The Absolute Chronology and Thermal Processing of Solids in the Solar Protoplanetary Disk

Abstract

Dating the First Solids: The solar system's first solids: calcium-aluminum–rich inclusions and chondrules are found in meteorites and provide a direct record of the dynamics of the solar protoplanetary disk that led to the formation of the solar system. Previous results indicate that chondrules formed 1 to 2 million years after the inclusions—an age difference that has been used in constructing models of chondrule formation. Based on uranium- and lead-isotope measurements of a collection of these primitive materials,Connellyet al.(p.651) show that chondrules in fact started to form at the same time as the inclusions, 4.567 billion years ago, and that their formation took about 3 million years.