It is now widely recognized that paleomagnetic studies of Paleozoic North American carbonate rocks have revealed mostly secondary (but ancient) magnetization; shallow-water carbonates that contain primary or early magnetizations are rare and exceptional. Recent studies have revealed that the magnetization of these carbonates resides in (probably authigenic) magnetites. In this project the PIs will investigate to study these magnetites with electron microscopic techniques, (2) to fully characterize the paleomagnetic and rock magnetic properties, and (3) to integrate these observations with isotopic characterization (K, Ar, O, C, H) of the magnetites and surrounding mineral phases.