The Origins of I-type Spherules and the Atmospheric Entry of Iron Micrometeoroids.
The Earth's extraterrestrial dust flux includes a wide variety of dust particles that include FeNi metallic grains. During their atmospheric entry iron micrometeoroids melt and oxidize to form cosmic spherules termed I-type spherules. These particles are chemically resistant and readily collect...
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ftimperialcol:oai:spiral.imperial.ac.uk:10044/1/30404 2023-05-15T13:55:47+02:00 The Origins of I-type Spherules and the Atmospheric Entry of Iron Micrometeoroids. Genge, MJ Science and Technology Facilities Council (STFC) 2016-03-09 http://hdl.handle.net/10044/1/30404 https://doi.org/10.1111/maps.12645 unknown Wiley Meteoritics and Planetary Science © 2016 The Authors. Meteoritics & Planetary Sciencepublished by Wiley Periodicals, Inc. on behalf of The Meteoritical Society.This is an open access article under the terms of the Creative Commons Attribution License, which permits use,distribution and reproduction in any medium, provided the original work is properly cited. CC-BY 1081 1063 Science & Technology Physical Sciences Geochemistry & Geophysics PLATINUM-GROUP NUGGETS DEEP-SEA SEDIMENTS COSMIC SPHERULES ANTARCTIC MICROMETEORITES NICKEL ICE COLLECTION METEORITES OXYGEN DUST 0201 Astronomical And Space Sciences 0402 Geochemistry 0403 Geology Journal Article 2016 ftimperialcol https://doi.org/10.1111/maps.12645 2018-09-16T05:54:15Z The Earth's extraterrestrial dust flux includes a wide variety of dust particles that include FeNi metallic grains. During their atmospheric entry iron micrometeoroids melt and oxidize to form cosmic spherules termed I-type spherules. These particles are chemically resistant and readily collected by magnetic separation and are thus the most likely micrometeorites to be recovered from modern and ancient sediments. Understanding their behavior during atmospheric entry is crucial in constraining their abundance relative to other particle types and the nature of the zodiacal dust population at 1 AU. This paper presents numerical simulations of the atmospheric entry heating of iron meteoroids in order to investigate the abundance and nature of these materials. The results indicate that iron micrometeoroids experience peak temperatures 300-800K higher than silicate particles explaining the rarity of unmelted iron particles which can only be present at sizes of <50 m. The lower evaporation rates of liquid iron oxide leads to greater survival of iron particles compared with silicates, which enhances their abundance amongst micrometeorites by a factor of 2. The abundance of I-types is shown to be broadly consistent with the abundance and size of metal in ordinary chondrites and the current day flux of ordinary chondrite-derived MMs arriving at Earth. Furthermore, carbonaceous asteroids and cometary dust are suggested to make negligible contributions to the I-type spherule flux. Events involving such objects, therefore, cannot be recognized from I-type spherule abundances in the geological record. Article in Journal/Newspaper Antarc* Antarctic Imperial College London: Spiral Antarctic Meteoritics & Planetary Science 51 6 1063 1081 |
institution |
Open Polar |
collection |
Imperial College London: Spiral |
op_collection_id |
ftimperialcol |
language |
unknown |
topic |
Science & Technology Physical Sciences Geochemistry & Geophysics PLATINUM-GROUP NUGGETS DEEP-SEA SEDIMENTS COSMIC SPHERULES ANTARCTIC MICROMETEORITES NICKEL ICE COLLECTION METEORITES OXYGEN DUST 0201 Astronomical And Space Sciences 0402 Geochemistry 0403 Geology |
spellingShingle |
Science & Technology Physical Sciences Geochemistry & Geophysics PLATINUM-GROUP NUGGETS DEEP-SEA SEDIMENTS COSMIC SPHERULES ANTARCTIC MICROMETEORITES NICKEL ICE COLLECTION METEORITES OXYGEN DUST 0201 Astronomical And Space Sciences 0402 Geochemistry 0403 Geology Genge, MJ The Origins of I-type Spherules and the Atmospheric Entry of Iron Micrometeoroids. |
topic_facet |
Science & Technology Physical Sciences Geochemistry & Geophysics PLATINUM-GROUP NUGGETS DEEP-SEA SEDIMENTS COSMIC SPHERULES ANTARCTIC MICROMETEORITES NICKEL ICE COLLECTION METEORITES OXYGEN DUST 0201 Astronomical And Space Sciences 0402 Geochemistry 0403 Geology |
description |
The Earth's extraterrestrial dust flux includes a wide variety of dust particles that include FeNi metallic grains. During their atmospheric entry iron micrometeoroids melt and oxidize to form cosmic spherules termed I-type spherules. These particles are chemically resistant and readily collected by magnetic separation and are thus the most likely micrometeorites to be recovered from modern and ancient sediments. Understanding their behavior during atmospheric entry is crucial in constraining their abundance relative to other particle types and the nature of the zodiacal dust population at 1 AU. This paper presents numerical simulations of the atmospheric entry heating of iron meteoroids in order to investigate the abundance and nature of these materials. The results indicate that iron micrometeoroids experience peak temperatures 300-800K higher than silicate particles explaining the rarity of unmelted iron particles which can only be present at sizes of <50 m. The lower evaporation rates of liquid iron oxide leads to greater survival of iron particles compared with silicates, which enhances their abundance amongst micrometeorites by a factor of 2. The abundance of I-types is shown to be broadly consistent with the abundance and size of metal in ordinary chondrites and the current day flux of ordinary chondrite-derived MMs arriving at Earth. Furthermore, carbonaceous asteroids and cometary dust are suggested to make negligible contributions to the I-type spherule flux. Events involving such objects, therefore, cannot be recognized from I-type spherule abundances in the geological record. |
author2 |
Science and Technology Facilities Council (STFC) |
format |
Article in Journal/Newspaper |
author |
Genge, MJ |
author_facet |
Genge, MJ |
author_sort |
Genge, MJ |
title |
The Origins of I-type Spherules and the Atmospheric Entry of Iron Micrometeoroids. |
title_short |
The Origins of I-type Spherules and the Atmospheric Entry of Iron Micrometeoroids. |
title_full |
The Origins of I-type Spherules and the Atmospheric Entry of Iron Micrometeoroids. |
title_fullStr |
The Origins of I-type Spherules and the Atmospheric Entry of Iron Micrometeoroids. |
title_full_unstemmed |
The Origins of I-type Spherules and the Atmospheric Entry of Iron Micrometeoroids. |
title_sort |
origins of i-type spherules and the atmospheric entry of iron micrometeoroids. |
publisher |
Wiley |
publishDate |
2016 |
url |
http://hdl.handle.net/10044/1/30404 https://doi.org/10.1111/maps.12645 |
geographic |
Antarctic |
geographic_facet |
Antarctic |
genre |
Antarc* Antarctic |
genre_facet |
Antarc* Antarctic |
op_source |
1081 1063 |
op_relation |
Meteoritics and Planetary Science |
op_rights |
© 2016 The Authors. Meteoritics & Planetary Sciencepublished by Wiley Periodicals, Inc. on behalf of The Meteoritical Society.This is an open access article under the terms of the Creative Commons Attribution License, which permits use,distribution and reproduction in any medium, provided the original work is properly cited. |
op_rightsnorm |
CC-BY |
op_doi |
https://doi.org/10.1111/maps.12645 |
container_title |
Meteoritics & Planetary Science |
container_volume |
51 |
container_issue |
6 |
container_start_page |
1063 |
op_container_end_page |
1081 |
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1766262625452163072 |