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Olivine settling in cosmic spherules during atmospheric deceleration: An indicator of the orbital eccentricity of interplanetary dust

Genge, Matthew J., Suttle, Martin, van Ginneken, Matthias (2016) Olivine settling in cosmic spherules during atmospheric deceleration: An indicator of the orbital eccentricity of interplanetary dust. Geophysical Research Letters, 43 (20). pp. 10646-10653. ISSN 0094-8276. E-ISSN 1944-8007. (doi:10.1002/2016GL070874) (KAR id:88129)

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https://doi.org/10.1002/2016GL070874

Abstract

A new type of cosmic spherule is reported with textures suggesting settling of olivine during atmospheric deceleration. Numerical simulations of entry heating reveal that relict forsterite, which survives melting, can settle over the 1–2 s of flight at high entry angles and entry velocities up to 16 km s−1. Enhanced crystallization of phenocrysts by heterogeneous nucleation on accumulated relict forsterites is the most likely origin of the observed cumulate textures in cosmic spherules. Such textures in cosmic spherules reveal interplanetary dust with higher encounter velocity with the Earth that correspond to orbital eccentricities >0.3. The relative abundance of cumulate spherules suggests that 14% of ordinary chondrite‐related, S(IV)‐type asteroid dust over the last 800 kyr had relatively high orbital eccentricity owing to secular and planetary perturbations. The textures of cosmic spherules collected from sediments can therefore be used to trace dust orbital variations with time, which may influence terrestrial climate.

Item Type: Article
DOI/Identification number: 10.1002/2016GL070874
Uncontrolled keywords: cosmic spherules
Subjects: Q Science > QE Geology > QE515 Geochemistry
Divisions: Divisions > Division of Natural Sciences > Physics and Astronomy
Depositing User: Matthias van Ginneken
Date Deposited: 14 May 2021 10:27 UTC
Last Modified: 25 Jan 2022 22:26 UTC
Resource URI: https://kar.kent.ac.uk/id/eprint/88129 (The current URI for this page, for reference purposes)
van Ginneken, Matthias: https://orcid.org/0000-0002-2508-7021
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