George Perkins Merrill's Analyses of Chondrules and Chondritic Meteorites

Abstract. George Perkins Merrill (1854–1929) was the preeminent American meteoriticist of the first quarter of the 20^th Century. He applied to that science his pioneering knowledge and skill in the petrographic analysis of chondritic meteorites. Throughout his long and distinguished career with the United States National Museum, now the Smithsonian Institution of Washington, D.C., Merrill authored over seventy publications on meteorites. While many of those contributions described new irons and stones which had come into the museum’s collection, a pair of papers concerning the origin of chondrules and the evidence for and causes of metamorphism of chondritic meteorites led directly to his selection as the second recipient of the J. Lawrence Smith Medal which was awarded by the National Academy of Sciences in 1922 for outstanding accomplishments in the study of meteorites. The origins, primary arguments, and subsequent reception of those two landmark papers are herein reviewed. Particular attention is given to how Merrill’s hypotheses on chondrule formation and the evidence for thermal and dynamic metamorphic alteration of chondrites have come to underpin and advanced modern understandings of the early history of the solar system.