Fried Schwerdtner (Emeritus)
University of Toronto Department of Earth Sciences
22 Ursula Franklin St. Toronto Ontario, Canada M5S 3B1
Tel.: 416 978 5080
2022 GAC MAC Poster:
2021 GAC MAC Abstracts:
Field-based structural geology of heterogeneously strained orthogneisses and associated metamorphic rocks, westernmost Grenville Province (Ontario)
Assisted by a few undergraduate students, Dennis Waddington, Toby Rivers and Fried Schwerdtner are continuing their field-based geological study of heterogeneously strained gneisses and associated metamorphic rocks in the Ontario portion of the Ottawa River Gneiss Complex (ORGC; see Toby Rivers’ sketch map, figured below). In the early summer of 2023, Dennis, Fried and their junior field assistant will focus special attention on families of vein-filled tension gashes (see field photo below), locally observed in refolded orthogneisses with quasi-homogeneous composition (Schwerdtner et al. 2023, virtual poster presented at the GAC-MAC Meeting, Sudbury 2023). This will include a detailed inspection of road cuts in the hanging wall of the Grenville Front east of Sudbury and north of Verner, northern French River area.
In addition, Dennis, Fried and their junior field assistants will continue mapping the distribution of mesoscopic structures within asymmetrical megaboudins, Muskoka domain and its vicinity, southeastern ORGC (Schwerdtner and Rivers 2021. GAC-MAC Meeting of London ON, Abstracts Volume 44, p. 271, 272). Special emphasis will be placed on 10m-scale, dilational normal faults filed with potassic pegmatite (see photo below), apparently characterizing the banded gneiss and well-foliated amphibolite comprising the marginal zones and tails of the megaboudins.
Schwerdtner, W.M., Rivers, T., Tsolas, J., Waddington, D.H., Page, S., and Jang, J. 2016. Transtensional origin of multi-order cross-folds in a high-grade gneiss complex, south- western Grenville Province: formation during postpeak gravitational collapse. Canadian Journal of Earth Sciences, 53: 1511-1538.
Rivers, T. and Schwerdtner, W.M. 2015. Post-peak evolution of the Muskoka Domain, western Grenville Province: ductile detachment zone in a crustal-scale metamorphic core complex. Geoscience Canada, 42: 403-436.
Schwerdtner, W.M.,Rivers, T., Zeeman, B., Wang, C.C., Tsolas, J., Yang, J., and Ahmed, M. 2014. Post-convergent structures in lower parts of the 1090-1050 Ma (early Ottawan) thrust-sheet stack, Grenville Province of Ontario, southern Canadian Shield. Canadian Journal of Earth Sciences, 51 243-265
Schwerdtner, W.M. 2013. Photograph of the month. Journal of Structural Geology, 48 (October issue): 1-2.
Schwerdtner, W.M. and Yang, J.F. 2011. Photograph of the Month: Pseudotachylite at the basal contact of the Parry Sound allochthon, Grenville Province of Ontario, Canada. Journal of Structural Geology, 33: 1714.
Schwerdtner, W.M., Lu, S. J. and Yang, J.F., 2010. Wall-rock structure at the present contact surfaces between repeatedly deformed thrust sheets, Grenville Orogen of central Ontario, Canada. Canadian Journal of Earth Sciences, 47: 875-899.
Schwerdtner, W.M., Lu, S.J. and Landa, D., 2010. S/Z buckle folds as shear-sense indicators in the ductile realm: Field examples from the Grenville Province of Ontario and the Appalachians of South Carolina. In ‘From Rodinia to Pangea: The Litho- tectonic record of the Applachian Region, Geological Society of America Memoir 206, Chapter 30, p. 773-794.
Schwerdtner, W.M. and Klemens, W.P., 2008. Structure of the Ahmic domain and its vicinity, southwestern Central Gneiss Belt, Grenville Province of Ontario (Canada). Precambrian Research, 167: 16 – 34.
Schwerdtner, W.M., Riller, U.P. and Borowik, A., 2005. Structural testing of tectonic hypotheses by field-based analysis of distributed tangential shear: examples from major high-strain zones in the Grenville Province and other parts of the Canadian Shield. Canadian Journal of Earth Sciences, 42: 1927 – 1947.
Schwerdtner, W.M., Downey, M.W. and Alexander, S.A., 2004. L-S shape fabrics in the Mazinaw domain and the issue of NW-directed thrusting in the Composite Arc Belt, southeastern Ontario. Geological Society of America, Memoir 197, p. 183 – 2008.
Rivers, T. and Schwerdtner, W.M. 2014. New ideas on the post-peak development of the Central Gneiss Belt in the Muskoka Region. Field trip guide, Friends of the Grenville weekend in Gravenhurst, Ontario; October 3-5, 2014.
Schwerdtner, W.M., Robin, P.-Y. F., Alexander, S., Burke, J., Downey, M.W., and Serafini, G., 2003. Connection between Grenvillian deformation and granitoid pluton emplacement in the Composite arc Belt (Tweed-Kaladar area), southestern Ontario, Canada. Guidebook for Friends of the Grenville (Amis du Grenville) field trip, Department of Geology, University of Toronto.
Schwerdtner, W.M., Klemens, W.P., Robin, P.-Y. F., Vertolli. V.M., and Waddington, D.H., 2005. Geological structure and lithology in parts of the Muskoka region, southwestern Central Gneiss Belt, Grenville Province of Ontario. Field trip guide, 25th annual workshop of the Canadian Tectonics Group and Structural Geology-Tectonics Division of the Geological Association of Canada, Department of Geology, University of Toronto.
Schwerdtner, W.M., Dickin, A.P. and Robin, P.-Y. F., 2009. Rocks, structures and tectonic scenarios: Introduction to the Grenville Province of Ontario. Guidebook for a pre-sessions field trip (Geological Association of Canada), Joint Assembly (AGU- GAC-MAC Meeting), Department of Geology, University of Toronto.