Silicate inclusions in the Kodaikanal IIE iron meteorite

KURAT GERO,; MARIA EUGENIA VARELA; ZINNER ERNST,

Houston NASA

Congreso; XXXVI Lunar and Planetary Science Conference; 2005

Silicate inclusions in iron meteor-ites display an astonishing chemical and mineralogical variety, ranging from chondritic to highly fractionated, silica- and alkali-rich assemblages [e.g., 1]. In spite of this, their origin is commonly considered to be a sim-ple one: mixing of silicates, fractionated or unfraction-ated, with metal [1-4]. The latter had to be liquid in order to accommodate the former in a pore-free way which all models accomplish by assuming shock-melting.II-E iron meteorites are particularly interesting because they contain an exotic zoo of silicate inclu-sions, including some chemically strongly fraction-ated ones [e.g., 1, 5-9]. They also pose a formidable conundrum: young silicates are enclosed by very old metal [e.g., 4, 10-13]. This and many other incom-patibilities between models and reality forced the formulation of an alternative genetic model for irons [14]. Here we present preliminary findings in our study of Kodaikanal silicate inclusions.