@article{Shah:2017:10.1016/j.epsl.2017.07.035,
author = {Shah, J and Bates, H and Muxworthy, AR and Hezel, DC and Russell, SS and Genge, MJ},
doi = {10.1016/j.epsl.2017.07.035},
journal = {Earth and Planetary Science Letters},
pages = {106--118},
title = {Long-lived magnetism in chondrite parent bodies},
url = {http://dx.doi.org/10.1016/j.epsl.2017.07.035},
volume = {475},
year = {2017}
}

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TY  - JOUR
AB  - We present evidence for both early- and late-stage magnetic activity on the CV and L/LL parent bodies respectively from chondrules in Vigarano and Bjurböle. Using micro-CT scans to re-orientate chondrules to their in-situ positions, we present a new micron-scale protocol for the paleomagnetic conglomerate test. The paleomagnetic conglomerate test determines at 95% confidence, whether clasts within a conglomerate were magnetized before or after agglomeration, i.e., for a chondritic meteorite whether the chondrules carry a pre- or post-accretionary remanent magnetization. We found both meteorites passed the conglomerate test, i.e., the chondrules had randomly orientated magnetizations. Vigarano's heterogeneous magnetization is likely of shock origin, due to the 10 to 20 GPa impacts that brecciated its precursor material on the parent body and transported it to re-accrete as the Vigarano breccia. The magnetization was likely acquired during the break-up of the original body, indicating a CV parent body dynamo was active ∼9 Ma after Solar System formation. Bjurböle's magnetization is due to tetrataenite, which transformed from taenite as the parent body cooled to below 320 °C, when an ambient magnetic field imparted a remanence. We argue either the high intrinsic anisotropy of tetrataenite or brecciation on the parent body manifests as a randomly orientated distribution, and a L/LL parent body dynamo must have been active at least 80 to 140 Ma after peak metamorphism. Primitive chondrites did not originate from entirely primitive, never molten and/or differentiated parent bodies. Primitive chondrite parent bodies consisted of a differentiated interior sustaining a long-lived magnetic dynamo, encrusted by a layer of incrementally accreted primitive meteoritic material. The different ages of carbonaceous and ordinary chondrite parent bodies might indicate a general difference between carbonaceous and ordinary chondrite parent bodies, and/or format
AU  - Shah,J
AU  - Bates,H
AU  - Muxworthy,AR
AU  - Hezel,DC
AU  - Russell,SS
AU  - Genge,MJ
DO  - 10.1016/j.epsl.2017.07.035
EP  - 118
PY  - 2017///
SN  - 1385-013X
SP  - 106
TI  - Long-lived magnetism in chondrite parent bodies
T2  - Earth and Planetary Science Letters
UR  - http://dx.doi.org/10.1016/j.epsl.2017.07.035
UR  - http://hdl.handle.net/10044/1/51605
VL  - 475
ER  - 

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