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Fried Schwerdtner (Emeritus)


 Emeritus Professor

University of Toronto Department of Earth Sciences

22 Ursula Franklin St. Toronto Ontario, Canada M5S 3B1

Tel.: 416 978 5080 

e-mail: fried@es.utoronto.ca



2023 GAC-MAC abstract

2023 GAC-MAC Virtual Poster (final version)

2022 GAC MAC Poster:

Field evidence for the formation of two common strain-induced structures conflicts with the starting geometry of numerical models

2021 GAC MAC Abstracts:

2021 GAC-MAC abstract (WMS & TR) with graphic component (one page)

2021 GAC-MAC Abstract, DHW & WMS

2021 CTG abstract, final version

2020 Nov 10 PM, submitted CTG Abstract 2020 Nov 21 pm, PPF final version, CTG Workshop

2020 Nov 21 pm, PPF final version, CTG Workshop

2020 July 16, GSA Absract #1, corrected final version (Carter et al.)

2020 GSA Poster #1, Carter et al. GSA Poster #1 (003)

2020 July 27, final GSA Abstract #2 with Joy.

2020 GSA Poster #2; Schwerdtner et al. GSA Poster #2 (003)

2019 Oct 18 geological notes for the Rock Walk (Fried’s Part)

Notes for ES 2018 grad student field trip

grad field trip photo  geologic feature seen on field trip

Canadian Tectonics Group “Muskoka 2016” Revised Programme with Abstracts

Field Guide Muskoka 2016

Late-orogenic cross-folds in the Ottawa River Gneiss Complex, western Grenville Province: Shear-induced sheath folds or products of superimposed deformation?


Research interests

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.

rock face with light coloured veins and a green hat used as a scale

vein-filled tension gashes

Geological sketch map showing late to post-Ottawan structural levels and active structures in the western Grenville Province

Above: Geological map by Toby Rivers, based in part on Culshaw et al. (1983, Current Research, Geological Survey of Canada Paper 83-1B, p. 242–252).

rock outcrop folds Huntsville area Ontario

Above: Monoclinic flexures in the gneissic banding flanking a weakly deformed pegmatite dike, Hwy. 60 northeast of Hunsville ON (see upright crutch as scale). Schwerdtner and Rivers interpret the flexures as truncated fault-propagation folds rather than genuine flanking folds.   

line diagram

Above: Hypothetical formation of a winged inclusion by shear-induced deformation of a straight lenticular boudin (black lens shown at the top) surrounded by low-viscosity material (sketch by D.H. Waddington, modified from Grasemann and Dabrowski 2015, their Fig. 1c, Jour. Struct. Geol., v. 70, p. 78–94)

outcrop with rock hammer

Above: Winged mafic inclusion in banded orthogneiss, high-strain zone between the allochthonous Huntsville and Seguin subdomains (Culshaw et al. 1983, Current Research, Geological Survey of Canada Paper 83-1B, p. 242–252), southwestern Ottawa River Gneiss Complex, Hwy.11 near Port Sydney, central Ontario.

rock outcrop

Above: Boudin-like mafic inclusion with a folded tail surrounded by banded orthogneiss. Note closures in the gneissic banding at both ends of the inclusion ruling out an origin by lenticular boudinage. Roadcut near Baysville, central Ontario.

Refereed Publications

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.

Non-refereed publications

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.