Institut für Mineralogie und Kristallographie
Fakultät für Geowissenschaften, Geographie und Astronomie
Universität Wien

Althanstraße 14 (UZA 2), A-1090 Wien

Sekretariat: Mo-Mi: 9-12 & 13-16; Do: 13-17; Fr: 9-13;
Tel.: (+431) 4277 53201, FAX: (+431) 4277 9532,
Email.: mineralogie@univie.ac.at

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Lutz Nasdala


Lutz Nasdala, Univ.-Prof.

Raumnummer 2A251
Tel.: (+431) 4277 53220
 lutz.nasdala[at]univie.ac.at

 

   

   
 
Research interests and current co-operation and activities:
 

My main research interests lie in the general area of mineralogy and mineral physics. They are particularly related to the study of real structures of minerals (i.e., deviations from the ideal structural and chemical composition) and their use for the interpretation of mineral and rock formation and alteration processes. They include the following areas in which I plan to continue my research in the next years (selection, not complete):

(a) Radiation damage in U-Th-bearing minerals: Structural determination, and characterization of the variations in the chemical and physical behaviour. The main research goal is to contribute to the understanding of effects on radiometric age determinations and potential immobilization and alteration processes in radioactive waste forms.

 

        Co-operation with J.M. Hanchar (St. John's, NL, Canada), P.W. Reiners (Tucson, AZ,), A.K. Kennedy (Perth, WA), J. Mattinson (Santa Barbara, CA), R. Wirth, D. Rhede (Potsdam), A. Kronz (Göttingen), and others.

Zircon M257

Zircon M257, a moderately metamict but nevertheless extremely homogeneous, gem-quality specimen from Sri Lanka. Its chemical, isotopic, and structural composition has been characterised in detail. The 561.3 Ma old zircon will be used as U–Pb ion microprobe standard material in the SHRIMP labs in Perth, Beijing, and St. Petersburg.

Reference:
Nasdala, L., Hofmeister, W., Norberg, N., Mattinson, J. M.,  Corfu, F.,  Dörr, W.,  Kamo, S. L.,  Kennedy, A. K., Kronz, A.,  Reiners, P. W.,  Frei, D., Kosler, J.,  Wan, Y.,  Götze, J.,  Häger T., Kröner, A., Valley, J.W. (2008): Zircon M257 - a homogeneous natural reference material for the ion microprobe U-Pb analysis of zircon. Geostandards and Geoanalytical Research, 32, 247-265.


Cross-polarised transmitted light (a) and BSE image (b) of a heterogeneous zircon from the Saranac Prospect, Ontario. Finger-like altered areas (which are not affected by notable U leaching!) at the ends of fractures are recognised from their birefringence and dark BSE.

Reference:
Nasdala, L., Hanchar, J.M., Rhede, D., Kennedy, A.K., Váczi, T. (2010): Retention of uranium in complexly altered zircon: An example from Bancroft, Ontario. Chemical Geology, 269, 299-300.


zircon

  (b) Optically active defect centres in minerals: Study of absorption and emission centres in natural minerals. Generation of analogous centres by (i) the synthesis of individually or multi-doped minerals or (ii) light- and heavy-ion irradiation. Main goals include the understanding of the radiation-induced green or brown colouration of diamond, to contribute to the interpretation of cathode- and photoluminescence spectra, and to unravel gem enhancement procedures.
 

       Co-operation with D. Grambole, A. Kolitsch (Dresden-Rossendorf), M. Wildner, C. Lenz (Wien), T. Váczi (Budapest), A.M. Zaitsev (Staten Island, NY), A. Gigler (München),
J. Götze (Freiberg), W. Hofmeister (Mainz), T. Hainschwang (Balzers), J.W. Harris (Glasgow), and others.

beamline The nuclear reaction analysis beamline at the 5 MV tandem accelerator of the Forschungszentrum Dresden-Rossendorf, Germany, where light-ion irradiation experiments (He, C, O) were done.

Luminescence images of light-ion irradiated samples: (a) UV-excited PL image of a diamond slice irradiated along the direction of view. (b) OM-CL image of a synthetic zircon crystal (irradiation direction marked with arrow). In both cases, the ion irradiation has created defect-related emission centres.

Reference:
Nasdala, L., Grambole, D., Götze, J., Kempe, U., Váczi, T. (2011): Helium irradiation study on zircon. Contributions to Mineralogy and Petrology, 161, 777-789.

diamond

 

(c) Experimental improvement and application of spectroscopic in situ-analyses: Identification of micrometre-sized phases and characterisation of their structural state, to contribute to the reconstruction of the samples’ formation and post-growth history. An important motivation is also the recognition and avoidance of analytical artefacts.

 

        Co-operation with R. Grötzschel, S. Akhmadaliev (Dresden-Rossendorf), B. Bleisteiner (Bensheim), V. Stähle (Heidelberg), and others.

(a) Suevite clast from the Ries impact crater (BSE image), showing a pseudotrachylite vein with stishovite (bright) whose presence indicates shock compression to ca. 30 GPa. The neighbouring diaplectic quartz is characterized by numerous planar deformation features. (b) Selection of Raman spectra supporting the phase identification.

Reference:
Stähle, V., Altherr, R., Koch, M., Nasdala, L. (2008): Shock-induced growth and metastability of stishovite and coesite in lithic clasts from suevite of the Ries impact crater (Germany). Contributions to Mineralogy and Petrology, 155, 457-472.

suevite
   
confocal spectrometer


(a) Sketch visualising the depth resolution of a confocal spectrometer. (b) Preparation of thin samples in a focused ion beam (SE image). Conducting experiments with samples whose thicknesses are well below the spectrometer’s depth resolution performance helps a lot to exclude artefacts that may be caused by confocality limits.

Reference:
Nasdala, L., Grötzschel, R., Probst, S., Bleisteiner, B. (2010): Irradiation damage in monazite-(Ce): an example to establish the limits of Raman confocality and depth resolution. Canadian Mineralogist, 48, 351-359.


 

(d) Application of imaging and mapping techniques: Visualisation and characterisation of internal growth and alteration textures of minerals. Main goals include the physical understanding of the observed heterogeneity, investigation of artefacts as caused by the electron beam in the EPMA or the SEM, and the visualisation of patterns of internal stress / strain.

 

        Co-operation with D. Howell (Sydney), K. Ruschel (Wien), J. Götze (Freiberg), A. Kronz (Göttingen), R. Wirth, D. Rhede (Potsdam), and others.

cutted zircon


In contrast to previous assumptions, the BSE intensity of natural zircon crystals was found not to be mainly controlled by the chemical composition: (a) Sketch of a heterogeneous zircon crystal that was cut in half, with one half being annealed to reconstitute the structure. (b) BSE image. (c) Colour-coded Raman map, visualising the degree of disorder. Note that the chemical zoning has rather mild effects on the observed BSE, whereas the BSE intensity correlates with the structural disorder (Raman FWHM broadening). In conclusion, the electron back-scatter intensity is strongly enhanced by structural damage.

Reference:
Nasdala, L., Kronz, A., Hanchar, J.M., Tichomirowa, M., Davis, D.D., Hofmeister, W. (2006): Effects of natural radiation damage on back-scattered electron images of single-crystals of minerals. American Mineralogist, 91, 1739-1746.


fergusonite


Colour-coded EPMA element distribution images of an altered region adjacent to a large fracture in a fergusonite specimen from Madagascar. Uranium shows a rather chaotic distribution pattern, suggesting a non-uniform or even multi-step alteration progress. Yttrium is depleted in altered fergusonite areas compared to the unaltered bulk, but is a main constituent of the young fracture filling.

Reference:
Ruschel, K., Nasdala, L., Rhede, D., Wirth, R., Lengauer, C.L., Libowitzky E. (2010): Chemical alteration patterns in metamict fergusonite. European Journal of Mineralogy, 22, 425-433.

   
 
06.05.2014/ZW