What are those "polystrate trees" from Kingston, Ontario?

See here for a citation from creationist literature, from Taylor, Ian T., 1987. In The Minds of Men: Darwin and the New World Order. TFE publishing, page 104, 114:

"polystrate trees"

Actually, these structures are not trees (but if they were, see here for the reason why "polystrate trees" are not a problem anyway).

Here is a better illustration, with a human for scale, from Baker, 1916, one of the earlier descriptions of these structures:

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The structure on the right appears identical to Taylor's illustration (absent a bit of modern tree growth :-)), and is located at (p.19 of Baker, 1916) "Blake's quarry, lot 9, concession V, Pittsburgh township, on the Rideau canal."

The structures are in the Potsdam Formation, which is Cambrian to Ordovician in age, and occurs on top of slightly older conglomerate units, and Precambrian igneous and metamorphic rocks of the Canadian Shield.

[Note: nomenclature for these units has changed in recent years, but for the sake of consistenty, I will refer to them as the Potsdam Formation.]

Douglas Cox (tcc@sentex.net) has claimed these structures are a "puzzle" for conventional geologists and are formed by some sort of chemical "disintegration process" that can explain other "pothole" structures, crossbedding, and the "purity" of the sandstone in the Potsdam Formation. He has not offered an explanation for the bioturbation found in the Potsdam Formation (e.g., Bjerstedt and Erikson, 1989), or for the precise correspondance between the structure of cross-bedding and modern ripples and dunes (e.g., Allen, 1982a and 1982b).

These columnar structures are probably dewatering pipes or "boiling sand springs" (Gruhman and Pederson, 1992, which also contains other citations), both related to groundwater flow through unconsolidated sediment along vertical channels that cross-cut the bedding -- i.e they formed after the bedding and other sedimentary structures. These structures have been observed in the process of formation in modern deposits. Similar columnar structures can be formed in the lab by causing recently-deposited sediment to dewater (e.g., by shaking).

Further information:

A posting to the newsgroup talk.origins contains more information on this occurrence.

Acknowledgements:

My thanks to Robert MacNaughton (macnaugh@geolserv.geol.QueensU.CA) and Darby South (southdar@tyrell.net) for pointers to relevant references and discussion.

References:

Allen, J.R.L., 1982a. Sedimentary structures: Their character and physical basis, Volume I. Elsevier Scientific Publishing Company: Amsterdam, p.1-593.

Allen, J.R.L., 1982b. Sedimentary structures: Their character and physical basis, Volume II. Elsevier Scientific Publishing Company: Amsterdam, p.1-663.

Baker MB. 1916. The geology of Kingston and vicinity, Ontario Bureau of Mines Annual Report, v.25, pt.3, p.1-36.

Bjerstedt, T.W. and Erikson, J.M., 1989. Trace fossils and bioturbation in peritidal facies of the Potsdam-Thersa formations (Cambrian-Ordovician), northwest Adirondacks. Palaios, v.4, p.203-224.

Cox, D., 1977. Pillars, polystrate formations, and potholes. Creation Research Society Quarterly, v.14, p.149-155.

Gruhman, A.I. and Pederson, D.T., 1992. Boiling sand springs, Dismal River, Nebraska: Agents for formation of vertical cylindrical structures and geomorphic change. Geology, v.20, p.8-10.

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