Tuesday 29 December 2015

More Evidence of Microbial Mats in Potsdam Sandstone near Newboro, Eastern Ontario

Winter has arrived in Eastern Ontario.  Eight centimeters of snow fell last night and more is forecast for today.   I’m glad that on December 26th I took the opportunity offered by the absence of snow  to revisit the area around Newboro and to look at outcrops near Westport.  I’d wanted to check for glacial meltwater eroded outcrops (and found some) and wanted to look again for further evidence of microbial mats.  Below I report on three outcrops  near Newboro.   The first two outcrops are mapped as Potsdam Group sandstone.  All of the outcrops are about  four kilometers south of the Rideau Lakes Fault. 

The silver ruler in the following photographs is one meter (39 inches long).  The blue ruler is 12 inches (30 cm) long.

First: An Outcrop Revisited


This is one of the outcrops from my last blog posting, the one mentioned under the subheading
‘Biofilm Structures’ where I provided  two photographs showing  a bedding parallel view of distorted laminations in quartz sandstone.    Below are photographs of additional distorted sandstone laminations visible at this outcrop.  The structures are difficult to envisage in sandstone unless the beds were bound by microbial mats.   The first photograph  may show a mat roll up structure.


Second:  Distorted Layers in Flat Lying Beds of Potsdam Sandstone


Below are photographs showing a distorted bed that is up to about 12 inches (30 cm) thick contained  within a sequence of flat lying beds of sandstone.




This distorted bed contains broken,  folded and crinkled layers, plus layers that appear to have been thrust over or under other layers.    I believe that this distorted bed represents pre-lithification  distortion of  biomats and stromatolitic layers in the sandstone, probably caused by seismic activity along the Rideau Lakes Fault.    Seismic activity caused rupturing and folding of the unconsolidated sediment, but the biofilms preserved the laminations in the strata. 

The mechanism that I have proposed to account for the  30 cm wide distorted bed near Newboro is analogous to the model proposed by Donaldson and Chiarenzelli (2004) to account  for the meter thick convoluted layer in the Nepean sandstone outcrops in Kanata, Ontario, photographs of which were included in my  November 4,  2015 blog posting.    Both outcrops display soft-sediment deformation   in  sandstone, where seismic activity is the likely cause of the deformation.  
   

Third:  A Badly Weathered Outcrop



I’ve included this outcrop because it has weathered in such a manner that it looks like the outcrop in Kanata, in a field off the Old Quarry Trail, photographs of which were included in my  November 4,  2015 blog posting.   It is missing the convoluted folds shown at the outcrop in Kanata, but otherwise the pattern of weathering is the same.  Both the outcrop in Kanata and this outcrop show repetitive, weathered out, thin layers in sandstone.   Below are photographs of the side view and the top view of the outcrop near Newboro.



I did not have my rock pick or sledgehammer with me on the 26th, but pulled a piece off the third outcrop, took it home, and cracked it with a small sledge.  It’s sandstone, badly weathered sandstone, but sandstone.

Christopher Brett
Perth, Ontario
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Addendum (January 5, 2016):         

In the comment below Howard Allen of Calgary has suggested that the second outcrop may represent evaporite accumulation, subsequent solution and collapse.  Others have reported on evaporites in Potsdam sandstone, and have suggested that they are responsible for observed structures in the sandstone. 

Wolf and Dalrymple (1984) mention that “At one locality near Phillipsville, a zone of disrupted laminae caps the burrowed beds.  The nature of the laminae suggests collapse into small cavities. .... The disrupted laminae which cap the cycle at the Phillipsville locality may represent the collapse of overlying sand into cavities formed by the dissolution of evaporites, such as gypsum or halite (B.W. Selleck, Colgate University, personal communication, 1983).” 

Wolf and Dalrymple (1985) mention that “the tops of cycles are disrupted by soft-sediment deformation, due either to the leaching of evaporites or to (earthquake induced?) liquifaction. ....Evaporite moulds in one outcrop of this facies near Gananoque... give evidence of elevated salinities, a finding that is compatible with an evaporite-solution origin of the soft-sediment deformation features.”

Donaldson and Hilowle (2002) report for an outcrop of quartz arenites of the Nepean Formation in Kanata that they observed “evaporite pseudomorphs, including silica-replaced rosettes of barite and/or gypsum” and “a distinctive unit of synsedimentary breccia inferred to have formed in response to dissolution of a layer of bedded evaporites”.

Donaldson and Chiarenzelli (2004) suggest,  for one of the outcrops of Potsdam sandstone (Nepean Formation)  at Kanata, that “a few beds that stand out as glassy markers display abrupt truncations (Figure 6), suggesting that they may have been penecontemporaneously cemented, and then locally disrupted by erosional undercutting of unconsolidated substrate, localized upwards pressure associated with dewatering, or dissolution of intercalated evaporites.”    

Sanford and Arnott (2010) reported that the  “Imperial Oil Ltd., Laggan No.1 borehole encountered numerous gypsum interbeds throughout the upper half of the Nepean Formation.”  In addition they noted that “Fairly extensive brecciation in the GSC Lebreton No.1 borehole, and to a lesser extent in the GSC Russell No.1 borehole, might also suggest the initial presence of minor halite in those areas, with subsequent dissolution and collapse.”  Further, “The widespread paucity of normal marine fossils, except for local occurrences of trace fossils, represents evidence of elevated salinity throughout the Ottawa embayment.   The occurrence of stromatolites, which can survive and even thrive in hypersaline conditions, is also a good indicator of evaporitic conditions.”

(Added: September 28, 2016)
David Lowe (2015, 2016), in his work on the Potsdam strata has recognized six siliciclastic paleoenvironments: (a) braided fluvial, (b) ephemeral fluvial, (c) aeolian erg, (d) coastal sabkha, (e) tide-dominated marine and (f) open-coast tidal flat.   Wikipedia mentions that “Sabkhas are supratidal, forming along arid coastlines and are characterized by evaporite-carbonate deposits with some siliciclastics. Sabkhas form subaerial, prograding and shoaling-upward sequences .”   The sabkha facies of the Potsdam Group are found in sandstone that  in Ontario we call the Nepean Formation, in Quebec they  call the Cairnside and in New York State they call the Keeseville.

Wednesday 23 December 2015

Dewatering Structures, Biofilm Structures, Glacial Striae and Chatter Marks in Potsdam Sandstone near Newboro, Eastern Ontario

It has been a remarkably warm December for Eastern Ontario and we have yet to receive anything more than a light dusting of snow.  Yesterday, December 22nd, it was 8 degrees Celsius (46 degrees Fahrenheit), and  I couldn’t help but take the morning off work to do some Christmas shopping and to look at some outcrops. 

Below are photographs that I took yesterday of glacially polished  outcrops of Potsdam Sandstone a few kilometers north of Newboro, Ontario.    The sandstone has most recently been mapped as the Nepean Formation of the Potsdam Group by the Ontario Geological Survey and as the Covey Hill Formation of the Potsdam Group by the Geological Survey of Canada.

Dewatering Structures

The first three photographs show parts of three outcrops that are within about 270 feet (80 meters) of each other.  The first and the second photos show excellent examples of small dewatering structures.  The third photo is less convincing, but likely shows small dewatering structures.

     
In the second photo it is not clear what has weathered out of the surface layer to produce the pockmarked surface.   Many of the holes are rounded or peanut shaped.  One possible interpretation is that they represent gas bubbles trapped below a biomat.   Below are three more photographs of the pockmarked surface.   It appears that many of the bubbles have merged into chains or patches, resulting in  structure analogous to Kinneyia.


Biofilm Structures

The next two photographs provide a bedding parallel view of distorted laminations in quartz sandstone.  I believe the laminations to be biofilm structures in the quartz sandstone (rather than a distorted dewatering structure), where interlayered microbial mats provided cohesion during deformation.

It is possible that these distorted laminations are seismites.  The outcrops are about four kilometers south of the Rideau Lakes Fault and about the same distance from the soft-sediment deformation structures (seismites) mentioned in my October 22,  2015 blog posting.

Glacial Striae and Chatter Marks

Glacial striae and chatter marks were present on the surfaces of a number of the outcrops that I looked at.   In addition a few of the outcrops show prominent noses pointing in the same direction as the striae and chatter marks.   The next two photos provide examples of the glacial striae and chatter marks.


Possible Sandstone Dikes in Sandstone (or a Torn Microbial Mat)


Christopher Brett
Perth, Ontario       

Tuesday 15 December 2015

Problematic Markings (Dubious Fossils) in Potsdam Sandstone

Below are two photographs that I took over two years ago of one side of a loose slab of Potsdam sandstone that I noticed at the quarry at Ellisville in Eastern Ontario.    The photographed side has a yellow coating that is probably Limonite.   All other sides of the slab are the pink and beige colours of the Covey Hill formation sandstone, Potsdam Group that is found in this quarry. 





Questions that have puzzled me for the last few years include: Are the raised forms fossils?  If the raised forms are fossils, are they body fossils or trace fossils?  and  If the raised forms aren’t fossils, how were they formed?   I’ve not found a convincing answer to any of those questions. My initial impression was that the raised forms were dubious fossils (markings possibly not of biogenic origin), and that is still how I would classify them.

Interestingly, I’ve found some photographs of somewhat similar problematic forms in two papers authored or co-authored by the late Dr. Hans Hofmann in rocks reported to be of Ediacaran age.  See:

Hofmann, H.J., 1988,  Synopsis of Precambrian Fossil Occurrences in North America, Chapter 4 in Geology of the Precambrian Superior and Grenville Provinces and  Precambrian Fossils in North America, (Co-ord.)  S. B. Lucas and M. R. St-Onge, Geological Survey of Canada, Geology of Canada, No. 7, p. 271-376, Plate 2E at pages 302-303.

Hofmann, H.J., Mountjoy, E.W. and Teitz, M.W., 1991
Ediacaran fossils and dubiofossils, Miette Group of Mount Fitzwilliam area, British Columbia; Canadian Journal of Earth Sciences, v. 28(10), p. 1541-1552, Plates 8C, 8D,  8E, 8F, 8J.
www.nrcresearchpress.com/doi/abs/10.1139/e91-138

Below I’ve provided Plate 2E from Hofmann (1988) which was originally plate 8F in Hofmann, Mountjoy and Teitz (1991).   The scale bar is 1 cm.




Below I’ve  provided Plates 8C, 8D,  8E and 8J from  Hofmann, Mountjoy and Teitz (1991).



Copyright in the photographs shown in the Plates belongs to National Research Council of Canada and Canadian Science Publishing. They  are reproduced under license from NRC Research Press.

Hofmann, Mountjoy and Teitz (1991) found and reported on a number of disc and elliptical shaped fossils (including Charnodiscus and Nimbia) that are worth reading their article to look at (but don’t resemble anything that I found), a vermiform structure that they equated with Zolotytsia, and seven types of dubiofossils which they classified alphabetically under the headings from Dubiofossil A to Dubiofossil G.

Hofmann, Mountjoy and Teitz (1991)  describe plate 8F as showing “Two partly overlapping vermiform markings.... The two specimens juxtaposed in such a way as to give the impression of being wound around each other ... or lying contiguous side-by-side for at least half their lengths.”   They  mention that “The markings appear to [be] those of some limp, soft-bodied cylindrical organism, or part of an organism, rather than a trace fossil. ... Structures of comparable physical consistency appear to be the much more regular spiraliform fossil Zolotytsia of Fedonkin (1985) and the Cylindrichnus of Glaessner (1969).

Plates 8C and 8D show two specimens which were discussed under the heading Dubiofossil C and were described as a tapering  “rectilinear frond-like structure” with rounded end, which they noted “resemble an unnamed frond-like impression from the Ediacaran... [and] also are like the proximal portions of the stems of Charnodiscus oppositus ... and may represent the stalk of similar organisms.” 

Plates 8E and 8J they assigned to Dubiofossil D and described as a “Cleavage reliefs of short, undulating furrow and corresponding ridges,... some portions having pinch-and-swell appearance.  Cross sections indistinctly round.”  They remarked that  the specimens “may be burrows comparable to Phanolites or Torrowangea.”
   
I’m not prepared to speculate as to whether the raised markings on the slab that I photographed could be body fossils or trace fossils, and if they are such, what they resemble.  All I can say is that the markings on the slab that I photographed are somewhat similar to and as problematic as the dubiofossils identified by Hofmann, Mountjoy and Teitz (1991). 

Second Specimen


Below are photographs of a loose specimen of Potsdam sandstone that I collected over about two years ago in Burgess Ward of Tay Valley Township, Lanark County from a waste pile resulting from the digging of drainage ditch along Stanley Road.   Both Nepean sandstone and Covey Hill sandstone of the Potsdam Group have been mapped in this area.  I believe the specimen to be Nepean sandstone as numerous other specimens from the same drainage ditch display U-shaped burrows. 


The circular, elliptical and spheroidal markings, which are composed of the same sandstone as the host, are problematic.   Are they concretions? Trace fossils? 

Christopher Brett
Perth, Ontario

Wednesday 4 November 2015

In 1924 a report of Stromatolites in Nepean Sandstone by Dr. Morley E. Wilson of the Geological Survey of Canada, and Other Reports of Stromatolites and Biofilms in the Potsdam

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


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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.

Monday 26 October 2015

A Good Year to Look at the Stromatolites along the Ottawa River - Part 2, near Dunrobin

The water level of the Ottawa River is still low.  As a consequence outcrops that form the river bed are visible and accessible.   Below are photographs that I took a few days ago of the domal stromatolites that outcrop in the bed of the Ottawa River near Dunrobin, just downstream from the  Port of Call Marina.







The blue ruler in the photos is 12 inches (30 cm) long.

A map showing the location of the marina can be found at Port of Call Marina’s web site:  www.portofcall.ca

Christopher Brett
Perth, Ontario

Thursday 22 October 2015

Soft-Sediment Deformation (Seismites) in Nepean Sandstone Close to the Rideau Lake Fault

Soft-sediment deformation structures are deformations that occur in sediments that have not undergone lithification before the deformation structures form.  They are the result of liquefaction or fluidization in water-saturated unconsolidated sediments.  Liquefaction or fluidization may be caused by various  processes.  Soft-sediment deformation structures related to seismically induced liquefaction or fluidization are named seismites.

Below are photographs that I took over two years ago of an outcrop of Nepean sandstone that I found in June, 2013  that is less than a kilometer southwest of the lock at The Narrows on the Rideau Canal.






The pen in the first photo is about 15 cm long.

The photographs show deformed beds of Nepean Sandstone that occur above flat lying beds of sandstone and below flat lying beds of sandstone.   These deformed beds are also less than a kilometer south of the Rideau Lakes Fault that was identified by Wynne-Edwards (1967).  I believe the deformed beds in the Nepean sandstone to be seismites that could have resulted from movement along the Rideau Lakes Fault, which suggests that the fault was active in the Cambrian.    Below is an extract from Wynne-Edwards’ map of the Westport area showing the location of the outcrop that I photographed in relation to the Rideau Lakes Fault.




Wynne-Edwards (1967) identified the Rideau Lakes Fault as a major structural feature at least 100 miles (160 kilometers) long.  He mentions that “there is abundant evidence that the shear zone represents a Precambrian wrench fault of major proportions. ... Although post-Ordovician movement can be demonstrated in several places, evidence that the Rideau Lakes fault originated before the deposition of these sediments in abundant.”   As evidence of Precambrian movement he mentions that “On Turnip Island in Rideau Lake, a shear zone 10 feet wide is in the Precambrian rocks beneath the basal Cambro-Ordovician conglomerate, and consists of a soft mass of serpentine and talc separating a sheared quartzo-feldspathic rock from shattered crystalline limestone.”  As evidence of post-Ordovician movement he mentions that “At Narrows Lock, the fault separates Ordovician limestone from Precambrian monzonite, and is marked by a linear gully containing boulders of brecciated limestone.”  As noted above, I believe that the deformed beds that I photographed provide evidence that the fault was also active in the Cambrian (the accepted age of the Nepean formation sandstones) .

A recent paper by Hilbert-Wolf,  Simpson, Simpson, Tindall and Wizevichz (2009) summarized
criteria that permit the interpretation of soft-sediment deformation initiated by seismic activity.  They mention that:

“Generally accepted seismite criteria include: (1) a clear association with potential originating faults, (2) observed deformation that is consistent with seismic origin, (3) a widespread occurrence that is temporally constrained, (4) systematic change in intensity or increase in frequency towards possible epicentre, (5) exclusion of other causal mechanisms, (6) recurrence of deformed horizons over time, (7) underlain and overlain by undisturbed horizons, and (8) faults associated with wedges of interclastic breccias, conglomerates, or massive sandstones. The more criteria that are satisfied the greater the likelihood features are of seismic origin.  In addition, soft-sediment deformation should cross-cut regional and local facies boundaries.”
[Citations Omitted]   

The outcrop that I’ve found meets their first, second, and seventh criteria.


Disruption of Stromatolite Zones in Nepean Sandstone By Seismic Activity


Others have proposed that seismic activity has caused soft-sediment deformation in the Nepean formation sandstone.  In my last posting, on Stromatolites, I mentioned a field trip guide by Donaldson and Chiarenzelli (2004).    For two of their stops they proposed that seismic activity had caused deformation in a stromatolite unit in Nepean sandstone.  Their Stop 7 was at an outcrop of Nepean Formation quartz arenite that displayed cross-sections of random tilted,  laminated, domal stromatolites.  They 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.”
 

Cylindrical structures in Sandstone: A Type of Soft-Sediment Deformation Sometimes Linked to Seismic Activity


A number of my recent postings have been on cylindrical structures in Potsdam Group sandstones.   These cylindrical structures are a type of soft-sediment deformation.    The generally accepted view is that these are dewatering structures resulting from springs.  The leading paper is by Hawley and Hart (1934), who proposed that the cylindrical structures were formed “by circulating waters at some time following the deposition of the sandstone. .. [T]hat following, or throughout, the period of deposition of the sandstone, possibly while it was still submerged, there appeared on top of the sands a series of springs, fed by columns of water rising from an unexposed horizon, such as the basal conglomerate or the underlying pre-Cambrian rocks.   The nature of the adjacent landmass and the structure of the basement rocks... must have controlled the locus of the springs, their rate of flow, and the hydrostatic head.”

Recently Dave Forsyth (2011), when discussing the Cambrian cylindrical structures found in Potsdam (Group) sandstones of southeastern Ontario and northern New York wrote that “The structures are considered to represent the result of vertically upward water flow originating near or at the Grenville basement to produce spring-like conduits of fluidized sand. ... [T]he combination of fluctuating water table, basement relief on the order of 100 meters and well sorted mainly medium to coarse grained quartz grains, enabled the formation of conduit structures of fluidized sand.  The apparent lack of an aquifer cap suggests conduit formation resulted from an unconfined, water table aquifer as opposed to being artesian. ... Changing water table conditions produced a variable internal conduit structure featuring truncated earlier structures and internal concentric annular rings. ”

Intriguingly, many recent papers on cylindrical and conical structures found in sandstone (that is not Potsdam Group sandstone) debate whether the cylindrical and conical structures formed as a result of seismic shock.   For example, see Mathieu, Turner, and Rainbird (2013), who provide a recent review of the issue,  note that the “means by which these cylinders developed is controversial, particularly with respect to the mechanism of fluidization.” and mention that in some studies sediment liquification “was attributed to a seismic event.”   They also note that “It could be argued that multiple seismic events could account for the pulsing flow or the cross-cutting relationships between cylinders.”   However, for their cylinders in Cambrian sandstones on Victoria Island in the Northwest Territories, they reject a seismic trigger and conclude that “the pillar-like structures are attributed to water escape through submarine springs, where groundwater flowing through the karst network emerged onto the Cambrian seafloor.” 

The only publication that I’ve found that suggests that the cylindrical and conical structures in the Potsdam Group sandstones of the Ottawa Embayment may have resulted from seismic activity was by Shrock (1948), who raised the possibility that the cylindrical structures from the Cambrian sandstones found near Kingston may have been formed as a result of seismic shock, but acknowledged that “in reply to a query from the author, Dr. Hawley wrote that he had found no evidence to support” this theory.   Would the answer be different today when geologists are aware that the faults along the St. Lawrence River and along the Ottawa River have been active since the Pre-Cambrian, when seismites have been found in the Nepean Formation close to the Rideau Fault that has been active since the Pre-Cambrian, and when soft-sediment deformation of a stromatolite bed in the Nepean Formation resulted from seismic disturbance?

One feature that may (or may not) lend support to the suggestion that seismic activity initiated  the fluidization that led to the formation of the cylindrical structures is the presence of large numbers of spheroidal concretions in association with a number of the cylindrical columns.  For example,

(A)  Anglin, Boyle and James (1888), which was the first published  report on Canadian cylindrical columns in Potsdam sandstone, mention specimens from the Gildersleeve’s Cataraqui Stone Quarries ten miles from Kingston, and report that Dr. A. R. C. Selwyn, Director of the Geological Survey of Canada “is of opinion that in all probability the columns have been formed by the filling up of what were geyser tubes, or passages for the emission of hot water from some ancient gushing wells like those of Iceland. In association with the columns are found large numbers of roughly spheroidal nodules, or concretionary bodies, also of sandstone, measuring from one to five or six inches in diameter, which to the unscientific mind suggest an idea of fossilized fruit.  It is noticeable that in every case these are marked by an encircling groove.” 

(B)  Franklin Hough (1853), mentions the cylindrical structures in the sandstones at Rossie, New York  and comments “In some places the rock is made up of balls, having a concentric structure like the coats of an onion ... In the vicinity of the iron mines at Rossie, this spheroidal structure is very common and makes up the whole of the rock.  They are of all sizes, from a pen to an orange”

I make the suggestion that the presence of spheroidal concretions might lend support to seismic activity being related to the formation of the cylindrical structures, as there are reports where seismic activity has resulted in soft-sediment deformation structures in the form of balls and pseudo-nodules (for example, Bowman,  Korjenkov, and Porat,  2004).  While I concede that concretions are associated with hot springs and with mineral springs, there is at least one report of “ball-and-pillow” structures in Potsdam sandstones: 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 ball-and-pillow structures at three horizons and mention in their report that ball-and-pillow structures “are locally well developed” in the Upper Unit of the Cairnside.  

Christopher Brett
Perth, Ontario

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References:

Anglin, T. W., Boyle, D., and James, C.C., 1888
Mineral Exhibit of the Province of Ontario, Descriptive Catalogue, Centennial Exposition of the Ohio and Central States; Cincinnati, July 4 to October 27, 1888, 64 pages  at page 34
https://books.google.ca/books?id=_MdCAQAAMAAJ

Bowman, D.,  Korjenkov, A. and Porat, N., 2004
Late-Pleistocene seismites from Lake Issyk-Kul, the Tien Shan range, Kyrghyzstan;
 Sedimentary Geology 163 (2004) 211–228
 http://activetectonics.la.asu.edu/N_tien_shan/Seismite.pdf

Donaldson, J. Allan  and Chiarenzelli, Jeffrey R., 2004
Stromatolites and Associated Biogenic Structures in Cambrian and Ordovician Strata in and Near Ottawa, Ontario; 76th Annual Meeting, Field Trip Guidebook, New York State Geological Association, 283 pages, at pages 1-20. 

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 page 66    www.mineralogicalassociation.ca/doc/Ottawa2011AbstractsVolume.pdf

Hawley, J. E. and Hart, R. C.,  1934
Cylindrical Structures in Sandstone;
 Bulletin of the Geological Society of America, Volume 45, pages 1017-1034

Hough, Franklin B., 1853
A History of St. Lawrence and Franklin Counties, New York, from the earliest period to the present time; Albany, Little & Co., 708 pages, at page 678.

Hilbert-Wolf, Hannah L.,  Simpson,  Edward L., Simpson, Wendy S., Tindall, Sarah E. and
Wizevichz, Michael C.,  2009,
Insights into syndepositional fault movement in a  foreland basin; trends in seismites of the Upper Cretaceous, Wahweap  Formation, Kaiparowits  Basin, Utah, USA;
Basin Research (2009)   doi: 10.1111/j.1365-2117.2009.00398.x
   
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.

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

Shrock, R.R., 1948
Sequence in Layered Rocks: A Study of Features and Structures Useful for Determining Top and Bottom Order of Succession in Bedded and Tabular Rock Bodies;
McGraw Hill, New York, 507 pages, at pages 136, 220 and 221

Wynne-Edwards, H.R.,  1967,
Map 1182A, Geology, Westport, Ontario; to accompany Memoir 346, Westport Map-Area, Ontario, With Special Emphasis on the Precambrian Rocks, Geological Survey of Canada.

Wynne-Edwards, H.R., 1967,
Westport Map-Area, Ontario, With Special Emphasis on the Precambrian Rocks;
Geological Survey of Canada,  Memoir 346, 146 pages
http://geoscan.nrcan.gc.ca/starweb/geoscan/servlet.starweb?path=geoscan/fulle.web&search1=R=100533


Thursday 1 October 2015

A Good Year to Look at the Stromatolites along the Ottawa River

We were blessed with a fairly dry summer in Eastern Ontario.  As a consequence  the Ottawa River is low and it is a very good year to look at the stromatolites that outcrop along the Ottawa River (which are best viewed when the Ottawa River is low).  The most frequently visited outcrop is likely the one that is in Quebec just across the Champlain Bridge from Ottawa.

Below are photographs that I took two weekends ago on my visit to look at the outcrop.




The outcrop is easy to locate.  Take the first left when you cross the Champlain Bridge, and look on your left for the Champlain Parking Lot about 150 meters from the stoplights.   Then walk about 50 meters back towards the bridge along the bike path.  The outcrop is the river bed.

A little over decade ago J. Allan Donaldson and Jeffrey R. Chiarenzelli provided the following description of the “closely packed domal stromatolites” visible at this outcrop, when describing ‘Stop 4. Stromatolites in Pamelia Formation (Ordovician)’:

“Mapping at 1:25 scale has revealed strong local north-south trends of elongation for the stromatolite heads.  In many places two or more are coalesced in parallel, strings oriented in the same (north-south) direction.   ...these trends are readily attributed to the action of tides and onshore-wind-driven waves .  Some small stromatolites are elongate perpendicular to the prominent north-south trend ...[which] is attributed to longshore currents.   ...  [A] hypersaline environment in which biofilm predators  could not survive is inferred.  This is supported by the observation that, whereas the underlying stromatolite-free beds of carbonate are fossiliferous (with gastropods and vermiform trace fossils particularly abundant), the stromatolite unit is free of megafossils.  Only conodonts have been observed, and those extracted from the stromatolite unit are compatible with a hypersaline environment...”
[Citations omitted]

J. Allan Donaldson and Jeffrey R. Chiarenzelli, 2004a,
Stromatolites and Associated Biogenic Structures in Cambrian and Ordovician Strata in and Near Ottawa, Ontario; 76th Annual Meeting, Field Trip Guidebook, New York State Geological Association, 283 pages, at pages 1-20. 

That field trip guidebook can be downloaded in pdf format from:
http://www.nysga-online.net/    Click on the tab “NYSGA Guidebook Archive”, select “2000s NYSGA Guidebooks” and then select 76th NYSGA 2004.pdf

If you download the guidebook be sure to also look at the following field trip:
J. Allan Donaldson and Jeffrey R. Chiarenzelli, 2004b,
Precambrian Basement and Cambrian-Ordovician Strata , as Displayed in Three Provincial Parks of Canada, 76th Annual Meeting, Field Trip Guidebook, New York State Geological Association, 283 pages, at pages 63-78.       Stop 1 is a visit to Fitzroy Provincial Park to look at the stromatolites while  Stop 3 is a visit to Almonte, Lanark County to look at the stromatolites.


If you are planning to visit  the Champlain Bridge stromatolites I’d recommend that you first visit the following web sites:       

1)    http://http-server.carleton.ca/~jadonald/fieldtrips.html
Ottawa-Gatineau Geological Field Trips, by Professor Allan Donaldson for a course at Carleton University.   This guide contains six stops, including the outcrop of Stromatolites on the Quebec side of the Champlain Bridge.  It includes a map showing the location of stromatolites in relation to the Champlain Bridge, together with two detailed maps of the stromatolites, that I assume is the mapping at 1:25 scale  referred to by Donaldson and Chiarenzelli, 2004a.  (Note that the Blvd. Champlain on Dr. Donaldson’s map is now Blvd. de Lucerne.)
           
2)  http://geo-outaouais.blogspot.ca/2009/11/colonie-de-stromatolites-gatineau.html
This blog posting contains some very good photographs of the outcrop.

3)  http://www.ottawagatineaugeoheritage.ca/subsites/4
This web page of the Ottawa Gatineau Geoheritage Project  is devoted to this outcrop.  


Geoheritage Day, Sunday, October 18, 2015


The Champlain Bridge Stromatolites  is one of the eight sites for Carleton University’s annual Geoheritage Day to be held on Sunday, October 18, 2015 from 10:00 a.m. - 3:00 p.m.  Volunteers from Carleton University’s Department of Earth Sciences and the Ottawa Gatineau Geoheritage Project will be on hand at each of the sites  to explain what there is to see and how each site fits into the local geological history.   I first visited this outcrop two years ago for Geoheritage Day and enjoyed Dr. Donaldson’s description and explanation.

Further details on the sites for this year's Geoheritage Day can be obtained at:

http://www.earthsci.carleton.ca/outreach/explore-geoheritage-day

Christopher Brett
Perth, Ontario

Monday 28 September 2015

A Map Showing the Location of Cylindrical and Conical Structures in Potsdam (Group) Sandstone of Ontario and New York



The locations in New York State are mainly based on Field Trip Guidebooks issued at Annual Meetings of the New York Geological Association.  The locations in Ontario have been mentioned in earlier blog postings.  There are a few additional reports of cylindrical and conical structures that are outside of the boundaries of the map.

Christopher Brett
Perth, Ontario

Tuesday 1 September 2015

Franklin B. Hough, M.D. (1822-1885), the First to Write on Cylindrical Structures in Potsdam Sandstone

This blog posting is written to right an historical wrong.  The wrong or slight that needs to be corrected is the failure to acknowledge that Franklin B. Hough, M.D., of Sommerville, New York was the first to write about cylindrical structures in sandstone.    In 1850 he authored two papers (the second of which was published a year after being presented) on the subject of cylindrical structures:
           
Hough, Franklin B., 1850,
Catalogue of Mineral and Geological Specimens, Received From  Franklin B. Hough, A.M., M. D., of Somerville, St. Lawrence County, N. Y;  Third  Annual Report of the Regents of the University on the Condition of the State Cabinet of Natural History and the Historical and Antiquarian Collection Annexed Thereto, Printed by order of the Assembly of the State of New York, pages 3-35. (“Report of the Regents”)

Hough, Franklin B., 1851,
On the Cylindrical Structure Observed in Potsdam Sandstone,  Proceedings of the American Association for the Advancement of Science, Volume 4, pages 352-354, Read by Prof. C. U. Shepard on Saturday, August 24, 1850 before the Section of Geology and Natural History   (“Proceedings of the American Association”)

Unfortunately those two papers have been ignored since they were last referred to in 1891  by Charles Doolittle Walcott in Correlation Papers Cambrian, Bulletin 91 of the United States Geological Survey.   Since Walcott credit for the first written report on cylindrical structures has usually been credited to the following paper:

Kavanagh, S.J., 1889. On Modern Concretions from the St. Lawrence; with Remarks by J.W. Dawson on Cylinders found in the Potsdam Sandstone. Canadian Record of Science, 3: 292-294
   
Walcott, in the text of Correlation Papers Cambrian, mentions three papers by Franklin Hough (the two mentioned above and a third on the geology of Lewis County, New York).  Walcott references the Report of the Regents for the following sentence: “In 1850 he called attention to cylindrical masses from 3 inches to 15 to 20 feet in diameter that occur in the Potsdam sandstone near Somerville, St. Lawrence County.”   Walcott references the Proceedings of the American Association as supporting the following sentences: “ ...later attention was again called by Mr. Hough to the cylindrical masses.  They are described as vertical cylinders from 2 inches to 20 feet and upward in diameter, and show a concentric structure.”
[Walcott, Charles Doolittle, 1891, Correlation Papers Cambrian, Bulletin No. 81, United States Geological Survey, 447 pages, 3 plates, at page 206]

Regrettably, papers by (A) Cushing et al. in 1910, despite reporting on cylindrical structures in upper New York state and covering an area where Franklin Hough reported numerous cylindrical structures, (B) Hawley and Hart in 1934, which provides a summary of cylindrical structures in Eastern Ontario and New York,  and (C)  Dietrich in 1953, despite reporting on cylindrical structures from a locality mentioned by Franklin Hough, all fail to reference  Franklin Hough’s above two papers and fail to refer to Correlation Papers Cambrian.   Hawley and Hart refer to Kavanagh’s paper, and  Dietrich compounds his omission by stating “Vertical cylindrical structures withing flat lying Upper Cambrian Potsdam sandstone... have attracted the attention of many geologists since their first description in the literature (Kavanagh, 1888-89).” 

[Cushing, H. P., Fairchild, H.L, Ruedemann, R. And Smyth, C.H. Jr. (1910), Geology of the Thousand Islands Region, New York State Museum Bulletin 145.

Hawley, J.E. and Hart, R.C., 1934, Cylindrical Structures in Sandstone, Bulletin of the Geological Survey of America, Volume 45, pages 1017-1034.

Dietrich, R.V. (1953), Conical and Cylindrical structures in the Potsdam Sandstone, Redwood, New York, New York State Museum Circular 34]

Not surprisingly, papers on cylindrical structures written since the ones by Cushing and Dietrich fail to note Franklin B. Hough’s much earlier contributions.    Recent papers invariably cite Dietrich (1953), Hawley and Hart ((1934),  Kavanagh (1888-1889) and the papers by Weston (1895), Weston (1899) , Dawson   (1890),  Ells (1905), Baker, (1913), Baker (1916) that were mentioned in my January 29, 2014 blog posting, but not Hough.    My August 27, 2015 blog posting may have been the first to cite one of Franklin B. Hough’s papers on cylindrical structures since before Cushing’s paper in 1910 and possibly as far back as Correlation Papers Cambrian that was published in 1891.

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Below I’ve provided the text of the important parts of the Dr. Hough’s first paper on Cylindrical Structures:

CATALOGUE OF  MINERAL AND GEOLOGICAL SPECIMENS, RECEIVED FROM
FRANKLIN B. HOUGH, A.M., M. D., OF SOMERVILLE, ST. LAWRENCE COUNTY, N. Y.


The following is Dr. Hough's description of the specimens:
....
17.  Potsdam sandstone, with spherical concretions. Vicinity of the Caledonia or old Parish iron mine, Rossie, St. Lawrence  county.
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29. Potsdam sandstone, (cylindrical structure.) Rossie, St. Lawrence county.

This curious structure is frequently observed in this section of the  country, and I do not recollect of having seen a satisfactory theory to account for its formation. These cylindrical masses are of all sizes, from three inches, to fifteen or twenty feet in diameter ; and their axes are always nearly, if not exactly vertical. At times, two or more encroach on each other.

The large circle represented in the following figure, is about twelve feet in diameter, at the locality in Somerville, and the whole is nearly of the same level. The concentric lines of stratification are sometimes obscure, but the cylindrical structure is always sufficiently apparent.
To no active agent can we attribute these interesting appearances with more plausibility, than that of water, revolving in the little vortices or eddies, and causing the sand, which is the principal constituent in the  rock, to be deposited in circular layers ; or entirely excavating a cylindrical cavity in the sand, before it had assumed the consistence of rock, and leaving it to be filled subsequently.

The following sketch is from the surface of the rock, in a field adjoining Somerville village.






The existence of smaller circular masses in the border of, or entirely within a larger one, without in the least interfering with the stratification of it, shows that the causes which produced them operated at distinct intervals of time, although their ages appear to be very nearly the same.

This must, upon the whole, be considered a very interesting problem
in Geology.  F. B. H.”    

The New York State Museum likely still has those specimens.  One of the museum’s web pages gives a partial summary of collections, contents and dates of acquisition, and mentions:  “In 1851 and 1852 minerals and geological specimens from Mr. Franklin B. Hough were added to the collections. These were mostly specimens from St. Lawrence County.”
http://www.nysm.nysed.gov/research_collections/collections/geology/mineralcollect.html

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In his later paper entitled  On the Cylindrical Structure Observed in Potsdam Sandstone, Franklin B. Hough reports on vertical cylinders in Potsdam sandstone in Jefferson and St. Lawrence Counties, New York, with diameters from two inches to twenty feet and upward, where the concentric lines are more conspicuous in those from one to two feet in thickness; that it is frequently observed that the larger masses contain within them those of a smaller size, sometimes partly within and partly without; that cylinders a foot in diameter, five feet in length, have been observed without change in size or structure; that a conical figure is occasionally observed with the cone directed downwards; that the strata often exhibit ripple marks; that a spheroidal structure, seldom larger than an orange, with perfect concentric stratification, is often met.  He proposed that “the cylindrical masses above described may have had their origin in small eddies, or whirlpools, produced by local causes acting upon the surface of the water, and transmitted to the sand at the bottom.  The conical figure occasionally observed, and more especially the uniform direction of the vertex fo the cone, confirm the idea, while all the attendant appearances unite to prove that they were produced in shallow water.   ... When two are found occupying the same area, it is evident that they were formed at distinct, although not probably at distant, intervals of time.”

[Hough, Franklin B., 1851, On the Cylindrical Structure Observed in Potsdam Sandstone,  Proceedings of the American Association for the Advancement of Science, Volume 4, pages 352-354]   

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Franklin B. Hough’s Additional References to Cylindrical Structures in the Potsdam Sandstone



Franklin B. Hough was a prolific writer.   He included geological notes in his general publications.  For example in 1853 he published his A History of St. Lawrence and Franklin Counties, from the earliest period to the present time (Albany, Little & Co., 708 pages).  This included Chapter XI on Geology, Mineralogy and Meteorology, which at pages  678 and 679 included a reference to the cylindrical structures when discussing the Potsdam sandstone:

“But perhaps there is no structure, either of this or of any other rock, more worthy of study then the remarkable cylindrical stratification frequently observed at Rossie, Antwerp, Theresa, &c.  These cylinders are vertical, and of all diameters, from two inches up to twenty feet or more, and their section where exposed to the surface, shows them to be made of concentric strata of sand of different colors and degrees of fineness, firmly consolidated and capable of being detached, when they present to the casual observer the appearance of huge logs of wood, and has led to them being called “petrified logs.”   As the kind of rock in which they occur does not possess cleavage, it is seldom quarried, and opportunities have not been found to learn the depth to which they descend.  From what the author has seen, he infers that they are sometimes conical, and probably run out at no great depth.... The cylinders at times encroach upon each other, the last formed being perfect, while the older has its stratification interrupted by the other.   No rational theory has occurred to us by which this wonderful structure could be explained , than that they were formed by vortices or whirlpool playing upon the surface of water, and imparting their gyrating motions to the mobile sands of the bottom, which gave the circular arrangement notice, and which has become consolidated and remains.”

In 1854 he published A history of Jefferson County in the state of New York, from the earliest period to the present time (Watertown, N.Y., Sterling & Riddell, 633 pages)  This included Chapter XV on Geology, Mineralogy, which at page 531 references the cylindrical structures in the Potsdam:

“In the vicinity of Theresa, Redwood, &c., there occurs in numerous places in this rock , the cylindrical structures, common at many localities in St. Lawrence county, and apparently produced by eddies acting upon the sands at the bottom of shallow water.”

In 1860 he published  A history of Lewis County, in the state of New York, from the beginning of its settlement to the present time  (Albany : Munsell & Rowland, 1860, 319 pages).  While he includes a section entitled Topography and Geology, and reports on outcrops of Potsdam Sandstone, he does not report any cylindrical structures.
   
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Franklin Hough’s Early Interest in Minerals



Franklin Hough’s interest in mineralogy and geology began when he was fifteen years old.  Here is an extract from his reminiscences:

“During the summer of 1837 ... Mr. Bannister... had visited a mineral locality, at or near the Natural Bridge, in Jefferson County, and gave me directions how to reach it.   I started out on foot, on a journey which must have been not less than twenty-five miles....  I found an abundance and variety of minerals which quite astonished me.  Augite, tabular spar, cocolite, sphene, tourmaline in large black crystals, scapolite, blue calcite, crystals of feldspar, quartz crystals lining cavities in chalcedony and other varieties ...  I found myself loaded with forty or fifty pound of treasures which I walked back over the twenty-five mile that I came.”

[As quoted in an article entitled Franklin B. Hough, M.D., Ph.D.,  by David Murray, 1886,
Annual Report of the Regents of the University of the State of New York,  Volume 99, pages 300-347 at pages 303-304 ]       

Murray also mentions that “During the summer of 1839 [Franklin Hough]  took a trip down the Mohawk valley to Saratoga and back, spending much of his time in collecting minerals, in which he had become greatly interested....”


Franklin B. Hough’s Additional Papers on Geology



In addition to the above two papers on cylindrical structures, and his three general interest publications on counties in New York which contained chapters on geology and minerals,  Franklin B. Hough authored or co-authored at least nine additional papers on geology.  Here are the papers  that I’ve found:

Hough, Franklin B., 1847, Observations on the Geology of Lewis County, New York, Volume 5, Am. Journal Sci. And Agric., pages 267-274, 314-327

Hough, Franklin B., 1850, New Mineral Localities in New York.  Silliman, Journal IX, [The American Journal of Science and Arts] pp 288-289

Hough, Franklin B., 1851, New American localities of  Minerals .  The American Journal of Science and Arts, Second Series, Volume XII,  pp 395-396

Hough, Franklin B., 1850, On the existing  Mineral Localities of Lewis, Jefferson and St. Lawrence counties,  New York.  Silliman, Journal IX, [The American Journal of Science and Arts] pp 424-429

Hough, Franklin B., 1851, On the association of certain minerals  in Northern New York.  Amer. Assoc. Proc. pp 205-206

Hough, Franklin B., 1851,  List of  Mineral and Geological Specimens Received From  Franklin B. Hough, A.M., M. D., of Somerville, St. Lawrence County, N. Y;  Fourth Annual Report of the Regents of the University on the Condition of the State Cabinet of Natural History and the Historical and Antiquarian Collection Annexed Thereto, State of New York, pages 82-90.

Hough, Franklin B., 1852, On the existence of diluvial agencies during the earlier geological periods.  Proceeding of the American Association for the Advancement of Science, [Held at Albany, New York, August, 1851] pp 262-264

Hough, Franklin B., 1852, A report on the mines and lands of the St. Lawrence Mining Company. New York, Arthur & Burnet, 9 pages

Hough, Franklin B. And S. W. Johnson, 1850, On the discovery of Sulphuret of Nickel in Northern New York.  Silliman, Journal IX, [The American Journal of Science and Arts] pp 287-288

Almost all of those papers are available from  https://archive.org/   or http://www.biodiversitylibrary.org


Donation of Minerals and Fossils  to the Smithsonian



In addition to donating specimens to the New York State museum, Dr. F. B. Hough donated a box of minerals and fossils from St. Lawrence County, New York to the Smithsonian
[See: Baird, Spencer F.  1851,  List of Principal Accessions to the Museum of the Smithsonian Institution Made Prior to January 1, 1851, in Annual Report of the Secretary of the Smithsonian Institution for the years 1850, 1851, pp 41-50, as quoted in George Brown Goode, 1883,    Bulletin No. 20 of the United States National Museum. ]

Unfortunately, while the Smithsonian has an online search engine that allows one to search the collections, I could not locate the specimens donated by Dr. Hough.

In 1873 Dr. Hough  donated a box of ethnological specimens to the Smithsonian.
   

Houghite -- A Mineral Named After Franklin B. Hough



Franklin B. Hough discovered a mineral that is named after him, Houghite, a variety of Hydrotalcite that is derived from the alteration of spinel. [C. U. Shepard, 1851, An Account of several new Mineral Species, American Association for the Advancement of Science, Volume 4, pages 311-319 at pages 314-315]    See also: www.mindat.org/min-27354.html 


Franklin B. Hough’s Original Notebooks, Maps and  Papers on Geology


   
The New York State Library keeps a collection of 117 boxes of Franklin B. Hough's papers that were donated to the New York State Library by the Hough Family in 1915.   Included in the collection is “a notebook with nine maps entitled “Mineral Localities of Northern New York,” and oversize manuscript copy maps of Lot 611 in the village of Philadelphia, Jefferson County, and a map showing townships in Jefferson, Lewis, and Herkimer counties in New York State.”
This would be worth looking by those with an interest in  historical mineral localities.

[See Franklin Benjamin Hough Papers - New York State Library
 http://www.nysl.nysed.gov/msscfa/sc7009.htm   ]


Other Aspects of Franklin Hough’s Life



Franklin B. Hough, M.D., had an interesting life.  I would recommend reading David Murray’s article from 1886 and the summary in the Franklin Benjamin Hough Papers - New York State Library at: http://www.nysl.nysed.gov/msscfa/sc7009.htm   The following is but a brief summary.

Franklin B. Hough, M.D., (1822-1885) was trained as a medical doctor, but practiced as a medical doctor only briefly from 1848 to 1852 and from 1862 to 1864 when he served as a surgeon during the American Civil War.   He is remembered today for his writings on botany, as a writer on historical topics, as the person responsible for overseeing the New York State census for 1855, 1865 and 1870, and as the father of American forestry.    His work on the census of New York revealed the declining availability of timber and caused him to devote the latter part of his life to the preservation of forests.   He should also be credited as the first to write on cylindrical structures in sedimentary rocks and for his early work in identifying mineral collecting localities in New York State.
       
Interestingly, Franklin B. Hough’s real name was Benjamin Franklin Hough.   In an account of himself, furnished in 1860 to the New England Historic Genealogical Society, he states that he was “originally named Benjamin Franklin Hough, but having a cousin of the same name, he assumed in childhood the name as now written [i.e., Franklin B. Hough], to distinguish him from his cousin.  The B.” he adds, “is retained without attaching to it any particular significance, and it is invariably written with the initials only.”

 [from a review of A Bibliography of the Writings of Franklin Benjamin Hough, Ph.D., M.D, by John H. Hickox., that appeared in Volume 40, New England Historical and Genealogy Register, 1886, page 423]

Christopher Brett
Perth, Ontario