Continental drift not push-me but pull-you, the Rockhall Plateau

 A funny thing happened when I showed my last blog post to my mom: "what is that blob right above where it says 'Atlantic Ocean'?". Widow and mother to geologists, she learned to read maps: she spotted the Rockhall Rise as it shows in the zoomed-in view below; it's also known as Rockhall Plateau (Perplexity), briefly a piece of crust left behind in the spreading of the North Atlantic. The tectonic plate margins, incl. the mid-Atlantic Ridge top right, are highlighted in cyan below. Same as the second-last blogpost showed interesting geomorphology only seen in North polar view, this portion of the far North Atlantic also shows better than in a normal or equatorial map view shown at right.

click to enlarge (can be slow), original

I first heard of the Rockhall Plateau in then-new plate tectonics classes by John Dewey & Kevin Burke (Can. Jour. Earth Sci.) @ Univ. of Calgary in 1980, and then Ed Farrar (Queen's U.) @ Queen's Uni. in 1982, resp. in W & E Canada. They distinguished rafts left behind like this, from fragments left in place like the Seychelles & Reunion in the Indian Ocean. The discussion resulted 40 yrs later in seeing tectonic plates dragged by sinking ocean trenches at the margins, rather than pushed by mid oceanic ridges at the center (Perplexity). See also this blog post about continent & ocean rafts & terranes re: exhuming my thesis 40 yrs later.

click to enlarge (can be slow), original

So what my mom spotted jumps out if you look at it carefully above:

• the Reykjanes Ridge portion of the mid-Atlantic Ridge shows a spread at a slight angle (dashed line) to the median itself (cyan), with matching original continental shelf margins (brown)
• the Rockhall Plateau is however separated from the UK Ireland mass by a trough with matching continental shelf outlines (blue), not unlike the original brown ones
• if the mid-oceanic ridge were the motor, the plateau would have been pressed against not separated from the NW Europe continental mass
• the small offset orphaned ridge next to the Faroe Islands further underscores the pull you rather than the push me aspect
• this is a patent example on geomorphology alone, and a keen eye, of the slab pull driver of plate tectonics, rather than ridge push or mantle drag theories detailed in the Perplexity link above.

Thanks to @John Nelson LinkedIn post here, w far superior cartography on global plate tectonics, inspired in turn by his daughter - this rattled about in my brain and y'all prompted me to post it - aptly enough, our posts bridge International Women's Day!

Mapping Arctic Boreal Peatlands, cont.

 This follows on the original post here, with more news on "Arctic fires" that are counterintuitive a priori:

Perplexity summary of NASA captured it from space, and it looks like a bad joke: fire burning on the ice of the North Pole. The scary thing is that it has been multiplying for 10 years: NASA satellites have detected a dramatic rise in Arctic wildfires over the past decade, with fires spreading farther north into icy regions, fuelled by an Arctic warming four times faster than the global average. These blazes, now more frequent and intense, are shifting from the Arctic's edges to a broad northern band, burning drier tundra and releasing ancient carbon from permafrost, turning some areas into carbon sources. Lightning ignites many of these deep-burning fires, whose smoke travels globally, worsening air quality and signalling urgent climate impacts as noted in recent Arctic assessments. 

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:

Mapping Arctic Boreal Peatlands

This follows on East Anglia environment in a global context. A recent article, Peatlands across the Arctic are expanding as the climate warms, research shows  via @physorg_com, made me look to map data for that. I posted a fair bit on East Anglia peatlands in this blog. I also recently used polar Arctic basemaps N of 50°lat., like Arctic Waterfront, a measure of geopolitical stakes, amongst this blog's Arctic coverage. Next post is Mapping Arctic Boreal Peatlands, cont..

Mapping USAF Global Range

This follows on a previous post mapping long-haul flights (this blog) in a similar manner.

Currently in the news, the UK prohibited the use of forward bases by the US, whereas that issue was sidestepped last summer for US intervention in Iran (Perplexity). Having looked at the range of fighter jets in Arctic War games (this blog), I did the same for B52 bombers (Perplexity). Here are the relevant data:

The travels of La Macareña

 ... Aaand now for something completely different! Following on tracing travels & travails on simple maps for my travels over a decade ago and recently Samurais & Richard Lionheart, I traced the journey of that song&dance everyone knows.

It all started with ye olde beer advert popping up on YouTube shorts:

Henry VIII Dissolution of Monasteries in England

This continues history posts from Roman Roads vast network and local effect, to medieval travels by Richard I and by Samurais.

Inspired by National Archives' story map: Discover the Dissolution of Monasteries by Henry VIII from 1536 to 1540, here is its intro:

 Henry VIII's break from Rome and the creation of the Church of England set in motion a revolutionary chain of events that resulted in the closure of almost 900 religious houses, displacing 12,000 people from their religious orders. While some were allowed to remain or convert, many were given pensions to surrender their churches and many still were simply evicted with no compensation. The dissolution changed the kingdom's schooling, medical care, land ownership and powerful figures - but why did it happen, and how did it affect your local area?

A Belgian holiday

 This picks up from A Roman Holiday about aspects of Roman Roads. A friend pointed out this YouTube video, How A Roman Road Changed Belgium Forever, here is their synopsis:

Why does Belgium speak two languages? The answer is a 2,000-year-old Roman road.

In this video, I explain how the Via Belgica, a highway built by the Roman empire around 50 BC, created a language border that still divides Belgium today. The road ran from Tongeren to Bavay, separating Romanized Gaul in the south from Germanic tribes in the north. That linguistic divide has persisted through the Middle Ages, Spanish rule, Austrian rule, French occupation, and Belgian independence.

Today, Dutch speakers live north of the line, French speakers live south of it, and the border is still influenced by that ancient Roman road. Even Belgium's election results are decided by this 2,000-year-old line.

Having mapped Roman Roads, I recreated a focussed map on the region, adding the Belgian Wallonie region in green. As roads were unidentified in the AWNC database, I selected them per video. I found a source (no metadata in arcgis.com) that put Via Belgica right along it, confirming my choice.

3D maps in current affairs

This picks up on the previous Beautiful maps... as well as Arctic Waterfront... re: the distribution of influence over the Arctic in the news of late.

Update: see in A view from the top of the world more on an intriguing lineament bisecting the Arctic from top to bottom on an Alaska Polar Strereographic projetion.

This time let's look at the elevation maps of the area:

• High Resolution Elevation Model of the Arctic (Esri Living Atlas)
• Seabed Sediment Thickness (Esri Living Atlas)

Arctic Waterfront, a measure of geopolitical stakes

 Update: next in the series on the Arctic is here with more data & a 3D view.

A mid-2011 post Beautiful maps in current affairs (note the updates) said: 

UN Convention on the Law of the Sea [...] by Dr Parson of the Southampton UK National Oceanographic Centre [...] described how nations were given an opportunity to claim Exclusive Economic Zones (EEZ) beyond the standard 200 nautical mile limit (viz. UNCLOS and UNEP). [...]