11 Applications of Igneous Petrology, Geochemistry, and Geochronology to Understanding Earth and Other Planetary Systems (Posters)

This session invites contributions that explore igneous systems through traditional and nontraditional methods. Studies that link crustal evolution, planetary formation, resource potential, and comparative planetology across temporal and spatial scales are especially encouraged.

Monday, 9 March 2026
9:00 AM - 5:00 PM
RCC, Lower Level Hall

A Mineralogical and Geochemical Characterization of the Amo Meteorite, Central Indiana

Paper number: 11-8
Program: Technical Sessions
Time: 9:00 AM – 9:00 AM

Authors

Abstract

Meteorites provide a wealth of information about solar system evolution, planetary formation and differentiation, and provide clues to the origins of water and life on Earth. On December 10th, 2024 (4:04 EST), a meteor fall was observed approximately 50 km west of Indianapolis, over the small town of Amo, Indiana (Hendricks County). Several pieces of the meteor ranging from about 1g to >60kg were recovered. A local Greencastle, IN resident collected a 1451.4g sample, of which a 7.5g piece was donated to DePauw University for detailed textural, mineralogical, and geochemical characterization using stereomicroscopy, scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), and μ-XRF. 

Stereomicroscopy on a polished surface of the 7.5g sample has identified significant microfracturing, a thin (<500μm), partially vesiculated fusion crust, several possible chondrules (~1mm), and a variably thick melt vein (<50-500μm). Combined SEM/EDS analyses reveal that the sample is composed of anhedral feldspars, olivine, pyroxene, chromite, spinel, apatite, and Fe-bearing phases (possibly kamacite and troilite). Feldspars grains are albitic (avg. Ab84An10Or6; n=14), olivine grains are forsteritic (avg. Fo88; n=7), and there are low-Ca (avg. En87Fs12Wo1; n=4) and high-Ca pyroxenes (En56Fs4Wo40). Although the feldspar compositions are nearly identical to reported Meteoritical Database values (Ab83, An11, Or6; n=53), our measured olivine and pyroxene EDS analyses are more Mg-rich, indicating greater heterogeneity than previously recognized. False-color μ-XRF element maps also reveal considerable textural and mineralogical heterogeneity within the sample along with several notable element correlations (e.g., Fe and Mn; Fe and Ni; W and Hf).

Our observations are consistent with the preliminary Ordinary L5 Chondrite classification reported in the Meteoritical Bulletin database, but also reveal the need for additional detailed mineral-scale investigations to better characterize and understand the heterogeneous composition of this meteorite and place it within established petrological and geochemical frameworks for the L5 chondrite subgroup.

 

Geological Society of America Abstracts with Programs. Vol. 58, No. 1

doi: 10.1130/abs/2026SE-411659

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