apl. Prof. Dr. Thomas Will

Geodynamic evolution of the Mid‐German Crystalline Zone, and other key areas in the European Variscides

This is long-term project with the main aim to delineate the geodynamic history of the Mid-German Crystalline Zone (MGCZ) and adjacent areas in Central Europe during the Variscan orogeny by a combination of petrological, structural, geochemical and geochronological studies. Initially, the work focused on the determination of the conditions of formation of metamorphic rocks of the Odenwald, Spessart and Erzgebirge basement areas and the recognition of the respective tectonic settings in which these rocks formed. Prominent results include the discovery of formerly unrecognized eclogite-facies rocks in the Odenwald (Will & Schmädicke, 2001), the proposition of a late Variscan paired metamorphic belt in the same region and the recognition of previously unknown Variscan terrane boundaries in the MGCZ (Will & Schmädicke, 2003; Will et al., 2015, 2018). In the last few years the research concentrated more on geochemical and geochronological aspects of the metamorphic but also magmatic rocks as well as provenance studies of lithologically different rocks from these areas. This led to a wealth of new geochemical, isotope geochemical and Ar-Ar white mica, in-situ electron microprobe monazite but, especially, SIMS U-Pb zircon, monazite and rutile age data for numerous igneous, metasedimentary and metabasic rocks from the Odenwald, Spessart and Erzgebirge basement areas (Will et al., 2015, 2017, 2018, 2021a; Schmädicke et al., 2018; Schmädicke & Will, 2021a; 2023). For example, in a recent study we could show that in the Odenwald-Spessart basement, which is the largest outcrop area of the MGCZ, S-type granitic rocks formed at an active continental margin at c. 425 Ma, whereas younger, medium- to high-K calc-alkaline I-type granodiorite and diorite formed by partial melting of the upper mantle in an inferred anorogenic setting at c. 340 Ma (Will et al., 2021a). Currently work is in progress on the origin, petrogenesis, tectonic setting(s) and the possible processes responsible for the widespread high-temperature late Carboniferous (<345 Ma) igneous and metamorphic activity during the final stages of the Variscan orogeny.

Correlation of Neoproterozoic to Cambrian orogenic belts across the South Atlantic

The aim of this project is to compare the tectonic history of the southern Dom Feliciano Belt in South America and coeval Neoproterozoic belts in SW Africa (i.e., the Kaoko, Gariep and Saldania belts in Namibia and South Africa as well as the Richtersveld Igneous Complex in South Africa) in order to establish a possible correlation of the various belts across the South Atlantic. We focus on geochronological, petrological and geochemical aspects of Neoproterozoic to Cambrian metamorphic and igneous rocks from the exotic Cuchilla Dionisio Terrane (CDT) in the southern Dom Feliciano Belt in Uruguay and those from Neoproterozoic orogens in South Africa and Namibia.

So far we could show that the CDT basement and equivalent terranes in the coastal areas of southeastern Brazil and eastern Argentina are displaced fragments of southwest Africa that constitute the so-called ‘Arachania’ microplate. This microplate is part of the Mesoproterozoic Namaqua Province in southern Africa, which separated from the Kalahari Craton (KC) in the Tonian (Will et al., 2019, 2020, 2021b, 2023). Felsic rift-related rocks of the CDT formed by crustal anatexis of the Namaqua Province basement at the western margin of the KC during the initial stages of Rodinia break-up prior to opening of the Adamastor ocean at c. 780 Ma (Will et al., 2019, 2020). A high-temperature metamorphic event occurred in the CDT at c. 655-640 Ma and was associated with subduction of the Adamastor ocean underneath the western African margin and initiation of diachronous calc-alkaline magmatism along a c. 1200 km long magmatic arc along this margin (Will et al., 2020). Oceanic rocks from the CDT provide evidence that a first back-arc basin that had opened between this arc and the African margin must have already started to close at c. 628-625 Ma (Will et al., 2014, 2019). In the late Ediacaran/early Cambrian the CDT was amalgamated to South America along the Sierra Ballena Shear Zone, which separates rocks of Río de la Plata Craton and KC affinities (Gaucher et al., 2021, 2022). This was associated with a transition from early Ediacaran subduction-related, arc-type magmatism to intraplate and, finally to late Ediacaran/early Cambrian collision-related igneous activity in the Uruguayan sector of the southern Dom Feliciano Belt (Will et al., 2021b, 2023). As a spin-off we could show (Will et al., 2023) that the early Cambrian collision-related Santa Teresa Granite in easternmost Uruguay and the coeval Cape Granite in South Africa were part of the same pluton that was separated during the opening of the modern South Atlantic in the Cretaceous.

2003: Appointment to ‚Außerplanmäßiger Professor’

since 1996: Research/Senior Research Scientist, Universität Würzburg

1995: Habilitation, Universität Würzburg [Phasengleichgewichte in metamorphen Gesteinen]

1990: Doctor of Philosophy, University of Melbourne, Australia [ Theoretical studies in metamorphic geology and structural geology ]

1987: Master of Science, State University of New York at Albany, USA [ Structural investigations of experimentally and naturally produced slickensides ]

67 published research articles (including 6 peer-reviewed book chapters) in international journals, numerous conference abstracts (amount is unknown), 3 major theses, 1 field guide, 1 textbook (Phase Equilibria in Metamorphic Rocks - Thermodynamic Background and Petrological Applications. Springer-Verlag, Berlin Heidelberg New York).

Reviewer for 16 international professional journals, three national research agencies and several external Ph.D. theses

View profile on Researchgate

International peer-reviewed papers

 [1] Will TM, Wilson CJL (1989) Experimentally produced slickenside lineations in pyrophyllitic clay. Journal of Structural Geology 11: 657-667

[2] Will TM, Powell R, Holland T, Guiraud M (1990) Calculated greenschist facies mineral equilibria in the system CaO-FeO-MgO-Al2O3-SiO2-CO2-H2O. Contributions to Mineralogy and Petrology 104: 353-368

[3] Will TM, Powell R, Holland T (1990) A calculated petrogenetic grid for ultramafic rocks at low pressures in the system CaO-FeO-MgO-Al2O3-SiO2-CO2-H2O. Contributions to Mineralogy and Petrology 105: 347-358

[4] Wilson CJL, Will TM (1990) Slickenside lineations due to ductile processes. In: Knipe RJ, Rutter EH (eds) Deformation Mechanisms, Rheology and Tectonics. Geological Society of London Special Publication 54: 455-460

[5] Powell R, Will TM, Phillips GN (1991) Metamorphism in Archean greenstone belts: calculated fluid compositions and implications for gold mineralisation. Journal of Metamorphic Geology 9: 141-150

[6] Will TM, Powell R (1991) A robust approach to the calculation of paleostress fields from fault plane data. Journal of Structural Geology 13: 813-821

[7] Will TM, Powell R (1992) A robust approach to the calculation of paleostress fields from fault plane data: Reply. Journal of Structural Geology 14: 639-640

[8] Wilson CJL, Will TM, Cayley RA, Chen S (1992) Geologic framework and tectonic evolution in Western Victoria, Australia. Tectonophysics 214: 93-127

[9] Will TM, Powell R (1992) Activity-composition relationships in multi-component amphiboles: an application of Darken’s Quadratic Formalism. American Mineralogist 77: 954-966

[10] Stüwe K, Will TM, Zhou S (1993) On the timing of fluid production and metamorphism in metamorphic piles—some implications on the origin of postmetamorphic gold mineralisation. Earth and Planetary Science Letters 114: 417-430

[11] Xu G, Will TM, Powell R (1994) A petrogenetic grid for contact metamorphic pelitic assemblages: The system K2O-FeO-MgO-Al2O3-SiO2-H2O at low pressures and intermediate to high temperatures. Journal of Metamorphic Geology 12: 99-119

[12] Xu G, Powell R, Wilson CJL, Will TM (1994) Contact metamorphism associated with the Stawell granite, Victoria, Australia. Journal of Metamorphic Geology 12: 609-624

[13] Schubert W, Will TM (1994) Granulite-facies rocks of the Shackleton Range, Antarctica. Conditions of formation and preliminary petrogenetic implications. Chemie der Erde 54: 355-371

[14] Will TM, Okrusch M, Schmädicke E, Chen G (1998) Phase relations in the greenschist-blueschist-amphibolite-eclogite facies in the system Na2O-CaO-FeO-MgO-Al2O3-SiO2-H2O (NCFMASH), with applications to the PT-evolution of metamorphic rocks from Samos, Greece. Contributions to Mineralogy and Petrology 132: 85-102

[15] Will TM (1998) Phase diagrams and their application to determine pressure-temperature paths of metamorphic rocks. Neues Jahrbuch für Mineralogie Abhandlungen 174: 103-130

[16] Schüssler U, Bröcker M, Henjes-Kunst F, Will T (1999) P-T-t evolution of the Wilson Terrane metamorphic basement at the Oates Coast, Antarctica, derived from migmatites with granulite-facies relics. Precambrian Research 93: 235-258

[17] Will TM (2001) Paleostress-tensor analysis of late deformation events in the Odenwald Crystalline Complex and comparison with other units of the Mid-German Crystalline Rise, Germany. Mineralogy and Petrology 72: 229-247

[18] Will TM, Schmädicke E (2001) A first report of retrogressed eclogites in the Odenwald Crystalline Complex: evidence for high-pressure metamorphism in the Mid-German Crystalline Rise, Germany. Lithos 59: 109-125

[19] Will TM (2001) Activity-composition relationships and pressure-temperature determinations in metamorphic rocks. In: Geiger CA (ed) Solid Solutions in Silicate and Oxide Systems. European Mineralogical Union, Notes in Mineralogy Vol 3: 101-118

[20] Klemd R, Schröter FC, Will TM, Gao J (2002) PT-evolution of glaucophane-omphacite bearing HP-LT rocks in the western Tianshan orogen, NW China: new evidence for ‘Alpine-type’ tectonics. Journal of Metamorphic Geology 20: 239-254

[21] Will TM, Schmädicke E (2003) Isobaric cooling and counter-clockwise P-T paths in the Variscan Odenwald Crystalline Complex, Germany. Journal of Metamorphic Geology 21: 469-480

[22] Abu El-Enen MM, Okrusch M, Will TM (2003) Metapelitic assemblages in the Umm Zariq schists, central western Kid Belt, Sinai Peninsula, Egypt. Neues Jahrbuch für Mineralogie Abhandlungen 178: 277-306

[23] Schmädicke E, Will TM (2003) Pressure-temperature evolution of blueschist-facies rocks from the island of Sifnos, Greece, and constraints on exhumation processes. Journal of Metamorphic Geology 21: 799-811

[24] Abu El-Enen MM, Will TM, Okrusch M (2004) P-T Evolution of the Taba Metamorphic Belt, Sinai, Egypt: Constraints from metapelite assemblages. African Journal of Earth Sciences 38: 59-78

[25] Abu El-Enen MM, Okrusch M, Will TM (2004) Metamorphism and metasomatism at a dolerite-limestone contact in the Gebel Yelleq area, Northern Sinai, Egypt. Mineralogy and Petrology 81: 135-164

[26] Will TM, Gruner BB, Okrusch M (2004) Progressive metamorphism of pelitic rocks from the Pan-African Kaoko Belt, NW Namibia: geothermobarometry and phase petrological studies of Barrovian and Buchan sequences. South African Journal of Geology 107: 431-454

(Paper [26] received the best paper award (‘Jubilee Award’) from the South African Geological Society in 2005!)

[27] Zeh A, Gerdes A, Will TM, Millar IL (2005) Provenance and magmatic-metamorphic evolution of a Variscan island-arc complex: Contraints from U-Pb dating, petrology, and geospeedometry of the Kyffhäuser Crystalline Complex, Central Germany. Journal of Petrology 32: 1393-1420

[28] Schmädicke E, Will TM (2006) First evidence of eclogite-facies metamorphism in the Shackleton Range, Antarctica: Tracer of a suture between East and West Gondwana? Geology 34: 133-136

[29] Ring U, Will T, Glodny J & 6 others (2007) Early exhumation of high-pressure rocks in extrusion wedges: The Cycladic blueschist unit in the eastern Aegean, Greece and Turkey. Tectonics 26: doi: 10.1029/2005TC001872

[30] Brandt S, Will TM, Klemd R (2007) Magmatic loading in the Proterozoic Epupa Complex, NW Namibia, as evidenced by ultrahigh-temperature sapphirine-bearing orthopyroxene-sillimanite-quartz granulites. Precambrian Research 153: 143-178

[31] Ring U, Glodny J, Will T, Thomson S (2007) An Oligocene extrusion wedge of blueschist-facies nappes on Evia, Aegean Sea, Greece: implications for the early exhumation of high-pressure rocks. Journal of the Geological Society of London 164: 637-652

[32] Will TM, Zeh A, Gerdes A, Frimmel HE, Millar IL, Schmädicke E (2009) Palaeoproterozoic to Palaeozoic magmatic and metamorphic events in the Shackleton Range, East Antarctica: constraints from zircon and monazite dating, and implications for the amalgamation of Gondwana. Precambrian Research 172: 25-45

[33] Will TM, Miller RMcG, Frimmel HE (2009) Orogenic tectono-thermal evolution of the Kaoko Belt. In: Gaucher C, Sial AN, Halverson GP, Frimmel HF (eds) Neoproterozoic-Cambrian tectonics, global change and evolution. A focus on southwestern Gondwana. Developments in Precambrian Geology, Elsevier, Amsterdam, vol 16, p 205-218

[34] Miller RMcG, Frimmel HE, Will TM (2009) Geodynamic synthesis of the Damara orogen sensu lato. In: Gaucher C, Sial AN, Halverson GP, Frimmel HF (eds) Neoproterozoic-Cambrian tectonics, global change and evolution. A focus on southwestern Gondwana. Developments in Precambrian Geology, Elsevier, Amsterdam, vol 16, p 231-235

[35] Thomson SN, Ring U, Brichau S, Glodny J, Will TM (2009) Timing and nature of formation of the Ios metamorphic core complex, southern Cyclades, Greece. In: Ring U, Wernicke B (eds) Extending a continent: architecture, rheology and heat budget. Geological Society of London Special Publication 321: 139-167

[36] Ring U, Glodny J, Will TM, Thomson SN (2010) The retreating Hellenic subduction system: high-pressure metamorphism, exhumation, normal faulting and large-scale extension. Annual Review of Earth and Planetary Sciences 38: 45-76

[37] Zeh A, Will TM (2010) The Mid-German Crystalline Rise. In: Linnemann U, Romer RL (eds) Pre-Mesozoic geology of Saxo-Thuringia–From the Cadomian active margin to the Variscan orogen. Schweizerbart, Stuttgart, pp 195-220

[38] Will TM, Frimmel HE, Zeh A, Le Roux P, Schmädicke E (2010) Geochemical and isotopic constraints on the tectonic and crustal evolution of the Shackleton Range, East Antarctica, and correlation with other Gondwana crustal segments. Precambrian Research 180: 85-112

[39] Schmädicke E, Gose J, Will TM (2010) High-temperature metamorphism of garnet-bearing ultramafic rocks from the Saxonian Granulite Core Complex, Germany. Journal of Metamorphic Geology 28: 489-508

[40] Zeh A, Gerdes A, Will TM, Frimmel H (2010) Hafnium isotope homogenisation in metasediments under amphibolite-facies conditions (<650 °C): examples from the Shackleton Range (Antarctica). Geochimica et Cosmochimica Acta 74: 4740-4758

[41] Will TM, Schmädicke E, Frimmel HE (2010) Deep solid-state equilibration and deep melting of plagioclase-free spinel peridotite from the slow-spreading Mid-Atlantic Ridge, ODP Leg 153. Mineralogy and Petrology 100: 185-200

[42] Ring U, Glodny J, Will TM, Thomson SN (2011) Normal faulting on Sifnos Island and the South Cycladic Detachment System, Aegean Sea, Greece. Journal of the Geological Society of London 168: 751-768

[43] Schmädicke E, Gose J, Will TM (2011) Heterogeneous mantle underneath the North Atlantic: Evidence from water in orthopyroxene, mineral composition and equilibrium conditions of spinel peridotite from different locations at the Mid-Atlantic Ridge. Lithos 125: 308-320

[44] Schmädicke E, Okrusch M, Rupprecht-Gutowski P, Will TM (2011) Garnet pyroxenite, eclogite and alkremite xenoliths from the off-craton Gibeon Kimberlite Field, Namibia: a window into the upper mantle of the Rehoboth Terrane. Precambrian Research 191: 1-17

[45] Will TM, Frimmel HE (2013) The influence of inherited structures on dyke emplacement during Gondwana break-up in southwestern Africa. J Geol 121: 455-474.

[46] Will, T.M., Frimmel, H.E., Gaucher, C., Bossi, J., 2014. Geochemical and isotopic composition of Pan-African metabasalts from southwestern Gondwana: Evidence of Cretaceous South Atlantic opening along a Neoproterozoic back-arc. Lithos 202-203, 363-381.

[47] Will, TM, Lee S-H, Schmädicke E, Frimmel HE, Okrusch M (2015) Variscan terrane boundaries in the Odenwald-Spessart basement, Mid-German Crystalline Zone: new evidence from ocean ridge, intraplate and arc-derived metabasaltic rocks. Lithos 220-223: 23-42

[48] Schmädicke E, Gose, J, Reinhardt J, Will TM, Stalder R (2015) Garnets in cratonic and non-cratonic mantle and lower crustal xenoliths from southern Africa: composition, water incorporation and geodynamic constraints. Precambrian Research 270: 285-299

[49] Schmädicke E, Will TM, Mezger K (2015) Garnet pyroxenite from the Shackleton Range, Antarctica: intrusion of plume-derived picritic melts in the continental lithosphere during Rodinia breakup? Lithos 238: 185-206

[50] Will TM, Frimmel HE, Pfänder, JA (2016) Möwe Bay Dykes, Northwestern Namibia: Geochemical and geochronological evidence for different mantle source regions during the Cretaceous opening of the South Atlantic. Chemical Geology 44: 141-157

[51] Will TM, Schulz B, Schmädicke E (2017) The timing of metamorphism in the Odenwald-Spessart basement, Mid-German Crystalline Zone. International Journal of Earth Sciences 106: 1631-1649

[52] Pamoukaghlián K, Gaucher C, Frei R, Poiré DG, Chemale F, Frei D, Will TM (2017) U-Pb age constraints for the La Tuna Granite and Montevideo Formation (Paleoproterozoic, Uruguay): unravelling the structure of the Río de la Plata Craton. Journal of South American Earth Sciences 79: 443-458.

[53] Will TM, Frimmel HE (2018) Where does a continent prefer to break up? Lessons from the South Atlantic margins. Gondwana Research 53: 9-19

[54] Will TM, Schmädicke E, Ling XX, Li XH, Li QL (2018) New evidence for an old idea: Geochronological constraints for a paired metamorphic belt in the Central European Variscides. Lithos 302-303: 278-297.

[55] Schmädicke E, Will TM, Ling XX, Li XH, Li QL (2018) Rare peak and ubiquitous post-peak zircon in eclogite: constraints for the timing of high-pressure metamorphism in Erzgebirge, Germany. Lithos 322: 250-267.

[56] Will TM, Gaucher C, Ling XX, Li XH, Li QL, Frimmel HE (2019) Neoproterozoic magmatic and metamorphic events in the exotic Cuchilla Dionisio Terrane, Uruguay, and possible correlations across the South Atlantic. Precambrian Research 320: 303-322.

[57] Will TM, Höhn S, Frimmel HE, Gaucher C, le Roux PJ, Macey PH (2020) Petrological, geochemical and isotopic data of Neoproterozoic rock units from Uruguay and South Africa: Correlation of basement terranes across the South Atlantic. Gondwana Research 80: 12-32.

[58] Gaucher C, Frei R, Samaniego L, Will TM, Chemale F, Gargiulo MF, Frei D, Poiré D, Ling XX, Li XH, Li QL (2021) The Tapes Complex (Nico Pérez Terrane, Uruguay): constraining the Mesoproterozoic evolution of the Río de la Plata Craton. Journal of South American Earth Sciences 105, 102906.

[59] Schmädicke E, Will TM (2021) No chemical change during high-T dehydration and re-hydration reactions: constraints from Erzgebirge HP and UHP eclogite. Lithos 386-387, 105995.

[60] Owen-Smith TM, Trumbull RB, Bauer K, Keiding, JK, Will, TM (2021) A neural network application to assess magma diversity in the Etendeka igneous province, Namibia. South African Journal of Geology 124, 481-498.

[61] Will TM, Schmädicke E, Ling XX, Li XH, Li Q (2021) Geochronology, geochemistry and tectonic implications of Variscan granitic and dioritic rocks from the Odenwald-Spessart basement, Germany. Lithos 404-405, 106454.

[62] Will TM, Gaucher C, Ling XX, le Roux PJ, Li XH, Li Q (2021a) Age, source and tectonic setting of Ediacaran bimodal volcanism in the southernmost Dom Feliciano Belt, Uruguay. Lithos 406-407,106539.

[63] Will TM, Gaucher C, Ling XX, le Roux PJ, Li XH, Li Q (2021b) Ediacaran bimodal volcanism in the southernmost Dom Feliciano Belt, Uruguay: implications for the evolution of SW Gondwana. Lithos 406-407, 106539.

[64] Höhn S, Frimmel HE, Will TM, Brodtmann N, Price W (2022) The depositional environment of the Koeris Formation at the Aggeneys-Gamsberg ore district, South Africa. South African Journal of Geology 125, 323-336.

[65] Gaucher C, Will TM, Finney, SC (2022). The Río de la Plata Craton from Rodinia to Gondwana: new U-Pb-Hf-O data. X Congreso Uruguayo de Geología Montevideo.

[66] Will TM, Gaucher C, Frimmel HE, Ling XX, Shi W, Li XH, Li Q (2023) Ediacaran to Cambrian tectonomagmatic events in the southern Dom Feliciano Belt, Uruguay: from a plate margin to an intraplate setting and the assembly of SW Gondwana. Gondwana Research 115, 155-182.

[67] Schmädicke E, Will TM (2023) Origin of Erzgebirge garnetite: formation from a basaltic protolith by serpentinization-assisted metasomatism? Journal of Metamorphic Geology 41, 1237-1259.

Books and Field guides

Will TM (1998) Phase Equilibria in Metamorphic Rocks—Thermodynamic Background and Petrological Applications. Springer-Verlag, Berlin Heidelberg New York

Ring U, Okrusch M, Will TM (2007) Samos Island, Part I: metamorphosed and non-metamorphosed nappes and sedimentary basins. Journal of the Virtual Explorer 27, 29 p.

since 2010: Listed in Marquis’ Who’s Who in the World and Who’s Who in Science and Engineering

2005: Jubilee Medal (Best paper award), Geological Society of South Africa

1996: Heisenberg Scholarship, German Research Foundation

• Prof. Dr. C. Gaucher, Departamento de Geología, Facultad de Ciencias, Universidad de la República, Iguá 4225, 11400 Montevideo, Uruguay
• Prof. Dr. Q.-L. Li, State Key Laboratory of Lithospheric Evolution, Chinese Academy of Sciences, Beijing 100029, China
• Prof. Dr. X.-H. Li, State Key Laboratory of Lithospheric Evolution, Chinese Academy of Sciences, Beijing 100029, China
• Dr. X.-X. Ling, State Key Laboratory of Lithospheric Evolution, Chinese Academy of Sciences, Beijing 100029, China
• Dr. P. le Roux, Department of Geological Sciences, University of Cape Town, Rondebosch 7701, South Africa
• Dr. J. Reinhardt, Department of Earth Sciences, University of the Western Cape, Bellville 7335, South Africa.
• Prof. Dr. E. Schmädicke, Geozentrum Nordbayern, Universität Erlangen-Nürnberg, Schlossgarten 5a, 91054 Erlangen
• Prof. Dr. U. Ring, Department of Geological Sciences, University of Stockholm, Sweden

Petrologie (Vorlesungen), Gesteinsmikroskopie für Fortgeschrittene (Vorlesung mit praktischen Übungen)

Andreas Rausch (2019). Petrologie der Odenwald- und Spessartdiorite.

Fraziska Dittmaier (2020). Geochemie und Petrologie ediacarischer Granite des südlichen Dom Felicianogürtels, Uruguay.

Sebastian Kraiß (2022). Die D’’-Schicht und Mantelkonvektion in der Erde.

Tobias Feuerstein (2023). Spätvariszische Hochtemperaturereignisse im Saxothuringikum und Moldanubikum Mitteleuropas.

Bianca Büttner (2024). Petrologie der Amphibolite des Böllsteiner Odenwalds.