Prof. Dr. Thorsten Geisler-Wierwille

Kontakt

Poppelsdorfer Schloss
Raum 2.102
Telefon: +49 228 73-2733
E-Mail: tgeisler [at] uni-bonn.de

Scientific Career

Research & Teaching

Research interests

Current research mainly focuses on following projects:

Stability of ceramic materials proposed as nuclear waste forms under experimental hydrothermal conditions

Based on present familiarity with production technology, the two best candidate materials for the immobilization of high-level nuclear waste (e.g., ⁹⁹Tc, ¹²⁹I, ⁷⁹Se, ¹³⁵Cs, ²³⁹Pu, and ²³⁷Np) are glasses and crystalline ceramics. The main objectives of the research are to understand the fundamental atomic-scale mechanisms at the fluid-ceramic interface and their dependence on self-irradiation damage, the thermodynamics, and kinetics of fluid-ceramic interaction under moderate P-T conditions expected in deep borehole repositories and near-surface environments. Hydrothermal experiments with natural samples under different physicochemical conditions are linked (i) to detailed studies on natural analogues, which were altered under geological conditions and thus representing real case scenarios, and (ii) to carefully designed hydrothermal experiments with 238Pu-doped synthetic samples. Experiments with ²³⁸Pu-doped synthetic samples are carried out in collaboration with the V. G. Khlopin Radium Institute in St. Petersburg (Russia) and the Institute of Transuranium Elements (ITU) in Karlsruhe (Germany).

Vibrational spectroscopy of self-irradiated minerals

Self-irradiation of minerals due to incorporated actinides such as ²³⁸Pu, U, and Th can cause (i) the swelling of the unit-cell due to the accumulation of defects, (ii) amorphization of the structure, and/or (iii) a complex microstructure, which affect their vibrational properties. Raman and infrared spectroscopy are powerful tools to analyse such structural disorder and are used to study the kinetics of thermal recovery and damage accumulation of various self-irradiated minerals.

Vibrational spectroscopy of zircon solid-solutions

Very little is known about the vibrational and thermodynamic properties of zircon solid solutions of the form (Zr_1-x,REE_x) (Si_1-x,P_x)O₄ and (Zr_1-x, M_x)SiO₄ with M = U, Pu, Th, Np. Experimental investigations have shown that these solid solutions are characterized by a large miscibility gap. The reason is a large mismatch of the radius of the substituting atoms, which cause elastic strain fields. The length scale of the strain fields overlap with that of phonons, which allows studying the strain fields by vibrational spectroscopy.

U-Th-total Pb dating of U- and Th-bearing minerals by electron microprobe

The ability to determine trace U, Th and Pb contents accurately by modern electron microprobes (EMP) has caused renewed interest in chemical dating of U- and Th-bearing accessory minerals like zircon, allanite, pyrochlore, gadolinite, and monazite. Although the U, Th, and Pb analyses by EMP are by far less precise compared to mass-spectrometric analytical techniques, the high spatial resolution of the electron beam potentially allows age relationships to be resolved within altered and/or polygenetic minerals on a µm-scale.

Geochronology of the Eckergneis (Harz Mountains, Germany)

The Eckergneiss Complex (EGC) is a geologically unique medium- to high-grade mainly metasedimentary metamorphic unit within the Rhenohercynian domain of the Mid-European Variscides. The high-grade metamorphism, which is a matchless feature within the low-grade Rhenohercynian domain, and a “Cadomian” age of the metamorphism obtained from conventional U-Pb zircon data has led to controversial speculations about the tectonic setting of the EGC. Currently, we are carrying out detailed SHRIMP work on detrital zircons and U-Pb dating of metamorphic minerals to unravel the source provenance and the geological history of the EGC.

Further research interest is located within the fields of Quaternary Geology and indicator rock studies for the reconstruction of Pleistocene ice-sheet movements.
 

Co-operations

Boris Burakov (The V.G. Khlopin Radium Institute, St. Petersburg, Russia), Jonathan Icenhower (Lawrence Berkeley National Laboratory, USA), Rudy Konings (Institute of Transuranium Elements, Karlsruhe, Germany), Gregory R. Lumpkin (ANSTO, Australia), Ewan Madrell (British Nuclear Fuels, Sellafield, UK), Kilian Pollok (University of Jena), Robert T. Pidgeon (Curtin University, Perth, Australia), Andrew Putnis (University of Münster, Germany), Alexander A. Nemchin (Curtin University, Perth, Australia), Meinert K.W. Rahn (HSK, Villigen-HSK, Schweiz), Jochen Schlüter (University of Hamburg, Germany), Kostya Trachenko (Quenn Mary University of London, UK), Michael Wiedenbeck (GeoForschungsZentrum Potsdam, Germany), Martin Whitehouse (Swedish Museum of Natural History, Sweden), Ming Zhang (University of Cambridge, UK) and many more.

Teaching

At the Steinmann-Institut für Geologie, Mineralogie und Paläontologie, University of Bonn (Germany)

B.Sc. courses

• 4^th Semester: Practical: Rock-forming Minerals (Optics and Polarization Microscopy)

M.Sc. courses

• 1^st Semester: Lecture: Isotope Geochemistry
• 1^st Semester: Lecture and Practical: Mineralogical Processes I
• 1^st Semester: Lecture and Practical: Vibrational Spectroscopy I (Introduction to Vibrational Spectroscopy I – Molecule Symmetry, GroupTheory: Molecules)
• 2^nd Semester: Lecture: Isotope Geochemistry
• 2^nd Semester: Lecture and Practical: Mineralogical Processes II

At the Mineralogisch-Petrographisches Institut, University of Hamburg (Germany)

• Macroscopic rock determination (practical)
• Introduction to statistics for geoscientists / Modelling of magmatic processes (external university teaching position)
• Introduction to electron microprobe analysis (external university teaching position)

At the Department of Earth Sciences, University of Cambridge (UK)

• Module 2: Disordered materials: Radiation damage
• Module A: Structure of materials (Practical of Materials and Mineral Sciences)

At the Institut für Mineralogie, University of Münster

• Optics/polarisation microscopy
• Vibrational spectroscopy in mineralogy
• Diffusion in condensed matter
• Mineralogical practical (Raman and IR spectroscopy, X-ray diffraction analysis)

Computer programs

• ChemAge: a Windows program for the calculation of chemical U-Th-total Pb age of accessory minerals, including algorithms for electron microprobe data reduction (program BgReg).
• CirMap: a Windows program for the presentation of indicator rock counts according to the Circle-Map-Method of Smed (1992).

Both programs are running under Windows 95/98/2000 and NT and are available on request.

Publications

None-reviewed Contributions

• Geisler T. (1996) The Permocarboniferous dolerites in Scania, south Sweden: Petrographical and geochemical characteristics and their significance as Indicator Geschiebe. Archiv für Geschiebekunde, 2, 105-117 (in German).
• Geisler T. (1999) CirMap: A 32 bit Windows program for the analysis and presentation of indicator counts by the Circle Map Method. Archiv für Geschiebekunde, 2, 597-600 (in German).
   

Peer-reviewed Contributions

• Geisler T. and Schleicher, H. (2000) Improved U-Th-total Pb dating of zircons by electron microprobe using a new background modeling method and Ca as a chemical criterion of fluid-induced U-Th-Pb discordance in zircon. Chem. Geol., 163, 269-285.
• Geisler T. and Schleicher, H. (2000) Composition and U-Th-total Pb model ages of polygenetic zircons from the Vånga granite, south Sweden: An electron microprobe study. Geol. Fören. Förh., 122, 227-235.
• Geisler T., Ulonska M., Schleicher H., Pidgeon R.T., and van Bronswijk W. (2001) Leaching and differential recrystallization of metamict zircon under experimental hydrothermal conditions. Contrib. Mineral. Petrol., 141, 53-65.
• Geisler T., Pidgeon R.T., van Bronswijk W., and Pleysier R. (2001) Kinetics of thermal recovery and recrystallization of partially metamict zircon: a Raman spectroscopic study. Eur. J. Mineral., 13, 1163-1176.
• Geisler T. and Pidgeon R.T. (2001) Significance of radiation damage on the integral SEM cathodoluminescence intensity of zircon: An experimental annealing study. N. Jhb. Mineral. Monatsh., 10, 433-445.
• Geisler T. (2002) Isothermal annealing of partially metamict zircon: evidence for a three-stage recovery process. Phys. Chem. Min., 29, 420-429.
• Geisler T. and Pidgeon R.T. (2002) Raman scattering from metamict zircon: Comments on “Metamictisation of natural zircon: accumulation versus thermal annealing of radioactivity-induced damage” by Nasdala et al., 2001 (Contrib. Mineral. Petrol., 141, 125-144). Contrib. Mineral. Petrol., 143, 750-755.
• Geisler T., Pidgeon R.T., van Bronswijk W., and Kurtz R. (2002) Transport of uranium, thorium, and lead in metamict zircon under low-temperature hydrothermal conditions. Chem. Geol., 191, 141-154.
• Geisler T., Rashwan A.A., Rahn M., Poller U., Zwingmann H., Pidgeon R.T., Schleicher H., and Tomaschek F. (2003) Low-temperature hydrothermal alteration of natural metamict zircons from the Eastern Desert, Egypt. Mineral. Mag., 67, 485-508.
• Geisler T., Zhang M., and Salje E.K.H. (2003) Recrystallization of almost fully amorphous zircon under hydrothermal conditions: An infrared spectroscopic study. J. Nucl. Mater., 320, 280-291.
• Geisler T., Pidgeon R.T., Kurtz R., van Bronswijk W., and Schleicher H. (2003) Experimental hydrothermal alteration of partially metamict zircon. Am. Mineral., 86, 1496-1518.
• Geisler T., Trachenko K., Ríos S., Dove M., and Salje E.K.H. (2003) Impact of self-irradiation damage on the aqueous durability of zircon (ZrSiO4): Implications for its suitability as nuclear waste form. J. Phys: Condens. Matter, 15, L597-L605.
• Trachenko K., Dove M.T., Geisler T., Todorov I., and Smith B. (2004) Radiation damage effects and percolation theory. J. Phys.: Condens. Matter, 16, S2623-S2627.
• Trachenko K., Dove M.T., Pruneda M., Artacho E., Salje E.K.H., Geisler T., Todorov I., and Smith B. (2004) Radiation-induced structural changes, percolation effects, and resistance to amorphization. Mat. Res. Soc. Symp. Proc., 792, 509-524.
• Geisler T., Seydoux-Guillaume A.-M., Wiedenbeck M., Berndt J., Wirth R., Zhang M., Mihailova B., Putnis A., Salje E.K.H., and Schlüter J. (2004) Periodic precipitation pattern formation in hydrothermally treated metamict zircon. Am. Mineral., 89, 1341-1347.
• Geisler T., Berndt J., Meyer H.-W., Pollok K., Putnis A. (2004) Low-temperature aqueous alteration of crystalline pyrochlore: Correspondence between nature and experiment. Mineral. Mag., 68, 905-922.
• Zhang M., Salje E.K.H., Ewing R.C., Daniel P., and Geisler T. (2004) Application of near-infrared FT-Raman spectroscopy in metamict and annealed zircon: oxidation state of U ions. Phys. Chem. Min., 31, 405-414.
• Geisler T., Burakov B.E., Yagovkina M., Garbuzov V., Zamoryanskaya M., Zirlin V., and Nikolaeva L. (2005) Structural recovery of self-irradiated natural and 238Pu-doped zircon in an acidic solution at 175°C. J. Nucl. Mater., 336, 22-30.
• Geisler T., Vinx R., Martin-Gombojav N., and Pidgeon R.T. (2005) Ion microprobe (SHRIMP) dating of detrital zircon grains from quartzites of the Eckergneiss Complex, Harz Mountains (Germany): Implications for the provenance and geological history. Int. J. Earth Sci., 94, 369-384.
• Geisler T., Seydoux-Guillaume A.-M., Pöml P., Golla-Schindler U., Berndt J., Wirth R., Pollok K., Janssen A., and Putnis A. (2005) Experimental hydrothermal alteration of crystalline and radiation-damaged pyrochlore. J. Nucl. Mater., 344, 17-23.
• Geisler T., Pöml P., Stephan T., Janssen A., and Putnis A. (2005) Experimental observation of an interface-controlled pseudomorphic replacement reaction in a natural crystalline pyrochlore. Am. Mineral., 90, 1683-1687.
• Geisler T., Burakov B.E., Zirlin V., Nikolaeva L., and Pöml P. (2005) A Raman spectroscopic study of high-uranium zircon from the Chernobyl “lava”. Eur. J. Mineral., 17, 883-894.
• Geisler T., Popa K., Konings R.J.M., and Popa A.F. (2006) A Raman spectroscopic study of the phase transition of BaZr(PO4)2: evidence for a trigonal structure of the high-temperature polymorph. J. Sol. State Chem., 197, 1489 - 1495.
• Pöml P., Geisler T., and Konings R.J.M. (2006) High-temperature heat capacity of zirconolite (CaZrTi2O7). J. Chem. Thermodynamics, 38, 1013-1016. (*)
• Popa K., Konings R.J.M., Beneš, Geisler T., and Popa A.F. (2006) Thermodynamic and spectroscopic studies of the phase transitions of BaHf(PO4)2. Thermochem. Acta, 451, 1-4.
• Popa K., Konings R.J.M., Bouëxière D., Popa A.F., and Geisler T. (2006) Synthesis and characterisation of BaMIV(PO4)2 in the view of conditioning of the actinides. Adv. Sci. Techn., 45, 2012-2017.
• Putnis C.V., Geisler T., Stephan T., Schmid-Beurmann P., and Giampaolo C. (2007) An experimental study of the replacement of leucite by analcime. Amer. Mineral., 92, 19-26.
• Pidgeon R.T., Nemchin A.A., van Bronswijk W., Geisler T., Meyer C., Compston W., and Williams I.S (2007) Complex history of a zircon aggregate from lunar breccia 73235. Geochim. Cosmochim. Acta, 71, 1370-1381.
• Popa K., Konings R.J.M., and Geisler T. (2007) High-temperature calorimetry of (La1-xLnx)PO4 solid solutions. J. Chem. Thermodynamics, 39, 236-239.
• Geisler T., Schaltegger U., and Tomaschek F. (2007) Re-equilibration of zircon in aqueous fluids and melts. Elements, 3, 45-51.
• Menneken M., Nemchin A.A., Geisler T., Pidgeon R.T., and Wilde S.A. (2007) Hadean diamonds in zircon from Jack Hills, Western Australia. Nature, 448, 917-920. (*)
• Pöml P., Menneken M., Stephan T., Niedermeier D., Geisler T., and Putnis A. (2007) Mechanism of hydrothermal alteration of natural self-irradiated and synthetic titanate-based pyrochlore. Geochim. Cosmochim. Acta, 71, 3311-3322. (*)
• Popa K., Bregiroux D., Konings R.J.M., Gouder T., Popa A.F., Geisler T., and Raison P.E. (2007) The chemistry of the phosphates of barium and tetravalent cations with 1:1 stoichiometry. J. Sol. State Chem., 180, 2346-2355.
• Nemchin A.A., Whitehouse M.J., Menneken M., Geisler T., Pidgeon R.T., and Wilde S.A. (2008) A light carbon reservoir recorded in zircon-hosted diamond from the Jack Hills. Nature, 454, 92-96.
• Janssen A., Putnis A., Geisler T., Putnis C.V., and Golla-Schindler U. (2008) The mechanism of experimental oxidation and leaching of ilmenite in acid solution. Australasian Inst. Mining and Metallurgy, Publ. Ser., Vol. 8, 503-506. (*)
• Raison P.E., Jardan R., Bouëxière D., Konings R.J.M., Geisler T., Pavel C.C., Rebizant J., and Popa K. (2008) Structural investigation of the synthetic CaAn(PO4)2 (An= Th and Np) cheralite-like phosphates. Phys. Chem. Mineral., 35, 603-609.
• Niedermeier D.R.D., Putnis A., Geisler T., Golla-Schindler U., and Putnis C. (2009) The mechanism of cation and oxygen isotope exchange in alkali feldspars under hydrothermal conditions. Contrib. Mineral. Petrol., 157, 65-76. (*)
• Nemchin A.A., Timms N., Pidgeon R.T., Geisler T., Reddy S., and Meyer C. (2009) Timing of crystallization of the lunar magma ocean constrained by the oldest zircon. Nature Geoscience, 2, 133-136.
• Janssen A., Pöml P., Beneš O., Geisler T., and Konings R.J.M. (2009) High-temperature heat capacity of Gd-pyrochlore (Gd2Ti2O7). J. Chem. Thermodynamics, 41, 1049-1051. (*)
• Hövelmann J., Putnis A., Geisler T., Schmidt B.C., and Golla-Schindler U. (2010) The replacement of plagioclase feldspars by albite: Observations from hydrothermal experiments. Contrib. Mineral. Petrol., 159, 43-59. (*)
• Schlüter J., Geisler T., Pohl D., and Stephan T. (2010) Krieselite, Al2GeO4(F,OH)2: A new mineral from the Tsumeb Mine, Namibia, representing the Ge analogue of topaz. N. Jb. Mineral. Abh., 187 , 33-44.
• Kasioptas A., Geisler T., Perdikouri C., Putnis C.V., and Putnis A. (2010) Kinetic study of experimental replacement of biogenic aragonite by apatite. J. Cryst. Growth & Design, 312, 2431-2440. (*)
• Geisler T., Janssen A., Scheiter D., Stephan T., Berndt J., and Putnis A. (2010) Aqueous corrosion of borosilicate glass under acidic conditions: A new corrosion mechanism. J. Non-Cryst. Sol., 356, 1458-1465.
• Lenting C., Geisler T., Gerdes A., Kooijman E., Scherer E., and Zeh A. (2010) The behaviour of the hafnium isotope system in radiation-damaged zircon during experimental hydrothermal alteration. Amer. Mineral., 95, 1345-1348. (*)
• Janssen A., Putnis A., Geisler T., and Putnis C.V. (2010) The experimental replacement of ilmenite by rutile in HCl solutions. Mineral. Mag., 74, 633-644. (*)
• Soman A., Geisler T., Tomaschek F., Grange, M., and Berndt J. (2010) Alteration of crystalline zircon solid solutions: A case study on zircon from an alkali pegmatite from Zomba-Malosa, Malawi. Contrib. Mineral. Petrol., 160, 909-930. (*)
• Pöml P., Geisler T., Heimink J., Cobos-Sabate J., Wiss T., Raison, P.E., Schmid-Beurmann P., Golla-Schindler U., Deschanels X., and Putnis, A. (2011) The mechanism of the hydrothermal alteration of Cerium- and Plutonium-doped zirconolite. J. Nucl. Mater., 410, 10-23. (*)
• Kasioptas A., Geisler T., Perdikouri C., Trepmann C., Gussone N., and Putnis A. (2011) Polycrystalline apatite synthesized by hydrothermal replacement of calcium carbonates. Geochim. Cosmochim. Acta, 75, 3486-3500. (*)
• King H.E., Plümper O., Geisler T., and Putnis A. (2011) Experimental investigations into the silicification of olivine: Implications for the reaction mechanism and acid neutralization. Amer. Mineral., 96, 1503-1511. (*)
• Roszjar J., Metzler K., Bischoff A., Barrat J.-.A., Geisler T., Greenwood R.C., Franchi I.A., and Klemme S. (2011) Thermal history of Northwest Africa (NWA) 5073 - a coarse-grained Stannern-trend eucrite containing cm-sized pyroxenes and large zircon grains. Meteor. Planet. Sci., 46, 1754-1773. (*)
• Perdikouri C., Kasioptas A., Geisler T., Schmidt B.C., and Putnis A. (2011) Experimental study of the aragonite to calcite transition in aqueous solution. Geochim. Cosmochim. Acta, 75, 6211-6224. (*)
• Geisler T., Perdikouri C., Kasioptas A., and Dietzel M. (2012) Real-time monitoring of the overall exchange of oxygen isotopes between aqueous CO32- and water by Raman spectroscopy. Geochim. Cosmochim. Acta, 90, 1-11.

(*) Student paper

Book Chapters

• Linnemann U., Romer R.L., Pin C., Aleksandrowski P., Buła Z., Geisler T., Kachlik V., Krzemińska E., Mazur S., Motuza G., Murphy J.B., Nance R.D., Pisarevsky S.A., Schulz B., Ulrich J., Wiszniewska J., Zaba J., and Zeh A. (2008) Precambrian. In: T. McCann (ed.) The Geology of Central Europe. Geol. Soc. London, Spec. Publ., 1, 21-103.
• Pollok K., Langenhorst F., Hopf J., Kothe E., Geisler T., Putnis C.V., and Putnis A. (2008): Microstructural controls on monosulfide weathering and heavy metal release (MIMOS). In: Stroink, L. (Ed.) Mineral Surfaces – From Atomic Processes to Industrial Applications, Geotechnologien Science Report, 12, 79-88.
• Lumpkin G.R. and Geisler T. (2012) Minerals and natural analogues. In: Konings R.J.M. (ed.) Comprehensive Nuclear Materials, 563-600, (Elsevier, 3560 pp).

Extended Abstracts

• Menneken M., Geisler T., Nemchin A.A., Gasharova B., and Grange M.L. (2010) Implications of carbon dioxide inclusions in Jack Hills zircons. 5th International Archean Symposium, Abstracts, 98-100. (*)

Conference Abstracts/Reports (Selection)

• Geisler T., Janssen A., and Putnis A. (2009) The interaction of borosilicate glass with aqueous solutions. Geochim. Cosmochim. Acta, 73, A424.
• Kasioptas A., Perdikouri C., Putnis C.V., Geisler T., and Putnis A. (2009) Apatite from calcium carbonates: a pseudomorphic replacement reaction. Geochim. Cosmochim. Acta, 73, A624. (*)
• Rozjar J, Geisler T., Scherer E. E., and Bischoff A. (2009) The thermal history of zircon grains from the NWA 5073 eucrite as revealed by Raman spectroscopy. Meteor. & Planet. Sci., 44, A178. (*)
• Geisler T. and Putnis A. (2009) The interaction of minerals with aqueous solutions. Hallesches Jahrb. Geowiss., 31, 74.
• Menneken M., Geisler T., Strauss H., and Kooijman E. (2009) Applicability and limitations of Raman mass-spectroscopy on CO2 inclusions. Hallesches Jahrb. Geowiss., 31, 164. (*)
• Schmid-Beurmann P., Geisler T., Huyskens M., and Többens D. (2009) Spectroscopic investigations of synthetic ferrisicklerite. Hallesches Jahrb. Geowiss., 31, 218.
• Putnis C.V., Jamtveit B., Malthe-Sørenssen A., and Geisler T. (2009) Reaction-induced fracturing during fluid-rock interaction. Hallesches Jahrb. Geowiss., 31, 188.
• Kasioptas A., Geisler T., Perdikouri C., and Putnis A. (2009). The complexity of replacement reactions: The calcium carbonate to calcium phosphate hydrothermal transition. Hallesches Jahrb. Geowiss., 31, 121. (*)
• Geisler T., Janssen A., Scheiter D., Denkler R., Berndt J., Stephan, T., and Putnis A. (2010) Is the corrosion of borosilicate glass really controlled by diffusion processes? Abstract Volume CIMTEC 2010 - 5th Forum on New Materials, FF-10.3:LO3, 68-69.
• Pöml P., Heimink J., Schmid-Beurmann P., Golla-Schindler U., Geisler T., and Putnis A. (2010) Synthesis and hydrothermal stability of Ce-doped zirconolite ceramics. Abstract Volume CIMTEC 2010 - 5th Forum on New Materials, FF-10.3:LO7, 69. (*)
• Rozjar J., Geisler T., and Bischoff A. (2009) Constraints on the thermal evolution of meteorites applying Raman spectroscopic and electron microprobe analyses on zircon grains. Meteor. & Planet. Sci., 45, A174. (*)
• Pöml P., Cobos-Sabate J., Wiss T., Raison P.E., Deschanels X., and Geisler T. (2010) Hydrothermal stability of amorphous and crystalline Pu-doped zirconolite ceramics. MRS Spring Meeting in San Francisco, Scientific Basis for Nuclear Waste Management XXXIV, AA7.4. (*)
• Menneken M., Geisler T., and Nemchin A.A. (2010) Implications of CO2 inclusions in Jack Hills zircons for early Earth environment. 88th Annual Meeting of the German Mineralogical Society, Abstracts, 41. (*)
• King H.E., Geisler T., and Putnis A. (2010) Olivine reaction with acidic solutions: Implications of oscillatory textures. 88th Annual Meeting of the German Mineralogical Society, Abstracts, 144. (*)
• Geisler T., Kasioptas A., and Perdikouri C. (2010) The oxygen isotope exchange between (CO32-)aq and water: An in situ Raman spectroscopic study. 88th Annual Meeting of the German Mineralogical Society, Abstracts, 1
• Lenting C., Geisler T., Gerdes A., Kooijman E., Scherer E.E., and Zeh A. (2010) The stability of the Hf isotope system in metamict zircons: hydrothermal experiments. 88th Annual Meeting of the German Mineralogical Society, Abstracts, 278. (*)
• Geisler T., Denkler R., Janssen A., Kilburn M., and Putnis A. (2011) Pattern formation during the alteration of ancient glasses: Insights from static corrosion experiments. Glass & Optical Materials Division Annual Meeting, Abstract Volume, 89.
• Geisler T., Janssen A., Denkler R., Kilburn M., and Putnis A. (2011) Evidence for a new glass corrosion mechanism from isotope tracer experiments. Glass & Optical Materials Division Annual Meeting, Abstract Volume, 76.

(*) Student paper