Protracted storage of CR chondrules in a region of the disk transparent to galactic cosmic rays

Renazzo‐type carbonaceous ( CR ) chondrites are accretionary breccias that formed last. As such they are ideal samples to study precompaction exposures to cosmic rays. Here, we present noble gas data for 24 chondrules and 3 dark inclusion samples ( DI s) from Shişr 033 ( CR 2). The meteorite was selected based on the absence of implanted solar wind noble gases and an anomalous oxygen isotopic composition of the DI s; the oxygen isotopes match those in CV 3 and CO 3 chondrites. Our samples contain variable mixtures of galactic cosmic ray ( GCR )‐produced cosmogenic noble gases and trapped noble gases of presolar origin. Remarkably, all chondrules have cosmogenic 3 He and 21 Ne concentrations up to 4.3 and 7.1 times higher than the DI s, respectively. We derived an average 3 He‐ 21 Ne cosmic ray exposure ( CRE ) age for Shişr 033 of 2.03 ± 0.20 Ma (2 SD ) and excesses in cosmogenic 3 He and 21 Ne in chondrules (relative to the DI s) in the range (in 10 −8  cm 3 STP /g) 3.99–7.76 and 0.94–1.71, respectively. Assuming present‐day GCR flux density, the excesses translate into average precompaction 3 He‐ 21 Ne CRE ages of 3.1–27.3 Ma depending on the exposure geometry. The data can be interpreted assuming a protracted storage of a single chondrule generation prior to the final assembly of the Shişr 033 parent body in a region of the disk transparent to GCR s.