Geology Department Postgraduate Web Pages
Name: Hilde Koch
Tel:+353 (0) 89 221 3013
Fax: +353 (0)1 6711199
Title of Project
The chemostratigraphy of Mississipian volcanigenic clay bands (tuffs) in the Irish Midlands
Carbonates of the Irish Carboniferous yield the highest concentration of Zn per km2 on the planet. These Zn-Pb deposits are stratigraphically and structurally controlled, but uncertainty exists in the timing of mineralisation relative to host rock ages. But ash layers in the succession provide an opportunity for high resolution correlation and can be used as absolute time markers.
The conventional approach to fingerprinting volcanogenic ash is to use the elemental chemistry of volcanogenic glass shards. The ashes are bentonites with no glass shards preserved, so a new multi-proxy approach is undertaken. The correlation of these volcanic ash horizons is based on high-precision trace element bulk-rock geochemistry, a best match comparison method, U-Pb zircon geochemistry, as well as apatite characterisation to provide a chemostratigraphic framework.
Additionally, the chemistry of the ore hosting rock is used as a secondary marker to test the results from the bentonite layers. Therefore, a new in-situ sampling method is developed, using the laser as a sampling tool.
I am also passionate about science communication. I love to present my work as posters, talks, lighting talk or in podcasts.
Name of supervisors
Professor David Chew
Professor Balz Kamber
Postgraduate personal details
In 2013 I finished my Bachelor studies in Geoscience at the University of Tuebingen. My Bachelor thesis dealt with the origin of the chromitite layers of the UG2 chromitite from the Bushveld Complex of South Africa, which contains the world’s largest platinum and chromium reserves. The aim of the study was to achieve an improved understanding of the chromitite formation processes. Applied methods were polarisation microscopy of thin sections, as well as C and H isotope analyses of mineral separates, taken from every subunit of the UG2.
In 2016 I graduated from the University of Tuebingen with a Master’s degree in Geoscience. In the related thesis I observed large variation in δ53/52Cr of ultramafic rocks from Etang de Lherz, French Pyrenees, which indicates that Cr isotope fractionation may occur within the Earth’s mantle due to processes involving partial melting or metasomatism.
Project Start Date
Koch, H. (2013) Bachelor thesis: “ Untersuchung der Chromitbildung des UG2 Melanorites, Bushveld Komplex, Südafrika anhand der Petrographie und δ18O-Mineralsignaturen”
Koch, H. (2016) Master thesis: “Evidence for Natural Variations in Chromium Isotope Composition in Geologically Related Earth’s Mantle Rocks From Etang de Lherz”
FameLab, Feb. 2020, Fingerprinting Irish Volcanic Ash: https://www.youtube.com/watch?v=1Rm8A3qY5Gg
iCRAGorama Podcast, June 2020, Exploring for Metals Using Ash and Beer: https://open.spotify.com/episode/7aTrOUA3EV51NpqfBAFQFW
Sustainable Earth Scientist, Nov. 2020, Your Actions Have A Big Impact: https://www.youtube.com/watch?v=PZ0IM6Un6k0&feature=youtu.be
School of Natural Sciences Lightning Talks TCD – 1st place (Dublin; Ireland; Nov. 2019)
iGEO – Early Career Symposium – Best Poster; Best Lightning Talk (Galway; Ireland; Jan. 2020)
IGRM – Irish Geological Research Meeting – 2nd best Student Talk (Athlone, Ireland, Feb. 2020)
Science Communication Bootcamp; EIT RawMaterials – Best Lightning Talk (online, Oct. 2020)