At the end of this blog posting I’ve provided a list of articles discussing stromatolites and biofilm structures in Potsdam (Group) Sandstone. Almost all of the articles will be known to those who have worked on the Potsdam or who have written about stromatolites or biofilms in siliclastic sediments. There are two references that will catch people by surprise, the first of which is Dr. Morley E. Wilson’s publication from 1924:
Wilson, M.E., 1924,
Arnprior-Quyon and Maniwaki Areas, Ontario and Quebec, Geological Survey of Canada, Memoir 136, 163 pages.
Dr. Wilson’s article is worth reading if you are interested in stromatolites, as he reports on stromatolites found in three different formations: Nepean sandstone, Beekmantown Dolomite (now Oxford Formation dolostone) , and the Chazy/Aylmer Limestone (now St. Martin Member of Rockcliffe Formation). More importantly, Dr. Wilson’s report has been overlooked as being the first to report on stromatolites in Phanerozoic quartz sandstones. In this publication Dr. Wilson mentions that in the Arnprior-Quyon map area he found two small outcrops of “exceedingly fine grained, white, granular” Nepean sandstone with a maximum thickness of two feet. One of these outcrops, a small outcrop of Nepean sandstone on the roadside at the south end of lot 20, concession VIII in Fitzroy township, Ontario, is important because in places the weathered surface of the sandstone “exhibits concentric ridge forms up to 8 inches in diameter, somewhat similar in appearance to the Cryptozoon structure seen in the Beekmantown dolomite farther to the eastward.” I believe that Dr. Morley Wilson’s report is significant because it is generally accepted that a 1968 article by Richard A. Davis was the first to report on quartz sandstone stromatolites in Phanerozoic rocks. Dr. Wilson deserves the credit as Memoir 136 was published forty-four years prior to Davis’ paper.
A little over a week ago I drove to Fitzroy township in an attempt to find Dr. Wilson’s outcrop of Nepean sandstone on the roadside at the south end of lot 20, concession VIII in Fitzroy township. Regrettably, I could not find an outcrop of sandstone. I did find a very small outcrop of marble along the roadside. A geological map accompanied Dr. Wilson’s memoir. He did not identify Nepean sandstone in the legend to the geological map, mainly, I believe, because he found only two small outcrops of Nepean sandstone in the map area, and the outcrops were too small to map. On his map he shows an outcrop along the roadside at the south end of lot 20, Concession VIII. The outcrop is oval to peanut shaped, and composed of marble. As noted above, I found only a very small outcrop of marble. I noted that the road along the south side of lot 20 is built up above the level of the surrounding ground. In addition, a house, barn and a number of structures are on one side of the road where Dr. Wilson mapped his outcrop. I suspect that the outcrop was to a large part destroyed in the grading of the road and the construction of the buildings.
Dr. Wilson’s map shows additional outcrops of marble along the road that runs along the south side of Concession VIII. I looked at a large outcrop at the south end of lot 18, but found no sandstone on top of the outcrop.
While Dr. Wilson does not include a photograph of either of the sandstone outcrops in Memoir 136, he does include photographs of outcrops of Beekmantown dolomite exhibiting Cryptozoon and photographs of other outcrops. Natural Resources Canada provides an online searchable database of photographs taken by field officers of the Geological Survey of Canada. That database contains a number of photographs taken in 1917 by M.E. Wilson when he conducted the field work of the Arnprior-Quyon area, including photographs that found their way into Memoir 136, but does not contain a photograph of the sandstone outcrop of interest.
In 1982 the Ontario Geological Survey re-mapped Fitzroy Township. See:
Williams, D.A., Wolf, R.R. and Rae, A.M., 1982,
Paleozoic Geology of the Arnprior- Quyon Area, Southern Ontario; Ontario Geological Survey, Map P2726, Geological Series -Preliminary Map. Scale 1:50,000. Geology 1982
http://www.geologyontario.mndmf.gov.on.ca/mndmfiles/pub/data/imaging/P2726/P2726.pdf
Williams, Wolf and Rae’s map does not show an outcrop of Nepean Formation sandstone on lot 20, Concession VIII of Fitzroy Township. They do show a small outcrop of Nepean Formation sandstone fifteen kilometers southeast of Lot 20, Concession VIII at the corner of Kinburn Side Road and Limestone Road. I examined that outcrop, but it does not exhibit Stromatolites or biofilms.
Sir William ‘Eozoön canadense’ Dawson (1879) - A report of Stromatopora in the Potsdam Sandstone
I believe that Sir William Dawson also noted stromatolites or biofilm structures in Potsdam sandstone, but that he misidentified the specimen as Stromatapora when he mentioned the specimen in the following article:
Dawson, J. W., 1879
On the Microscopic Structure of Stromatoporidae, and on Palaeozoic Fossils mineralized with Silicates, in illustration of Eozoon (Read June 5, 1878); The Quarterly Journal of the Geological Society of London, Volume 35, pages 48 - 67, plus Plates III and IV, at pages 51 and 57
http://www.biodiversitylibrary.org/item/86266#page/5/mode/1up
In that article, when discussing occurrences of Stromatopora, Dawson mentions that:
“They occur also in the Lower Silurian, though less abundantly; and the oldest specimen that I have seen is in the Potsdam Sandstone; and this, its structure not being preserved, may have belonged to Eozoon rather than to Stromatopora. The Lower Silurian species have usually very thin and continuous walls.”
When reading that extract from Dawson’ paper it is important to keep in mind that when he is referring to the “Lower Silurian” he is referring what we now call the Cambrian and Ordovician. The Ordovician was defined by Charles Lapworth in 1879, the same year Dawson’s paper was published.
Later in the same article Dawson provides a chart giving the geological distribution of the American Stomatoporidae and lists Stromatopora, sp., in the Potsdam formation.
I believe that Dawson’s references to Stromatopora in the Potsdam formation are actually references to stromatolites or biofilm structures in the Potsdam, mainly because (A) I believe that it would be very easy to mistake a poorly preserved specimen of a stromatolite for Stromatopora (and vice versa), (B) others have found stromatolites and biofilms in Potsdam Sandstones, (C) I have found no reference to anyone else finding Stromatopora in the Potsdam sandstone, and (D) while the Potsdam sandstones are considered to be Cambrian, Stromatoporidae appear to have existed from the Ordovician to the Devonian. Unfortunately, Dawson does not provide the location of the specimen from the Potsdam.
In fairness to Sir William Dawson, his paper from 1879 was published four years before James Hall (1883) provided the original description for Cryptozoön proliferum (the first named and scientifically described stromatolite). In addition, others including S.A. Miller (1889) have noted that Cryptozoon resembles Stromatopora. Further, I have found references which have acknowledged that certain structures were described as stromatopora before Hall gave them the name Cryptozoon. (For example, William Alden (1918), when describing laminated, elliptical, domal structures – that we now call stromatolites – in the Medotta limestones of Wisconsin stated “They resemble certain structures which have been described as stromatoporoid growths , but to which Hall has given the name Cryptozoon....). Dawson cannot be faulted for identifying a structure as stromatopora, when the first stromatolite had not been described when he wrote his paper.
Interestingly, eighteen years later Dawson (1896-97) corrected Walcott’s identification of Precambrian structures found in the Grand Canyon from stromatopora to Cryptozoon, and corrected other earlier identifications of stromatopora to Cryptozoon, but did not go back to look at his own identification of stromatopora from the Potsdam sandstone.
Outcrops of Biofilms and Stromatolites in the Nepean Formation Sandstone at Kanata
We are blessed in Eastern Ontario with outcrops of seismically disturbed beds of stromatolites and biofilms in the Nepean formation quartz arenites. In their field trip guide Donaldson & Chiarenzelli (2004) provide two stops in Kanata where one can look at seismically disturbed beds of stromatolites and biofilms in the Nepean formation. The two stops are different outcrops of the same bed. Their stop 7 is an outcrop that is beside the on-ramp to the Queensway (Highway 417) from Terry Fox Drive if you want to head west on the Queensway (to Arnprior or to Perth). (Please note that it is illegal to stop a car on the on-ramp to a 400 series highway unless it is an emergency.) Their stop 8 is in a field off the Old Quarry Trail over National Capital Commission Greenbelt and is much safer to access. Detailed descriptions of the outcrops at the two stops can be found in their 2004 paper and in (a) Hilowle, Donaldson and Arnott (2000) and (b) Donaldson and Chiarenzelli (2007). Also worth reading are Donaldson and Hilowle (2002), and Donaldson, Chiarenzelli and Aspler (2005).
Below are photographs that I took a little over a week ago of the outcrop at stop 8 along the Old Quarry Trail.
The blue ruler is 12 inches (30 centimeters) long. The silver ruler is 1 meter (39 inches) long.
Donaldson and Chiarenzelli (2004) mention that the outcrop shows “Convolute folds in a 1-m thick unit below a thin unit of foundered ‘half-moons and bananas’ formed by disruption of an early cemented layer of stromatolites above still -unconsolidated sand” caused by seismic activity.
Below are directions to Stop 8 (amended from those in the field trip guide):
Exit the Queensway heading south on Eagleson Road. Cross Robertson Road/Hazeldean Road. Keep in the left hand lane and make a left hand turn at the first stop light into the parking lot marked with a blue P5 sign. Park your car. With your back to Eagleson Road you will see three trails. Take the trail farthest to your right, the most southerly trail. Walk along the trail for about 200 meters. You will pass under some overhead electric power lines. Continue walking along the trail for another 100 meters. The outcrop is about 10 meters to your right through the grass.
Additional outcrops of the convoluted layer can be found along the Old Quarry Trail, which is a 3.1 km long official trail plus additional unofficial loops. The convoluted layer is highlighted in a brochure discussing the geology along that trail that was published by the National Capital Commission in 2000 entitled “Old Quarry Trail, The Making of a Landscape” that is available online at
http://www.ncc-ccn.gc.ca/sites/default/files/pubs/NCC-Old-Quarry-Trail-Brochure-2000.pdf
The brochure provides a cross-section showing the relationship of the convoluted layer to the underlying and overlying flat layers of sandstone, and directs one to outcrops showing ripple marks in the sandstone, worm burrows in sandstone, glacial striations, glacial erratics, dolomite outcrops and the old flagstone quarry in sandstone. The brochure mentions that “Even geologists are puzzled by ... (how the) convoluted layer formed” and suggests that “Perhaps one layer of sand did not lose its moisture as fast as the layers above and below it. Remaining plastic... this layer may have buckled up in response to a sudden shock – perhaps a distant earthquake.”
Hilowle, Donaldson and Arnott (2000) and Donaldson and Hilowle (2002)’s identification of the convoluted layer as representing deformed biofilms and stromatolites, coupled with Donaldson and Chiarenzelli (2004 and 2007)’s suggestion that seismic activity had caused deformation in a stromatolite unit in Nepean sandstone provides an answer to the puzzle posed in the NCC’s brochure. Donaldson and Chiarenzelli (2004) suggest that “to account for the random tilted arrangement of stromatolites” their model “requires early cementation of the stromatolite unit above a still-unlithified substrate of water charged sand. As a result of a seismic disturbance, the rigid unit of laterally linked silica-cemented stromatolites snapped apart along the thin inter-stromatolite links, allowing the now-separated heads to rotate and founder in random directions into the overpressurized sand.”
The convoluted bed in the outcrops found along the Old Quarry Trail has puzzled geologists for over sixty years. In 1956 Dr. Alice E. Wilson included the outcrops in her field trip guide to the Ottawa area. When discussing the sandstone outcrops south of Eagleson’s Corners she mentioned:
“The sandstone is made up of great swirls, each with a hard quartzite centre. The beds below are flat, and the beds above, across the field, are flat. Explanations are in order. Several have been suggested but none proved. One possibility is a slump before consolidation, but why the almost uniform size of the quartzite centres, and the uniformity in the size of the swirls? Another suggestion is that the unconsolidated sand has been pushed up by ice on the seafloor. The same objection holds for this theory, and the additional one that no other evidence has been found indicating ice at this time.”
Donaldson and Chiarenzelli (2004 and 2007)’s suggestion that seismic activity caused deformation in a stromatolite unit in Nepean sandstone appears more likely than Dr. Alice E. Wilson’s suggestions.
Additional Reports of Stromatolites in Potsdam (Group) Sandstone
I have found the following additional references to stromatolites in the Potsdam (Group) sandstones:
Hofmann and Chartier (2006) report on two occurrences in Cairnside formation (the Quebec equivalent of the Nepean formation) orthoquartzites in the Montreal area. They found:
A) “stromatolite-like strain patterns” at Melocheville, Pointe-du-Buisson. They include a photograph as figure 22B with the caption “Plan view of ‘stromatolite-like’ strain patterns,” and a map of Point Du Buisson as Figure 21 upon which the structures have been mapped, including a note of one “area of abundant swarms of stromatolite-like strain patterns.” The map is said to be by “Hofmann, in Clark, 1963.”
B) a “Chaotic bed indicating pre-lithification deformation, possibly as microbially bound sand (microbiolite)” at a roadcut beside the highway 132 entrance to the tunnel below the St. Lawrence Seaway at the Beauharnois Locks. A photograph of that feature appears as Figure 25 Y at page 38 of their report. That photograph could easily have been taken at the outcrops in Kanata that are described above.
Donaldson & Chiarenzelli (2007) provide photographs of deformed stromatolites and biofilms, plus a photograph of an outcrop near Chippewa Bay, New York. For their Figure 8(b)-1 Primary Structures, they mention “(B) Low-amplitude, laterally-linked stromatolites from the Potsdam Sandstone, along Highway 12 just east of Chippewa Bay, New York State, approximately 85 km due south of Ottawa. The host rock is a medium grained, quartz cemented, quartz arenite.”
Professor Bruce Selleck (2008) reported stromatolites in dolomitic beds
in the lower cyclic unit of the Upper Potsdam Member (=Keeseville
Member) in the Southern Lake Champlain Valley at Stop 1 near Lake George
Village and in outcrops close to his Stop 3off NYS Route 22 north of Dresden
Sanford and Arnott (2010) mention the outcrops in Kanata and also mention that stromatolites occur “in various areas of New York State, notably near Chappel Corners where numerous solitary stromatolites were observed at station N-66". Chappel Corners is about 10 km northeast of Theresa, 5 km east of Redwood and 10 km South of Chippewa Bay.
The Société de Paléontologie du Québec provides on its web site a Paleo guide to the Melochville area (written by Mario Lacelle, Pierre Groulx and Paul Racicot) that discusses the outcrop at Pointe-du-Buisson and mentions that “des structures d’origine stromatolitique ont également été rapportés par Hofmann (1972).” See:
http://www.paleospq.org/NewPaleospq/paleoguides.html
I have not yet been able to locate a copy of Hofmann (1972) or Clark (1963).
Evidence of biofilms in the Potsdam Group sandstone has been provided in scores of articles too numerous to individually mention, other than the following.
Brand and Rust (1977) on a stratigraphic log of the type section of the Nepean Formation near Ottawa show three horizons where they recorded rip-up clasts in sandstone. These are likely preserved biofilm structures that correspond with those reported by Erickson (1993) who found sub-cylindrical and sub-triangular structures in the Potsdam Sandstone near Malone, New York that he classified as dubiofossils. Professor Mark Erickson concluded that “algal layers were likely responsible for the quality of preservation of these unusual specimens.”
Salad Hersi and Lavoie (2000) on a stratigraphic section of the Cairnside Formation sandstone (the Quebec equivalent of Ontario’s Nepean Formation sandstone, and New York State’s Keeseville sandstone), show “Breccia (soft sediment deformation)” at a horizon in the lower Cairnside and mention in their report that “In the lower part of the unit at locality 1, there is a brecciated zone due to soft-sediment deformation. The breccia clasts are lithologically similar to the clean quartz arenite of the Cairnside sandstone.” This is consistent with biomat structures preserved during a seismic event.
Christopher Brett
Perth, Ontario
+++++++++++++++++++++++++++++++++++++++++++++
References and A Selected Bibliography of Articles on Stromatolites and Biofilm Structures in Potsdam Group Sandstone
Alden, William , 1918
The Quaternary Geology of Southeastern Wisconsin, with a chapter on the Older Rock Formations; U.S. Geological Survey Professional Paper 106 at page 74
Anderson, K., Dobie, N. Donaldson, J.A., and Arnott, R.W.C., 2004
Complex cementation history of a laterally extensive section within the Cambro-Ordovician Nepean Formation, Ottawa; Program with abstracts GAC, MAC, CGU-AGC, AMC, UCG : joint annual meeting, May 12-14, 2004, Brock University, St. Catherines
http://gac.esd.mun.ca/gac_2004/search_abs/sub_program.asp?sess=98&form=10&abs_no=395
Brand, Uwe and Rust, Brian R. 1977
The age and upper boundary of the Nepean Formation in its type section near Ottawa, Ontario;
Canadian Journal of Earth Sciences, Volume 14, pages 2002-2006.
Clark, T. H., 1963
Field Trip 10- Breccia localities. In: T. H. Clark (editor) Guide Book. Geological Association of Canada, 16th Annual Meeting, Montreal, pp. 95-104
Davis, Richard A. 1968
Algal stromatolites composed of quartz sandstone; Journal of Sedimentary Research, v. 38 no. 3 p. 953-955
Dawson, J. W., 1879
On the Microscopic Structure of Stromatoporidae, and on Palaeozoic Fossils mineralized with Silicates, in illustration of Eozoon; (Read June 5, 1878); The Quarterly Journal of the Geological Society of London, Volume 35, pages 48 - 67, plus Plates III and IV, at pages 51 and 57
http://www.biodiversitylibrary.org/item/86266#page/5/mode/1up
Dawson, J. W., 1896-97
Note on Cryptozoon and other ancient fossils; Canadian Record of Science, volume 7, October 1896, 203-219
Donaldson, J. Allan 2009,
Geoheritage 2. Examples of Geoeducation, Geoconservation and Georescue Projects in Ontario;
Geoscience Canada, Volume 36 Number 3 September 2009, pages 102-106
Donaldson, J. A., and Hilowle, M.A., 2002,
Organic mats, evaporite pseudomorphs and soft-sediment deformation in quartz arenites of the Cambro-Ordovician Nepean Formation; GAC–MAC, Saskatoon 2002, Program with Abstracts,
http://gac.esd.mun.ca/gac_2002/search_abs/sub_program.asp?sess=98&form=10&abs_no=73
Donaldson, J.A., Munro, I., and Hilowle, M.A., 2002,
Biofilm structures, trace fossils and stromatolites in Early Paleozoic quartz arenites and carbonates of the Ottawa region, Ontario: Twelfth Canadian Paleontology Conference (CPC - 2002), 29-30 September, Program and Abstracts, page 12.
Donaldson, J. A., and Chiarenzelli, J. R., 2004,
Stromatolites and associated biogenic structures in Cambrian and Ordovician strata in and near Ottawa, Ontario: New York State Geological Association, 76th Annual Meeting, Fieldtrip Guidebook, SUNY, Potsdam, New York, Trip F-1, p. 1–20.
Donaldson, J.A., and Chiarenzelli, J.R., 2007,
Disruption of Mats by Seismic Events, chapter 8(b) in Atlas of Microbial Mat Features Preserved within the Siliciclastic Rock Record; edited by Juergen Schieber, Pradip K. Bose, P.G. Eriksson, Santanu Banerjee, Subir Sarkar, Wladyslaw Altermann, Octavian Catunean;
Elsevier, 324 pages at p. 245-247
Donaldson, J.A., Chiarenzelli, J.R., and Aspler, L.B., 2005,
Siliciclastic stromatolites and biofilm structures: Conditions for preservation:
GAC–MAC–CSPG–CSSS Halifax 2005, Abstracts, p. 45-46.
Erickson, J. Mark, 1993
A Preliminary Evaluation of Dubiofossils from the Potsdam Sandstone; New York State Geological Association, 65th Annual Meeting, Field Trip Guidebook, Trip A3; pages 121-130
Hagadorn, James W. and Belt, Edward S., 2008
Stranded in Upstate New York: Cambrian Scyphomedusae from the
Potsdam Sandstone; PALAIOS, 2008, v. 23, p. 424–441
DOI: 10.2110 /palo .2006.p06-104r
Hall, James (1883)
Cryptozoön, n.g.; Cryptozoön proliferum, n.sp; New York State Museum of Natural History, 36th Annual Report of the Trustees, plate VI and Explanation
Hilowle, M.A., Donaldson, J.A., Arnott, R.W.C., 2000,
Biofilm-mediated structures in quartz arenites of the Cambro-Ordovician Nepean Formation.
GAC-MAC Program with Abstracts v. 25, GeoCanada2000 – The Millenium Geoscience Summit, Calgary, conference CD, [www.ironleaf.com, abstract 868.]
Hofmann, H J., 1972
Stratigraphy of the Montreal Area - Stratigraphie de la région de Montréal; International Geological Congress, 24th Session, Montreal Guidebook for Field Excursion B-03: 1-32
Hofmann, Hans J. And Chartier, Michel D., 2006
Canadian Paleontology Conference Field Trip Guidebook No. 11, CPC 2006, Redpath Museum, McGill University, October 13-16, 2006
Miller, S.A. (1889)
North American Geology and Paleontology; Western Methodist Book Concern, Cincinnati, Ohio, 793 pages
Salad Hersi, O. and Lavoie, D., 2000
Lithostratigraphic revision of the Upper Cambrian Cairnside Formation, upper Potsdam Group, southwestern Quebec; Geological Survey of Canada, Current Research 2000-D4, 8 pages
Sanford, B. V. and Arnott, R. W. C. , 2010,
Stratigraphic and structural framework of the Potsdam Group in eastern Ontario, western Quebec, and northern New York State; Geological Survey of Canada, Bulletin 597,
Selleck, Bruce , 2008
Stratigraphy, Sedimentology and Diagenesis of the Potsdam Formation, Southern Lake Champlain Valley, New York; New York State Geological Association, 80th Annual Meeting, Fieldtrip Guidebook
Williams, D.A., Wolf, R.R. and Rae, A.M., 1982,
Paleozoic Geology of the Arnprior- Quyon Area, Southern Ontario; Ontario Geological Survey, Map P2726, Geological Series -Preliminary Map. Scale 1:50,000. Geology 1982
http://www.geologyontario.mndmf.gov.on.ca/mndmfiles/pub/data/imaging/P2726/P2726.pdf
Wilson, Morley E., 1924,
Arnprior-Quyon and Maniwaki Areas, Ontario and Quebec, Geological Survey of Canada, Memoir 136, 163 pages.
Wilson, Alice E., 1956
A Guide to the Geology of the Ottawa District; Volume 70, The Canadian Field Naturalist, pages1-68, Plates I-V, Route Map of Excursions
I have not included the recent papers on Climactichnites and Protichnites that discuss the preservation of the trackways due to biofilms, as I’ve mentioned most of them in previous blog postings and they are well known.
