Eighty-one feet of Dark Grey Paleozoic Shale was Logged under the Potsdam by Bruce A. Liberty in Core from a Hole Drilled at Knowlton Lake, Ontario and reported in a Geological Survey of Canada Paper published in 1971

I expect that many  people reading the title of this posting, if they have a working knowledge of the sedimentary rocks of Eastern Ontario, will read the title at least twice, and will ask themselves the following three questions:

 - How can there be Paleozoic shale under the Potsdam given that the Potsdam Group is considered to be the oldest sedimentary series in Eastern Ontario? 
 - If Liberty reported shale under the Potsdam, why hasn’t anyone followed up on it?   
 - How does this shale formation tie in with Dalrymple, Narbonne and Smith’s  1985 paper  “Eolian action and the distribution of Cambrian shales in North America” (Geology, 13, 607–610)?

I have to admit that I can’t presently answer those questions and may not have an answer until 2018.   Below I’ve provided the source for the title, a summary of my investigations,  what I hope to find, and why it will take to 2018.

The title to this posting is derived from statements in  the following paper and in the legend to the following map.
   
Liberty, B. A, 1971.  Paleozoic geology of Wolfe Island, Bath, Sydenham and Gananoque map areas, Ontario.  Geological Survey of Canada  Paper 70-35, 1971, ; 12 pages (4 sheets), doi:10.4095/102360

Liberty, B. A, 1970 ,  Geology Sydenham Ontario, Map 17-1970,  Geological Survey of Canada , Preliminary Series, to accompany Paper 70-35. Geology by B. A. Liberty, 1961, 1964, 1966
       
Liberty devotes the first paragraph at page 2 of his paper to the Potsdam Formation, and concludes with the following three sentences:

“At least 70 feet of the formation occur in outcrop in the area and a boring at Knowlton Lake indicates a total thickness there of 149 feet. An additional 81 feet of dark grey Paleozoic shale was logged, by the writer, at the base of the formation in the first Dominion Observatory boring
at Knowlton Lake.  This unit is separated as a lower member at this one location only.”

I thought at first that Liberty’s  reference to “81 feet of dark grey Paleozoic shale” at the base of the Potsdam must have been a mistake, but on his accompanying  Map 17-1970 Liberty has the  legend:

“2  POTSDAM SANDSTONE: red, white, grey and yellow, evenly textured, fine-grained sandstone, and siltstone: in Knowlton Lake area this formation includes 81 feet of underlying dark grey shale as lower member (not included above).”   [my emphasis]

One of my initial thoughts was that someone else must have noted Liberty’s statements and commented on the underlying shale.   While I found that a number of authors reference Liberty’s paper,  I’ve been unable to find a reference to the shale.   For example, when Carson (1981a, 1981b) re-mapped this area for the Ontario Geological Survey he referenced Liberty’s earlier work, but doesn’t mention the shale.  Carson (1981a)  mentions that “Geological mapping of the Kingston area involved the reexamination of three map-areas previously mapped by B.A. Liberty for the Geological Survey of Canada (Liberty1971)” and that “Although no fossils have been recovered from the Potsdam formation, it is considered to be of Cambrian age (Liberty 1971)” , but doesn’t mention the shale.   Carson (1981b)  mentions that “Liberty (1971) estimated a total thickness in excess of 21 m” for the Potsdam Formation,  but doesn’t mention the shale.

Carson, D.M., 1981a: No. S13 Paleozoic Geology of the Kingston  Area, Southern Ontario; in  Ontario Geological Survey Miscellaneous Paper 100, Summary of Field Work, 1981, pages 134-136

Carson, D.M., 1981b: Paleozoic Geology of the Tichborne-Sydenham  Area, Southern Ontario; Ontario Geological Survey Preliminary Map P. 2413, Geological Series. Scale 1:50000. Geology 1980.

Sanford and Arnott (2010, GSC Bulletin 597, page 14)  mention that Liberty (1971) “established the presence of a large number of sandstone outliers, which were identified as a single unit, the Potsdam Formation” but again fail to mention Liberty’s description of the shale.

I knew from prior research that Liberty had been an authority on the Paleozoic rocks of Ontario.   (Liberty authored or co-authored over fifty  papers and maps for the Geological Survey of Canada on the Paleozoic sedimentary rocks of Ontario that were published over a period from about 1950 to 1973.)   As he had a wealth of knowledge on the Paleozoic rocks of Ontario,  I thought it unlikely that he could have mistaken, for example, Precambrian shale for Paleozoic shale.   I could have looked briefly at the core and assumed black shale to be Paleozoic,  but Liberty logged the core and made that decision.  Accordingly, why did he think the shale was Paleozoic in age?   The answer to that question has to be found in the core and in his notes from when he logged the core.

I expect everyone reading this posting is asking themselves the question  “Where would one look for the core from the Dominion Observatory boring at Knowlton Lake and for Liberty’s notes when he logged the core?”   I expect that there are many others like me who grew up in Ottawa knowing that the Dominion Observatory was on Carling Avenue in Ottawa, that geophysicists had been associated with the observatory, and that those geophyicists later worked for various sections of Energy Mines and Resources, now Natural Resources Canada, and worked with the geologists at the Geological Survey of Canada, also now Natural Resources Canada, and would check first with the Natural Resources Canada.   

As a first stab at finding the core I looked on GEOSCAN, Natural Resources Canada’s online database of Geological Survey of Canada publications.   I did locate  "A user's guide to core-storage facilities in Canada ', Geological Survey of Canada Paper 84-23, 1985  doi:10.4095/120217 " but it wasn't much help, other than for telling me that the Ontario Geological Survey had core from Eastern Ontario stored at Tweed.

I then sent an email to a contact at the Geological Survey of Canada/Natural Resources Canada  and was told that they didn’t have the core or Liberty’s notes. 

Next I sent an email to the District Geologist at the Ontario Geological Survey  in Tweed and was told they didn’t have the core.

Partly in desperation, I sent emails to two geologists (both retired, but still active) that I knew had worked for Energy Mines and Resources or the Geological Survey of Canada at the same time as Liberty.  The first, a geophysicist, replied that he had no idea where the core would be, that  after the  GSC,  Bruce Liberty was at Brock University and  Guelph,  that I might look there for his records, but that many records had been tossed out on various reorganizations.   The second, a geologist, also had no knowledge of the core, but noted “Instead of older Paleozoic, perhaps it is an unrecognized unit of post-Grenville Proterozoic strata, or maybe a thick patch of regolith developed on Grenville? I've seen shale-like regolith of unknown thickness below Potsdam SS elsewhere.”

I also sent an email to Mark Badham,  the curator of the Miller Museum at Queen's, asking if he had any knowledge of the core.  He assumed that I was talking about three drill holes drilled by the Dominion Observatory at the Holleford Crater and sent me the following  paper by Brian St. John. 

Brian E. St. John, 1968
Paleolacustrine arenites in the Holleford meteorite Crater, Ontario.   Canadian Journal of Earth Sciences, 5, 935-943   www.nrcresearchpress.com/doi/pdf/10.1139/e68-090
   
Mark also told me that Queen’s has  select pieces of the core from the three drill holes, mostly from  the sediment layers in the crater. 

I'd forgotten how close the Holleford crater was to Knowlton Lake, but suspect that Brian St. John's work does not explain Liberty finding shale below the Potsdam.  Brian St. John comments on three holes drilled  within the boundary of the crater.  None of these intersected Potsdam sandstone.  The drill hole I'm looking for  would be outside the crater, but only a half mile due south of Diamond Drill Hole 3 on Brian St. John's Figure 1, and on the southwest shore of Knowlton Lake. 

Brian St. John reported that the Holleford Crater is filled by sedimentary rocks which he divided into seven lithic units.  The top two units, his Units 6 and 7,  he correlated with the Rideau formation and the Pamela formation that outcrop in Eastern Ontario.   He  included a basal “explosion breccia” which he designated unit 1, overlain by unit 2, a thin breccia layer, both related to the meteor impact.   His units 3, 4 and 5 are:

Unit 3: calcareous shales and argillaceous limestones and sandstones, which contain a small quantity of carbonaceous matter, “which imparts a black colour to most of the unit”,
Unit 4: gray calcareous quartz arenite, and
Unit 5: white calcareous quartz arenite.   

It is only St. John’s unit 3 that sounds remotely like Liberty’s “ 81 feet of dark grey Paleozoic shale.”   While I suspect that St. John’s unit 3 is not Liberty’s shale, if Liberty’s shale is the same shale that St. John reported then it answers a question St. John posed in his paper as to  whether the crater is pre-Potsdam or post-Potsdam.
   
I was subsequently contacted by my source at the GSC/NRC.  She had done some more sleuthing and  told me that “The core might be stored at our Tunney’s Pasture collections facility but I’m afraid that the collections are closed for the next many months as we are moving out of the building.  If [another person at the GSC/NRC] is not able to help out with information, I’m afraid you will have to wait until the collection is reopened in 2018.  There is no one from collections who can look this up at this time.”   Accordingly, it appears that my search will be placed on hold until 2018.

In 2018 it will be interesting to see if the core stored at Tunney’s Pasture is the core from the three holes drilled within the Holleford Crater, or from the hole I’m looking for that was drilled at the edge of Knowlton Lake.  If the core can be located, is Liberty’s “dark grey Paleozoic shale” actually Paleozoic shale, or is it  Precambrian shale or  Precambrian regolith?  If it is shale, does it correlate with the shale within the Holleford Crater?  If it is a new formation that is older than the Potsdam what secrets will it yield? 

What is interesting about Liberty’s report from 1971 is how much has changed.   In 1971 when Liberty logged 81 feet of dark grey Paleozoic shale he did so before geologists recognized the  Ediacaran/Vendian period, before geologists were interested in Ediacaran/Vendian fossils, and  before geologists were interested in small shelly fossils.  What prompted Liberty  to identify the core as being Paleozoic shale?  Did he see find small shelled fossils?

The core in the possession of Queen’s, particularly the carbonaceous material, might also be worth a fresh look with modern techniques.   In 1968 when Brian St. John looked at the sedimentary rocks in the Holleford crater he did so before the Queen’s Geology Department had a scanning electron microscope.   I can remember using the electron microscope in the Geology Department at Queen’s.   I had to modify the software every time I went on the machine, and then had to take my results over to campus mainframe computer to get the results of my analysis.  Today when results are available instantaneously, it would be a shame not to re-analyze St. John’s core.

Christopher Brett
Perth, Ontario

Below is an extract from Liberty's map 17-1970.  On the map I’ve used red squares to show the locations of the three Dominion Observatory drill holes within the Holleford meteorite crater that were described by Brian St. John.  I’ve shown in acquamarine where Potsdam sandstone outcrops at the southwest corner of Knowlton Lake, and where I believe Dr. Bruce A. Liberty reported the Dominion Observatory drill hole where he logged “ 81 feet of dark grey Paleozoic shale” at the base of the Potsdam.  Liberty's Unit 1 is Precambrian; Unit 2, Potsdam Formation; Unit 3, Shadow Lake Formation; Unit 4, Gull River Formation, Member A; Unit 5, Gull River Formation, Member B.

Frothed Sandstone and Cylindrical Structures Found in Potsdam Sandstone

If you  love coffee and in the past decade have visited Perth, Ontario you have undoubtedly stopped at Coutts Coffee at Code’s Mill (corner of Herriott and Wilson Streets).  Coutts Coffee roasts their own coffee beans and consistently provides an excellent cup of coffee.   I’ve particularly liked going for coffee because two types of Potsdam sandstone were used in the construction of Code’s Mill, and in the construction of  Mr. Code’s house which is to be found directly across Herriott Street from Code’s Mill, and on my walk over I pass the Royal Bank building which is also made of Potsdam sandstone.   “Perth stone”, a distinctive purple-banded sandstone from the Hughes Quarry in Lanark County, was used as an accent stone in the construction of all three buildings.   (See my blog posting from Monday, December 17, 2012 for a description of the Hughes Quarry.)   There are also interesting structures in the March/Theresa flagstones used as the floor of the atrium at Code’s Mill.  It is worth the price of a cup of coffee just to admire the various stones.

This summer Coutts Coffee opened a new location on Gore Street East in Perth beside the Tay River.  It will be closing the outlet in Code’s Mill in December.   Code’s Mill incorporates five buildings built from 1842 and 1932, with the three-storey building facing onto Herriott Street having been built in 1903.   Interestingly, the new location is also in an historic building made of Potsdam sandstone.  It was constructed about 1845 for the then Sheriff of Bathurst District (the predecessor of Lanark County).

At the new location it is a stone that was used in the construction of an original fireplace that will be of most interest to geologists.  Below are two photos of that stone.

The photos show what I believe to be cross-sections of cylindrical structures and frothed sandstone (under the ruler).   I believe that the frothed sandstone was injected/frothed by water flowing through the sandstone.   The stone is clearer than the photos and is worth a look, as you sip your coffee.

An Occurrence 4.5 kilometers south of Elgin (2 miles north of Brier Hill)

In my blog posting from  August 27, 2015 I mentioned an occurrence 4.5 kilometers south of Elgin that shows numerous cylindrical structures and provided photographs of a number of small structures from that location.   Subsequently I determined that this location was first mentioned by Dr. Wynne-Edwards (1967, GSC Memoir 346, at page 120):

“Vertical cylindrical concretions resembling tree trunks, the best examples of which are exposed in a 30-foot cliff beside the road west of Lower Beverley Lake 2 miles north of Brier Hill, occur in the lower parts of the formation and cut across the bedding. Most of the concretions there taper out downward and are about a foot in diameter, but the mould of a much larger one was left in the cliff face as a cylindrical indentation more than 6 feet wide. Hawley and Hart (1934) attributed these concretions to the upward flow of water and the consequent development of tubular bodies of quicksand that disrupted the bedding in the as yet unconsolidated sand.”

This is the same occurrence that  I described, because 4.5 kilometers south of Elgin is  2 miles north of Brier Hill.

I revisited the occurrence last August with Dr. Donaldson and took the following pictures:

In the first photograph the angular holes that have weathered out of the sandstone could represent casts of gypsum.  The photo could also show multiple stages of dewatering, as the smaller cylinder cuts into the larger cylinder.  The last two photos are interesting because they show frothed sandstone and conglomerate around the edges of the cylinder.   The conglomerate is not present in the rock surrounding the cylinders and  must have been pushed up from below or pulled down from above  (there is a conglomerate a little higher in the stratigraphic column).

The Elgin/Brier Hill occurrence is worth a visit as there are over 200 small structures with a diameter 2 to 6 inches, a number a foot in diameter, plus a number as big or bigger than those at the Hughes quarry in Pittsburgh Township near Kingston Mills.   I have to admit that I have not yet seen the largest ones: Dr. Dave Forsyth was good enough to send me a photo of them. 

The number of cylindrical structures at the Elgin/Brier Hill occurrence rivals the number of cylindrical structures found at Victoria Island and described in the following paper: 
Mathieu, J., Turner, E.C., and Rainbird, R. H., 2013
Sedimentary architecture of a deeply karsted Precambrian-Cambrian unconformity, Victoria Island, Northwest Territories; Geological Survey of Canada, Current Research 2013-1, 15 p.
  

Cylindrical Structures and Sand Injectites

      
I’ve noted that cylindrical structures in Potsdam sandstone have features in common with sandstone injectites that  form by the flow of a mobilized sand slurry through fractures in
overlying rock.   Interestingly, most sedimentary injectite systems are explained by elevated pore fluid pressure combined with a catastrophic triggering mechanism, likely seismic shaking.  An article that I found helpful is:

Sherry, T. J., C. D. Rowe, J. D. Kirkpatrick, and E. E. Brodsky (2012), Emplacement and dewatering of the world’s largest exposed sand injectite complex, Geochemistry Geophysics  Geosystems, Volume 13, No. 1, 17 pages,  Q08008, doi:10.1029/2012GC004157.  

The article is worth reading because their figured laminae look like the bands that we in Eastern Ontario see in our cylindrical structures, and the authors provide a compelling explanation for the formation of the laminae.

Sherry, Rowe, Kirkpatrick, and  Brodsky  report that the injectite complex in California contains granular textures that record processes of sand slurry flow, multiple pore fluids, and dewatering after emplacement.    They suggest that compaction of the injectite deposit and pore fluid escape caused spaced compaction bands and dewatering pipes which created  laminae.   They describe alternating 6 mm thick laminae of iron oxide-cemented and uncemented sand and mention that the laminae are always locally parallel and consistent in thickness.    They suggest that during sand emplacement, the system must have transitioned from a flowing to geometrically locked grain geometry.  They suggest that iron oxide, precipitated from fresh pore water at a later stage, is preferentially concentrated in alternating laminae, that iron oxide cement occurs in the laminae with slightly higher apparent aspect ratio (consistent with stronger shape lineation). They suggest this reflects a difference in the permeability of the laminae, caused by and preserved from the initial orientation of the sand grains, that affected late stage groundwater flow.   

It would be an interesting exercise to look as closely at the orientation of the sand grains, and cement in Eastern Ontario’s cylindrical sandstone structures, as Sherry, Rowe, Kirkpatrick, and  Brodsky looked at the orientation of grains and cement in the sand injectite complex that they studied.


I’ve previously written about cylindrical structures and below  provide the dates and titles of my blog posts.

Christopher Brett
Perth, Ontario


January 29, 2014  - Cylindrical Structures in Potsdam Group Sandstone in Eastern Ontario
August 27, 2015 - Cylindrical Structures in Potsdam Group Sandstone in Eastern Ontario - Part 2
September 28,  2015 - A Map Showing the Location of Cylindrical and Conical Structures in Potsdam (Group) Sandstone of Ontario and New York
October 22, 2015  - Soft-Sediment Deformation (Seismites) in Nepean Sandstone Close to the Rideau Lake Fault - Cylindrical structures in Sandstone: A Type of Soft-Sediment Deformation Sometimes Linked to Seismic Activity
December 23,  2015 Dewatering Structures, Biofilm Structures, Glacial Striae and Chatter Marks in Potsdam Sandstone near Newboro, Eastern Ontario

Mark your calendars for a Guided Quarry Tour on September 10, 2016 - Second Notice

Below is an advertisement from the September 1st edition of the Perth Courier for the tour of OMYA’s Tatlock quarry on September 10th from 10 am to 2pm, rain or shine.  

As noted in my July 5th blog posting, the Tatlock quarry is located about 30 km north of Perth up Highway 511, turning right on McIlraith Road.  There is more than ample parking available in the fields opposite the quarry entrance.

Christopher Brett
Perth