Mineralogical, Chemical, and Isotopic Heterogeneity in Zagami: Evidence for a Complex Petrogenesis

• Main Authors: Park, J., Misawa, K., Nyquist, L. E., Shih, C-Y., Niihara, T.
• Format: Other/Unknown Material
• Language: unknown
• Published: 2013
• Subjects: Lunar and Planetary Science and Exploration; DML
• Online Access: http://hdl.handle.net/2060/20140003575

Textural variations in the shergottite Zagami were initially interpreted as evidence that it formed in a heterogeneous lava flow. Variations in initial Sr-87/Sr-86 ratios between a Coarse Grained (CG) and a Fine Grained (FG) lithology and evidence for more extensive fractionation of the Rb/Sr ratio in a Dark Mottled Lithology (DML) are consistent with such an interpretation. More recently, Niihara et al. and Misawa et al. have reported the mineralogy and Sr-isotopic systematics of an Olivine Rich Lithology (ORL) found in association with the coarse-grained DML lithology in the Kanagawa Zagami specimen [6,7]. Here we call this lithology DML(Ka) to maintain a distinction with DML(USNM) as studied. An Ar-Ar study by Park et al. of a late stage K-rich melt enriched in K2O to approx 7% and intruded into ORL yielded an Ar-Ar age of 202+/0 7 Ma. The present work extends the study of Kanagawa Zagami to Nd-isotopes.