EuroPeg_PetroDB: A petrophysical database of European pegmatite ores and wall rocks

Abstract

In the frame of the GREENPEG project NGU and terratec Geophysical Services have compiled a petrophysical database of European pegmatite ores and wall rocks from so far four different sites with different types of pegmatites in different settings. With the aim to develop toolsets for hidden pegmatite exploration, the GREENPEG project wants to overcome the lack of exploration technologies for pegmatite ore deposits. Here, a comprehensive petrophysical database contributes with knowledge on petrophysical contrast between pegmatites and wall rocks facilitating a right choice of geophysical methodologies and a more efficient exploration. Petrophysical measurements were therefore performed on hand specimens, drill cores and in selected boreholes at two of the three project demonstration sites Tysfjord (Norway), Wolfsberg (Austria) and Leinster (Ireland). In addition, hand specimens from a pegmatite test site in Portugal/Spain were included as well. The measurements on specimens were carried out at the NGU petrophysical laboratory, acquiring density, susceptibility, remanence, thermal conductivity and radiometric isotopes content for U, Th and K. Specimens represent samples from both pegmatites and wall rock to map potential contrasts in the petrophysical parameters between these two lithologies as a basis for geophysical exploration. Within the GREENPEG project two wireline downhole geophysical logging campaigns were performed and measurements done in several boreholes at the demonstration sites Leinster and Wolfsberg. The borehole probes measured with a sample interval of 1 to 10 cm over the entire depth of the borehole and therefore provide a highresolution in-situ data set of the rock formation. The database is uploaded and available on the open data repository Zenodo (www.zenodo.com) under a Creative Commons Attribution 4.0 International (CC BY 4.0) license. This repository is used by the GREENPEG project to give access to data collected and acquired by the project.