smart Citation

The Influence of Interfacial Energies on Igneous Microstructures

Holness

Vernon

2015

Springer Geology

View full text Add to dashboard Cite

The thermal history of igneous rocks is encoded in their microstructures via the control by cooling rate on crystal growth. If temperatures remain close to the liquidus, with small undercoolings, growth rates are low and microstructures are strongly affected by constraints imposed by interfacial energies. The minimisation of interfacial energy results in the melt topology becoming a function of dihedral angle and porosity. Further effects include the loss of the smallest crystals (Ostwald ripening), though this process is restricted to very small grainsizes. For large crystals, interfacial energy controls the microstructure by determining the shapes, but not the size or number of crystals. In mafic-ultramafic magmas, minerals with a larger structural anisotropy (e.g., plagioclase) commonly form crystals with low-energy faces, with or without some rounding of corners, whereas minerals with lower structural anisotropy (e.g., olivine) form crystals with rounded to locally planar boundaries.Microstructures in partially solidified material from lava lakes and entrained glassy enclaves suggest that interfacial energies play only a minor role in the supersolidus of rapidly-cooled or coarse-grained rocks. They are most important for slowly-cooled bodies of hot magma crystallizing as crystallographically simple minerals, especially adcumulates in layered complexes.Interfacial energies may also play a role in the sub-solidus, leading to the development of a granular microstructure in some adcumulates. This is, however, only important for very fine-grained rocks such as chill zones, or for monomineralic rocks. Elsewhere there is little or no evidence for significant grain growth in the sub-solidus, demonstrating that the end-stage of microstructural equilibration generally is not reached in crustal layered intrusions.

show abstract

“…Keywords: Mush disaggregation, basalt, automated mineralogy, crystal size distributions, textures, Dynamics of Magmatic Processes iNtroDuctioN Macrocryst entrainment from disaggregating crystal mushes is a widely recognized process in basaltic plumbing systems (Rhodes et al 1979;Lange et al 2013a;Neave et al 2014). For example, primitive olivine crystals carried by evolved liquids have been interpreted as entrained macrocrysts in samples from Iceland (Thomson and Maclennan 2013), Hawai'i (Vinet and Higgins 2010), Réunion (Albarède and Tamagnan 1988), and mid-ocean ridges (Donaldson and Brown 1977). Basalt-hosted high-anorthite plagioclase macrocrysts have also been understood as disaggregated mush remnants in a range of geological settings (Hansen and Grönvold 2000;Ridley et al 2006).…”

Section: Introductionmentioning

confidence: 99%

Continuous mush disaggregation during the long-lasting Laki fissure eruption, Iceland

Neave

Buisman

Maclennan

2017

American Mineralogist

View full text Add to dashboard Cite

Plagioclase textures were investigated in the products of the voluminous 1783-1784 CE Laki eruption from the Eastern Volcanic Zone (EVZ) of Iceland to establish whether mush disaggregation occurred solely at the onset of the eight-month eruption or throughout its whole duration. Phase proportions and plagioclase size distributions were determined using standard optical and manual techniques as well as automated approaches based on Quantitative Evaluation of Minerals by SCANing electron microscopy (QEMSCAN). Based on optical microscopy and the explicit combination of textural and compositional information in QEMSCAN images, plagioclase crystals were divided into two populations: small (<0.5 mm long), high-aspect ratio (length/width >4) microcrysts with low-anorthite (0.5 mm long), low-aspect ratio (length/width = 2-3) macrocrysts with high-anorthite (An 84 -An 92 ) cores. Small microcrysts grew from their carrier liquid during the final phase of pre-eruptive crystallization while large macrocrysts, which are out of geochemical equilibrium with their carrier liquids, were entrained from crystal mushes. Changes in phase proportions and plagioclase size distributions between eruptive episodes demonstrate that macrocryst entrainment efficiency varied substantially during the eruption; material erupted in later episodes contain proportionally more mush-derived material. Using stereologically corrected plagioclase size distributions, we estimate that the pre-eruptive residence times of microcrysts in the Laki carrier liquid were probably of the order of 2-20 days. Because microcryst crystallization was concurrent with macrocryst rim growth, these day-to-week residence times also indicate that macrocryst entrainment occurred on much shorter timescales than the eruption's eight-month duration. In line with constraints from independent geochronometers, macrocryst entrainment and mush disaggregation thus appears to have continued throughout the eruption. Magmas were assembled on an episode by episode basis, and the volume of eruptible magma in the plumbing system at any given time was probably closer to 1-2 km 3 than the final erupted volume of 15.1 km 3 .

show abstract

Magma Solidification Processes beneath Kilauea Volcano, Hawaii: a Quantitative Textural and Geochemical Study of the 1969-1974 Mauna Ulu Lavas

Cited by 67 publications

References 92 publications

Crystal size and shape distribution systematics of plagioclase and the determination of crystal residence times in the micromonzogabbros of Qisir Dagh, SE of Sabalan volcano (NW Iran)

Crystal size and shape distribution systematics of plagioclase and the determination of crystal residence times in the micromonzogabbros of Qisir Dagh, SE of Sabalan volcano (NW Iran)

The Influence of Interfacial Energies on Igneous Microstructures

Continuous mush disaggregation during the long-lasting Laki fissure eruption, Iceland

Contact Info

Product

Resources

About