TY - JOUR
T1 - The flash melting of chondrules
T2 - An experimental investigation into the melting history and physical nature of chondrule precursors
AU - Connolly, Harold C.
AU - Jones, Brian D.
AU - Hewins, Roger H.
N1 - Funding Information:
We would like to thank Jeremy S. Delaney, Gary E. Lofgren, Richard D. Ash, Brigitte Zanda, and Claude Herzberg for numerous discussions and constructive comments. The quality of the paper was greatly improved by helpful reviews from G. E. Lofgren, S. S. Russell, and C. M. Alexander. We also thank Bill Seldon of the Rutgers Geology Museum for the gift of minerals for use in our starting composition. This research was funded by NASA grants NGW 9-35 to Roger H. Hewins, PI, NAGW 3391 training grant for Harold C. Connolly Jr. and NASA NAG5-4319 to D. S. Burnett, PI. California Institute of Technology Division contribution number 5813.
PY - 1998/8
Y1 - 1998/8
N2 - Constraints placed on chondrule formation have largely been generated from experiments which use a long duration, below liquidus isothermal melting (minutes to hours) rather than a short duration, above liquidus flash melting event (seconds to minutes). In this paper we examine how a short duration, superliquidus heat pulse can produce chondrule textures. By incompletely melting material with a type of flash melting we show that the maximum temperature limit of chondrule formation was approximately 2100°C, almost 400°C higher than previously constrained. Previous experiments also have not studied the effect of variations in precursor grain size on the formation of chondrule textures. For this reason we simultaneously investigate the effect of variations in the grain size of a starting composition on the formation of chondrule textures. We show how MgO-rich (Type IA) chondrules and other fine-grained chondrules could only have been formed from the incomplete melting of a rather uniformly grain sized precursor of less than 63μm. Because fine-grained, MgO-rich chondrules have the some of the highest chondrule liquidus temperatures, we proposed that these types of textures define a minimum melting temperature for chondrule formation.
AB - Constraints placed on chondrule formation have largely been generated from experiments which use a long duration, below liquidus isothermal melting (minutes to hours) rather than a short duration, above liquidus flash melting event (seconds to minutes). In this paper we examine how a short duration, superliquidus heat pulse can produce chondrule textures. By incompletely melting material with a type of flash melting we show that the maximum temperature limit of chondrule formation was approximately 2100°C, almost 400°C higher than previously constrained. Previous experiments also have not studied the effect of variations in precursor grain size on the formation of chondrule textures. For this reason we simultaneously investigate the effect of variations in the grain size of a starting composition on the formation of chondrule textures. We show how MgO-rich (Type IA) chondrules and other fine-grained chondrules could only have been formed from the incomplete melting of a rather uniformly grain sized precursor of less than 63μm. Because fine-grained, MgO-rich chondrules have the some of the highest chondrule liquidus temperatures, we proposed that these types of textures define a minimum melting temperature for chondrule formation.
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U2 - 10.1016/S0016-7037(98)00176-8
DO - 10.1016/S0016-7037(98)00176-8
M3 - Article
AN - SCOPUS:0344959401
SN - 0016-7037
VL - 62
SP - 2725
EP - 2735
JO - Geochimica et Cosmochimica Acta
JF - Geochimica et Cosmochimica Acta
IS - 15
ER -