Primary vs. secondary geochemical (elemental and isotopic) signatures in Precambrian chemical sedimentary rocks
Undergraduate student Stephen Hanson is currently working on a UROP project to identify primary textures and minerals in samples of the ~1.9 Ga Biwabik Iron Formation, MN. The use of geochemical fingerprinting for primary and secondary processes is an active and ongoing field of research in my lab.
In hydrothermal depositional settings, volcanic rocks are often altered and changed from their primary or original composition. Silicification is a common process involving the replacement of primary minerals by silica phases in a closed or open system regardless of the original rock composition. Such silicified rocks formed by secondary mineral replacement of non-quartz phases may not always record the primary geochemical and isotopic information of the original rock, but instead could record information regarding the fluid associated with replacement.
I am interested in a continued investigation into silicification as a depositional mechanism of chert and chert layers in iron formation in hydrothermal depositional settings, and the geochemical and isotopic exchange involved in this process.
Undergraduate Earth and Environmental Sciences major Stephen Hanson ha…