Evaluation of the tungsten potential in the Eastern Alps: New insights from geological, mineralogical and chemical (LA-ICP-MS) data on scheelite

Research output: ThesisDoctoral Thesis

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Abstract

Tungsten is a raw material of great economic and strategic importance for the European industry subjected to an increased supply risk. Consequently, tungsten has been included in the EU's list of critical raw materials by the European Commission since 2011. To ensure future supply and improve strategic autonomy, more intensive investigation of the national raw material potential is crucial. Europe's largest tungsten mine and one of the world's largest scheelite deposits is located at Felbertal in Austria. Its discovery in 1967 was followed by extensive mineral exploration in the Eastern Alps in the 1980s, which only led to the discovery of numerous small (subeconomic) tungsten occurrences.
In this PhD project, assessment criteria ("fingerprints") for the evaluation of the regional tungsten potential in Austria were developed as part of the "W(olfram) Alps" project, in collaboration of Montanuniversität Leoben with GeoSphere Austria and Wolfram Bergbau und Hütten AG. The mineralogical-chemical signatures of 17 tungsten-dominated deposits/occurrences in the Eastern Alps, including the world-class Felbertal deposit, serve as indicators for evaluating the potential of regional tungsten anomalies. Scheelite (CaWO4) is the most common tungsten mineral in the Eastern Alps and occurs in various geological units and mineralization styles. The identification of a "primary" scheelite signature that reflects the actual mineralization process is often hampered by the presence of multiple scheelite types showing a broad petrographic and chemical variation in most ore settings. Accordingly, several analytical methods were combined including cathodoluminescence imaging, electron probe microanalysis and laser ablation-inductively coupled plasma-mass spectrometry. For the processing of LA-ICP-MS trace element data, the new software G.O.Joe was developed as part of this study, providing innovative correction methods for interference problems in scheelite analysis.
The combination of geological-mineralogical information and scheelite trace element data allows to distinguish three mineralization styles: (1) intrusion-related (e.g. Felbertal), (2) polymetallic (e.g. Schellgaden) and (3) carbonate-hosted stratabound scheelite mineralization (e.g. Kleinarl, Tux-Lanersbach). Trace element distribution in scheelite shows that particularly the elements Na, Sr, Nb, Mo and REE+Y are suitable for identifying scheelite of distinct ore-forming environments. A newly developed discrimination diagram (Sr/Mo vs. Na/Nb) demonstrates that scheelite in the Eastern Alps covers the entire spectrum of these mineralization styles. This diagram not only confirms that the world-class Felbertal tungsten deposit clearly stands out from subeconomic tungsten mineralization in the Austrian Eastern Alps, but also represents a robust tool for tungsten exploration on a global scale.
This study also includes two detailed geological-mineralogical studies, providing important contributions to the metallogeny of tungsten in the Eastern Alps. New U-Pb scheelite age data from Mallnock, a unique type of tungsten occurrence in the Eastern Alps, link its polyphase evolution with large-scale Permian-Triassic geodynamics. At Lienzer Schlossberg, scheelite is part of a magmatogenic skarn system related to a pluton of the Periadriatic Fault System. These findings indicate that in addition to the Variscan and Alpine orogenic events to also the Permian-Triassic as well as Cenozoic geodynamics have to be considered in the metallogenetic model for tungsten.
Translated title of the contributionEvaluierung des Wolframpotentials in den Ostalpen: Neue Erkenntnisse aus geologischen, mineralogischen und chemischen (LA-ICP-MS) Daten von Scheelit
Original languageEnglish
QualificationDr.mont.
Awarding Institution
  • Montanuniversität
Supervisors/Advisors
  • Raith, Johann G., Supervisor (internal)
  • Paulick, Holger, Co-Supervisor (external), External person
  • Schulz, Bernhard, Assessor A (external), External person
  • Pohl, Walter L., Assessor B (external), External person
DOIs
Publication statusPublished - 2025

Bibliographical note

no embargo

Keywords

  • scheelite
  • tungsten
  • Eastern Alps
  • critical raw materials
  • ore deposits

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