Petrography and bulk composition of Miller Range 05035: a new lunar VLT gabbro

For guidance on citations see FAQs. c [not recorded] Version: [not recorded] Link(s) to article on publisher's website: Copyright and Moral Rights for the articles on this site are retained by the individual authors and/or other copyright owners. For more information on Open Research Online's data policy on reuse of materials please consult the policies page. Introduction: Miller Range (MIL) 05035 is a crystalline lunar mare gabbroic meteorite collected in Antarctica in 2005 [1]. It is an important new sample in the lunar meteorite (LM) collection as it is only one of ~8 to be classified as basaltic in nature. MIL 05035 is coarsely grained with large pyroxene grains (”8mm) subophitically enclosing plagioclase grains (”6mm), and accessory ilmenite, spinel, silica and sulphide phases. Methods: Minerals in MIL 05035,31 and MIL 05035,34 were investigated using a Cameca SX50 Wavelength Dispersive electron microprobe. Mineral X-ray maps were made using a LEO 1455VP SEM fitted with Oxford Instruments INCA energy disper-sive X-ray spectrometer and bulk major-and trace-element chemistry was obtained using ICP-AES and ICP-MS techniques on 140 mg chip of MIL 05035,19 (Table 1). Lunar Origin: Fe to Mn ratios in the bulk rock (62), and in pyroxene (average: 60) and olivine phases (average: 80), bulk rock Co/Cr (0.014), and a typical lunar anhydrous mineralogy confirm lunar origin for this meteorite. We will report the results on ongoing oxygen isotope analysis at the LPSC 2007 meeting. Petrography: MIL 05035 is an unbrecciated, holocrystalline lunar gabbroic meteorite. Its coarse-grained nature suggests a slow cooling history in a thick lava flow. Pyroxenes: are the dominant mineral phases in MIL 05035 (~54% of sample ,31 by mode). They are typically large with compositional zoning from calcic-augite and pigeonite cores to Fe-rich calcic-augite rims: Fs 29-68 ,Wo 13-43 ,En 2-42 (Fig.1a,2).