Pb-Pb dating of individual chondrules from the CBa chondrite Gujba: assessment of the impact plume formation model
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The CB chondrites are metal-rich meteorites with characteristics that sharply distinguish them from other chondrite groups. Their unusual chemical and petrologic features and a young formation age of bulk chondrules dated from the CB<inf>a</inf> chondrite Gujba are interpreted to reflect a single-stage impact origin. Here, we report high-precision internal isochrons for four individual chondrules of the Gujba chondrite to probe the formation history of CB chondrites and evaluate the concordancy of relevant short-lived radionuclide chronometers. All four chondrules define a brief formation interval with a weighted mean age of 4562.49±0.21Myr, consistent with its origin from the vapor-melt impact plume generated by colliding planetesimals. Formation in a debris disk mostly devoid of nebular gas and dust sets an upper limit for the solar protoplanetary disk lifetime at 4.8±0.3Myr. Finally, given the well-behaved Pb-Pb systematics of all four chondrules, a precise formation age and the concordancy of the Mn-Cr, Hf-W, and I-Xe short-lived radionuclide relative chronometers, we propose that Gujba may serve as a suitable time anchor for these systems.
Original language | English |
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Journal | Meteoritics and Planetary Science |
Volume | 50 |
Issue number | 7 |
Pages (from-to) | 1197-1216 |
Number of pages | 20 |
ISSN | 1086-9379 |
DOIs | |
Publication status | Published - 2015 |
ID: 144701120