I am now giving the novel that I wrote last year a 5th revision before I offer it to further publishers. I would like to fact-check a little detail I put in one chapter. Specifically, I describe a location in the novel as having once been a dune, which gave the lawn on that location a sandy quality. Given the exact location, I would like to know if this description is realistic.
The place described is in North York in Toronto, I would estimate half a mile to a kilometer from the city’s Northern border. Toronto is on Lake Ontario, which circa 12500 BP was a significantly deeper glacial lake retroactively named Lake Iroquois. Its shoreline extended some number of kilometers past Toronto’s downtown of today into the middle of the city. However, it doesn’t seem to have stretched all the way to Northern North York (however, I have found references to “Lake Lundy”, an even earlier iteration of the glacial lake, which apparently was even wider-stretching).
As I understand, sand dunes are formed when shorelines regress. Would a location as I describe above have ever held something like a dune, and if not, would there have been another manner for the lawn to become sandy?
Can’t speak specifically about North America, but wherever there is a prevailing wind and a geographical setting that creates sandy-silty-clayey sediment, it will get wind-blown and usually form a dune bordering the lake / river / claypan. There are source-bordering sand dunes on lakes in central Australia going back to the wet pre-glacial period, so distance from the open sea is irrelevant.
Shorelines in lakes can regress because they are tidal, or they are affected by cyclical weather [snowmelt, wet seasons etc].
Don’t know how you most easily get sand in a glaciated environment. Maybe an old moraine gets eroded and washed out?
There are sand dunes in Death Valley which is at least 200 miles from the coastline.
Though I guess they may have been formed when a former lake dried up?
Manitoba’s Spirit Sands is a region of particularly sandy soil and dunes that is quite far inland. It arose as the delta where the Assinboine River flowed into Lake Agassiz, a glacial lake that formed at the south margin of the retreating ice cap near the end of the last ice Age.
In your part of the country you had a glacial lake called Lake Ojibway, so it’s plausible that you could have similar land formations there. Whether or not they actually exist is another question.
The glacier grinds and scrapes the bedrock into almost every imaginable grain size, from dust to house-sized boulders, which glacial meltwaters then segregate and transport into various deposits, sand included. That’s roughly how it went here, where there was c. 3km of glacial ice on top of the bedrock, and very quickly (geologically speaking) none at all.
Also, there are sand dunes hundreds of kilometers from a mentionable shore. Or what others already said.
as said above, there is no requirement for proximity to water:
Sand dunes are created when wind deposits sand on top of each other until a small mound starts to form. Once that first mound forms, sand piles up on the windward side more and more until the edge of the dune collapses under its own weight.
If you need to know more science and how the many different types of dune are formed, you can read the full article here:
North York seems to have a mix of clay and sand soil, at least from a gardening perspective so a given property might be as you described it in your book. Whether that area might ever have been described as a “dune”, I don’t know.
I’ve opened a couple of documents that came up when I searched “geology north York Ontario” which seem to align with that one to different levels of detail. It’s a very well researched area but well beyond my knowledge level!
Fans of inland sand dunes usually are aware of Bruneau Dunes State Park in Idaho. They claim that it " is the site of North America’s tallest single-structured sand dune, which is approximately 470 feet (140 m) in height."
There are numerous “Sand Hills” in Idaho. My g-grandfather had a ranch in one such locale and my cousins still ride 4-wheelers all over them.