Testing the Handheld XRF at The Slab

Undergraduates Ethan Wagner and Luke Whitenburg joined me for a quick trip to The Slab (aka "Xenolith City") in Kingsland, Texas, to collect bulk rock compositional data from the metamorphic xenoliths and the Town Mountain Granite using a handheld XRF (hXRF) analyzer. This is a continuation of a study that was started a year ago to learn more about the origin and formation of the xenoliths exposed here.

Our study has two goals: 1) determine the suitability and best methods for analyzing the bulk chemistry of crystalline rocks via hXRF; and 2) determine the bulk geochemistry of the metamorphic xenoliths in order to better determine their origins. The hXRF is particularly well-suited to this work, as sampling these rocks from the smooth, pavement-style outcrops at this popular swimming hole would be both irresponsible and physically difficult. Ethan will use the data from this work to compare the compositions of the xenoliths with those of local outcrops of metamorphic rocks for an independent study this semester.

The department's handheld XRF was acquired by Julie Bloxson, who will use it primarily for noninvasive study of salts and mudrocks in drill core.