Skip to main content
U.S. flag

An official website of the United States government

In situ U-Pb dating of apatite and rutile from St. Francois Mountains IOA and IOCG deposits, southeast Missouri

July 15, 2021

Apatite (Ca5(PO4)3(Cl/F/OH)) and rutile (TiO2) samples were collected by the U.S. Geological Survey (USGS) from the iron oxide-apatite-rare earth element (IOA-REE) and iron oxide-copper-gold (IOCG) deposits hosted by the Mesoproterozoic, St. Francois Mountains terrane, southeast Missouri. Samples were prepared and analyzed for direct age dating on a laser ablation inductively coupled plasma mass spectrometer (LA-ICP-MS) system at the USGS in Denver, Colorado from May 2016 to June 2019.