What’s New in Potsdam Sandstone?  (And a few that I missed)

This posting mentions articles published  since my June 1, 2021 posting, and few  that I missed previously.  

Lowe,  DeSantis,  Arnott, and  Conliffe (2022) report on silcrete in the Potsdam in upper New York State.  They postulate  groundwater silcrete linked to brine migration in a continental rift zone as an alternative to the near-surface model of silcrete.   More particularly,  a groundwater silcrete from Upper Cambrian strata of the Potsdam Group is described and interpreted to be formed in a rift where Cambrian fault reactivation coincided with silcrete formation.   They state “The silcrete horizon documented here caps strata of the middle allounit, termed Allounit 2, and consists of Upper Cambrian braided and ephemeral fluvial quartz arenite and quartzose conglomerate.  Based on its stratigraphic position, formation of this silcrete coincides with terminal Cambrian basin inversion and unconformity development in the Ottawa Graben.  ... The silcrete horizon that caps quartz arenite strata of Allounit 2 crops out over an area of ~0.3 km2 in northwestern New York State. ... The horizon is 8–142 cm thick,”  [ I have not been down to look at their outcrops, but note that I  found a large, meter diameter, angular, loose  block of silcrete in an abandoned March formation quarry about 3 km east of Perth, Ontario.]

David Lowe (2024) discusses the aulacogens of the Neoproterozoic to Ordovician Laurentian Iapetan Margin.   He ties the deposition of the various formations of the Potsdam group into Continental rifting theory.    (Most of his paper doesn’t deal with the Potsdam.)

Daniela Garcia Ramos (2023) looked at the Thermal History of the Frontenac Arch in Southeastern Ontario, Canada Constrained From Low-temperature Thermochronology.  One interesting comment she makes is “On the basis of lithological, stratigraphic, paleontological, paleogeographic reconstructions, and thermochronological evidence, I suggest that ~ 3-4 km thick sedimentary rocks contributed to bury and reheat the rocks of the Frontenac Arch until the late Paleozoic. However, the sedimentary material has been removed by erosion since at least the Mesozoic, and only remnants of the Ordovician and Pre-Ordovician sequences are preserved today.”  Her Figure 2.8 B is a photograph of Potsdam sandstone showing soft sediment deformation/ seismites in the Nepean quartzarenite, a photo that I supplied,   Location: 44.69577°N, 76.30165°W, that had appeared in my October 22,  2015 blog post.

Elliot et al. ( 2025) looked at Potsdam sandstone outcrops in New York to provide insights into folds, deformation bands, and fractures that could influence permeability, heat exchange, and stimulation outcomes of geothermal reservoir targets.  They found that fractures show four chronological Sets A–D, striking NNW, NE, NW, and ENE, respectively. Fracture lengths and heights range from millimeters to tens of meters. Sets A and C macro-fractures, and possibly B and D, contain quartz deposits.  All sets had abundant associated quartz cemented microfractures that also record set orientations and crosscutting relations.  They state that quartz cement deposits—evidence of diagenesis—are the key to identifying attributes of outcrop fractures suitable for extrapolation to geothermal targets in sandstones because they show which fractures formed in the subsurface.

Konstantinovskaya et al. ( 2023)  conducted 3D reservoir simulations of supercritical CO 2 injection  in the  Potsdam Sandstone of the St Lawrence Platform (Gentilly Block), Quebec to predict safe CO 2 injection rates, evaluate reservoir pressure build-up in the presence of sealing and permeable faults, and estimate the gas injection cumulative, in part to estimate the risk of top and bottom seal failure and fault shear-slip reactivation.

Graham A. Young  & James W. Hagadorn (2020) looked at the  facies distribution of fossil jellyfish through time.  Their Figure 1, Plate 1 shows undescribed scyphozoan from a Cambrian arenite of the Potsdam Group, Carrières Ducharme, Québec, Canada; Pointe-du-Buisson/Musée Québéquois d’archéologie, Québec.  Their Figure 1, Plate 2 shows  Domical mouldic medusae on bedding plane surface of a Cambrian arenite in the Potsdam Group, Ausable Chasm, New York,    For the Keeseville Formation, Potsdam Group,  Ausable Chasm, New York, they report numerous medusae, stating that “The fossils are preserved as moulds  in medium-grained quartz arenites, and often appear  as simple circular mounds, but some are twisted or folded, exhibit evidence of transport, or have tripartite or  quadripartite axial regions ... They  are interpreted as scyphozoan medusae, but have not yet  received systematic description. More than 1000 medusae are known, occurring in more than six horizons. Diameters range from about 50 to 660 mm, with an average of  just over 200 mm. The depositional environment is interpreted to have been intermittently emergent, and the  arenites containing medusae have sedimentary structures indicating deposition in very shallow water less than 2 m deep.” 

One that I missed is Minter,  Buatois, Mángano , MacNaughton, Davies,  & Gibling, ( 2016)  who suggest that the eolian beds in Ontario where MacNaughton et al. ( 2002 ) reported  Diplichnites and two varieties of  Protichnites  are similar in age to interfingering eolian dunes in New York State where Hagadorn et al. ( 2011) reported  Diplichnites,  Protichnites , and paired grooves (cf.  Diplopodichnus). They provide photographs of Protichnites and Diplichnites from the eolian beds in Ontario.

I previously gave the citation for Brink,  Mehrtens  & Maguire (2019) but didn’t summarize it.  I haven’t mentioned Landing, Amati, & Franzi (2009).  Both are important.  Brink et al. (2019) describe in detail the  Altona Formation, the oldest unit in Potsdam Group, identifying six lithofacies including nonmarine sheet flood, nearshore bay/estuary, and upper and middle shoreface.   Landing et al. (2009) described fragments of an Olenellid trilobite as well as specimens of Ehmaniella from a unit below the  Ausable Sandstone which led them to suggest that the  horizons should be recognized as a separate unit termed the Altona Formation.    Landing et al. (2009) also  reported occurrences of small Cruziana and Rusophycus trace fossils from their Altona formation.

Christopher Brett

Ottawa

References and Suggested Reading

Brett, Christopher,  2015   Soft-Sediment Deformation (Seismites) in Nepean Sandstone Close to the Rideau Lake Fault.  Blog posting dated  October 22,  2015 https://fossilslanark.blogspot.com/2015/10/soft-sediment-deformation-seismites-in.html

Brett, Christopher,  2016.  What’s New in Potsdam Sandstone?  Blog posting dated  August 5,  2016 https://fossilslanark.blogspot.com/2016/08/

 Brett, Christopher, 2021.  What's New in Potsdam Sandstone? Blog posting dated  June1,  2021 

https://fossilslanark.blogspot.com/2021/06/whats-new-in-potsdam-sandstone.html

Brink, R., Mehrtens, C. & Maguire, H. 2019. Sedimentology and petrography of a lower Cambrian transgressive sequence: Altona Formation (Potsdam Group) in northeastern New York. Bulletin of Geosciences 94(3), 369–388 (18 figures, 2 tables, appendix). Czech Geological Survey, Prague. ISSN 1214-1119.   http://www.geology.cz/bulletin/fulltext/1728_Brink_191208.pdf

Elliott SJ, Forstner SR, Wang Q, Corrêa R, Shakiba M, Fulcher SA, Hebel NJ, Lee BT, Tirmizi ST, Hooker JN, Fall A, Olson JE and Laubach SE (2025)     Diagenesis is key to unlocking outcrop fracture data suitable for quantitative extrapolation to geothermal targets.  Frontiers in Earth Science, Economic Geology,  1 April 2025, Volume 13 - 2025 |      https://doi.org/10.3389/feart.2025.1545052

Garcia Ramos, Daniela, 2023    Thermal History of the Frontenac Arch in Southeastern Ontario, Canada Constrained From Low-temperature Thermochronology.  Masters of Science Thesis. Queen’s University, Kingston, Ontario 206 pages   http://hdl.handle.net/1974/31426  https://qspace.library.queensu.ca/items/c276a99a-078d-45c0-afc1-538e986686c5

Konstantinovskaya, Elena,  Jose A. Rivero, Valentina Vallega. John Brodylo, Peter Coldham

3D reservoir simulation of CO 2 injection in a deep saline aquifer of the Lower Paleozoic Potsdam Sandstone of the St Lawrence Platform, Gentilly Block, Quebec  January 2023 Geoenergy 1(1) DOI:10.1144/geoenergy2022-001

Landing, E., Amati, L. & Franzi, D.A.,  2009   Epeirogenic transgression near a triple junction; the oldest (latest EarlyMiddle Cambrian) marine onlap of cratonic New York and Quebec. Geological Magazine 146(4), 552–566.   DOI 10.1017/S0016756809006013  

Lowe, D.G.,  2024   Aulacogens of the Neoproterozoic to Ordovician Laurentian Iapetan Margin,

Earth-Science Reviews, Volume 255, 104829,

https://www.sciencedirect.com/science/article/pii/S0012825224001569

Lowe, D.G. ,  E. DeSantis, R. Arnott, J. Conliffe, 2022   Groundwater silcrete linked to brine migration in a continental rift: an alternative to the near-surface model of silcrete .  Geosphere, 18 (3) (2022), pp. 1055-1076  https://pubs.geoscienceworld.org/gsa/geosphere/article/18/3/1055/612948/Groundwater-silcrete-linked-to-brine-migration-in

Minter, N. J., Buatois, L., Mángano, G., MacNaughton, R., Davies, N., & Gibling, M., 2016.  The prelude to continental invasion. In G. Mángano, & L. Buatois (Eds.), The trace-fossil record of major evolutionary events: Volume 1: Precambrian and Paleozoic (Vol. 39, pp. 157-204). (Topics in Geobiology; Vol. 39). Springer. https://doi.org/10.1007/978-94-017-9600-2

https://www.researchgate.net/publication/310483425_The_Prelude_to_Continental_Invasion

Yochelson, E.L.  and M. Parrish, 1992    Reconstruction of the enigmatic Late Cambrian Climactichnites.   The Paleontological Society Special Publications , Volume 6: Fifth North American Paleontological Convention-Abstracts and Program , 1992 , pp. 321.  Published online by Cambridge University Press:  26 July 2017  DOI: https://doi.org/10.1017/S2475262200008819 https://www.cambridge.org/core/journals/paleontological-society-special-publications/article/reconstruction-of-the-enigmatic-late-cambrian-climactichnites/3704BDF67A29C82871FD8C394BF468B6

Young, Graham A.  & James W. Hagadorn, 2020  Evolving preservation and facies distribution of fossil jellyfish:  a slowly closing taphonomic window .  Bollettino della Società Paleontologica Italiana, 59 (3), 2020, 185-203. Modena   https://www.academia.edu/48910995/Evolving_preservation_and_facies_distribution_of_fossil_jellyfish_a_slowly_closing_taphonomic_window