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: Mounting Zircon Crystals in Epoxy Part 1

Zircon crystals have been picked to put into an epoxy mount! The photo on the left shows the selected zircon crystals in a petri dish of ethanol. This reduces the static and helps see the high relief of zircon which can give the crystals a little bit of glare. Notice that they are kind ofContinue reading “Lab Work: Mounting Zircon Crystals in Epoxy Part 1”

Lab Work: Separating Zircon Crystals with Heavy Liquids

Lab Work: Extracting U and Pb from Zircon Crystals The images below show the heavy liquids technique we use to separate zircon. We use bromoform which has a density of 2.85 g/cm3. Minerals heavier will sink (like zircon!), lighter stuff will float (like quartz!). After heavy liquids, we are hopefully just left with a bunchContinue reading “Lab Work: Separating Zircon Crystals with Heavy Liquids”

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: Separating Sample using the Water Table

The next step in processing our samples is to separate crystals out by density. Once the rock sample has been crushed and milled to a size of less than one millimeter, we use a water table to extract zircon by density separation. The sample is added to the top of the table while water isContinue reading “Lab Work: Separating Sample using the Water Table”

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”