HIGH-TECH METAL POTENTIAL OF SPHALERITE FROM EASTERN ALPINE LEAD-ZINC DEPOSITS AND DEVELOPMENT OF A MATRIX-MATCHED SPHALERITE (ZnS) CALIBRATION MATERIAL (MUL-ZnS-1) FOR CALIBRATION OF IN SITU TRACE ELEMENT MEASUREMENTS BY LASER ABLATION INDUCTIVELY COUPLED PLASMA MASS SPECTROMETRY (LA-ICP-MS)

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Abstract

The “Ad-Hoc working Group on defining critical raw materials” of the European Union (EU) has identified twenty commodities as being critical; some of them are used in high-technology products and green technologies (EU, 2014). Austria hosts numerous mineralizations with significant potential of the rare high-tech metals germanium, gallium, indium and cobalt, as indicated by chemical data of sulphide ore concentrates. In situ measurements of trace elements in natural sphalerite samples using LA-ICP-MS are hampered by a lack of homogenous matrix-matched sulphide reference materials available for calibration. The preparation of the MUL-ZnS1 calibration material containing the trace elements V, Cr, Mn, Co, Ni, Cu, Ga, Ge, As, Se, Mo, Ag, Cd, In, Sn, Sb, Tl, and Pb besides Zn, Fe and S is reported. The results show that MUL-ZnS-1 is an appropriate material for calibrating trace element determination in sphalerite using LA-ICP-MS. The three investigated ore types are: (1)Carbonate-hosted “Alpine-type“ or “Bleiberg-type“ deposits hosted by Triassic limestones and dolomites of the Drau Range and the Northern Calcareous Alps are characterized by low Fe, high Cd (~2000 µg/g), Ge (200-400 µg/g) and Tl concentrations (~100 µg/g) in sphalerite and by the absence of Co (max. 1 µg/g), Cu, Ni. The Lafatsch deposit hosted in the Northern Calcareous Alps is a special case within this Group, hosting high amounts of Ag, but lower amounts in Mn, Ge, As and Tl compared to the other deposits of this type. (2)In the Austroalpine nappe system, SEDEX-type deposits are known from the Graz Paleozoic and the Gurktal nappe. The Pb-Zn-Ba ores located in the Graz Paleozoic (Styria) formed in the Lower Devonian in a euxinic basin structure associated with submarine alkaline volcanism (Weber 1990). In a sphalerite concentrate from the deposit Arzberg-Haufenreith, 10 µg/g Ge, 11 µg/g Ga, 1800 µg/g Cd, 29 µg/g In, and 5 µg/g Tl have been reported (Cerny and Schroll, 1995). In-situ LA-ICP-MS measurements of sphalerite grains collected from five ancient mining sites and one exploration adit reveal a large variation of trace element concentrations with median values of 4.7 wt% Fe, 1832 µg/g Cd, 138 µg/g Co, 18 µg/g Ag, 9 µg/g Ga, 0.36 µg/g Ge, 1 µg/g In, 1 µg/g Sn and 5 µg/g Sb. Maximum values reach 220 µg/g for Ge, 399 µg/g for Ag and 83 µg/g for In. SEDEX deposits hosted in Palaeozoic units outside the Graz Palaeozoic like Meiselding (Gurktal nappe), sphalerite carries up to 1900 µg/g In, 250 µg/g Ge, 65 µg/g Ga, 282 µg/g Co and 2.9 wt% Cd. In the Walchen deposit located in Koralm-Wölz nappe system is characterised by high In values (98 µg/g) but low values in Co (55 µg/g), Ga (1.53 µg/g) and Ge (0.07 µg/g). Sphalerite from the Leogang deposit hosted by upper Silurian-Middle Devonian dolomite (Südfazies-Dolomit) showed the most elevated In concentrations (Md= 247 µg/g), the measured values for Ga (1.05 µg/g), Ge (0.11 µg/g) and Co (128 µg/g) are in the range of the other investigated SEDEX deposits. (3)Vein deposits of different genesis and age are widespread in the Eastern Alps. Pb-Zn-mineralization at Vellach-Metnitz in the Gurktal Nappe (Carintia) unit shows vein-like NW-SE trending structures (WEBER, 1997). Metnitz, sphalerite carries up to 65 µg/g In, 924 µg/g Ge, 381µg/g Ga, 679 µg/g Co and 4380 µg/g Cd. High indium concentrations have been previously reported for the Zn-Cu-Pb veins of Koprein (Palaeozoic of the Karawanken Range). Our LA-ICP-MS analyses of sphalerite show between 10 and 35 µg/g In (maximum 276 µg/g), Ge up to 2.2 µg/g, Ga 0,8- 9,8 µg/g, Co 217- 1221 µg/g, Cd 1121- 3560 µg/g, and Fe 2.8 – 6.5 wt%. The Achselalm-Flecktrogalm deposit hosted in the Habach Group only contains slightly elevated Ga concentration (26 µg/g), In (1.5 µg/g) and Co 59 (µg/g) are low compared to the other vein-type deposits, Ge is below detection limit.

Details

Translated title of the contributionHoch Technologie Metall Potential von Sphalerit in Ostalpinen Blei-Zink Lagerstätten und die Entwicklung eines Matrix mached Referenzmaterials für die in situ Spurenelement Analytik mittels Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS)
Original languageEnglish
QualificationDr.mont.
Awarding Institution
Supervisors/Advisors
  • Hauzenberger, Christoph Anton, Assessor B (external), External person
  • Melcher, Frank, Assessor A (internal)
Publication statusPublished - 2018