Olivine growth rates in a tholeiitic basalt: An experimental study of melt inclusions in plagioclase

Jambon, Albert; Lussiez, Patricia; Clocchiatti, R.; Weisz, J.; Hernandez, Jean

doi:10.1016/0009-2541(92)90059-e

Cited by 72 publications

(49 citation statements)

References 21 publications

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“…We estimate their compositions range from Fo 52 to about Fo 30 . This texture corresponds to a fast-growth habit as shown by Donaldson (1976) and Jambon et al (1992). The second type are microphenocrysts that overgrow the former.…”

Section: Olivine and Kirschsteinitementioning

confidence: 99%

“…Crystallization of olivine from a melt with a spinifex-like texture. This implies a high degree of supercooling (see Donaldson 1976;Jambon et al 1992 ( 1) This permits to explain the high Ca activity from the beginning to the end of the crystallization sequence and the anomalous Ca/Al ratio of this rock. The porous aspect of carbonate contained in vesicles is the expression of its destabilization.…”

Section: Crystallization Of Nwa 1296mentioning

confidence: 99%

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Mineralogy and petrology of the angrite Northwest Africa 1296

Jambon

Barrat

Boudouma

et al. 2005

Meteorit & Planetary Scien

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Abstract-We report on a new angrite, Northwest Africa (NWA) 1296, a fine-grained rock with a magmatic texture of rapid cooling. Dendritic olivine (≈Fo 50 ) crystallized first in association with anorthite microcrysts (An 98-100 ) forming composite chains separated from one another by intergrown Al-Fe diopside-hedenbergite pyroxenes. In addition, some olivines with lower Mg# and increased CaO (up to 12%) are found between the chains as equant microphenocrysts. Pyroxenes and olivines are both normally zoned from Mg# = 0.52 to less than 0.01 in the rims. Ca-rich olivines are surrounded by, intergrown with, or replaced by subcalcic kirschsteinite. They appear after plagioclase crystallization stopped, at the end of the crystallization sequence. Minor phases are pyrrhotite, Fapatite, and titanomagnetite. Pyroxene is the last silicate phase to grow, interstitial to idiomorphic olivine-kirschsteinite. Numerous small vesicles and some channels are filled with microcristalline carbonate. The mode (vol%) is about 28% olivine, 3% kirschsteinite, 32% anorthite, 34% pyroxene, and 3% of the minor phases-close to that reported previously for D'Orbigny and Sahara (SAH) 99555. The bulk chemical composition of NWA 1296 is similar to D'Orbigny and SAH 99555; NWA 1296 differs by its texture and mineralogy, which are interpreted as resulting from rapid crystallization-an evidence of impact melting. Angrites cannot be produced by partial melting of a CV source because segregation of a "planetary" core is necessary to explain the low FeO/MgO ratio of magnesian olivines. Neither the odd Ca/Al ratio nor the very low SiO 2 content can be explained by conventional partial melting scenarios. We suggest that carbonate is the key to angrite genesis. This is supported by the striking similarities with terrestrial melilitites (low SiO 2 , superchondritic Ca/Al ratio, presence of carbonate). The lack of alkalies could be the result of either loss after impact melting or absence of alkalies in the source.

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Section: Olivine and Kirschsteinitementioning

confidence: 99%

Section: Crystallization Of Nwa 1296mentioning

confidence: 99%

Mineralogy and petrology of the angrite Northwest Africa 1296

Jambon

Barrat

Boudouma

et al. 2005

Meteorit & Planetary Scien

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“…According to Jambon et al (1992), P-Al-rich areas of olivine may grow in minutes, whereas P-Al-poor zones represent a few weeks. Furthermore, high-resolution X-ray mapping of P in olivine reveals narrow P-rich bands parallel to rim of the crystals (Fig.…”

Section: Discussionmentioning

confidence: 99%

Phosphorus Zoning From Secondary Olivine in Mantle Xenolith From Middle Atlas Mountains (Morocco, Africa): Implications for Crystal Growth Kinetics

Mavrogonatos¹,

Flemetakis²,

Papoutsa³

et al. 2017

geosociety

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“…Adopting, for example, a value of G of olivine ranging from 10 −5 to 10 −6 mm/s (Jambon et al 1992) and of pyroxene from 10 −6 to 10 −7 mm/s (Castro et al 2003) and using the formula τ=−1/GS (where τ=residence time, S=slope, G=growth rate of mineral), the residence time of the mafic microcrystals (<0.1 mm) is very short, ranging from minutes to an hour. However, these values of G appear to be too high and would give skeletal forms of the crystals which are instead not present in the dolerites.…”

Section: Crystal Size Distributionmentioning

confidence: 99%

Transient processes in Stromboli’s shallow basaltic system inferred from dolerite and magmatic breccia blocks erupted during the 5 April 2003 paroxysm

et al. 2009

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We describe the mineralogy, geochemistry, and mesomicrostructure of fresh subvolcanic blocks erupted during the 5 April 2003 paroxysm of Stromboli (Aeolian Islands, Italy). These blocks represent ∼50 vol.% of the total erupted ejecta and consist of fine-to medium-grained basaltic lithotypes ranging from relatively homogeneous dolerites to strongly or poorly welded magmatic breccias. The breccia components are represented by angular fragments of dolerites entrapped in a matrix of vesiculated (lava-like to scoriae) crystal-rich (CR) basalt. All of the studied blocks are cognates with the CR basalt of the normal Strombolian activity or lavas and they are often coated by a few-centimeter thick layer of crystal-poor (CP) basaltic pumice erupted during the paroxysm. We suggest that they result from the rapid increase of pressure and related subvolcanic rock failure that occurred shortly before the 5 April 2003 explosion, when the uppermost portion of the edifice inflated and suffered brecciation as the result of the sudden rise of the gas-rich CP basalt that triggered the eruption. Dolerites and magmatic matrix of the breccias show major and trace element compositions that match those of the CR basalts erupted during normal Strombolian activity and effusive events at Stromboli volcano. Dolerites consist of (a) phenocrysts normally found in the CR basalts and (b) late-stage magmatic minerals such as sanidine, An 60-28 plagioclase, Fe-Mn-rich olivines (Fo 68-48 ), phlogopite, apatite, and opaque mineral pairs (magnetite and ilmenite), most of which are never found both in lava flows and scoriae erupted during the persistent explosive activity that characterizes typical Strombolian behavior. Subvolcanic crystallization of the Stromboli CR magma, leading to slowly cooled equivalents of basalts, could result from transient drainage of the magma from the summit craters to lower levels. Fingering and engulfing of the material that collapsed from the summit crater floor into the shallow basaltic system during the late evening of 28 December 2002 coupled with the short break in the summit persistent explosions between December 2002 and March 2003 permitted the CR magma pockets to solidify as dolerites, which were confined to the uppermost portion of the system and thus not involved in the ongoing flank effusive activity. Crystal size distribution of the basaltic blocks and crystallization of the finer-grained (<0.1 mm) mafic minerals of the dolerites over a time interval of ∼100 days closely agrees with the above interpretation. Vesicle filling (miarolitic cavities) locally found in some dolerites, with minerals deposited as vapor-phase crystallization is a result of continuous gas percolation through the rocks of the uppermost portion of the volcanic system. Poorly welded magmatic breccias formed during syn-eruptive processes of 5 April 2003, when the paroxysm strongly shattered the shallow subvolcanic system and many dolerite fragments were entrapped in the CR magma. In contrast, the high degree of welding between the dolerit...

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Olivine growth rates in a tholeiitic basalt: An experimental study of melt inclusions in plagioclase

Cited by 72 publications

References 21 publications

Mineralogy and petrology of the angrite Northwest Africa 1296

Mineralogy and petrology of the angrite Northwest Africa 1296

Phosphorus Zoning From Secondary Olivine in Mantle Xenolith From Middle Atlas Mountains (Morocco, Africa): Implications for Crystal Growth Kinetics

Transient processes in Stromboli’s shallow basaltic system inferred from dolerite and magmatic breccia blocks erupted during the 5 April 2003 paroxysm

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