Organics preserved in anhydrous interplanetary dust particles : Pristine or not? / Chan, Queenie H. S.; Franchi, Ian A.; Zhao, Xuchao; Stephant, Alice; Wright, Ian P.; Alexander, Conel M. O'D.

In: Meteoritics & planetary science, Vol. 55, No. 6, 06.2020, p. 1320-1348.

Research output: Contribution to journalArticlepeer-review

Published
  • Queenie H. S. Chan
  • Ian A. Franchi
  • Xuchao Zhao
  • Alice Stephant
  • Ian P. Wright
  • Conel M. O'D. Alexander

Abstract

The chondritic-porous subset of interplanetary dust particles (CP-IDPs) are thought to have a cometary origin. Since the CP?IDPs are anhydrous and unaltered by aqueous processes that are common to chondritic organic matter (OM), they represent the most pristine material of the solar system. However, the study of IDP OM might be hindered by their further alteration by flash heating during atmospheric entry, and we have limited understanding on how short-term heating influences their organic content. In order to investigate this problem, five CP-IDPs were studied for their OM contents, distributions, and isotopic compositions at the submicro- to nanoscale levels. The OM contained in the IDPs in this study spans the spectrum from primitive OM to that which has been significantly processed by heat. Similarities in the Raman D bands of the meteoritic and IDP OMs indicate that the overall gain in the sizes of crystalline domains in response to heating is similar. However, the Raman GammaG values of the OM in all of the five IDPs clearly deviate from those of chondritic OM that had been processed during a prolonged episode of parent body heating. Such disparity suggests that the nonaromatic contents of the OM are different. Short duration heating further increases the H/C ratio and reduces the delta13C and deltaD values of the IDP OM. Our findings suggest that IDP OM contains a significant proportion of disordered C with low H content, such as sp2 olefinic C=C, sp3 C-C, and/or carbonyl contents as bridging material.
Original languageEnglish
Pages (from-to)1320-1348
Number of pages29
JournalMeteoritics & planetary science
Volume55
Issue number6
Early online date19 Nov 2019
DOIs
Publication statusPublished - Jun 2020
This open access research output is licenced under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License.

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