Adhesive growth and abrasion of chondrules during the accretion process

• Main Authors: Masao Kitamura, Seiko Watanabe
• Format: Report
• Language: English
• Published: Department of Geology and Mineralogy, Faculty of Sciences, Kyoto University 1986
• Subjects: Memoirs of National Institute of Polar Research; Polar Research
• Online Access: https://nipr.repo.nii.ac.jp/?action=repository_uri&item_id=1966; http://id.nii.ac.jp/1291/00001966/; https://nipr.repo.nii.ac.jp/?action=repository_action_common_download&item_id=1966&item_no=1&attribute_id=18&file_no=1

Droplet chondrules are classified into three groups based on the surface features. The group A chondrules, common in the equilibrated chondrites, do not have a clear boundary with the matrix. The ambiguity of the surfaces of group A can be explained by adhesion of the matrix materials coarsened during slow cooling. Chondrules in the unequilibrated chondrites belong to groups B and C. Though both groups B and C inherit spherical shapes of the melt droplets, the group B chondrules are characterized by zig-zag surfaces due to crystallization of olivine and pyroxene and/or adhesion of fine dusts. The group C chondrules have defined surfaces. Some of them are abraded by fine dusts into rounded shapes with smooth surfaces. The adhesion and abrasion of chondrules suggest that the accretion processes have occurred successively after the chondrule formation, and that the mechanical interaction between chondrules and dust during the accretion was different among the chemical groups and petrologic types of the chondrites.