Characterization of Nanoparticles in Ejecta Fallout of Lonar Crater, India (original) (raw)

2016

Abstract

Nanoparticles formed within the ejecta plume are thought to play an important role in the catastrophic events due to meteorite impacts. However, the mode of origin of these nanoparticles in the ejecta fallout is still not clearly known due to its poor preservation potential and alteration. Conclusions The presence of single domain crystalline nanoparticles, i.e. non-biogenic titanomagnetite with distinct hexagonal and octahedral crystal habit, in the ejecta fallout supports its formation due to vapor-solid condensation within the impact ejecta plume and the prevalence of the metallic phases (i.e. Fe and Ti) in the ejecta plume probably facilitated the nano-phase crystallization. Objectives To understand the development of the nano-phase in the ejecta fallout, isolated magnetic particles from the ejecta blanket of the Lonar Crater in India Methods To understand the development of the nano-phase in the ejecta fallout, isolated magnetic particles from the ejecta blanket of the Lonar Crater in India were analyzed using a transmission electron microscope (TEM) and EELS. a high sensitivity scanning electron microscope (SEM) equipped with energy dispersive spectrum analyzer (EDS). Methods Isolated magnetic particles from the ejecta blanket of the Lonar Crater in India were obtained through manual separation of magnetic particles, sieving, washing the less than 62 um size fraction with 7N HCL, followed by sonication and settling in deionized water. The isolated magnetic particles were analyzed using a transmission electron microscope (TEM) and equipped with electron energy loss spectroscope (EELS), to determine the composition of the nanoparticles. TEM analysis was carried out in a Libra 120 Zeiss system operating at 120 kV with a point to point resolution of 0.34 nm. The images were taken using bright field imaging and selective area electron diffraction was performed in an area of 100 nm with high population of nanoparticles.

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