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:2016:10.1111/maps.12805,
author = {Genge, MJ},
doi = {10.1111/maps.12805},
journal = {Meteoritics & Planetary Science},
pages = {443--457},
title = {Vesicle dynamics during the atmospheric entry heating of cosmic spherules},
url = {http://dx.doi.org/10.1111/maps.12805},
volume = {52},
year = {2016}
}
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RIS format (EndNote, RefMan)

TY  - JOUR
AB  - Cosmic spherules are unique igneous objects that form by melting due to gas drag heating during atmospheric entry heating. Vesicles are an important component of many cosmic spherules since they suggest their precursors had finite volatile contents. Vesicle abundances in spherules decrease through the series porphyritic, glassy, barred, to cryptocrystalline spherules. Anomalous hollow spherules, with large off-centre vesicles occur in both porphyritic and glassy spheres. Numerical simulation of the dynamic behaviour of vesicles during atmospheric flight is presented that indicates vesicles rapidly migrate due to deceleration and separate from non-porphyritic particles. Modest rotation rates of tens of radians s-1 are, however, sufficient to impede loss of vesicles and may explain the presence of small solitary vesicles in barred, cryptocrystalline and glassy spherules. Rapid rotation at spin rates of several thousand radians s-1 are required to concentrate vesicles at the rotational axis and leads to rapid growth by coalescence and either separation or retention depending on the orientation of the rotational axis. Complex rapid rotations that concentrate vesicles in the core of particles are proposed as a mechanism for the formation of hollow spherules.  High vesicle contents in porphyritic spherules suggest volatile-rich precursors, however, calculation of volatile retention indicates these have lost >99.9% of volatiles to degassing prior to melting. The formation of hollow spherules, by rapid spin, necessarily implies pre-atmospheric rotations of several thousand radians s-1. These particles are suggested to represent immature dust, recently released from parent bodies, in which rotations have not been slowed by magnetic damping.
AU  - Genge,MJ
DO  - 10.1111/maps.12805
EP  - 457
PY  - 2016///
SN  - 1086-9379
SP  - 443
TI  - Vesicle dynamics during the atmospheric entry heating of cosmic spherules
T2  - Meteoritics & Planetary Science
UR  - http://dx.doi.org/10.1111/maps.12805
UR  - http://hdl.handle.net/10044/1/42446
VL  - 52
ER  -
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