Fossil leaf? Niagara, Ontario, Canada

[Martianskyes]

I'm new to this forum but thought you might be able to help. I found this fossil near to the whirlpool rapids in the Niagara River gorge in southern Ontario, Canada. 

 

As far I can figure out this looks like a leaf, perhaps some sort of angiosperm. It is a few centimetres long.

 

However, the geology of the area is almost completely Silurian rocks. This wasn't found in situ so could be from rocks in the cliffs above, younger rocks no longer found in the area or introduced by people (unlikely). 

 

So two questions really. 

1. Type of fossil?

2. Geological time period/range of fossil?

 

Thanks!

[Ludwigia]

Yes, there certainly are leaves there, but if they're at all fossiliferous, then definitely not very old, at the oldest Holocene, I'd say. It looks like they originate from a sinter deposit similar to the one in the photo below which is only a few decades old.

 

 

 

 

[Martianskyes]

Thanks for the reply Ludwigia!

 

That makes a lot of sense - it is almost certainly what you suggested. There are many sinter/tufa deposits along the Niagara escarpment in Ontario.

 

A nice addition to the collection.

[abyssunder]

Very interesting topic!
I agree with Roger.
Just to add, there are people who call them 'leaf prints', also people who call the holding matrix 'Tufa', others are using the term 'Travertine'. (see reference below)

 

" High quality data are frequently preserved in tufa sediments as prints of organic remains which have decayed. (...)
Leaf prints appear to be considerably more common in Europe (Pentecost, 2005). The best known Quaternary tufa flora comes from important sites in Central Germany: Weimar-Ehringsdorf, Bilzingsleben and Burgtonna tufas (Thuringia, Germany; Fig. 1) have provided a rich and exceptionally well preserved collection of leaf associated to insect prints (Fig. 4; Meyrick and Schreve, 2002).
Some other major European vegetal print collections come from Marsworth (UK; Green et al., 1984; Field, 1993), the Queyras Massif (French Alps; Ali et al., 2004) and La Celle (France; Limondin- Lozouet et al., 2006, Figs. 1 and 4). Processes leading to leaf impressions in tufa have been little studied but observation of active tufa deposits shows that they require fast burial of the vegetal (or any organic) remains by very fine tufa allowing anaerobic conditions and preservation of the organic matter for at least a few years (Pentecost, 2005). Encrustation of living plants is also common and leads to erected (in life position) moulds of mosses, algae, stems and reeds, or even trunks. After decay of the organic support the remaining calcite mould may provide external details allowing specific identification and thus environmental investigations. " - as stated in High potential of calcareous tufas for integrative multidisciplinary studies and prospects for archaeology in Europe. Journal of Archaeological Science 52 : 72-83

 

In Tufa or travertinic formations the plant remains are progressively replaced and coated in CaCO3 due to the precipitation process of carbonate rich waters.
Usually they could be found in the presence of waterfalls, springs, streams, rivers, lake shorlines.. Here are few samples from Pisoaia waterfall (situated on a stone-paved, crystalline limestone threshold of Paleozoic age, framed in a forest of deciduous and isolated resinous trees at the top), Apuseni Mountains, Romania, in my collection: leaves, branches and trunk  fragments of deciduous trees in calcareous Tufa

 

 

Terms of Tufa and Travertine were in debate from a very long time. I would quote from Ford & Pedley, 1996:

 

"A general review of the nature and classification of tufas is presented and the available literature is summarised. An attempt is made to standardise the terminology currently in use and to distinguish clearly between ambient temperature deposits (tufas), thermal deposits (travertines) and speleothems. Consideration is also presented of the physico-chemical and biological processes, often acting together, which are responsible for the precipitation of freshwater calcium carbonate within tufa systems. These processes appear to be climatically controlled. Therefore, tufas may be of value in palaeo environmental reconstruction, especially if intercalated with peaty material. While the majority of tufa deposits are of post-glacial age some of the most spectacular carbonate precipitates are thermal travertines. "

 

Reference:

 

A. Pentecost. 2005. Travertine. Springer

A, Pentecost. 1995. The quaternary travertine deposits of Europe and Asia Minor. Quaternary Science Reviews, Vol. 14, pp. 1005-1028

T. D. Ford, H.M. Pedley. 1996. A review of tufa and travertine deposits of the world. Earth-Science Reviews 41(3), pp. 117-175

 

 

 

 

[Martianskyes]

Thanks also for your reply abyssunder!

 

It's a fascinating subject - one that I have not come across before but now I will be informed enough to take keep my eyes peeled whilst out rock hunting.

Bearing in mind the locality of this find - I would describe it as a calcareous tufa formed from ambient temperature deposits. It's probably recent as it was exposed on a river bank which is part of a high energy environment (5km downstream from Niagara Falls) that was only exposed in the last few hundred to a thousand years.

[abyssunder]

I'm glad to help!

 

More details related to fluvial tufa can be found, for example, in J. Aranbarri et al. 2016. Palaeobotanical insights from Early-Mid Holocene fluvial tufas in the Moncayo Natural Park (Iberian Range, NE Spain): Regional correlations and biogeographic implications. Review of Palaeobotany and Palynology 234: 31–43

 

" Fluvial tufa deposits (Pedley, 1990; Ford and Pedley, 1996) have provided to be excellent palaeobotanical archives (Bertini et al., 2014; Dabkowski, 2014). Charcoal remains and detailed leaf imprints preserved in fluvial tufa sequences, constitute extraordinary proxies to develop Quaternary palaeoenvironmental studies (Pentecost, 2005) and to disentangle biogeographic aspects regarding past distributions of vascular taxa (Ollivier et al., 2010). (...)

The present study fills a palaeobotanical and palaeoclimatic information gap in middle altitudes of the northern flank of the Iberian Range, where the available vegetation traits were only reconstructed by high-altitudinal pollen profiles or by records confined to the southernmost Mediterranean areas. The location of the range, strategically-placed between the Eurosiberian climatic region and the Mediterranean continental realm, allows some interesting vegetation, climatic and hydrological features to be recognized: (...) " - as stated in the document mentioned above.