On February 28, 1857, at 12:00 noon, sonic booms were heard followed by the fall of two stones weighing 134 pounds and 37 pounds. Parnallee is said to be 16 miles south of Madura, India but no village with this name can be traced in the area. The place of fall is probably Perunali, Ramnad district, 52 miles SSE of Madura.
This is a very primitive chondrite full of slightly flattened chondrules (ave. 10% deformation) ranging in size from 0.2 mm to 2.5 mm, but some as large as 4 mm have been identified. They include radial pyroxene, barred olivine, and porphyritic types. Shock effects include fractured olivine and extensive undulatory extinction, likely the result of the impact shock that also produced the chondrule foliation. In a study of two LL chondrites, NWA 1701 and LAR 06298, Weirich et al. (2009) determined an Ar–Ar age of ~1 b.y., possibly reflecting the last major impact on the LL chondrite parent body. A shock stage of S3 was determined for Parnallee.
Parnallee was previously classified as an LL3.6 ordinary chondrite, consistent with results based on the induced thermoluminescence technique. However, utilizing Raman spectroscopy along with other independent petrologic tracers (i.e., noble gas content, presolar grain abundance, and zoning of olivine phenocrysts), Bonal et al. (2006) it was concluded that the actual petrologic type of Parnallee should lie between 3.7 and 3.8, and they suggested that a classification of LL3.7 would be appropriate.
Most of the metal and sulfide occurs between chondrules, with some within or as rims on chondrules. Much of the glassy mesostasis within chondrules has been devitrified to very fine-grained aggregates, but some chondrules preserve a transparent, isotropic, brown glass. Light brown limonitic staining around metal particles is widespread but not pervasive, and does not mask the excellent textures of the chondrules. Investigators have identified an achondritic clast (a microgabbro), and a chondritic clast isotopically related to carbonaceous chondrites (Sokol et al., 2007, and references therein).
Trapped primitive noble gases in components of Parnallee reveals the presence of primordial Q-gas, Ar-rich gas, and a subsolar component (Matsuda et al., 2010). They determined a CRE age for Parnallee of 6.8–10 m.y. The specimen shown above is a 2.4 g partial slice, while the photo below shows a large cut slab of Parnallee, courtesy of the Elbert A. King Collection, showing the amazingly rich concentration of chondrules in this meteorite.
