Experimental crystal growth in glass inclusions: the possibilities and limits of the method

Clocchiatti, R.; Massare, D.

doi:10.1007/bf00379453

Cited by 33 publications

(14 citation statements)

References 25 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…[34] Because high MgO Ã lavas are missing from the inner floor Rift, we used melt inclusions trapped in Bytownite phenocrysts from the Ardoukoba eruption as a starting parental magma composition for the recent lava flows [Clocchiatti and Massare, 1985]. These high MgO liquid compositions (red dots in Figure 6) are different from those erupted on the rift shoulders (black dots with MgO Ã > 8% in Figure 6).…”

Section: Fractional Crystallizationmentioning

confidence: 99%

Petrological constraints on melt generation beneath the Asal Rift (Djibouti) using quaternary basalts

Pinzuti

Humler

Manighetti

2013

Geochem Geophys Geosyst

View full text Add to dashboard Cite

[1] The temporal evolution of the mantle melting processes in the Asal Rift is evaluated from the chemical composition of 56 new lava flows sampled along 10 km of the rift axis and 9 km off-axis (i.e., erupted within the last 620 kyr). Petrological and primary geochemical results show that most of the samples of the inner floor of the Asal Rift are affected by plagioclase accumulation. Trace element ratios and major element compositions corrected for mineral accumulation and crystallization show a symmetric pattern relative to the rift axis and preserved a clear signal of mantle melting depth variations. While FeO, Fe 8.0 , Zr/Y, and (Dy/Yb) N decrease from the rift shoulders to the rift axis, SiO 2 , Na/Ti, Lu/Hf increase and Na 2 O and Na 8.0 are constant across the rift. These variations are qualitatively consistent with shallow melting beneath the rift axis and deeper melting for off-axis lava flows. Na 8.0 and Fe 8.0 contents show that beneath the rift axis, melting paths are shallow, from 81 6 4 to 43 6 5 km. These melting paths are consistent with adiabatic melting in normal-temperature fertile asthenosphere, beneath an extensively thinned mantle lithosphere. On the contrary, melting on the rift shoulders (from 107 6 7 to 67 6 8 km) occurred beneath thicker lithosphere, requiring a mantle solidus temperature 100 6 40 C hotter. In this geodynamic environment, the calculated rate of lithospheric thinning appears to be 4.0 6 2.0 cm yr À1 , a value close to the mean spreading rate (2.9 6 0.2 cm yr À1 ) over the last 620 kyr.

show abstract

Section: Fractional Crystallizationmentioning

confidence: 99%

Petrological constraints on melt generation beneath the Asal Rift (Djibouti) using quaternary basalts

Pinzuti

Humler

Manighetti

2013

Geochem Geophys Geosyst

View full text Add to dashboard Cite

show abstract

“…The Absence of Bubbles-During natural cooling of melt inclusions, the differential contraction of the host (a crystal) and the melt results in the formation of a shrinkage bubble and, depending mainly on the cooling rate, crystalline nuclei (Clocchiatti, 1975;Roedder, 1984;Clocchiatti and Massare, 1985). If the inclusion remains a closed system, the crystallization of daughter phases will produce an even larger empty volume with respect to that of the same inclusion that is only composed of glass.…”

Section: Discussion Previous Workmentioning

confidence: 99%

“…Many heating experiments on glass-bearing inclusions as experimental crystallization have been performed to obtain information regarding the liquidus, the sequence of crystallization of different phases, and to determine the physico-chemical conditions prevailing during crystallization of the host (e.g., Sobolev and Kostyuk 1975;Sobolev et al, 1976;Clocchiatti, 1975;Clocchiatti et al, 1978;Roedder, 1984;Clocchiatti and Massare, 1985).…”

Section: Heating Experiments Support Heterogeneous Trappingmentioning

confidence: 99%

Glass‐bearing inclusions in olivine of the Chassigny achondrite: Heterogeneous trapping at sub‐igneous temperatures

Varela

Kurat

Bonnin-Mosbah

et al. 2000

Meteorit & Planetary Scien

Self Cite

View full text Add to dashboard Cite

Abstract-Three types of glass-bearing inclusions are present in olivine and chromite of the Chassigny achondrite: pure glass, monocrystal (glass plus a single mineral grain), and multiphase (glass plus a variety of minerals) inclusions. The occurrence, texture, and mineralogy of these inclusions and the chemical composition of the glass suggest an origin by heterogeneous trapping of these phases. The glass is rich in Si02, A1203, Na20, K20; and poor in MgO, FeO, and CaO; and contains appreciable amounts of C1. The compositional variability of the glass is independent of the mineral content of the inclusions. Heating experiments with final temperatures of 900, 1000, and 1200 "C were performed with Chassigny inclusions for the first time. The glass of the heated inclusions has a chemical composition similar to that of unheated inclusions. This situation suggests that the glass cannot be a residual melt but rather is an independent component that was trapped with or without mineral phases. The extreme heterogeneity in alkali contents, and in particular Rb and Sr contents, also suggests precipitation and mixing of solid precursors. The most Rb-rich glasses have near-chondritic Rb/Sr ratios, possibly indicating a chondritic source for their precursor(s). None of the inclusions contain bubbles like those of typical melt inclusions in terrestrial igneous minerals. Furthermore, many inclusions are at the center of radial cracks in the host olivine, which indicates development of an overpressure within the inclusions at some time. A volume increase of the inclusions could have been achieved by differential thermal expansion of the content of the inclusion during a heating event. That mechanism requires bubble-free and solid preheating inclusion contents. These features are incompatible with an origin of the inclusions by trapping of a silicate melt and point toward heterogeneous trapping of solid phases. The first N analyses performed in Chassigny glass-bearing inclusions by nuclear reaction analysis (NRA) revealed high and variable N contents of the glass, which suggests trapping of a solid precursor (presumably at relatively low temperatures) from a fluid rather than a melt. In conclusion, the glass-bearing inclusions in Chassigny olivine are not residuals after a closedsystem evolution of a trapped melt, but rather heterogeneously trapped precipitates of a fluid that existed during formation of Chassigny constituents. Consequently, it is very unlikely that the host olivine has an igneous origin.

show abstract

“…However, this degree of superheating will be limited; glass inclusions burst above a certain temperature (the decrepitation temperature). The decrepitation temperature is clearly dependent on the size and position of an inclusion in the crystal, but can be optimized as a function of the nature of the crystals (Clocchiatti & Massare, 1985). Therefore, similar experiments performed with natural melt inclusions, overheated and then quenched at various temperatures, could allow accurate determination of metastable phase diagrams for complex magma compositions such as mid-ocean ridge basalt (MORB).…”

Section: Metastable Phase Diagrams Relevant For Natural Systemsmentioning

confidence: 99%

Contrasted Liquid Lines of Descent Revealed by Olivine-hosted Melt Inclusions and the External Magma

Fauré

Tissandier

2014

Journal of Petrology

View full text Add to dashboard Cite

To better understand the significance of the chemical compositions of forsterite-hosted melt inclusions, dynamic crystallization experiments were performed at atmospheric pressure and a low cooling rate (28C h À1 ) on a starting glass material with a composition in the CMAS system (12·21wt % CaO, 28·48 wt % MgO, 11·96 wt % Al 2 O 3 , 47·32 wt % SiO 2 ). Experiments were quenched at various temperatures, both above and below the theoretical solidus. Olivine is the liquidus phase and the mesostasis may exhibit a second crystalline phase corresponding to a metastable Al-rich pyroxene. Olivine crystal morphologies change from polyhedral to skeletal, depending on the quenching temperature. Regardless of the quenching temperature, the chemical compositions of liquids trapped in melt (now glass) inclusions in the olivines do not contain the boundary layer that should result from rapid growth of these crystals. The liquid compositions also show that down to temperatures far below the theoretical solidus, olivine is the only phase that crystallizes on the walls of these inclusions. Glass inclusion analyses can therefore be used to determine the chemical evolution of a liquid in metastable equilibrium with the host olivine, irrespective of the quenching temperature. Melt inclusions therefore follow their own liquid line of descent distinct from that of the whole charge. This experimental study suggests that it should be possible to (1) draw the metastable extensions of the liquidus from natural glass inclusions and (2) determine the real supersaturation degrees of the residual magmas.

show abstract

Experimental crystal growth in glass inclusions: the possibilities and limits of the method

Cited by 33 publications

References 25 publications

Petrological constraints on melt generation beneath the Asal Rift (Djibouti) using quaternary basalts

Petrological constraints on melt generation beneath the Asal Rift (Djibouti) using quaternary basalts

Glass‐bearing inclusions in olivine of the Chassigny achondrite: Heterogeneous trapping at sub‐igneous temperatures

Contrasted Liquid Lines of Descent Revealed by Olivine-hosted Melt Inclusions and the External Magma

Contact Info

Product

Resources

About