Friday 5 August 2016

What’s New in Potsdam Sandstone?

Actually, quite a lot.   For those with a keen interest in the Potsdam sandstone of Eastern Ontario, Quebec and Northern New York State, the following articles, abstracts and field trip guides are worth a look.  They are arranged from the most recent dating back to 2010.

The first article is instructive, as it explains how to recognize the differences between braided fluvial strata and ephemeral fluvial strata that are found in the Potsdam Group Sandstones, but you will want to read it numerous times.   (I did.)   Interestingly, the abstract for the first article mentions: “Two fluvial facies associations, braided and ephemeral fluvial, are recognized in strata of the Cambrian–Ordovician Potsdam Group in the Ottawa Embayment and Quebec Basin in northeastern North America.   ... [I]n the upper part of the Potsdam two regional ephemeral fluvial units are interstratified with two braided fluvial units, providing evidence for shifts in regional climate. ... These changes are correlated with documented Late Cambrian to Earliest Ordovician global climate fluctuations, with semiarid conditions and related ephemeral fluvial systems corresponding to global cooling events at ca. 491 and 487 Ma.”   

What I found most useful in Lowe and Arnott’s (2016a) article are the figures and the summary of the Potsdam Group which “is now recognized as a group comprising three formations that range in age from uppermost Lower Cambrian to Lower Ordovician. The oldest is the Altona Formation, which consists of arkose, siltstone, mudstone, and dolostone and records a marine transgression during the Early to Middle Cambrian in the Quebec Basin . The marine Altona Formation is overlain by the Middle Cambrian Ausable Formation, made up of braided fluvial arkose and conglomerate that are thickest in the eastern Ottawa Embayment and Quebec Basin, and overlain by redbed eolian quartz arenites present mainly in the southwestern part of the Ottawa Embayment.  An unconformity, in places angular, separates the Ausable Formation from the overlying Upper Cambrian–Lower Ordovician Keeseville Formation   The Keeseville Formation consists of quartz arenites and minor conglomerate of fluvial, eolian, marginal marine, and shallow marine origin. The contact between the Potsdam Group and overlying Theresa Formation is defined by a change from marine siliciclastic to mixed siliciclastic–carbonate strata associated with the epeiric Sauk transgression.  Age and contact relationships indicate that this contact is locally an erosional discontinuity but elsewhere conformable, ” [citations omitted].    That summary should be compared with their Figure 3, a regional correlation of cross-sections from three locations showing interstratified ephemeral units, braided fluvial units and the marginal to fully marine units, and with the cross-sections in Lowe,  Arnott, and Sanford (2013) and in Lowe (2014). 

Lowe (2014) reports that “new biostratigraphic analyses from this study (Nowlan, 2013) indicate that an interval stratigraphically below the uppermost Potsdam Group (the Riviere Aux Outardes Mb of the Covey Hill Fm) is Lowermost Ordovician (Early Tremadocian) (Figure 3). We therefore consider the uppermost Potsdam in the western Ottawa Embayment to be of Lower Ordovician age”.  Lowe (2014) also notes that “Existing and new ages of the basal Theresa Formation indicate that the switch from pure siliciclastic (Potsdam) to mixed siliciclastic-carbonate (Theresa) was diachronous, younging from the southwest to the northeast”.

In Ontario, from about 1982, we had been dividing the Potsdam Group into (a) a lower Covey Hill formation (feldspathic sandstone and conglomerate);  and  (b) an upper Nepean Formation (fluvial gravels and sandstone; eolian sandstone; and shallow marine facies sandstone).    Sanford and Arnott (2010) added numerous refinements, including noting the presence of a regional uncomformity within the Potsdam Group separating the underlying Covey Hill (Ontario and Quebec)/Ausable (New York) from the overlying Nepean (Ontario)/Keeseville (New York)/Cairnside (Quebec), and  subdividing the Covey Hill into four units – the Jericho/Altona, overlain by the Hannawa Falls, Chippewa Bay and Edwardsville members.

David Lowe (2014)  uses allostratigraphy (correlation of unconformity-bound units) to subdivide and correlate the  Potsdam Group and has proposed lithostratigraphic revisions.  He proposes (starting at the oldest, and using mostly his words):

Allomember 1: Altona Formation: uppermost Early Cambrian to Middle Cambrian: only recognized in  the Quebec basin... It consists of wave/stormdominated marine shoreface/shelf deposits.

Allomember 2:  Ausable Formation (proposed revision): Middle to lower Upper Cambrian:
consists of fluvial arkose that reach a thickness of ~600 m along the axis of the Oka-Beauharnois Arch and is exposed as outliers elsewhere (the Covey Hill Member, proposed) and of red bed aeolian quartz arenites (Hannawa Falls Member, proposed),   

Allomember 3: Chippewa Bay and Riviere Aux Outardes Members of the Keeseville Formation
(proposed revision): Upper Cambrian to Lowermost Ordovician: consists of widespread but thin quartz arenites and quartz cobble-boulder conglomerates of fluvial origin (Chippewa Bay Member, proposed) overlain in the northern Ottawa Embayment by marine sandstones with local mudstone and carbonate interbeds (Riviere Aux Outardes Member, proposed). The fluvial Chippewa Bay member of allomember 3 makes up the thickest part of the Potsdam [in upper NY State], and consists of braided perennial   and ephemeral   depositional facies associations.

Allomember 4:  Nepean Member of Keeseville Formation (proposed): Lower Ordovician: consists of basal  terrestrial and overlying marginal marine and tide-dominated shallow marine quartz arenite that forms the uppermost Potsdam. Allomember 4 is locally conformably but abruptly overlain   or unconformably overlain  by the mixed carbonate and siliciclastic Theresa Formation.  [T]he switch from pure siliciclastic (Potsdam) to mixed siliciclastic-carbonate (Theresa) was diachronous,  younging from the southwest to the northeast.

Jaret (2015) reports on U-Pb ages of zircons from the Potsdam at Alexandria Bay, NY, which yielded concordant ages of two populations: 1100 Ma and 2500 Ma.  Only the first can be Grenville sourced.   Allaz, Selleck, Williams and Jercinovic (2013) dated monazite from the Potsdam Formation, New York and reported that “Monazite core ages yield Proterozoic ages between 1.17 and 0.90 Ga (Shawinigan and Ottawan orogeny). Monazite overgrowth and xenotime ages indicate four to five major overgrowth events between ca. 500 Ma (shortly after the time of deposition) and ca. 200 Ma.”

Christopher Brett
Perth, Ontario

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David G. Lowe, R.W.C. Arnott, 2016a
 Composition and Architecture of Braided and Sheetflood-Dominated Ephemeral Fluvial Strata In the Cambrian–Ordovician Potsdam Group: A Case Example of the Morphodynamics of Early Phanerozoic Fluvial Systems and Climate Change
Journal of Sedimentary Research, v. 86, i. 6, p. 587-612, Published in June 2016, doi:10.2110/jsr.2016.39  

David G. Lowe and Bill Arnott, 2016b
Paleotopographic Controls on Fluvial Architecture of Pre-Vegetated Braided Fluvial Strata in a Basal Cambrian-Ordovician Sandstone: Potsdam Group of the Ottawa Embayment and Quebec Basin; Abstract with program, Article #90259, AAPG Annual Convention and Exhibition, Calgary, Alberta, Canada, June 22, 2016 
www.searchanddiscovery.com/abstracts/html/2016/90259ace/abstracts/2382851.html

Tadeusz Bartek Splawinski,  J Patterson,  M Kwiatkowski, 2016
The late Cambrian interface of sea and land: paleoecology and paleoenvironment of the Upper Cairnside Formation, Potsdam Group, near Beauharnois, Quebec, Canada. Northeastern Geoscience, Volume 34,  pages 13 – 22 
https://www.researchgate.net/publication/304952493_

David G. Lowe and Bill Arnott,  2015a
Supercritical strata in Lower Paleozoic fluvial rocks: a super critical link to upper flow regime processes and preservation in nature.   EGU General Assembly 2015, held 12-17 April, 2015 in Vienna, Austria. id.7279
meetingorganizer.copernicus.org/EGU2015/EGU2015-7279.pdf

David G. Lowe and Bill Arnott,  2015b
Supercritical strata in Lower Paleozoic fluvial rocks: a super critical link to upper flow regime processes and preservation in nature.   Dirt Talk, Department of Earth Sciences, Dalhousie University, April 10, 2015
http://www.dal.ca/faculty/science/earth-sciences/news-events/events/2015/04/10/dirt_talk___david_lowe.html

David Lowe, Charlotte Mehrtens  and Ryan Brink, 2015
Sedimentology and Stratigraphy of the Cambrian Potsdam Group (Altona, Ausable and. Keeseville Formations), Northeastern New York. Field Trip, New York State Geological Association, 87th Annual Meeting, State University of New York at Plattsburgh, Plattsburgh, NY, 12–13 September 2015

Ryan A Brink,  2015
Sedimentologic Comparison Of The Late/lower Early Middle Cambrian Altona Formation And The Lower Cambrian Monkton Formation; M.Sc. Thesis, University of Vermont, 134 p.
http://scholarworks.uvm.edu/graddis/370
http://scholarworks.uvm.edu/cgi/viewcontent.cgi?article=1369&context=graddis

Mángano, M.G. and Buatois, L.A., 2015,
The trace-fossil record of tidal flats through the Phanerozoic:  Evolutionary innovations and faunal turnover, in McIlroy, D., ed., ICHNOLOGY: Papers from ICHNIA III: Geological Association of Canada, Miscellaneous Publication 9, p. 157-177 at 159-161, Figure 7 and 171.

Steven Jaret, 2015
Provenance of the Potsdam Sandstone from laser ablation U-Pb ages of detrital Zircons. Geological Society of America Abstracts with Programs. Vol. 47, No. 3, p.80    
https://gsa.confex.com/gsa/2015NE/webprogram/Paper252725.html

MacNaughton, R.B., Hagadorn, J.W., Lacelle, M., and Groulx, P., 2014
The perils of Protichnites: The checkered history of an iconic ichnotaxon.
Alberta Palæontological Society, Paleo 2014, Annual  Symposium,  Abstracts  and  Short   Papers, Mount  Royal University, Calgary,  Alberta,   p.  34.  http://www.academia.edu/8412586/The_perils_of_Protichnites_the_checkered_history_of_an_iconic_ichnogenus_ABSTRACT_  

MacNaughton,  R.B.,  and  Hagadorn,  J.W., 2014
The perils of Protichnites:  Revisiting the earliest-named arthropod trackways.
GAC-MAC Joint Annual Meeting, Fredericton, 2014, Abstracts, Volume 37, page 170
http://www.mineralogicalassociation.ca/doc/AbstractVolume2014Final.pdf

David G. Lowe and Bill Arnott, 2014a
Variations in Braided Fluvial Styles Related to Topography and Climate in the Cambrian-Ordovician Potsdam Group, Ottawa Embayment and Quebec Basin
AAPG Annual Convention and Exhibition, Houston, TX, April 8, 2014
http://www.searchanddiscovery.com/pdfz/documents/2014/51004lowe/ndx_lowe.pdf.html
http://www.searchanddiscovery.com/abstracts/html/2014/90189ace/abstracts/1840976.html

David G. Lowe and Bill Arnott, 2014b
Coeval Tectonism and Epeiric Transgression on the Early Paleozoic Laurentian Platform Recorded by Strata of the Potsdam Group in the Northwestern Ottawa Embayment
 AAPG Annual Convention and Exhibition, Houston, TX, April 7, 2014
http://www.searchanddiscovery.com/abstracts/html/2014/90189ace/abstracts/1840946.html

David G. Lowe, 2014
Stratigraphy and Terrestrial to Shallow Marine Environments the Potsdam Group in the Southwestern Ottawa Embayment ; New York State Geological Association 86th Annual Meeting,  Field Trip B-4,  183
https://www.researchgate.net/publication/280924108_

Sören Jensen,  Luis A. Buatois  and M. Gabriela Mángano , 2013,
Testing for palaeogeographical patterns in the distribution of Cambrian trace fossils, Chapter 5 in  Early Palaeozoic Biogeography and Palaeogeography, Geological Society, London, Memoirs 2013, volume 38, p. 45-58
doi: 10.1144/M38.5

Seamus Magnus, Dave Lowe, Jamie Cutts, and Travis McCarron, 2013,
OCGC Field Trip – September 27th to 29th 2013
earthsci.carleton.ca/sites/default/files/Field%20Guide%202013.pdf

Julien Allaz, Bruce Selleck, Michael L. Williams, Michael J. Jercinovic 2013
Microprobe analysis and dating of monazite from the Potsdam Formation, New York: A progressive record of chemical reaction and fluid interaction.  American Mineralogist, 98 (7) 1106-1119     http://dx.doi.org/10.2138/am.2013.4304

Lowe, David G., Arnott, R.W.C., Chiarenzelli, Jeffrey R.,  and Sanford, B.V., 2013
Cratonic arch activity and basin dissection in early Paleozoic southeast Laurentia recorded by pre- and syn-transgressive strata of the Potsdam Group.  The Geological Society of America, 125th Annual Meeting,  Abstracts with Programs, Vol. 45, No. 7, p. 475, Paper 195-1
https://gsa.confex.com/gsa/2013AM/webprogram/Paper232272.html

David G. Lowe,  Robert W. C. Arnott, and Bruce V. Sanford, 2013,
Before the Great North American Carbonate Bank: A Complex Cambrian-Lower Ordovician Transgressive History Recorded in Siliciclastic Strata of the Potsdam Group, Southeast Laurentia
 Adapted from extended abstract prepared in conjunction with oral presentation at AAPG Annual Convention and Exhibition, Pittsburgh, Pennsylvania, May 19 -22, 2013
http://www.searchanddiscovery.com/pdfz/documents/2013/50859lowe/ndx_lowe.pdf.html

Mario Lacelle, James W. Hagadorn and Pierre Groulx, 2012
Prolific Potsdam Protichnites: Giant euhycarcinoid trackways from Beauharnois, Québec
Canadian Paleontology Conference, University of Toronto 2012,  Proceedings No. 10: 43.
www.mpe-fossiles.org/resources/Lacelle_etal_2012.pdf

James W. Hagadorn, Mario Lacelle, and Pierre Groulx, 2012
Mirabel's ancient surfers: Insights from Cambrian trace fossils and sedimentology of the Potsdam Group, Québec;  Canadian Paleontology Conference, University of Toronto 2012, Abstract Volume, page 37
http://www.mpe-fossiles.org/resources/Hagadorn_etal_2012.pdf

D.  Lowe and R.W.C. Arnott, 2012
The Potsdam Group in New York State, Ontario and Quebec: stratigraphic relationships and character of continental and shallow marine sedimentation in a tectonically active continental basin.  GAC-MAC Joint Annual Meeting, Volume 35, pages 80-81

James W. Hagadorn, Joseph H. Collette,  and Edward S. Belt, 2011
Eolian-aquatic deposits and faunas of the Middle Cambrian Potsdam Group
Palaios 26(5):314-334  May 2011
DOI: 10.2307/25835633

Anonymous, 2010
[Attributed to Selleck, B., Arnott,  R.W.C. and Sanford, B. V.]   Potsdam Formation Field Excursion, July 22-25, 2010, Thousand Island Region and St. Lawrence Lowlands.  Colgate University.
www.colgate.edu/.../Field%20trip%20Information%20July%2022%202010.pdf

Bruce V. Sanford and Robert W.C. Arnott, 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, 85 pages
publications.gc.ca/collections/collection_2010 /nrcan/M42-597