Imperial College London
Alternate

DrMatthewGenge

Faculty of Engineering, Department of Earth Science & Engineering

Senior Lecturer in Earth and Planetary Science
 
 
 
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Contact

 

+44 (0)20 7594 6499m.genge

 
 
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Location

 

1.45Royal School of MinesSouth Kensington Campus

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Summary

 

Publications

Citation

BibTex format

@article{Genge:2017:10.1130/G38352.1,
author = {Genge, MJ and Larsen, J and Van, Ginneken M and Suttle, M},
doi = {10.1130/G38352.1},
journal = {Geology},
pages = {119--122},
title = {An urban collection of modern-day large micrometeorites: evidence for variations in the extraterrestrial dust flux through the Quaternary},
url = {http://dx.doi.org/10.1130/G38352.1},
volume = {45},
year = {2017}
}
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RIS format (EndNote, RefMan)

TY  - JOUR
AB  - We report the discovery of significant numbers (500) of large micrometeorites (>100 μm) from rooftops in urban areas. The identification of particles as micrometeorites is achieved on the basis of their compositions, mineralogies, and textures. All particles are silicate-dominated (S type) cosmic spherules with subspherical shapes that form by melting during atmospheric entry and consist of quench crystals of magnesian olivine, relict crystals of forsterite, and iron-bearing olivine within glass. Four particles also contain Ni-rich metal-sulfide beads. Bulk compositions are chondritic apart from depletions in the volatile, moderately volatile, and siderophile elements, as observed in micrometeorites from other sources. The reported particles are likely to have fallen on Earth in the past 6 yr and thus represent the youngest large micrometeorites collected to date. The relative abundance ratio of barred olivine to cryptocrystalline spherule types in the urban particles of 1.45 is shown to be higher than a Quaternary average of ∼0.9, suggesting variations in the extraterrestrial dust flux over the past 800 k.y. Changes in the entry velocities of dust caused by quasi-periodic gravitational perturbation during transport to Earth are suggested to be responsible. Variations in cosmic spherule abundance within the geologic column are thus unavoidable and can be a consequence of dust transport as well as major dust production events.
AU  - Genge,MJ
AU  - Larsen,J
AU  - Van,Ginneken M
AU  - Suttle,M
DO  - 10.1130/G38352.1
EP  - 122
PY  - 2017///
SN  - 1943-2682
SP  - 119
TI  - An urban collection of modern-day large micrometeorites: evidence for variations in the extraterrestrial dust flux through the Quaternary
T2  - Geology
UR  - http://dx.doi.org/10.1130/G38352.1
UR  - https://pubs.geoscienceworld.org/gsa/geology/article/45/2/119/195213/An-urban-collection-of-modern-day-large
UR  - http://hdl.handle.net/10044/1/42484
VL  - 45
ER  -
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