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Prof. Dr. Timm John

 

 

Timm

Arbeitsbereich Mineralogie-Petrologie

Head of mineralogy-petrology group

Professor

Address
Malteserstr. 74-100
Room L642
12249 Berlin
Telephone
+49 30 838 70103
Fax
+49 30 838 470103
Email
timm.john@fu-berlin.de

Engagement in the Research System

  • Since 2023: Dean of the Department of Earth Sciences, Freie Universtät Berlin, Germany
  • Since 2021: Member of the extended board of the DVGeo (umbrella organization of all German geoscience-related societies).
  • 2019 – 2021:Vice chair of DVGeo.
  • 04-05/2019: Visiting professorship at École normale supérieure Paris, France
  • 06/2019: Visiting professorship at Université de Lausanne, Switzerland
  • 2019 – 2021:  Managing Director of the Institute of Geological Sciences, Freie Universtät Berlin, Germany
  • 2018: Theme coordinator for Goldschmidt in Boston, USA. Theme “Earth's Lithosphere Formation, Evolution, Recycling, and Subduction” (with M. Brown, F-Y Wu, and C. Till).
  • Since 2017: Member of the extended board of the Deutschen Mineralogische Gesellschaft (German Mineralogical Society, DMG).
  • 2017 – 2019: Chair of the Petrology-Petrophysics division of the DMG.
  • 2015: Theme coordinator for GeoBerlin “DYNAMIC EARTH – from Alfred Wegener to today and beyond”, combined annual meetings of several German Geo-societies and GeoX. Theme A1 Subduction Processes and Continental Collision (with O. Oncken and G. Franz).

Qualifications and Career

  • Since 2017: University Professor (W3) of Mineralogy and Petrology, Freie Universität Berlin, Germany.

  • 2013 – 2017: University Professor (W2) of Mineralogy and Petrology, Freie Universität Berlin, Germany.
  • 2012: Habilitation in Mineralogy and Geology, Universität Münster, Germany.
  • 2009 – 2013: Akademischer Rat auf Zeit at the Institute for Mineralogy, Universität Münster, Germany.
  • 2006 – 2008: Senior postdoc position at the centre for Physics of Geological Processes (PGP), University of Oslo, Norway, Norwegian Centre of Excellence.

  • 2002 – 2006: Postdoctoral fellow, at Kiel University, Germany.

  • 2001: Doctorate in Mineralogy, Kiel University, Germany
  • 1992 – 1998: Diploma in Geology, University of Bremen and RWTH Aachen, Germany

Education

  • 07/2012: Habilitation in Geology/Mineralogy, University of Münster, Germany.
    Thesis: Physical and chemical processes during the dehydration of subducting oceanic lithosphere: Reactive fluid flow under high-pressure conditions.

  • 12/2001:Dr. rer. nat., University of Kiel, Germany
    Thesis: Subduction and continental collision in the Lufilian Arc - Zambezi Belt orogen: A petrological, geochemical, and geochronological study of eclogites and whiteschists (Zambia).

  • 02/1998: Diplom in Geology, University of Bremen, Germany

  • 04/1994: Diplomvorprüfung in Geology, RWTH Aachen, Germany.
  • 03/1998-12/2001: Doctoral student, University of Kiel, Germany.
  • 10/1994-02/1998: Student of Geology, University of Bremen, Germany.
  • 04/1992-07/1994: Student of Mineralogy and Geology, RWTH Aachen, Germany.

Host of academic fellows

  • Thomas Ferrand; Alexander von Humboldt fellow
  • Xin Zhong; Alexander von Humboldt fellow
  • Lisa Kaatz; Elsa Neumann fellow
  • Shilei Qiao; China Scholarship Council (CSC) fellow

Current Research Topics

Urban Mining

The interaction of reactive fluids with solid matter is not only relevant for the evolution of the Earth but also plays a key role in modern approaches to the recovery of critical raw materials from end-of-life electronic devices. This is important to enable the transition to a sustainable high-tech society that will become heavily reliant on solar panels, hydrogen fuel cells, electric motors, wind turbines, etc. However, hydrometallurgical recycling of the most valuable raw materials that are critical for green technologies such as the elements of the platinum group (PGEs) and the rare earth elements (REE), is challenging due to their slow reaction kinetics and low solubility in traditionally utilized mineral acids. Our research group, in collaboration with the Hasenstab-Riedel group , specializes in the determination of dissolution kinetics and downstream extraction procedures for various critical metals from end-of-life devices (e.g., computer scrap, permanent magnets, vehicle catalytic converter) using newly developed ionic liquids. This Urban Mining Project makes extensive use of the group’s state-of-the-art experimental and analytical facilities.

See also:
Werner Siemens Foundation - WSS100
WSS100 research price award

Physical and chemical processes during the dehydration of subducting oceanic lithosphere (reactive fluid flow under high-pressure / low-temperature conditions).

During subduction, downgoing plates heat up and their hydrous minerals become progressively unstable and break down to produce water. It is now evident that the released fluids can reach the mantle wedge and cause melting. It is commonly assumed that the density increase of this reaction makes plate subduction self-sustained. Seismic studies indicate that this transformation happens under non-equilibrium conditions and field evidence points to fluids as a trigger. The details of intra-slab fluid flow are, however, not yet understood. Field evidence points to not yet quantified relationships between reactions, fluid flow, seismicity and mobilization of both major and trace elements. We use a combined field and laboratory-based approach to explore the interrelationships of these processes. By combining our findings and data with numerical simulations we investigate how fluids migrate within a slab, lead to metamorphic reactions, and cause element mobilization. Furthermore, we explore the interrelation between fluid flow and seismic slip.

See also

Saskia Bläsing

Konstantin Huber

CRC 1114 „Scaling cascades of complex systems”

Reactive fluid flow and transport of so-called fluid-immobile elements.

The presence of fluids in Earth's crust results in processes that enable significant element mobilization. Metasomatic changes in rocks due to open system reactive fluid flow often cause surprisingly high solubilities and transport rates of so-called fluid-immobile elements, such as HFSE (high field strength elements, e.g., Th, Nb, Ta, Ti) and the REE (rare earth elements). During metasomatism new minerals form, which are more stable under the changing physical and chemical conditions. The associated element transport and mineral growth may finally result in economic ore mineralization. We are currently investigating how fluorine in fluids is affecting the mobilization and transport of elements and how this leads to fractionation of geochemical twins such as Nb-Ta, Zr-Hf, and Ho-Y. Our research is built on experimental investigations, field-based case studies, and numerical simulations of the metasomatic processes.

See also

Anselm Loges

Shilei Qiao

CRC 1349 “Fluorine-Specific Interactions: Fundamentals and Functions”

Global halogen cycle: halogen concentrations and stable isotopes as tracer for fluid related processes.

The large recycling machines, such as subduction zones and spreading centers, are important for element exchange and transport on Earth. Even though the volatile element chlorine represents an important component of the fluids stored in subducting oceanic lithosphere, the behavior of chlorine and the other halogens (F, Br, and I) within subduction zones and during the formation of magmas in island arc, plumes or at spreading ridges is not fully understood yet. This part of our research mainly emphasizes on establishing a better knowledge about subduction zone fluids, i.e. halogen ratios and stable chlorine isotopes (delta37Cl), to identify different fluid sources and to quantify fluid-rock interaction and fluid fluxes. Therefore, two main topics are currently under investigation; (1) define the Cl isotope signal of the main fluid sources of the deeper fluid cycle, i.e. serpentinite and blueschist dehydration, (2) investigate how conservative the Cl isotopes and halogen ratios behave during fluid flow and fluid-rock interaction.

See also

Shilei Qiao

Tectonometamorphic evolution of continental margins during subduction and continental collision.

Geodynamic processes during orogenesis cause changes in pressure and temperature conditions (P-T conditions), which affect the rocks within an orogen. The reconstruction of the P-T evolution of a metamorphic rock allows to determine the geodynamic causes of metamorphism (e.g., subduction, tectonic thickening, extension during orogenic collapse or rifting, erosion, magmatic underplating). To be able to distinguish between the possible causes for metamorphism and to get a more complete understanding of geodynamic processes affecting slices of former continental or oceanic plates, knowledge about the P-T-t-d path of such slices is essential. Our current research is mainly focused on reconstructing the geodynamics of parts of former passive continental margins during the transition from subduction to collision. We apply detailed field work combined with petrological investigations. We use thermodynamic pseudosection modelling, trace element thermometry and Raman-based geothermobarometry. We are also extracting the effects on the petrophysical properties of some of the affected rocks by measuring e.g., the P- and S-wave velocities with a true triaxial press and link those data with thermodynamic calculations. Additionally, we use a combined field-based and numerical simulation approach to evaluate the effect of fluids on the transient deformation processes affecting nappes during burial.

See also

Xin Zhong

Iris Wannhoff

SPP 2017 „Mountain building processes in 4D“

Hydrothermal and gas-solid interaction in the early Solar system

We study volatile-rich clasts within chondritic and achondritic breccias that differ from known meteoritic materials and bulk meteorites. The project will also include comprehensive C isotope analysis of C-rich minerals (notably of graphite) within fragments and rocks of chondritic (E-chondrites, ordinary chondrites) and achondritic origin. Some of the clasts may not be present in our current collections of individual meteorites and hence may provide new insights into the provenance of early solar system material. The aim is to better understand how the most volatile elements such as hydrogen, nitrogen and carbon are affected by hydrothermal processes on their individual parent bodies and whether those may reflect potential sources for these elements for our planet Earth.

We also study the petrology, trace element composition, and isotopic composition of CAIs in carbonaceous chondrites to constrain the re-enrichment processes of volatile metals in refractory inclusions and the environments in which this enrichment took place. The aim is to answer the question whether the depletion of moderately volatile elements in Earth is inherited from nebular processes.

Our studies are based on characterization of the mineralogy, textures, and the distribution of the target elements by electron beam methods. This detailed in-situ data provide the petrologic context for the isotopic work.

See also:

TRR 170 “Late Accretion onto Terrestrial Planets”

Grants

Current funding

  • “Deciphering the duration of fluid-rock interaction” Reinhart Koselleck research project with several researcher positions; five years funded through DFG grant 2023-2028; PI: T. John
  • “Geochemical element mobilization due to poly(hydrogen fluoride) H···F bridged networks” research project with postdoctoral researcher position; four years funded through DFG grant within the SFB “Fluorine-Specific Interactions: Fundamentals and Functions” located at FUB; 2019-2022 & 2022-2026; PI: T. John
  • “Dynamics of rock dehydration on multiple scales” research project with doctoral student position; four years funded through DFG grant within the SFB 1114 “Scaling Cascades in Complex Systems” located at FUB; 2018-2022 & 2022-2026; PI: T. John
  • "Applying scattered wave tomography and joint inversion of high-density (SWATH D) geophysical and petrophysical datasets to unravel Eastern Alpine crustal structure" DFG research grant within the SPP 2017 - 4D-MB, 2020-2023
  • "How large are tectonic deviations from lithostatic pressure in a continent-derived, lithologically heterogeneous Alpine UHP nappe (Koralpe-Saualpe-Pohorje Complex, Austria and Slovenia)?" research project with doctoral student position, three years funded through DFG grant within the SPP 2017 - 4D-MB, since 2020-2023; PI: T. John
  • "Is the depletion of moderately volatile elements in Earth inherited from nebular processes?” research project with doctoral student position; four years funded through DFG grant within the TRR 170 “Late Accretion onto Terrestrial Planets” located at FUB; since 2020-2023; PI: T. John
  • "Early-formed rare and unique meteorites and clasts in meteorite breccias” research project with doctoral student position; four years funded through DFG grant within the TRR 170 “Late Accretion onto Terrestrial Planets” located at WWU and FUB; since 2020-2023; PI: T. John

Past funding

  • “Understanding subduction by linking surface exposures of subducted and exhumed crust to geophysical images of slabs” research project with doctoral student position; three years funded through DFG grant within the SPP 2017 - 4D-MB, since 2017-2020; PI: T. John
  • Early-formed, volatile-rich clasts in meteorite breccias: building materials of the terrestrial planets?” research project with doctoral student position; four years funded through DFG grant within the TRR 170 “Late Accretion onto Terrestrial Planets” located at FUB; since 2016-2019; PI: T. John
  • “Evolution of zircon chemistry and inclusion paragenesis of I- to S-type granitoids from the Wilson Terrane of northern Victoria Land (Antarctica): Zircon as a record of dynamic continental crust formation”; research project with doctoral student position; three years funded through DFG grant within the SPP 1158 (JO 349/7-1); 2013-2017; PI: T. John
  • “Zooming in between plates: deciphering the nature of the plate interface in subduction zones”; Partner in EU funded Marie Curie ITN; 2013-2017; PI: T. John
  • “Timing and rates of fluid release during the dehydration of subducting oceanic crust: reactive fluid flow under high-pressure conditions”; research project with doctoral student position; three years funded through DFG grant (JO 349/5-1); since 2011-2017; PI: T. John
  • “Halogen concentrations and stable Cl isotopes in apatite as a fluid probe: mapping regional-scale fluid pulses by Cl-isotopes”; research project with doctoral student position; three years funded through DFG grant (JO 349/3-1); 2010-2015; PI: T. John“
  • Decoding the transient porosity and permeability evolution during fluid-rock interaction” Research at Advanced Photon Source (Argonne-Chicago, USA) GUP 35213; Since 2013-2014, Co-PI: T. John

The current selection of the ten highlight papers

*denotes either first author being a student of T. John or T. John is corresponding author

  1. J.J. Ague, S. Tassara, M.E. Holycross, J.-L. Li, E. Cottrell, E.M. Schwarzenbach, C.G. Fassoulas, T. John, Slab-derived devolatilization fluids oxidized by subducted metasedimentary rocks. Nature Geoscience 2022: 15, 320-326, doi.org/10.1038/s41561-022-00904-7.
  2. G.M. Beaudoin, J.D. Barnes, T. John, J.E. Hoffmann, R. Chatterjee, D.F. Stockli, Global halogen flux of subducting oceanic crust. Earth and Planetary Science Letters 2022: 594, 117750.
  3. *A. Beinlich, T. John, J.C.Vrijmoed, M. Tominaga, T. Magna, Y. Podladchikov, Instantaneous rock transformations in the deep crust driven by reactive fluid flow. Nature Geoscience 2020: 13, 307-311. doi.org/10.1038/s41561-020-0554-9
  4. J. Bedford, M. Moreno, Z. Deng, O. Oncken, B. Schurr, T. John,J.C. Baez, M. Bevis, Months-Long thousand-km-scale wobbling before great subduction earthquakes. Nature 2020: 580, 628-635. DOI: 10.1038/s41586-020-2212-1
  5. *J.-L. Li, E.M. Schwarzenbach, T. John, J.J. Ague, F. Huang, J. Gao, R. Klemd, M. Whitehouse, X.-S. Wang, Uncovering and quantifying the subduction zone sulfur cycle from the slab perspective. Nature Communications 2020: 11, 514. DOI: 0.1038/s41467-019-14110-4
  6. S. Chen, R.C. Hin, T. John, R. Brooker, B. Bryan, Y. Niu, T. Elliott, Molybdenum systematics of subducted crust record reactive fluid flow from underlying slab serpentine dehydration. Nature Communications 2019: 10, 4773. DOI: 10.1038/s41467-019-12696-3
  7. *S. Taetz, T. John, M. Bröcker, C. Spandler, A. Stracke, Fast intraslab fluid-flow events linked to pulses of high pore fluid pressure at the subducted plate interface. Earth and Planetary Science Letters 2018: 482, 33–43.
  8. *O. Plümper, T. John, Y.Y. Podladchikov, J.C. Vrijmoed, M. Scambelluri, Fluid escape from subduction zones controlled by channel-forming reactive porosity. Nature Geoscience 2017: 10, 150–156.
  9. T. John, N. Gussone, Y.Y. Podladchikov, G. Bebout, R. Dohmen, R. Halama, R. Klemd, T. Magna, M. Seitz, Volcanic arcs fed by rapid pulsed fluid flow through subducting slabs. Nature Geoscience 2012: 5, 489-492.
  10. T. John, S. Medvedev, L.H. Rüpke, Y. Podladchikov, T.B. Andersen, H. Austrheim, Generation of intermediate-depth earthquakes by self-localizing thermal runaway. Nature Geoscience 2009: 2, 137-140.

Publications (peer reviewed)

2023

  • Kaatz, L., Schmalholz, S.M., John, T. Numerical Simulations Reproduce Field Observations Showing Transient Weakening During Shear Zone Formation by Diffusional Hydrogen Influx and H2O Inflow. Geochemistry, Geophysics, Geosystems, 24, e2022GC010830. https://doi.org/10.1029/2022GC010830
  • Segee-Wright, G., Barnes, J.D., Lassiter, J.C., Holmes, D.J., Beaudoin, G.M., Chatterjee, R., Stockli, D.F., Hoffmann, J.E., John,T. Halogen enrichment in the North American lithospheric mantle from the dehydration of the Farallon plate. Geochimica et Cosmochimica Acta, 348, 187-205. https://doi.org/10.1016/j.gca.2023.03.014

2022

  • Huber, K., Vrijmoed, J.C., John, T. Formation of Olivine Veins by Reactive Fluid Flow in a Dehydrating Serpentinite. Geochemistry, Geophysics, Geosystems, 23, e2021GC010267. https://doi.org/10.1029/2021GC010267
  • Anders, J., Göritz, F., Loges, A., John, T., and Paulus, B. Stability of Hydroxo/Oxo/Fluoro Zirconates vs. Hafniates—A DFT Study. Inorganics, 10 (12), 259, https://doi.org/10.3390/inorganics10120259
  • Bouvier, A.-S., Portnyagin, M.V., Flemetakis, S., Hoernle, K., Klemme, S., Berndt, J., Mironov, N.L., John, T. Chlorine isotope behavior in subduction zone settings revealed by olivine-hosted melt inclusions from the Central America Volcanic Arc. Earth and Planetary Science Letters, 581, 117414, https://doi.org/10.1016/j.epsl.2022.117414
  • Loges, A., Scholz, G., Sousa Amadeu, N. de, Shao, J., Schultze, D., Fuller, J., Paulus, B., Emmerling, F., Braun, T., John, T. (2022) Studies on the local structure of the F ∕ OH site in topaz by magic angle spinning nuclear magnetic resonance and Raman spectroscopy. European Journal of Mineralogy, 34 (5), 507–521, https://doi.org/10.5194/ejm-34-507-2022
  • Sippl, C., Dielforder, A., John, T., Schmalholz, S.M. Global Constraints on Intermediate‐Depth Intraslab Stresses From Slab Geometries and Mechanisms of Double Seismic Zone Earthquakes. Geochemistry, Geophysics, Geosystems, 23 (9), https://doi.org/10.1029/2022GC010498
  • Stubbs, D., Yang, R., Coath, C.D., John, T., Elliott, T. Tungsten isotopic fractionation at the Mariana arc and constraints on the redox conditions of subduction zone fluids. Geochimica et Cosmochimica Acta, 334, 135–154, https://doi.org/10.1016/j.gca.2022.08.005
  • Zertani, S., Pleuger, J., Motra, H.B., John, T. Highly variable petrophysical properties in felsic high-pressure rocks of the continental crust. Lithos, 410-411, 106572, https://doi.org/10.1016/j.lithos.2021.106572
  • Beaudoin, G. M., Barnes, J. D., John, T., Hoffmann, J. E., Chatterjee, R., & Stockli, D. F. Global halogen flux of subducting oceanic crust. Earth and Planetary Science Letters, 594, 117750. https://doi.org/10.1016/j.epsl.2022.117750
  • Kaatz, L., Reynes, J., Hermann, J., John, T. How fluid infiltrates dry crustal rocks during progressive eclogitization and shear zone formation: insights from H2O contents in nominally anhydrous minerals. Contrib Mineral Petrol 177, 72. https://doi.org/10.1007/s00410-022-01938-1
  • Zertani, S., John, T., Brachmann, C., Vrijmoed, J.C., Plümper, O. Reactive fluid flow guided by grain-scale equilibrium reactions during eclogitization of dry crustal rocks. Contrib Mineral Petrol 177, 61. https://doi.org/10.1007/s00410-022-01928-3
  • Ague, J.J., Tassara, S., Holycross, M.E., Li, J.L., Cottrell, E., Schwarzenbach, E.M., Fassoulas, C., John, T. Slab-derived devolatilization fluids oxidized by subducted metasedimentary rocks. Nature Geoscience. https://doi.org/10.1038/s41561-022-00904-7
  • Guo, S., Su, B., John, T., Zhao, K., Tang, P., Chen, Y. Li, Y. Boron release and transfer induced by phengite breakdown in subducted impure metacarbonates. Lithos, Volumes 408–409. https://doi.org/10.1016/j.lithos.2021.106548

2021

  • Zhong, X., Loges, A., Roddatis, V., John, T. Measurement of crystallographic orientation of quartz crystal using Raman spectroscopy: application to entrapped inclusions. Contrib Mineral Petrol 176, 89. https://doi.org/10.1007/s00410-021-01845-x
  • Schwarzenbach, E.M., Zhong, X., Caddick, M.J., Schmalholz, S.M., Menneken, M., Hecht, L., John, T. On exhumation velocities of high-pressure units based on insights from chemical zoning in garnet (Tianshan, NW China). Earth and Planetary Science Letters 570, 117065. https://doi.org/10.1016/j.epsl.2021.117065
  • Taetz, S., Scherer, E.E., Bröcker, M., Spandler, C., John, T. Petrological and Lu–Hf age constraints for eclogitic rocks from the Pam Peninsula, New Caledonia. Volumes 388–389, May 2021, 106073. https://doi.org/10.1016/j.lithos.2021.106073
  • Wudarska, A., Słaby, E., Wiedenbeck, M., Barnes, J.D., Bonifacie, M., Sturchio, N.C., Bardoux, G., Couffignal, F., Glodny, J., Heraty, L., John, T., Kusebauch, C., Mayanna, S., Wilke, F.D.H. and Deput, E., Inter-laboratory Characterisation of Apatite Reference Materials for Chlorine Isotope Analysis. Geostand Geoanal Res, 45: 121-142. https://doi.org/10.1111/ggr.12366
  • König, S., Rosca, C., Kurzawa, T., Varas-Reus, M. I., Dragovic, B., Schoenberg, R., John, T. Selenium isotope evidence for pulsed flow of oxidative slab fluids. Geochemical Perspectives Letters 17; 27-32. https://doi.org/10.7185/geochemlet.2110
  • Kaatz, L.,  Zertani, S.,  Moulas, E.,  John, T.,  Labrousse, L.,  Schmalholz, S. M., &  Andersen, T. B. Widening of hydrous shear zones during incipient eclogitization of metastable dry and rigid lower crust—Holsnøy, western Norway. Tectonics,  40, e2020TC006572. https://doi.org/10.1029/2020TC006572
  • Li, J. L., Schwarzenbach, E. M., John, T., Ague, J. J., Tassara, S., Gao, J., & Konecke, B. A.. Subduction zone sulfur mobilization and redistribution by intraslab fluid–rock interaction. Geochimica et Cosmochimica Acta, 297, 40-64. https://doi.org/10.1016/j.gca.2021.01.011
  • Groß, P,  Pleuger, J,  Handy, MR,  Germer, M,  John, T.  Evolving temperature field in a fossil subduction channel during the transition from subduction to collision (Tauern Window, Eastern Alps). J Metamorph Geol 2021; 39: 247– 269. https://doi.org/10.1111/jmg.12572

2020

  • Visser, R., John, T., Whitehouse, M., Patzek, M., Bischoff, A. A short-lived 26Al induced hydrothermal alteration event in the outer solar system: Constraints from Mn/Cr ages of carbonates. Earth and Planetary Science Letters Volume 547, 1 116440 https://doi.org/10.1016/j.epsl.2020.116440
  • Zertani, S.,  Vrijmoed, J. C.,  Tilmann, F.,  John, T.,  Andersen, T. B., &  Labrousse, L. (2020).  P wave anisotropy caused by partial eclogitization of descending crust demonstrated by modeling effective petrophysical properties. Geochemistry, Geophysics, Geosystems,  20, e2019GC008906. https://doi.org/10.1029/2019GC008906
  • Beinlich, A., John, T., Vrijmoed, J. C., Tominaga, M., Magna, T., Podladchikov, Y. Y. Instantaneous rock transformations in the deep crust driven by reactive fluid flow. Nature Geocience, http://doi.org/10.1038/s41561-020-0554-9
  • Peters, D., Pettke, T., John, T., Scambelluri, M. The role of brucite in water and element cycling during serpentinite subduction – Insights from Erro Tobbio (Liguria, Italy), Lithos 360, https://doi.org/10.1016/j.lithos.2020.105431
  • Bedford, J., Moreno, M., Deng, Z., Oncken, O., Schurr, B., John, T., Baez, J.C., Bevis, M. Months-Long thousand-km-scale wobbling before great subduction earthquakes. Nature. https://doi.org/10.1038/s41586-020-2212-1

  • Urann, B. M., Le Roux, V., John, T., Beaudoin, G. M., Barnes, J. D. The distribution and abundance of halogens in eclogites: An in situ SIMS perspective of the Raspas Complex (Ecuador), American Mineralogist 105: 307-318, https://doi.org/10.2138/am-2020-6994

  • Groß, P., Handy, M. R., John, T., Pestal, G., Pleuger, J. Crustal-Scale Sheath Folding at HP Conditions in an Exhumed Alpine Subduction Zone (Tauern Window, Eastern Alps), Tectonics 39
  • Bayet, L., Agard, P., John ,T., Menneken, M., Tan, Z., Gao, J. Tectonic evolution od the Tianshan Akeyazi metamorphic complex (NW China), Lithos, https://doi.org/10.1016/j.lithos.2019.105273
  • Patzek, M., Hoppe, P., Bischoff, A., Visser, R., John, T. Hydrogen isotopic composition of CI- and CM-like clasts from meteorite breccias - Sampling unknown sources of carbonaceous condrite materials, Geochemica et Cosmochemica Acta 272, p. 177-197, https://doi.org/10.1016/j.gca.2019.12.017
  • Li, J.-L., Schwarzenbach, E.M., John, T., Ague, J. J., Huang, F., Gao, J. Klemd, R., Whitehouse, M. J., Wang, X.-S. Uncovering and quantifying the subduction zone sulfur cycle from the slab perspective, Nature Communications 11, p. 1-12

2019

  • Su, W., Schwarzenbach, E. M., Chen, L., Li, Y., John, T., Gao, J., Chen, F., Hu, X., Suphur isotope compositions of pyrite from high-pressure metamorphic rocks and related veins (SW Tianshan, China): Implications for the sulphur cycle in subduction zones, Lithos 348, p. 105212, https://doi.org/10.1016/j.lithos.2019.105212
  • Incel, S., Schubnel, A., Renner, J., John, T., Labrousse, L., Hilairet, N., Freeman, H., Wang, Y., Renard, F., Jamtveit, B. Experimental evidence for wall-rock pulverization during dynamic rupture at ultra-high pressure conditions, Earth and Planetary Science Letters 528, p. 115832, https://doi.org/10.1016/j.epsl.2019.115832
  • Chen, S., Hin, R.C., John ,T., Brooker, R., Bryan, Niu, Y., Elliott, T. Molybdenum systematics of subducted crust record reactive fluid flow from underlying slab serpentine dehydration, Nature Communications 10, 4773, https://doi.org/10.1038/s41467-019-12696
  • Zertani, S., John, T., Tilmann, F., Motra, H.B., Keppler, R., Andersen, T.B., Labrousse, L. Modification of the seismic proerties of subduction continental crust by eclogitization and deformation processes, Journal of Geophysical Research - Solid Earth, doi.org/10.1029/2019JB017741
  • Sippl, C., Schurr, B., John, T., Hainzl, S. Filling the gap in a double seismic zone: Intraslab seismicity in Northern Chile, Lithos 346, p. 105155, https://doi.org/10.1016/j.lithos.2019.105155
  • Visser, R., John, T., Patzek, M., Bischoff, A., Whitehouse, M. J. Sulphur isotope study of sulfides in CI, CM, C2ung Chondrites and volatile-rich clasts - Evidence for different generations and reservoirs of sulfide formation, Geochemica et Cosmochemica Acta 261, p. 210-223, https://doi.org/10.1016/j.gca.2019.06.046
  • Tan, Z., Agard, P., Monié, P., Gao, J., John, T., Bayet, L., Jiang, T., Wang, X.-S., Hong, T., Wan, B., Caron, B. Architecture ant P-T-deformation-time evolution of the Chinese SW-Tianshan HP/UHP complex: Implications for subduction dynamics, Earth-Science Reviews 197, p. 102894, https://doi.org/10.1016/j.earscirev.2019.102894
  • Guo, S., Zhao, K., John, T., Tang, P., Chen, Y., Su, B. Metasomatic flow of metacarbonate-derived fluids carrying isotopically heavy boron in continental subduction zones: Insights from tourmaline-bearing ultra-high pressure eclogites and veins (Dabie terrane, eastern China). Geochimica Et Cosmochimica Acta 253, 159–200.
  • Zertani, S., Labrousse, L., John, T., Andersen, T.B., Tilmann, F. The Interplay of Eclogitization and Deformation During Deep Burial of the Lower Continental Crust—A Case Study From the Bergen Arcs (Western Norway). Tectonics 38.
  • Incel, S., Labrousse, L., Hilairet, N., John, T., Gasc, J., Shi, F., Wang, Y., Andersen, T. B., Renard, F., Jamtveit, B., Schubnel, A. Reaction-induced embrittlement of the lower continental crust. Geology 47 (3), 235-238.
  • Shu, Y., Nielsen, S. G., Marschall, H. R., John, T., Blusztajn, J., Auro, M. Closing the loop: Subducted eclogites match thallium isotope compositions of ocean island basalts. Geochimica et Cosmochimica Acta 250, 130-148.
  • Roszjar, J.,  Whitehouse, M.J., Terada, K., Fukuda, K., John, T., Bischoff, A., Morishita, Y., Hiyagon, H. Chemical, microstructural and chronological record of phosphates in the Ksar Ghilane 002 enriched shergottite. Geochimica et Cosmochimica Acta 245, 385–405.

2018

  • Bayet, L., John, T., Agard, P., Gao, J., Li, J. L. Massive sediment accretion at∼ 80 km depth along the subduction interface: Evidence from the southern Chinese Tianshan. Geology 46 (6), 495-498.
  • Liebmann, J., Schwarzenbach, E. M., Früh-Green, G. L., Boschi, C., Rouméjon, S.,  Strauss, H., Wiechert, U., John, T. Tracking Water-Rock Interaction at the Atlantis Massif (MAR, 30°N) Using Sulfur Geochemistry. Geochemistry, Geophysics, Geosystems, 19.
  • Bloch, W., John, T., Kummerow, J., Salazar, P., Krüger, O. S., Shapiro, S. A. Watching dehydration: Seismic Indication for Transient Fluid Pathways in the Oceanic Mantle of the Subducting Nazca Slab. Geochemistry, Geophysics, Geosystems, 19.
  • Visser, R., John, T., Menneken, M., Patzek, M., Bischoff, A. Temperature constraints by Raman spectroscopy of organic matter in volatile-rich clasts and carbonaceous chondrites. Geochimica et Cosmochimica Acta 241, 38–55.
  • Patzek, M., Bischoff, A., Visser, R., John, T. Mineralogy of volatile-rich clasts in brecciated meteorites. Meteoritics & Planetary Science, 1–22.
  • Taetz, S., John, T., Bröcker, M., Spandler, C., Stracke, A. Fast intraslab fluid-flow events linked to pulses of high pore fluid pressure at the subducted plate interface. Earth and Planetary Science Letters 482, 33–43.

2017

  • Macente, A., Fusseis, F., Menegon, L., Xiao, X, John, T. The strain‐dependent spatial evolution of garnet in a high‐P ductile shear zone from the Western Gneiss Region (Norway): a synchrotron X‐ray microtomography study. Journal of Metamorphic Geology 35 (5), 565-583.
  • Li, J.L., John, T., Gao, J., Klemd, R., Wang, X.S. Subduction channel fluid–rock interaction and mass transfer: Constraints from a retrograde vein in blueschist (SW Tianshan, China). Chemical Geology, 456, 28-42.
  • Tan, Z., Agard, P., Gao, J., John T., Li, J. L., Jiang, T., Bayet, L., Wang, X., Zhangg, X. P-T-time-isotopic evolution of coesite-bearing eclogites: Implications for exhumation processes in SW Tianshan. Lithos 281, 1-25.
  • Halama, R., Bebout G., Marschall H., John, T. Fluid-induced breakdown of white mica controls nitrogen transfer during fluid-rock interaction in subduction zones. International Geology Review, 59, 702–720.
  • Peters, D., Bretscher, A., John, T., Scambelluri, M., Pettke, T. Fluid-mobile elements in serpentinites: Constraints on serpentinisation environments and element cycling in subduction zones. Chemical Geology, 466, 654-666.
  • Plümper, O., John, T., Podladchikov,  Y. Y. , Vrijmoed, J. C. & Scambelluri, M. Fluid escape from subduction zones controlled by channel-forming reactive porosity. Nature Geoscience, 10,150–156.
  • Manzini M., Bouvier A.-S., Barnes J. D., Bonifacie M., Rose-Koga E. F., Ulmer P., Métrich N., Bardoux G., Williams J., Layne G. D., Straub S., Baumgartner L. P., John T. SIMS chlorine isotope analyses in melt inclusions from arc settings. Chemical Geology, 449, 112-122.
  • Bellucci, J. J., Whitehouse, M. J., John, T., Nemchin, A. A., Snape, J. F., Bland, P. A., & Benedix, G. K. Halogen and Cl isotopic systematics in Martian phosphates: Implications for the Cl cycle and surface halogen reservoirs on Mars. Earth and Planetary Science Letters, 458, 192–202.
  • Incel, S., Hilairet, N., Labrousse, L., John, T., Deldicque, D., Ferrand, T., et al. Laboratory earthquakes triggered during eclogitization of lawsonite-bearing blueschist. Earth and Planetary Science Letters, 459, 320–331.
  • Sarafian, A. R., John, T., Roszjar, J., & Whitehouse, M. J. Chlorine and hydrogen degassing in Vesta’s magma ocean. Earth and Planetary Science Letters, 459, 311–319.

2016

  • Halama, R., Bebout, G. E., Marschall, H. R., & John, T. Fluid-induced breakdown of white mica controls nitrogen transfer during fluid–rock interaction in subduction zones. International Geology Review, 1–19.
  • Li, J.-L., Gao, J., Klemd, R., John, T., & Wang, X.-S. Redox processes in subducting oceanic crust recorded by sul de‐bearing high‐pressure rocks and veins (SW Tianshan, China). Contributions to Mineralogy and Petrology, 171:72.
  • Raith, M. M., Brandt, S., Sengupta, P., Berndt, J., John, T., & Srikantappa, C. Element Mobility and Behaviour of Zircon during HT Metasomatism of Ferroan Basic Granulite at Ayyarmalai, South India: Evidence for Polyphase Neoarchaean Crustal Growth and Multiple Metamorphism in the Northeastern Madurai Province. Journal of Petrology, 57, 1729–1774.
  • Taetz, S., John, T., Bröcker, M., & Spandler, C. Fluid–rock interaction and evolution of a high-pressure/low- temperature vein system in eclogite from New Caledonia: insights into intraslab fluid flow processes. Contributions to Mineralogy and Petrology, 171:90.
  • Meyer, M., Klemd, R., John, T., Gao, J. & Menneken, M. An (in-)coherent metamorphic evolution of high-pressure eclogites and their host rocks in the Chinese southwest Tianshan. Journal of Metamorphic Geology, 34, 121-146.
  • Li, J.-L., Klemd, R., Gao, J., & John, T. Poly-cyclic metamorphic evolution of eclogite: evidence for multistage burial–exhumation cycling in a subduction channel. Journal of Petrology, 57, 119–146. 

2015

  • Kusebauch, C., John, T., Barnes, J., Klügel, A., & Austrheim, H. Halogen element and stable chlorine isotope fractionation caused 1 by fluid-rock interaction (Bamble sector SE Norway). Journal of Petrology, 56, 299-324.
  • Kusebauch, C., John, T., Whitehouse, M. & Engvik, A. Apatite as probe for the halogen composition of metamorphic fluids (Bamble Sector SE Norway). Contributions to Mineralogy and Petrology, 170:34.
  • Kusebauch, C., John, T., Whitehouse, M., Klemme, S. & Putnis, A. Distribution of halogens between fluid and apatite during fluid-mediated replacement processes. Geochimica et Cosmochimica Acta. 170, 225-246.
  • Collins, N., Bebout, G., Angiboust, S., Agard, P., Scambelluri, M., Crispini, L. & John, T. Subduction zone metamorphic pathway for deep carbon cycling: II. Evidence from HP/UHP metabasaltic rocks and ophicarbonates. Chemical Geology, 412, 132-150.

2014

  • Farber, K., Caddick, M. & John, T. Controls on solid-phase inclusion during porphyroblast growth: insights from the Barrovian sequence (Scottish Dalradian). Contributions to Mineralogy and Petrology, 168, 1-17.
  • Pollok , K., Heidelbach, F., John, T., & Langenhorst. Spherulitic omphacite in pseudotachylytes: Microstructures related to fast crystal growth from seismic melt at eclogite-facies conditions. Chemie der Erde, 74, 407–418.
  • Halama, R., Bebout, G., John, T. & Scambelluri, M. Nitrogen recycling in subducted mantle rocks and implications for the global nitrogen cycle. International Journal of Earth Science, 103, 2081-2099.
  • Majumdar, A., King, H., John, T., Kusebauch, C. & Putnis A. Pseudomorphic replacement of diopside during interaction with (Ni,Mg)Cl2 aqueous solutions: Implications for Ni-enrichment mechanism in talc- and serpentine-type phases. Chemical Geology, 380, 27-40.
  • Jonas, L., John, T., King, H., Geisler, T. & Putnis, A. The role of grain boundaries and transient porosity in rocks as fluid pathways for reaction front propagation. Earth and Planetary Science Letters, 386, 64-74.

2013

  • Klemme, S., John, T., Wessels, M., Kusebauch, C., Berndt, J., Rohrbach, A. & Schmid-Beurmann, P. Synthesis of trace element bearing single crystals of Chlor-Apatite (Ca5(PO4)3Cl) using the flux growth method. Chemistry Central Journal, 7, article number 56.
  • Vrijmoed, J.C., Austrheim, H., John, T., Hin, R., Davies, G.R. & Corfu, F. Metasomatism in the ultra-high pressure Svartberget garnet-peridotite (Western Gneiss Region, Norway): Implications for the transport of crust-derived fluids within the mantle. Journal of Petrology, 54, 1815-1848.
  • Jonas, L. John, T. & Putnis. A. Influence of temperature and Cl on the hydrothermal replacement of calcite by apatite and the development of porous microstrcutures. American Mineralogist, 98, 1516-1525.
  • Li, J.-L., Gao, J., John, T., Klemd, R., & Su, W. Fluid-mediated metal transport in subduction zones and its link to arc-related giant ore deposits: Constraints from a sulfide-bearing HP vein in lawsonite eclogite (Tianshan, China). Geochimica et Cosmochimica Acta, 120, 326–362.

2012

  • John, T., Gussone, N., Podladchikov, Y.Y., Bebout, G., Dohmen, R., Halama, R., Klemd, R., Magna, T. & Seitz, M.  Volcanic arcs fed by rapid pulsed fluid flow through subducting slabs. Nature Geoscience, 5, 489-492.
  • Herms, P., John, T., Bakker, R.J. & Schenk, V. Evidence for channelized external fluid flow and element transfer in subducting slabs (Raspas Complex, Ecuador). Chemical Geology, 310-311, 79-96.
  • van der Straaten, F., Halama, R., John, T., Schenk, V., Hauff, F. & Andersen, N. Tracing the effects of high-pressure metasomatic fluids and seawater alteration in blueschist-facies overprinted eclogites: Implications for subduction channel processes. Chemical Geology, 292-293, 69-87.

2011

  • John, T., Scambelluri, M., Frische, M., Barnes, J.D. & Bach, W. Dehydration of subducting serpentinite: implications for halogen mobility in subduction zones and the deep halogen cycle. Earth and Planetary Science Letters, 308, 65-76.
  • Smit, M., Scherer, E., John, T. & Janssen, A. Creep of garnet in eclogite: mechanisms and implications. Earth and Planetary Science Letters, 311, 411-419.
  • Klemd, R., John, T., Scherer, E.E., Rondenay, S. & Gao, J. Change in dip of subducting slabs at greater depths: petrological and geochronological evidence from HP-UHP rocks (Tianshan, NW-China). Earth and Planetary Science Letters, 310, 9-20.
  • John, T., Klemd, R., Klemme, S., Pfänder, J., Hoffmann, J.E. & Gao, J. Nb-Ta fractionation by partial melting at the titanite-rutile transition. Contributions to Mineralogy and Petrology, 161, 35-45.
  • Meyer, M., John, T., Brandt, S. & Klemd, R. Trace element composition of rutile and the application of Zr-in-rutile thermometry to UHT metamorphism (Epupa Complex, NW Namibia). Lithos, 126, 388-401.
  • Raufaste, C., Jamtveit, B., John, T., Meakin, P. & Dysthe, D.K. The mechanism of porosity formation during solvent-mediated phase transformations. Proceedings of the Royal Society A, 467, 1408-1426.
  • Halama, R., John, T., Herms, P., Hauff, F. & Schenk, V. A stable (Li, O) and radiogenic (Sr, Nd) isotope perspective on metasomatic processes in a subducting slab. Chemical Geology 281, 151-166.

2010

  • John, T., Layne, G., Haase, K. & Barnes, J.D. Chlorine isotope evidence for crustal recycling into the Earth´s mantle. Earth and Planetary Science Letters, 298, 175-182.
  • Putnis, A. & John, T. Replacement processes in the Earth’s crust. Elements, 6, 159-164.
  • Beinlich, A., Klemd, R., John, T. & Gao, J. Trace-element mobilization during Ca-metasomatism along a major fluid conduit: eclogitization of blueschists as a consequence of fluid-rock interaction. Geochimica et Cosmochimica Acta, 74, 1892-1922.
  • John, T., Scherer, E.E., Schenk, V., Herms, P., Halama, R. & Garbe-Schönberg, D. Subducted seamounts in an eclogite-facies ophiolite sequence: The Andean Raspas Complex, SW Ecuador. Contributions to Mineralogy and Petrology, 159, 265-284.
  • Halama, R., Bebout, G. E., John, T. & Schenk, V. Nitrogen recycling in subducted oceanic lithosphere: the record in high- and ultrahigh pressure metabasaltic rocks. Geochimica et Cosmochimica Acta. 74, 1636-1652.

2009

  • John, T., Medvedev, S., Rüpke, L.H., Podladchikov, Y., Andersen, T.B. & Austrheim, H. Generation of intermediate-depth earthquakes by self-localizing thermal runaway. Nature Geoscience, 2, 137-140.
  • Adamuszek, M., John, T., Dabrowski, M., Podladchikov, Y.Y. & Gertisser, R. Assimilation and diffusion during xenolith-magma interaction: A case study of the Variscan Karkonosze granite, Bohemian Massif. Mineralogy and Petrology, 97, 203-222.
  • Schmidt, A., Weyer, S., John, T. & Brey, G.P. HFSE systematics of rutile-bearing eclogites: New insights into subduction zone processes and implications for the Earth's HFSE budget. Geochimica et Cosmochimica Acta, 73, 455-468.

2008

  • John, T., Klemd, R., Gao, J. & Garbe-Schönberg, C-D. Trace-element mobilization in slabs due to non steady-state fluid-rock interaction: constraints from an eclogite-facies transport vein in blueschist (Tianshan, China). Lithos, 103, 1-24.
  • van der Straaten, F., Schenk, V., John, T. & Gao, J. Blueschist-facies rehydration of eclogites: implications for subduction channel fluid-rock interaction from the Tianshan, NW China. Chemical Geology, 255, 195-219.
  • Iyer, K., Austrheim, H., John, T. & Jamtveit, B. Serpentinization of the oceanic lithosphere and some geochemical consequences: Constraints from the Leka Ophiolite Complex, Norway. Chemical Geology, 249, 66-90.

2007

  • Zack, T. & John, T. An evaluation of reactive fluid flow and trace-element mobility in subducting slabs. Chemical Geology, 239, 199-216.
  • Gao, J., John, T., Klemd, R. & Xiong, X. Mobilisation of Ti-Nb-Ta during subduction: insights from rutile precipitates in eclogite-facies segregations and veins (Tianshan, NW China). Geochimica et Cosmochimica Acta, 71, 4974-4996.

2006 and before

  • John, T. & Schenk, V, 2006. Interrelations between intermediate-depth earthquakes and fluid flow within subducting oceanic plates: constraints from eclogite-facies pseudotachylytes. Geology, 34, 557-560.
  • Xiong X., John T., Gao J., Klemd R. & Huang D., 2006. Trace element mobilization in subducted slabs: Constraints on an eclogite-facies transport vein from the western Tianshan, NW China. Acta Geologica Sinica, 80, 53-60.
  • John, T., Scherer, E., Haase, K. & Schenk, V., 2004. Trace element fractionation during fluid-induced eclogitization in a subducting slab: trace element and Lu-Hf / Sm-Nd isotope systematics. Earth and Planetary Science Letters, 227, 441-456.
  • John, T., Schenk, V., Mezger, K. & Tembo, F., 2004. Timing and P-T evolution of whiteschist metamorphism in the Lufilian Arc-Zambezi Belt orogen (Zambia): implications to the Gondwana assembly. The Journal of Geology, 112, 71-90.
  • John, T. & Schenk, V., 2003. Partial eclogitisation of gabbroic rocks in a late Precambrian subduction zone (Zambia): prograde metamorphism triggered by fluid infiltration. Contributions to Mineralogy and Petrology, 146, 174-191.
  • John, T., Schenk, V., Haase, K., Scherer, E. & Tembo, F., 2003. Evidence for a Neoproterozoic ocean in south central Africa from MORB-type geochemical signatures and P-T estimates of Zambian eclogites. Geology, 31, 243-246.
  • John, T, Klemd, R., Hirdes, W. & Loh, G., 1999. The metamorphic evolution of the Paleoproterozoic (Birimian) volcanic Ashanti belt (Ghana, West Africa). Precambrian Research, 98, 11-30.
  • John, T., Klemd, R., Hirdes, W. & Loh, G., 1998. The metamorphic evolution of the Paleoproterozoic (Birimian) gold-bearing Ashanti volcanic belt, West Africa. Zeitschrift für Angewandte Geologie, 44, 108-110.