geology – Black Rock Desert Volcanoes

Lab Work: Obtaining Dates of Zircon Crystals

U/Pb dates are being collected from the mass spectrometer. Below are some photos of how the samples are loaded for analysis as well as a photo of the analyzing screen. After the U and Pb are extracted from column chemistry, it gets dried down and moved into the mass spectrometry lab. A couple drops ofContinue reading “Lab Work: Obtaining Dates of Zircon Crystals”

Lab Work: Extracting U and Pb from Zircon Crystals

One of the primary goals of this project is to date the various small volume eruptions in the Black Rock Desert in conjunction with chemical analyses of the lavas to better understand the processes that control magma evolution. To that end, we are using U/Pb dating and trace element geochemistry of zircon crystals to determineContinue reading “Lab Work: Extracting U and Pb from Zircon Crystals”

Lab Work: Zircon Elemental Chemistry

The zircon mounts are made, polished, and CL imaged. The next step in the process is to get the chemistry of different growth domains. CL images really come in handy for this. You can see in the images below what is called “sector zoning.” It looks like a little bowtie in the zircon. The brighterContinue reading “Lab Work: Zircon Elemental Chemistry”

Lab Work: CL Imaging Zircon Crystals

All of the mounts have been made, polished, and the zircon crystals have been imaged using cathodoluminesce (CL)! The photos below show parts of this process. Polishing: Similar to how we make thin sections, but all the polishing is done by hand with polishing papers that start around 30 micrometers, which is very coarse forContinue reading “Lab Work: CL Imaging Zircon Crystals”

Lab Work: Mounting Zircon Crystals in Epoxy Part 2

The zircon grain mounts were finally set in epoxy! Here are some photos. You’ll remember from the last update that the zircon crystals are placed on double-sided tape into rows within a 1-cm circle. Once that’s done, a glass ring is placed around the grains and then a plastic ring goes over that. Then theContinue reading “Lab Work: Mounting Zircon Crystals in Epoxy Part 2”

Lab Work: Separating Zircon Crystals with the Frantz

Now that we have obtained our high-density sample using the water table, it is further separated based on the sample’s magnetic properties. In order to do this, a machine called the “Frantz” is used, which is basically a large magnet. The sample is fed into a feeder that vibrates to funnel the particulates into theContinue reading “Lab Work: Separating Zircon Crystals with the Frantz”

Lab Work: Crushing Rocks for Mineral Separation

The first step to completing our research is, of course, collecting the rock samples from their erupted locations. Once we bring the rocks back to the Westminster College mineral separation lab, we start the crushing process. This allows us to separate the sub-centimeter sized sanidine and sub-millimeter sized zircon crystals from the bulk rock. ToContinue reading “Lab Work: Crushing Rocks for Mineral Separation”