Characterization of Potential Micrometeorites by Synchrotron Analysis

Madison Esposito,Juergen Thieme,Janet Kaczmarek,Anya Swiss,Kevin Souhrada,Mary Kroll,Aleida Perez,Victoria Hernandez,Vivian Stojanoff,Robert Bolen,Erin Garland,David Meisel,Paul Northrup

doi:10.3390/geosciences10070275

Abstract

Micrometeorites (MMs) are small particles that account for most of the extraterrestrial material deposited on Earth. Synchrotron X-ray fluorescence and diffraction allowed for chemical and mineral characterization to distinguish MM from atmospheric particulate. The relative components of iron, nickel, and other elements were considered in the identification of ferrous MM while high amounts of titanium were considered an indication that the particles were of atmospheric origin. Out of 100 samples collected by high school students and teachers, eight were taken to a synchrotron for analysis. Of those eight, three exhibited extraterrestrial compositions. X-ray absorption near-edge structure analysis revealed that the same three samples contained sulfide, the main sulfur form constituent in MM. X-ray microdiffraction analysis showed the presence of the minerals pentlandite and forsterite. Collectively, these results support the extraterrestrial nature of the three particles.

Highlights

Micrometeorites (MMs) are a subset of cosmic dust particles that compose most of the extraterrestrial material reaching Earth, making MMs integral in researching extraterrestrial chemistry and Earth’s geochemical supply of certain elements
Characterizing the origin of particles collected on suburban rooftops as extraterrestrial requires more than one method of chemical and structural analysis
Synchrotron X-ray fluorescence imaging at different energies enables the observation and distribution of key elements in cosmic spherules (CSs), including iron, nickel, and sulfur

Summary

Introduction

Micrometeorites (MMs) are a subset of cosmic dust particles that compose most of the extraterrestrial material reaching Earth, making MMs integral in researching extraterrestrial chemistry and Earth’s geochemical supply of certain elements. These particles are significant factors in extraterrestrial chemistry in our solar system due to their abundance and omnipresence. MM mineralogy and textures are a combination of parent body features mixed with phases formed by flash heating and quench cooling [1]. Estimates of MM mass flux are subtle and varied. Suttle and Folco (2020) provided a recent summary of estimates based on some of the most prominent collections [3]

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