Beneath Antarctica's ice, intriguing evidence of lost continents

LiveScience, via FoxNews.com/Science ^ | Nov 14, 2018 | Stephanie Pappas Live Science Contributor | LiveScience

[ETL]

The map shows that East Antarctica is made up of multiple cratons, which are the cores of continents that came before, according to study leader Jörg Ebbing, a geoscientist at Kiel University in Germany.

"This observation leads back to the break-up of the supercontinent Gondwana and the link of Antarctica to the surrounding continents," Ebbing told Live Science. The findings help reveal fundamental facts about Earth's tectonics and how Antarctica's land and ice sheets interact, he wrote in an email.

Because the continent is so remote and buried in ice, Antarctica is a bit of a blank spot on the geologic map, Ebbing said. The researchers used data from the European Space Agency's Gravity field and steady-state Ocean Circulation Explorer (GOCE) satellite to fill in the blanks. GOCE orbited Earth from 2009 to 2013, gathering data on the planet's gravity field. Gravity's pull differs very slightly from one point on Earth to another, depending on changes in topography and the density of the planet's interior. ..."

The East Antarctic crust is also a mishmash of old cratons, Ebbing said, including the Mawson Craton, which has a matching fragment in southern Australia.

The new data reveal more complexity in East Antarctica's ancient cratons than previously known, Ebbing said. The modern-day continent is also host to regions called orogens, which are crumpled-up regions where ancient continents would have rammed together to build mountains.

Another intriguing discovery was a low-density area beneath Marie Byrd Land in West Antarctica. The existence of this low-density portion of the upper mantle — the layer of the planet beneath the crust — may be due to an ancient mantle plume..."

Mantle plumes are places in the mantle where hot blobs of rock rise like the lumps in a lava lamp.

[ETL]

The following map I got from a different source. I believe it's from a 2016 piece. Don't know how the latest findings change the picture.

Tectonic sketch of East Antarctica (compiled on the basis of a [10,13,24,25]). 1. Archaean-Palaeoproterozoic cratons;
2. Mezoproterozoic-Neoproterozoic mobile belts (orogens); 3. Neoproterozoic-Early Palaeozoic platform cover inferred
from this study; 4. Late Palaeozoic-Mesozoic rift system (rift sedimentary basins). Dotted lines outline large subglacial
platform sedimentary basins. Grey arrows show direction of Palaeoproterozoic (1.6-1.8 Ga) zircon/monazite grains input;
black arrows show direction of Mezoproterozoic-Neoproterozoic (0.8-1.15 Ga) zircon/monazite grains input. Numbers on
the sketch show the areas of outcropped unmetamorphosed terrigenous sedimentary rocks of Late Neoproterozoic age (1)
and Late Palaeozoic-Early Mesozoic age (2). PCM-Prince Charles Mountains.

source:
https://www.researchgate.net/figure/Tectonic-sketch-of-East-Antarctica-compiled-on-the-basis-of-a-10-13-24-25-1_fig2_287110020

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North America Craton Map

[ETL]

Craton

A craton is an old and stable part of the continental lithosphere, where the lithosphere consists of the Earth’s two topmost layers, the crust and the uppermost mantle. Having often survived cycles of merging and rifting of continents, cratons are generally found in the interiors of tectonic plates.

They are characteristically composed of ancient crystalline basement rock, which may be covered by younger sedimentary rock. They have a thick crust and deep lithospheric roots that extend as much as several hundred kilometres into the Earth’s mantle.

The term craton is used to distinguish the stable portion of the continental crust from regions that are more geologically active and unstable. Cratons can be described as shields, in which the basement rock crops out at the surface, and platforms, in which the basement is overlaid by sediments and sedimentary rock.

The word craton was first proposed by the Austrian geologist Leopold Kober in 1921 as Kratogen, referring to stable continental platforms, and orogen as a term for mountain or orogenic belts. Later Hans Stille shortened the former term to kraton from which craton derives.[4]

Examples of cratons are the North China Craton, the Sarmatian Craton in Russia and Ukraine, the Amazonia Craton in South America, the Kaapvaal Craton in South Africa, the North American or Laurentia Craton, and the Gawler Craton in South Australia.

https://en.wikipedia.org/wiki/Craton

[Ruy Dias de Bivar]

So, where are the Mountains of Madness, and their vicious giant penguins?

[Red Badger]

They weren’t ‘lost’, we knew where they were the whole time!..............

[ETL]

[LYDIAONTARIO]

Wakanda??

[BobL]

Thanks ETL, it took until Post #6, but I knew there’d be pictures!

[jonascord]

Between the time when the oceans drank Atlantis and the rise of the Sons of Aryas, there was an age undreamed of...

Is this where Crom dreams, in his mountain?

[SamAdams76]

It just seems like a very cold and desolate place.

[BEJ]

Are there cities there or is it the only continent without cities?

[TigersEye]

What would a tossed salad be without some cratons? ;)

[Darksheare]

Tekeli-li!

[redangus]

Atlantis?

[StormEye]

Could Hillary's 30,000 emails be found there?
Just wondering.