A view from the top of the world

This follows on from 3D maps in current affairs: it showed an intriguing feature bisecting the Arctic on a proxy topography for the earth's crust; it's only visible on a Polar Stereographic projection, looking straight down the North Pole, mapped here for features N of 50° N lat.

This was seen when mapping ArcticDEM - High-resolution Elevation Models of the Arctic (Esri Living Atlas) and Seabed Sediment Thickness (clipped to N of 50°N, Esri Living Atlas).  From the poster & overlay at the bottom:

Hi-res. DEM and sediment thickness are a proxy for depth-to-basement. Approximating a level seafloor in a closed ocean with no continental shelf or abyssal plain, they form a continuous above- and below-sea-level proxy continent surface topography minus ice and sediments. The marked N-S lineament across North Pole likely reflects a crustal mega structure from the southern Baltic Sea to along the Alaska-Yukon border.

click to enlarge, original

Anecdote: the Lomonosov Ridge, looking above like the hand of a clock centred at the North Pole and indicating 08:30, is the basis for Russia to claim the North Pole as that ridge extends to it from Russia (Perplexity).

This visual has an actual underpining in the bedrock geology:

• the tectonic plate boundaries (Esri Education Services) running roughly left to right in this Alaska polar sterographic projection reflect the mid-oceanic ridges. Notice the sudden bend toward the vertical on this projection, forming a chicane immediately above the North Pole..
• the subsea geology shows also marked breaks & offsets in the bedrock geology compiled by the Geological Survey of Canada (Arctic Circumpolar GSC EN 1:5M Offshore Bedrock_Geology from Geological Map of the Arctic, 1:5 000 000). 
  
  

click to enlarge, original

Does it not seem like that break in the bedrock geology lines up with the chicane in the plate tectonic boundaries? Notice also that in the proxy topography 2nd from above, thick purple sections to the left have no counterparts to the right... The same goes for the bedrock geology in green above! This is not unlike the juxtapposition of precambrian terranes described here in this blog, in revisiting my thesis 40 yrs. later. That is why I said at the top that the "... lineament... likely reflects a crustal mega structure".

Poster & overlay:

click to enlarge, original

click to enlarge, original

Other anecdote: 40 yrs. ago I compiled Arctic Islands geology at Nat. Res. Can. in Calgary AB. We thought "wouldn't it be cool to add offshore bedrock geology to what we compiled onshore?" It took the Int'l Polar Year 20 yrs. later to compile what's used above. Did you also know that work there was part of my transition from geology to GIS? It's described in Medium and linked back to an earlier blogpost here.