What causes this circular pattern in the Canadian Arctic?

Look at this satellite view on Goolge Mpas in Victoria Island in northern Canada.

See how the “grain” of the land, made of low ridges and small lakes, seems to form a semicircle around the area I linked to? It’s not a full circle, and to the south the “grain” seems to break down and fan out towards the south.

Does anyone know what this is caused by? An ancient impact, or just freeze-thaw patterns?

Game trails?
Logging roads?

My first thought on reading the thread was an impact crater, but that doesn’t look right for the image at all. The key is that the land south of the semicircle still has the same sort of texture, but aligned completely differently. And just north of the semicircle, there’s more texture curving in the opposite direction. My guess would something glacial, perhaps the amount that glaciers retreated each year.

My guess would be glaciers. That would require the downhill direction to curve around like that which is not impossible.

ETA: I was thinking of glaciers flowing downhill and cutting grooves in the terrain. But then I saw Chronos’ idea of glaciers retreating across the grain. That’s more likely.

Whatever it is, I guarantee that it’s not logging roads. This is waaaaaay past the tree line.

I would imagine that the local geography is determined by how the glaciers of the last ice age melted. That’s the usual answer for every question about Canadian geography. :slight_smile: Why are those rocks over there? Glaciers. Why is it hilly over there? Glaciers. Why is it flat over here? Glaciers. Why is Lake Superior slowly tipping towards the south? Glaciers. Well, isostatic rebound caused by glaciers.

If I’m looking at the same thing, those look like image distortion from taking a photo taken at an angle and applying a filter to map it to appear flat. I really doubt there’s anything like that on the ground.

Peat bogs/muskegs. The organic material doesn’t really breakdown so anywhere that is dry enough for things to grow will start to build up creating more areas dry enough for things to grow. The water gets pushed into circular ponds with an outlet creating the semi circles.

Zoom in. They are real features. Seems to be shallow ridges and hollows, with the low points mostly now filled with small ponds, but they are orientated in a particular way. Where larger lakes cross perpendicularly to that orientation, the ridges show up as undulations in the shoreline. Example.
Glacial retreat makes sense, I suppose.

A hummock

That’s not to say there wasn’t a glacial component that lead to the formation of the hummocks.

There’s an impact crateron the other side of the island, but what you’ve linked to just looks like glacial landforms to me. Something like Veiki moraines or similar.

Actually, here, here’s the notes to the glacial geomorphology map of the whole island, go wild… Looks like lots of different kinds of moraine forms…plus all the drumlins and eskers and other bits that go with them.

I thought photographic artifacts, too, for a bit, but you can see that the lakes also follow the same texture.

I don’t think there are peat bogs or muskegs that far north.

And even if they are, it’s not the shapes of the individual lakes, so much as the orientation of them that I was asking about. Eg most of the lakes are much longer than they are wide, falling between small ridges, but the orientation of them varies across a wide range, with the long axis direction of each lake gradually changing and tracing out a semicircle - or rather a series of concentric semicircles, as there are lots of parallel ridges.

The orientation parallels ice flow.

It may be the cowlick caused by the hairy ball theorem, due to the linear velocity of ice flows?


Topologically speaking, there probably will be a glacial cowlick on the earth some place, but I don’t know if this is it or not.

And if not glaciers, then the answer is “ancient seabed”. :stuck_out_tongue:

“It has long been recognised that Victoria Island possesses an exceptionally well-preserved glacial landscape which contains an abundant array of glacial features that betray an extremely complex glacial history… Much of the island is dominated by highly convergent and divergent patterns of glacial lineations (and associated moraines and meltwater features), many of which lie superimposed on each other and often at abrupt angles.”
Robert Storrar & Chris R. Stokes (2007) A Glacial Geomorphological Map of
Victoria Island, Canadian Arctic, Journal of Maps, 3:1, 191-210, DOI: 10.1080/jom.2007.9710838

The OP asked about an area in the low-lying southeast.

“Glacial lineations (including drumlins and mega-scale glacial lineations) are
streamlined landforms whose long-axis is aligned with ice flow direction.
They are abundant in the low-lying areas of Victoria Island, predominantly
in the east, south, and southwest (see map).”

Cool, so it is a physical manifestation of the the hairy ball theorem!

The hairy ball theorem is completely irrelevant, because the Earth has plenty of glacial “bald spots”.