I have previously mentioned Dave Forsyth in four of my earlier postings (November 29, 2013; January 29, 2014; August 27, 2015; September 22, 2016). Dave is a retired geophysicist who has been interested in the rocks of eastern Ontario at least since 1968 when he authored a Bachelor’s thesis with the title “Studies in the Potsdam”. Dave spent his career with the Earth Physics Branch and the Geological Survey of Canada, Department of Energy, Mines and Resources, Ottawa . Since his retirement Dave has co-authored at least three geological field trip guides on the rocks of eastern Ontario, and has been active leading geological field trips for the Macnamara Field Naturalists’ Club, Arnprior, the Niagara Peninsula Geological Society and The Grenville Land Stewardship Council.
Last year I mentioned in numerous blog postings (Brett, 2019a-f) that I had found the Ediacaran fossil Aspidella and Ediacaran rocks at Tackaberry’s active quarry on Highway 7 about five kilometers (three miles) north of Perth, Lanark County, Ontario. Last year I sent the information to Dave and he replied that a number of years ago he had seen similar structures at an abandoned quarry close to Tackaberry’s active quarry, had photographed them, and would look through his collection of photographs for photos that he had taken at that time. This year Dave sent to me photographs from his 2008 visit to the Richmond quarry, which is located about one and a half kilometers to the west of Tackaberry’s active quarry. Below are three of the photos that Dave sent to me.
Dave Forsyth retains ownership of the copyright in the photos. They cannot be reproduced without his consent and credit being given to him as the photographer and owner of copyright in the photos.
I believe that the concentric features that Dave photographed are the Ediacaran fossil Aspidella. The third photo also shows many obscure markings, a few of which I have marked with neon pink boxes around the features. Some appear to be stalks, fronds, and the trace fossil Helminthopsis. Other obscure forms might be algae or an Ediacaran fossil such as Kimberella.
Below is a map showing the location of Tackaberry’s active quarry (red square) and the abandoned Richmond quarry (blue square). The map is based primarily on extracts from Ontario Geological Survey’s Maps P. 2724 and P. 2725 by Williams and Wolf (1984a, b). It also contains changes based on Wilson, Liberty and Reinhardt’s (1972) map.
The two quarries are located about six kilometers directly north of Perth in Drummond North Elmsley Township. The quarries are located in an irregular shaped area of flat lying sedimentary rocks covering approximately 140 square kilometers that I have previously designated the “Drummond Sequence” that has been mapped by the Ontario Geological Survey (Williams and Wolf, 1984a, b): and by the Geological Survey of Canada (Wilson and Dugas, 1961; Wilson, Liberty, and Reinhardt, 1972) as Ordovician March Formation rocks (interbedded quartz sandstone, dolostone and sandy dolostone). Finding the Ediacaran fossil Aspidella at the two quarries strongly suggests that the underlying rocks are of Ediacaran age.
The Drummond Sequence falls within the old Drummond Township (now Drummond North Elmsley Township). On Map P2725 Williams and Wolf (1984a) have mapped the March formation (and hence, the Drummond Sequence) as extending northwest into the old Lanark Township (now the Township of Lanark Highlands). Their mapping contradicts earlier mapping by Wilson, Liberty and Reinhardt (1972) who mapped Nepean sandstone, and Precambrian marble, amphibolite and gneiss in that part of old Lanark Township where Williams and Wolf (1984a) have mapped the March formation. I have preferred Wilson, Liberty and Reinhardt’s (1972) map and have shown their rock units in the northwest corner of the attached map. Interestingly, Wilson and Dugas (1961) mapped a small area of Nepean sandstone ( 2 miles by 1/4 mile) not shown by Williams and Wolf (1984a, b) that falls within the Drummond Sequence.
Williams and Wolf (1984a, b) show the block that is the Drummond Sequence as bounded by faults that separate it on the west from Cambrian Nepean Formation Sandstone, on the southeast from March Formation, on the Northeast from Cambrian Nepean Formation Sandstone, on the north and northwest from plutonic and metamorphic rocks of the Grenville Province of the Precambrian Shield. As I have preferred Wilson, Liberty and Reinhardt’s (1972) map, the Drummond Sequence is not bounded in the northwest by faults mapped by Williams and Wolf (1984a) . Intriguingly, Easton (2017) shows an additional geophysically defined fault trending southwest- northeast that falls just north of the two quarries. See Easton’s (2017) Figures 18.3. A) and B).
The rocks at the top of the Drummond Sequence have been mapped as the Ordovician March Formation by both the Ontario Geological Survey and the Geological Survey of Canada. I found no body fossils in these rocks, but found trace fossils suggesting that the rocks are Ordovician (or Cambrian) in age (see photos Sam_0180, Sam_182 and Sam_0525 shown on my September 13, 2013 blog posting). The trace fossils are similar to ones found by others in March (Theresa) Formation rocks in New York State. At Tackaberry’s active quarry the March Formation beds are at most a few meters thick..
At Tackaberry's active quarry, in the rocks that are mapped as the March Formation, is a meter thick layer of rock coloured pink and buff and showing Liesegang banding and rings (Brett, 2012a, first five photographs) likely caused by diagenetic processes involving the circulation of subsurface waters. The altered rock can be found in outcrops along Highway 7 just north of Perth where the rocks weather grey but the pink colour and the chemical banding in the rocks can still be seen. Below that layer are tens of meters of flat lying, thin siltstone and sandstone beds bearing Ediacaran fossils (mainly Aspidella) and showing ripple marks (Brett 2019b) and microbial mat textures (Brett2012b, Brett2019c). Minor carbonate beds are present. At the base of the quarry are thick sandstone beds that exhibit polygonal cracking (Brett2019c, ninth photo), and which have not yielded any fossils.
For ease of future reference I will define the ‘Drummond Formation’ as that part of the Drummond Sequence that consists of interbedded Ediacaran quartz sandstone, siltstone and minor carbonate rock. The quartz sandstones and siltstones are thinly to thickly bedded, fine grained, and well sorted. The sandstones and siltstones are coloured light grey, dark grey, brown, buff and reddish brown. Ripple marks and microbial mat textures are common. Liesegang banding is present in a layer close to the top of the sequence. Aspidella and other Ediacaran fossils are present.
Dr. Easton of the Ontario Geological Survey mapped the Precambrian geology of the Perth and Carleton Place areas over the last five years. He has a map in preparation -- Precambrian geology of the Perth area; Ontario Geological Survey, Preliminary Map P.3818 -- that will hopefully shed some light on the faults and rocks of the Drummond Sequence. Dr. Easton (2018) noted that “Most of the major faults shown on the Paleozoic geology map of Williams and Wolf (1984[b]) located solely in Precambrian rocks present in the western half of the Carleton Place map area could not be validated by geology or geophysics.” The Carleton Place map area covers the northern half of the Drummond Sequence.
Christopher Brett
Ottawa, Ontario
REFERENCES and SUGGESTED READING
Brett, C.P., 2012a
Mud cracks, Liesegang bands and Liesegang rings, and possible Soft-Sediment Deformation Structures in Sedimentary Rocks of Lanark County, Ontario in an Area Mapped as March Formation. Blog posting, 19 October 2012
http://fossilslanark.blogspot.com/2012/10/
Brett, C.P., 2012b
From Trails, to Mud Cracks to Evidence of Microbial Mats: Different Theories For Curved Lines in the troughs of ripple marks in Sandstone. Blog Posting 5 November 2012
http://fossilslanark.blogspot.com/2012/11/from-trails-to-mud-cracks-to-evidence.html
Brett, C. P., 2019a
Concentric Structures in the Sedimentary Rocks of Lanark County, Ontario that are identical to the Ediacaran Holdfast Aspidella. Blog posting dated 8 March 2019 -
http://fossilslanark.blogspot.com/2019/03/holdfasts-in-lower-ordovician-march.html
Brett, C. P., 2019b
Fossil Ripple Marks in Rocks Near Perth Ontario. Blog posting dated 17 March 2019,
Brett, C. P., 2019c
Possible Fossil Microbial Mat Structures in Rocks Near Perth, Ontario. Blog posting dated 28 March 2019.
Brett, C. P., 2019d
A Selection of Fossils from the ‘March Formation’ in Lanark County, Ontario - A Correction. Blog posting dated 24 March 2019
http://fossilslanark.blogspot.com/2019/03/a-selection-of-fossils-from-march.html
Brett, C. P., 2019e
If the Ediacaran discoid holdfast Aspidella, why not Ediacaran Stalks, Spindles and Fronds in Lanark County? Blog posting dated 29 March 2019
http://fossilslanark.blogspot.com/2019/03/if-ediacaran-discoid-holdfast-aspidella.html
Brett, C. P., 2019f - Tubular Structures in the Ediacaran Drummond Sequence in Lanark County, Ontario. Blog posting dated 22 October 2019 http://fossilslanark.blogspot.com/2019/
Easton, R. M., 2015
Project Unit 15-014. Precambrian and Paleozoic Geology of the Perth Area, Grenville Province, in Summary of Field Work and Other Activities, 2015. Ontario Geological Survey, OFR 6313
at pages 18-1 to 18- 13
Easton, R.M. 2016. Precambrian and Paleozoic geology of the Perth area, Grenville Province; in Summary of Field Work and Other Activities, 2016, Ontario Geological Survey, Open File Report 6323, p.17-1 to 17-13.
Easton, R.M., 2017
Precambrian and Paleozoic Geology of the Carleton Place Area, Grenville Province. Project SO-17-001, Chapter 18 in Ontario Geological Survey 2017. Summary of Field Work and Other Activities, 2017; Ontario Geological Survey, Open File Report 6333, 408p.
Easton, R. M. 2018
Precambrian Geology and Mineral Potential of the Carleton Place Area, Grenville Province . Chapter 14. Project SO-17-001. In Ontario Geological Survey 2018. Summary of Field Work and Other Activities, 2018; Ontario Geological Survey, Open File Report 6350, 426p.
Easton, R.M., 2020 [in press].
Precambrian geology of the Perth area; Ontario Geological Survey, Preliminary Map P.3818, scale 1:50 000.
Williams, D.A., and Wolf, R.R., 1984a
Paleozoic Geology of the Perth Area, Southern Ontario; Ontario; Geological Survey, Map P. 2724, Geological Series-Preliminary Map, scale 1:50 000. Geology 1982.
http://www.geologyontario.mndmf.gov.on.ca/mndmfiles/pub/data/imaging/P2724/P2724.pdf
Williams, D.A., and Wolf, R.R., 1984b
Paleozoic Geology of the Carleton Place Area, Southern Ontario; Ontario Geological Survey, Map P. 2725, Geological Series-Preliminary Map, scale 1:50 000. Geology 1982.
Wilson, A. E., Liberty, B. A., and Reinhardt, 1972,
Geology Carleton Place, Ontario. Map 1362, Geological Survey of Canada. Scale 1:50,000
Paleozoic geology by A. E. Wilson, 1946. Paleozoic compilation by B. A. Liberty, 1963, with changes and additions by E. W. Reinhardt, 1972. Precambrian geology and compilation by E. W. Reinhardt, 1963, 1969, 1972
Wilson, M E; Dugas, J., 1961
Geological Survey of Canada, "A" Series Map 1089A, 1961, 1 sheet; https://doi.org/10.4095/107951
FIELD TRIP GUIDES, ETC., CO-AUTHORED BY DAVE FORSYTH
Donaldson, Al, Forsyth, Dave, Findlay, Chris and Bud Andress, 2010
Fall geology/ecology boat tour - St Lawrence River 1000 Islands. October 17, 2010.
http://www.frontenacarchbiosphere.ca/explore/fab-education/geology/st-lawrence-river-thousand-islands-geology-boat-tour
Forsyth, D.A. and Forsyth, M.E. 2013a
Madawaska to Macnamara Trail and Macnamara Trail Geotours. Macnamara Field Naturalists Club. www.mfnc.ca
https://mfnc.ca/wp-content/uploads/2013/02/arnpriorgeotour.pdf
Forsyth, D.A. and Forsyth, M.E., 2013b
A geology primer for the Morris Island Conservation Area.. Macnamara Field Naturalists Club.
https://mfnc.ca/wp-content/uploads/2013/02/morrisislandconversationarea_geology.pdf
Forsyth, D.A. and Forsyth, M.E., 2011,
Pillars in the Park, GAC/AGC - MAC/AMC - SEG - SGA Joint Annual Meeting, Ottawa 2011, Abstracts Volume 34, at page 66
https://gac.ca/wp-content/uploads/2018/11/2011_Ottawa2011AbstractsVolume.pdf
Forsyth, D.A., 2011
Evidence and Hypothesis – How the Sandstone Cylinders Formed
GAC/AGC - MAC/AMC - SEG - SGA Joint Annual Meeting, Ottawa 2011, Abstracts Volume 34, at pages 66-67
https://gac.ca/wp-content/uploads/2018/11/2011_Ottawa2011AbstractsVolume.pdf
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