Somewhere in the Earth’s crust a hot fluid is seeping through tiny cracks and fissures in the rock. The fluid is water and it carries with it a cargo of dissolved ions like chloride, sulfate, or carbonate. It might also carry dissolved metal ions useful to humans such copper, gold, or, in the case that we are considering, rare earth elements (REE). Fluids like this play important roles in forming ore deposits where the REE are present in high enough amounts to be mined. We want to understand how the REE interact with other dissolved ions and the water itself in order to better understand the conditions that allow water to mobilize, transport, or deposit REE.
At the forefront of cutting-edge research at New Mexico Tech, we have been utilizing Raman spectroscopy to unravel the mysteries locked within minerals. By harnessing the power of visible and ultraviolet lasers, we can unlock a plethora of information. So, you may be asking, what is Raman spectroscopy? In simple terms, it's a technique that uses laser light to interact with the atomic vibrations of a material, producing a unique "fingerprint" of its molecular composition. By analyzing the scattered light, we are able to identify and characterize minerals such as apatite, fluorite, and calcite.
The world is changing fast. Advanced electronics such as smartphones and tablets are a staple of everyday life. Critical to these devices are the rare earth elements (REE). Unfortunately, the supply of REE around the world is limited, thus research into how REE mineral deposits form is needed to help guide us to new sources of these metals. One aspect of REE geochemistry that is not fully understood is how REE are transported in the hydrothermal fluids that form these deposits. How easily these elements can be transported depends upon the composition of the fluid and what ligands (negatively charged molecules) the REE elements bond to in the fluid, which is called complexation.
