title: A nebular origin for chondritic fine-grained phyllosilicates.
abstract: Hydrated minerals occur in accretionary rims around chondrules in CM chondrites. Previous models suggested that these phyllosilicates did not form by gas-solid reactions in the canonical solar nebula. We propose that chondrule-forming shock waves in icy regions of the nebula produced conditions that allowed rapid mineral hydration. The time scales for phyllosilicate formation are similar to the time it takes for a shocked system to cool from the temperature of phyllosilicate stability to that of water ice condensation. This scenario allows for simultaneous formation of chondrules and their fine-grained accretionary rims.
authors.affiliation: Department of Planetary Sciences, Lunar and Planetary Laboratory, University of Arizona, 1629 East University Boulevard, Tucson, AZ 85721, USA. fciesla@lpl.arizona.edu
authors.forename: Fred J
authors.initials: FJ
authors.lastname: Ciesla
authors.forename: Dante S
authors.initials: DS
authors.lastname: Lauretta
authors.forename: Barbara A
authors.initials: BA
authors.lastname: Cohen
authors.forename: Lon L
authors.initials: LL
authors.lastname: Hood
mesh_terms: D007053:Ice; D019110:Meteoroids; D011312:Pressure; D017640:Silicates; D013696:Temperature; D013816:Thermodynamics; D014867:Water
chemical_list: D007053:Ice; D017640:Silicates; D014867:Water