Schematic representation of formation of type I and II chondrules in CC. Previously condensed ¹⁶O-rich AOAs, mixed with other precursor material, experienced melting and gas–melt interactions that led to the formation of olivine-rich type I chondrules characterized by ⁵⁰Ti-⁵⁴Cr anomalies and the presence of ¹⁶O-rich olivine grains with Δ¹⁷O= ∼ −6‰. In CR chondrites, these type I chondrules mix with solar-like dust and experienced another melting episode. This results in the formation of larger chondrules with Δ¹⁷O= ∼ −2‰. Both types of type I chondrules were then recycled into type II chondrules with Mg-rich relic grains having Δ¹⁷O characteristics of the two generations of type I chondrules. This implies that the origin of chondrules must be extremely localized for producing type II chondrules without recycling all type I chondrules.