“Science is the acceptance of what works and the rejection of what does not. That needs more courage than we might think.”
– Jacob Bronowski.”
Research Interests
My research interests span the realms of geochemistry, mineralogy, and petrology. I focus on employing both field and laboratory methodologies to gain insights into the genesis, setting, and exploration of mineral deposits. I use geological field relationships from geological mapping and core logging as the basis for subsequent analytical work. My analytical toolbox encompasses a diverse array of techniques, including lithogeochemistry, stable isotopes (O-B), Raman and infrared spectroscopy, and several microanalytical methods (SEM, EPMA, LA-ICP-MS, SIMS) to understand how systems form and evolve. My specific research interests include:
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Analysis of hydrothermal alteration facies (and their protoliths) and minerals to understand the setting, alteration, and mineralization styles, in particular in Sn-W deposits, volcanogenic massive sulfides (VMS), and porphyry systems;
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Application of geochemical (lithogeochemistry, trace elements in minerals, stable isotopes, etc.) and mineralogical techniques to tackle the petrology of ore systems and understand the links between magmatism, tectonics, and ore-forming processes;
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Statistical and machine learning methods and their application to geochemistry, mineralogy, and mineral exploration;
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Numerical modeling of hydrothermal systems, in particular tracing fluid evolution and ore deposition in magmatic-hydrothermal systems.
DOME SPP 2238 – Phase 2: 2024-2026
Geochemical fingerprinting of volcanogenic massive sulfide systems using accessory minerals
Volcanogenic massive sulfide (VMS) deposits are major sources of copper and zinc and contain significant amounts of gold, silver, lead, selenium, cadmium, bismuth, and tin. They account for 22% of the world’s Zn production, 9.7% of Pb, and 6% of Cu, making them key exploration targets for the mineral industry and essential suppliers of technology metals for the low-carbon energy transition. Nevertheless, the discovery rate of mineral deposits is declining because most shallow high-grade deposits have already been discovered. Increasing the success of discovering concealed and deeply buried targets requires more effective tools to detect large-scale mineral systems and to allow explorers to vector from barren or weakly mineralized units to the economic cores of the systems. In the last decade, many studies have focused on mineral exploration tools based on fertility indicators and chemical vectoring to assist mineral exploration. This project aims to evaluate the potential of accessory minerals as recorders of mineralizing processes and as pathfinders for mineralization in VMS districts that have undergone metamorphism, and have a complex history. To this end, we aim to compare mineralized, hydrothermally altered (proximal), and unaltered (distal) rocks within VMS provinces with complex geological histories. We will conduct petrographic studies and high-resolution imaging combined with microprobe, LA-ICP-MS analysis, stable isotopes, and geochronology. This will allow us to: (1) establish the paragenetic sequence and timing of formation of the minerals, (2) identify the chemical signatures of the phases of interest across the metallogenetic province, and (3) find potential correlations between different provinces. We further aim to use machine learning to process the datasets and to identify patterns and trends in the datasets that can be used for mineral exploration. This proposal will contribute to DOME’s focus on hydrothermal ore deposits in ancient marine settings and has the potential to generate new concepts around the genesis of the orebodies and associated driving mechanisms, which will, in turn, contribute to improving exploration strategies in Europe and beyond. This study will be undertaken at GFZ Potsdam by Rebecca Volkmann under the supervision of Dr. Valby van Schijndel, Dr. Sarah Gleeson and Dr. Marta Codeço.
DOME SPP 2238 – Phase 1: 2021-2023
Melts-Fluids-Models: keys to understanding ore-forming processes at the world-class Neves Corvo massive sulphide deposit, Iberian Pyrite Belt
The Iberian Pyrite Belt (IPB) in Portugal and Spain is a world-class metallogenic province that contains more than 1600 Mt of massive sulfide ore in over 100 deposits (see map). The orebodies are hosted by submarine lithologies comprising felsic volcanic rocks and black shales and, therefore, share characteristics with the sedimentary-hosted (SEDEX) and the volcanogenic massive sulfide (VMS) deposits. Hydrothermal activity at mid-ocean ridges and submarine arc volcanoes has been inferred to be a modern analog for forming these giant submarine deposits, but none of the known modern hydrothermal fields contain the tonnage, density of occurrence, or size of the IPB district. The classic conceptual models assume that metal-bearing, high-salinity hydrothermal fluids (brines) vent into anoxic-euxinic domains of the paleo-ocean where they precipitate massive sulfide ores during sedimentation of black shales. However, most deposits lack unequivocal evidence for exhalation into anoxic seawater, and sulfide reduction may instead be related to early diagenetic processes of shales in oxygenated oceanic environments with high organic, where basin restriction may impose mass balance limitations of sulfur availability, hence inhibiting the formation of large, massive sulfide deposits. Nevertheless, the future supply of raw materials will come from giant ore deposits, so the formation mechanisms of world-class systems remain a key issue in economic geology.