Thomas Wagner

RWTH Aachen University · Institute of Applied Mineralogy and Economic Geology

Fluid inclusions from the Olserum-Djupedal REE-phosphate mineralisation in the Västervik region, SE Sweden, comprise different brine types with contrasting major cation compositions. Highly saline, Ca-rich brines occur in the Djupedal area and explain why different Ca-bearing REE minerals only formed in this area during alteration. This contrasts w...

The Xiong’ershan district in central China hosts broadly coeval porphyry Au (Qiyugou deposit), porphyry Mo (Leimengou deposit), and barren (Huashan pluton) systems. The key controls on the ore potential and different mineralization styles in these systems are not well understood, with first-order differences in fluid chemistry and melt sources bein...

The Huangshui’an deposit located in East Qinling (China) is an unusual case of a Si-rich carbonatite hosting economic Mo and minor Pb and REE mineralization. The role of mantle-sourced carbonatite melts and fluids in the formation of the Mo mineralization remains poorly understood. Our integrated study based on field geology, petrography, microther...

The fluid inclusion record of the miarolitic gem beryl-bearing Luumäki pegmatite (SE Finland) has been studied by petrography, microthermometry and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). Four types of fluid inclusion assemblages could be distinguished, which record the nature and timing of fluids exsolved in the pe...

Hydrothermal iron oxide-copper-gold (IOCG) ore deposits are globally important sources of Cu and Au. IOCG systems show many common features, but also considerable diversity in terms of geological setting, mineralization style and ore fluid characteristics. The key factors that control ore formation are controversially debated and no general ore dep...

The hydrothermal evolution of the chemically highly evolved Kymi topaz granite stock in southeastern Finland was reconstructed from fluid inclusion petrography, microthermometry, and LA-ICP-MS analysis. The Kymi stock shows a clear zonation and intrusion sequence consisting of an early porphyritic granite, a subsequent equigranular granite, and a l...

The Prominent Hill deposit is a world-class iron oxide copper–gold (IOCG) deposit in South Australia, characterized by a high Cu/S ratio of the dominant Cu-(Fe) sulfides hosted by hematite breccias. It contains a total resource of 278 Mt of ore at 0.98% Cu and 0.75 g/t Au. Prominent Hill is one of several IOCG deposits and numerous prospects in the...

Orogenic style gold mineralizations in the Archean Hattu schist belt (E Finland) are present in all major host rock lithologies including epiclastic sedimentary rocks, volcanic rocks, and felsic intrusives. The gold deposits are related to extensive quartz-dominated vein networks and the gold mineralization occurs as dissemination in altered wall r...

This study explores the suitability of apatite as a tracer of the source(s), chemistry, and evolution of ore-forming hydrothermal fluids. This is tested by analysing the halogen (F, Cl, Br, and I), stable Cl isotopic, and trace element compositions of fluorapatite from the regional-scale Olserum-Djupedal rare earth element (REE) phosphate mineralis...

Miarolitic pockets from the 1628 Ma Luumäki pegmatite in SE Finland contain gem-quality beryl (heliodor) within a matrix of reddish hematite, biotite, muscovite, chlorite, quartz, kaolinite, and bertrandite. Two different types of gem-beryl-bearing miarolitic pockets were observed, one in the intermediate zone of the pegmatite close to the contact...

Petrogenetic studies of carbonatites are challenging because carbonatite mineral assemblages and mineral chemistry typically reflect both variable pressure-temperature conditions during crystallization and fluid-rock interaction caused by magmatic-hydrothermal fluids. However, this complexity results in recognizable alteration textures and trace el...

The Swedish part of the Fennoscandian Shield hosts a variety of rare earth element (REE) deposits, including magmatic to magmatic-hydrothermal types. This paper focuses on the origin of the Olserum-Djupedal REE-phosphate mineralisation located in the sparsely studied Västervik region, SE Sweden. Here, mineralisation occurs in three main areas, Olse...

Thermodynamic database for GEM-Selektor modeling software http://gems.web.psi.ch/ HowToTDB.docx contains the instructions for using the database to create a GEM-Selektor modeling project.

How to create a modeling project in GEMS (http://gems.web.psi.ch/) using the Aq17 thermodynamic database.

The Prominent Hill deposit is a large iron oxide Cu-Au (IOCG) resource located in the Olympic IOCG province of South Australia. The deposit is hosted by brecciated sedimentary rocks and structurally underlying lavas of the ca. 1.6 Ga old Gawler Range Volcanics. Both rock units are altered and mineralized, forming characteristic hematite breccias. T...

Halogens are excellent tracers of hydrothermal fluid sources in sedimentary, magmatic, metamorphic and ore-forming environments. In situ LA-ICP-MS analysis of Cl and Br in single fluid inclusions has provided fundamentally new insight into the processes leading to the formation of economic mineral deposits. Enrichment and depletion of Br relative t...

The rapidly growing use of rare earth elements and yttrium (REE) in modern-day technologies, not least within the fields of green and carbon-free energy applications, requires exploitation of new REE deposits and deposit types. In this perspective, it is vital to develop a fundamental understanding of the behavior of REE in natural hydrothermal sys...

The REE mineralisation in the Olserum-Djupedal area is located at the border of the Palaeoproterozoic Västervik sedimentary formation and c. 1.8 Ga granitoids belonging to the Transscandinavian Igneous Belt (TIB) in SE Sweden. The mineralisation is dominated by the phosphates monazite-(Ce), xenotime-(Y) and variably REE-bearing fluorapatite. These...

Petrogenetic studies of carbonatites – carbonate-dominated igneous rocks – are challenging because carbonatite mineral assemblages and mineral chemistry typically reflect variable pressure-temperature conditions during crystallization, and fluid-rock interaction caused by magmatic-hydrothermal fluids. However, this complexity results in recognizabl...

The magmatic-hydrothermal fluid evolution in the Monte Mattoni mafic complex in the Adamello batholith was reconstructed by combination of fluid inclusion studies (microthermometry and LA-ICPMS microanalysis of individual fluid inclusions) and thermodynamic modeling of subsolidus fluid-mineral equilibria. The mafic complex consists of two main unit...

The Prominent Hill deposit is a world-class iron oxide copper–gold (IOCG) deposit in South Australia, characterized by a high Cu/S ratio of the dominant Cu-(Fe) sulfides hosted by hematite breccias. It contains a total resource of 278 Mt of ore at 0.98 % Cu and 0.75 g/t Au. Prominent Hill is one of several IOCG deposits and numerous prospects in th...

This study presents an internally consistent thermodynamic dataset for aqueous species in the system Ca-Mg-Na-K-Al-Si-O-H-C-Cl, obtained by adding species of calcium, magnesium and carbon to the core system Na-K-Al-Si-O-H-Cl (Miron and others, 2016). Critically evaluated experimental data on mineral solubility (Ca and Mg hydroxides, Ca and Mg silic...

The Kymi stock is a highly evolved topaz-bearing granite stock that has intruded into rapakivi granites in the central part of the Wiborg batholith (southwest Finland). The stock shows a well-defined zonation and intrusion sequence consisting of early porphyritic granites, subsequent equigranular granite and a late marginal stockscheider pegmatite....

In order to characterise the fluids for REE mineralisation in the Olserum-Djupedal area, the Cl isotope, halogen and trace element compositions of fluorapatite were determined by SIMS and LA-ICP-MS. Textural relations demonstrate that fluorapatite precipitated concurrently with primary monazite-(Ce) and xenotime-(Y). Later dissolution-reprecipitati...

Orogenic style gold mineralizations in the Archean Hattu Schist belt (E Finland) are present in all major host rock lithologies including epiclastic sedimentary and volcanogenic rocks, as well as felsic intrusives. The gold mineralizations occur as dissemination in altered wall rocks and within hydrothermal quartz veins. Hydrothermal tourmalines ar...

The sources of fluids and precious metals in orogenic gold deposits remain controversial, and a key question is whether auriferous magmatic-hydrothermal fluids are a decisive ingredient for economic orogenic gold mineralization. Contributions of magmatic-hydrothermal fluids have been proposed based on indirect arguments such as isotope data or empl...

The 1628* Ma old Luumäki gem beryl pegmatite is hosted by rapakivi granites of the Wiborg batholith in southeast Finland. The moderately evolved niobium-yttrium-fluorine (NYF) pegmatite system belongs to the topaz-beryl type of the rare-element pegmatite class. It has a simple major mineral assemblage of K-feldspar + plagioclase + quartz + biotite...

Quantitative analysis of microscopic fluid inclusions by laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) has greatly improved our understanding of fluid-rock interactions and ore deposit formation. Spatially resolved analysis can track the chemical evolution of fluids within texturally complex veins and along fluid pathways....

A large amount of critically evaluated experimental data on mineral solubility, covering the entire Na-K-Al-Si-O-H-Cl system over wide ranges in temperature and pressure, was used to simultaneously refine the standard state Gibbs energies of aqueous ions and complexes in the framework of the revised Helgeson-Kirkham-Flowers equation of state. The t...

Element mobility and fluid-rock interaction related to the formation of late-metamorphic quartz veins have been studied by combination of mineral chemistry, whole-rock geochemistry, mass balance analysis and fluid-mineral equilibria modeling. The quartz veins are hosted by very low-grade metasedimentary rocks of the fold-and-thrust belt of the Rhen...

The chemical evolution of fluids in Alpine fissure veins (open cavities with large free-standing crystals) has been studied by combination of fluid inclusion petrography, microthermometry, LA-ICPMS microanalysis and thermodynamic modeling. The quartz vein systems cover a metamorphic cross section through the Central Alps (Switzerland), ranging from...

Natural tourmalines exhibit wide variations in their major and trace element chemistry, reflecting tourmaline stability in diverse igneous, metamorphic and hydrothermal environments and over wide ranges of temperature and pressure. Many Archean greenstone belts host abundant tourmaline in hydrothermal orogenic gold-quartz veins, variably altered me...

Reactive transport simulation on unstructured meshes can provide fundamental insight into the effect that geometric complexity of geologic structures has on fluid flow and development of reaction fronts. When applied to conditions ranging from ambient to hydrothermal and combined with compressible flow, accounting for geometric complexity provides...

Tourmaline occurs in a wide range of magmatic, metamorphic and hydrothermal environments, including granite-related magmatic-hydrothermal systems, granitic pegmatites, boron-rich metasediments and orogenic gold deposits. Naturally occurring tourmaline shows wide variations in major element composition, reflecting many cationic and anionic crystal-c...

The late Archean Hattu schist belt, Eastern Finland, is composed of metamorphosed epiclastic and felsic volcanic rocks, intruded by tonalites and granodiorites. The schist belt hosts structurally controlled orogenic-type gold deposits, including the actively mined Pampalo deposit and many smaller prospects. The mineralization at Pampalo is characte...

Granitic pegmatites are important hosts for economically important rare-element and gemstone deposits, but the magmatic and hydrothermal processes responsible for enrichment of rare-elements and formation of gem-bearing miarolitic pockets are not fully understood. The Luumäki gem beryl-bearing pegmatite is located within the Wiborg batholith in SE...

The Kymi monzogranite stock features the chemically most evolved rocks of the 1.65 Ga Wiborg rapakivi batholith. The stock has a well-developed zonation from center to rim, which correlates with the degree of magmatic fractionation. The key rock types are (1) least evolved porphyritic granite (porphyroblasts up to 5 cm and fine-grained matrix), (2)...

GEMSFITS is a new code package for fitting internally consistent input parameters of GEM (Gibbs energy minimization) geochemical-thermodynamic models against various types of experimental or geochemical data, and for performing inverse modeling tasks. It consists of the gemsfit2 (parameter optimizer) and gfshell2 (graphical user interface) programs...

Unconformity-related hydrothermal ore deposits typically form by mixing of hot, deep, rock-buffered basement brines and cooler fluids derived from the surface or overlying sediments. Current models invoking simultaneous downward and upward flow of the mixing fluids are inconsistent with fluid overpressure indicated by fracturing and brecciation, fa...

Erratum to: Contrib Mineral Petrol (2014) 167:968 DOI 10.1007/s00410-014-0968-8Due to an unfortunate error, the equations [Eq. (25) on page 4, Eq. (35) on page 9, Eq. (37) on page 10 and Eqs. (38)–(40) on page 11] were published incorrectly. The correct version of equations is given below.The ideal contribution to the activity of sudoite is ...

The Altar porphyry Cu-(Mo-Au) deposit occurs in the Miocene to early Pliocene copper belt of the high Andes of Western Argentina, close to the Chilean border. A cluster of Late Miocene porphyries intruded a more extensive complex of Early Miocene rhyolitic to andesitic volcanic and subvolcanic rocks. Potassic alteration in the Central Porphyry was...

GEMSFIT, a parallelized open-source tool for fitting thermodynamic activity models has been developed. It is the first open-source implementation of a generic geochemical thermodynamic fitting tool coupled to a chemical equilibrium solver which uses the direct Gibbs energy minimization approach. This enables speciation-based fitting of complex solu...

We present a new thermodynamic activity-composition model for di-trioctahedral chlorite in the system FeO–MgO–Al2O3–SiO2–H2O that is based on the Holland–Powell internally consistent thermodynamic data set. The model is formulated in terms of four linearly independent end-members, which are amesite, clinochlore, daphnite and sudoite. These account...

The densities of aqueous solutions in the systems CaCl2-NaCl-H2O and MgCl2-NaCl-H2O were determined experimentally at temperatures from (298.15 to 523.15) K, pressures up to 70 MPa and over a range of composition at ionic strengths from (0.1 to 18) mol·kg-1. The vibrating-tube densimeters used for the experimental measurements have an accuracy on d...

The solubility of Yttrium (III) fluoride as a function of fluoride activity was investigated experimentally at 100, 150, 200 and 250 °C and vapor-saturated water pressure. Data obtained from the experiments were used to determine the solubility product of YF3(s), the fluoride speciation of Y and the stability constants of the corresponding complexe...

Reactive mass transport (RMT) simulation is a powerful numerical tool to advance our understanding of complex geochemical processes and their feedbacks in relevant subsurface systems. Thermodynamic equilibrium defines the baseline for solubility, chemical kinetics, and RMT in general. Efficient RMT simulations can be based on the operator-splitting...

Fluid mixing across unconformities between crystalline basement and overlying sedimentary basins is commonly invoked as an efficient chemical mechanism for ore deposition, but the origin of basement brines and the process of ore formation have rarely been linked by direct evidence. Using laser ablation–inductively coupled plasma–mass spectrometry m...

The chemical composition of fluid inclusions in quartz crystals from Alpine fissure veins was determined by combination of microthermometry, Raman spectroscopy, and LA-ICPMS analysis. The veins are hosted in carbonate-bearing, organic-rich, low-grade metamorphic metapelites of the Bündnerschiefer of the eastern Central Alps (Switzerland). This stro...

The Sailauf MnFeAs vein mineralization, located in the Spessart district (central Germany), is characterized by complex hydrothermal carbonate and oxide assemblages. The mineralization is hosted by a Permian rhyolite body and is structurally related to the Variscan unconformity that separates Permian sedimentary rocks from the underlying Variscan c...

The development of highly accurate and computationally efficient modeling software based on Gibbs energy minimization (GEM) makes it possible to thermodynamically simulate geochemically realistic subsurface fluid-rock interaction processes. This involves consideration of nonideal multicomponent-multiphase systems that include dilute to concentrated...

Post-Variscan hydrothermal base-metal mineralization of the Taunus ore district, SE Rhenish Massif (Germany), has been studied through combination of stable (S, C, O) and radiogenic (Pb) isotope geochemistry. Based on field and textural observations, five hydrothermal mineralization types can be distinguished. These are (1) tetrahedrite–tennantite...

We present one of the very rare natural examples of extremely negative Ce anomalies (up to 4 orders of magnitude) in manganese oxides, caused by higher mobility of Ce4+ compared to REE3+ in an aquatic environment. The young secondary Mn oxides formed together with fluorites and goethites during water–mineral interaction in a hydrothermal fluorite v...

Thermal water samples and related young and fossil mineralization from a geothermal system at the northern margin of the Upper Rhine Graben have been investigated by combining hydrochemistry with stable and Sr isotope geochemistry. Actively discharging thermal springs and mineralization are present in a structural zone that extends over at least 60...

Normalized rare earth element patterns of rock and mineral samples from evolved granitic systems and associated hydrothermal tin deposits frequently show an unusual split into four consecutive curved segments, referred to as tetrads. In the present contribution, the simultaneous occurrence of complementary convex and concave tetrads is described fo...

We have investigated fluid-rock interaction processes during formation of metamorphic quartz veins that are abundant in the fold-and-thrust belt of the Rhenish Massif, southwest Germany. These veins record two successive assemblages that were formed in a different fluid-rock environment, which are (1) massive vein filling (elongate-blocky quartz, c...

A consortium of research groups from ETH Zurich, EPF Lausanne, the Paul Scherrer Institut and the University of Bonn collaborates in a comprehensive program of basic research on key aspects of the Enhanced Geothermal Systems (EGSs). As part of this GEOTHERM project (www.geotherm.ethz.ch), we concentrate on the fundamental investigation of thermodyn...

The Spessart district (SW Germany), located at the southwestern margin of the Permian Kupferschiefer basin in Central Europe, hosts abundant stratabound and structurally controlled base metal mineralization. The mineralization styles identified are (1) stratabound Cu-Pb-Zn-(Ag) ores in Zechstein sedimentary rocks, (2) structurally controlled Cu-As-...

The solubility of REE(III) fluoride solids was determined in fluoride- and chloride-bearing solutions at 150, 200 and 250°C and saturated water vapor pressure. These experimental data, together with experimental data from previously published studies, were used to evaluate formation constants for chloride- and fluoride-bearing aqueous species of th...