Deposits of magnetite, apatite, and hematite are important ores of iron in many parts of the world. In addition, many of these deposits are associated with economic concentrations of Cu, Au, Ag, U, and rare earth elements. Most of these deposits appear to have formed from iron- and phosphorous-rich liquids (magmas or fluids) of extreme compositions which have either intruded at depth, erupted onto the surface, or hydrothermally replaced host rocks. Many of these deposits contain laterally-extensive, stratified, iron oxide- and apatite-rich units. These stratified iron oxide-apatite ores do not appear to have formed by the same mechanism in all localities. The purpose of this project is to examine the field relationships, textural characteristics, and compositions of stratified iron oxide-apatite ores from a variety of localities, to determine what characteristics can best be used to discriminate between the various mechanisms that have been proposed for their origin. Field studies will sample and map in detail stratified iron oxide-apatite ores from Sierra Bandera, Chile. Samples from stratified iron oxide-apatite ores at El Laco, Chile; Kiruna, Sweden; Pilot Knob, Missouri; and Cornwall, Pennsylvania have already been collected. Experimental studies will examine the stability of iron-oxide liquids and fluids over a range of temperatures, pressures, and volatile compositions. This project will be a cooperative study between the State University of New York at Binghamton, the Universidad de Santiago, Chile, and the Swedish Museum of Natural History.
