October 6, 2021 Program: Fluid Inclusions -- Happy Little Accidents Of The Mineralogical World

Presented by Dr. Joshua Field

by Yury Kalish, MSDC Vice President

We continue to follow the silver lining of the pandemic by bringing out-of-town speakers to MSDC meetings.  In October, our guest presenter will be Dr. Joshua Field from Bloomington, Indiana. Josh’s background is in geology and geochemistry. He earned a Ph.D. in Geology from the University of Missouri – Columbia. He then worked as a Geology Lab Instructor there, before becoming an application scientist for an X-ray diffraction equipment manufacturer. Josh will talk about fluid inclusions in minerals. The topic stems from his doctoral work, where Josh used powder X-ray diffraction and fluid inclusion analyses to research the process of dolomitization as it relates to generation of Mississippi Valley-Type (MVT) ore mineralization.

Minerals, by definition, are solid materials – they are naturally occurring, crystalline solids. However, all minerals precipitate from fluids, and no mineral forms perfectly. As Josh will discuss, many minerals crystallize imperfectly during growth and these imperfections can result in the mineral trapping small volumes of the surrounding fluid. Such imperfections are called fluid inclusions.  

Josh points out that although sometimes fluid inclusions are trapped post-crystallization in a fracturing/healing event, many fluid inclusions can be traced back to periods of primary mineral growth. Such fluid inclusions reflect the environment from which they crystallize, providing geologists with tiny (or not so tiny!) windows into the formation processes.