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dc.contributor.authorMaurel, Clara
dc.contributor.authorWeiss, Benjamin P
dc.contributor.authorBryson, James F.J.
dc.date.accessioned2020-05-14T21:26:44Z
dc.date.available2020-05-14T21:26:44Z
dc.date.issued2019-03
dc.date.submitted2018-09
dc.identifier.issn1385-013X
dc.identifier.urihttps://hdl.handle.net/1721.1/125252
dc.description.abstractMetallic microstructures in slowly-cooled iron-rich meteorites reflect the thermal and magnetic histories of their parent planetesimals. Of particular interest is the cloudy zone, a nanoscale intergrowth of Ni-rich islands within a Ni-poor matrix that forms below ∼350 °C by spinodal decomposition. The sizes of the islands have long been recognized as reflecting the low-temperature cooling rates of meteorite parent bodies. However, a model capable of providing quantitative cooling rate estimates from island sizes has been lacking. Moreover, these islands are also capable of preserving a record of the ambient magnetic field as they grew, but some of the key physical parameters required for recovering reliable paleointensity estimates from magnetic measurements of these islands have been poorly constrained. To address both of these issues, we present a numerical model of the structural and compositional evolution of the cloudy zone as a function of cooling rate and local composition. Our model produces island sizes that are consistent with present-day measured sizes. This model enables a substantial improvement in the calibration of paleointensity estimates and associated uncertainties. In particular, we can now accurately quantify the statistical uncertainty associated with the finite number of islands acquiring the magnetization and the uncertainty on their size at the time of the record. We use this new understanding to revisit paleointensities from previous pioneering paleomagnetic studies of cloudy zones. We show that these could have been overestimated by up to one order of magnitude but nevertheless still require substantial magnetic fields to have been present on their parent bodies. Our model also allows us to estimate absolute cooling rates for meteorites that cooled slower than <10,000 °C My −1 . We demonstrate how these cooling rate estimates can uniquely constrain the low-temperature thermal history of meteorite parent bodies. Using the main-group pallasites as an example, we show that our results are consistent with the previously-proposed unperturbed, conductive cooling at low temperature of a ∼200-km radius main-group pallasite parent body. ©2019 Elsevier B.V.en_US
dc.language.isoen
dc.publisherElsevier BVen_US
dc.relation.isversionof10.1016/J.EPSL.2019.02.027en_US
dc.rightsCreative Commons Attribution-NonCommercial-NoDerivs Licenseen_US
dc.rights.urihttp://creativecommons.org/licenses/by-nc-nd/4.0/en_US
dc.sourcearXiven_US
dc.titleMeteorite cloudy zone formation as a quantitative indicator of paleomagnetic field intensities and cooling rates on planetesimalsen_US
dc.typeArticleen_US
dc.identifier.citationMaurel, Clara et. al., "Meteorite cloudy zone formation as a quantitative indicator of paleomagnetic field intensities and cooling rates on planetesimals." Earth and Planetary Science Letters 513 (May 2019): 166-75 doi. 10.1016/j.epsl.2019.02.027 ©2019 Authorsen_US
dc.contributor.departmentMassachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciencesen_US
dc.relation.journalEarth and Planetary Science Lettersen_US
dc.eprint.versionOriginal manuscripten_US
dc.type.urihttp://purl.org/eprint/type/JournalArticleen_US
eprint.statushttp://purl.org/eprint/status/NonPeerRevieweden_US
dc.date.updated2020-05-08T13:05:37Z
dspace.date.submission2020-05-08T13:05:40Z
mit.journal.volume513en_US
mit.licensePUBLISHER_CC


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