Abstract
Compositional data for spinels in the chromite‐hercynite‐ulvöspinel system from three large basalts and for spinels in 48 basalt particles in four soil samples show: (1) that the range of compositions are comparable to those of spinels in Apollo 12 basalts; (2) that the spinel series is complete between 0.75 FeCr2O4 0.25 FeAl2O4 and Fe2TiO4; (3) that the Apollo 12 bimodal distribution is present insofar as chromite‐rich and ulvöspinel‐rich phases are more commonly present than compositions intermediate between these two end members; (4) well defined ionic relationships exist for those cations displaying high octahedral site preference energies in the spinel structure (viz. Cr vs Al and Ti vs Cr+ Al); (5) cations displaying low site preference energies (Fe2+, Mg) show poor correlation; and (6) the absence of a simple relationship between the divalent ions (Fe2+ and Mg), and the paucity (10% of 356 analyses) of intermediate compositions suggests a strong dependence on the structural stability of intermediate members of a normal (hercynite, chromite) — inverse (ulvöspinel) solid solution series
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
