Geochemical investigations of ordinary chondrites, shergottites, and Hawaiian basalts

Part I. Quantifying peak metamorphic temperatures is critical for understanding the thermal histories of ordinary chondrite parent asteroids. We performed two-pyroxene geothermometry, using QUILF95, on the same Type 6 chondrites for which peak temperatures were estimated using the plagioclase geothermometer. Pyroxenes record a narrow, overlapping range of temperatures in H6 (865--926°C), L6 (812--934°C), and LL6 (874--945°C) chondrites. Lower plagioclase temperature estimates may not reflect peak metamorphic temperatures because chondrule glass probably recrystallized to plagioclase prior to reaching the metamorphic peak. The average temperature for H, L, and LL chondrites (∼900°C) is at least 50°C lower than peak temperatures used in current asteroid thermal evolution models, which may require minor adjustments.; Part II. Lithium, beryllium, and boron indicate a component of recycled crust in the source regions of island arc lavas. Radiogenic isotopes and other geochemistry of basalts from Mauna Kea and Mars (basaltic shergottites) suggest their source regions may contain a crustal component. We measured Li, Be, and B to determine whether the crustal component identified in Mauna Kea and Martian basalts was altered at low temperatures.; Mauna Kea. Several samples show effects of alteration, but Li (3.9+/-0.9 ppm) and Be (0.47+/-0.09 ppm) preserve igneous compositions. Variable B/K ratios (0.0002--0.008) and B/Be ratios (1--25) suggest post-magmatic alteration modified the igneous B signature. Li and Be do not correlate with Pb isotopes or Nb/Zr ratios, which were used previously to identify geochemically distinct groups, or O isotopes, which were used to identify a crustal component altered at high temperatures. Our results confirm that the crustal component was not altered at low temperatures.; Mars. Shergottites contain Be (0.09--0.77 ppm) abundances similar to mid-ocean ridge basalts or ocean island basalts, whereas Li abundances (2.7--9.9 ppm) are similar to island arc basalts. The lack of correlation between Li, Be, or Li isotopes and oxygen isotopes suggest the "crustal" component in shergottites was not altered at low temperatures.