Talk:Vaalbara

Acasta Gneiss

Is there a connection with the Acasta Gneiss of the Slave craton? Vsmith 22:26, 26 July 2006 (UTC)

I cannot find any direct connection with the Acasta Gneiss in the Slave other than the corresponding Archaen time periods that do make such a connection highly probable. There might be some overlap with the Superior craton in other areas. It's a very complex tectonic stratigraphy in the Slave (see below):

"The Slave Province was not a simple continental rift as previously suggested, but represented a complex accretionary and collisional orogen with fragments of older ancient crust, juvenile arcs, mature arcs, and intervening accretionary prism material. All of these tectonostratigraphic units are cut by late granites and strike slip faults, and many are affected by late extensional collapse structures....Also of interest is the 3.0 Ga Steep Rock carbonate platform, one of the oldest most complete Archean platforms in the world. The Steep Rock platform preserves spectacular stromatolites and aragonite fans, and may be correlative with similar platforms disbursed across the Superior craton." Source: Kusky, Timothy M., Ph.D. "Homepage Research, Tectonics, Canada." Earth and Atmospheric Sciences Department, Saint Louis University. http://mnw.eas.slu.edu/People/TMKusky/canada.html

Acasta Gneiss Complex contains 4.03 Ga orthogneisses: the oldest rocks in the world. Slave craton has six distinct lithofacies and at least eight tectonothermal events." Source: Dr. Yuichiro Ueno, Assistant Professor, Research Center for the Evolving Earth and Planets, Department of Environmental Science and Technology, Tokyo Institute of Technology. Current Research Activities. Online: http://homepage.mac.com/yuee/H/research3.html

Compositional differences between Slave and other Archaen cratons (Superior, Siberian, Baltic, Kaaval): One study shows an extremely low electrical conductivity level of less than 1 Siemens in the lower crustal layer just beneath the Moho in the Slave craton which is "an order of magnitude smaller than other Archaen cratons....due to the highly anomalous composition....and absence of conducting material....In contrast, other mid- to late Archaen cratons (Superior, Siberian, Baltic, Kaavaal) have conducting material in their lower crust with a minimum conductance (conductivity-thickness product) of 20 Siemens compared to 1 Siemen for the Slave." Source: Jones, Alan J. and Ian J. Ferguson. (2001) "The Electric Moho." Nature, vol. 409, 18 January. Online: http://www.geophysics.dias.ie/~ajones/papers/74.pdfValich 10:19, 29 July 2006 (UTC)

Improvement

How about a map John D. Croft 03:26, 14 April 2007 (UTC)

age

This article is contradicted by Ur (continent) as being the first supercontinent. 76.66.202.139 (talk) 15:14, 5 May 2009 (UTC)

Ditto. I noticed that, too. TeigeRyan (talk) 20:27, 15 August 2009 (UTC)

I put a short sentence in the Ur article about the theory of Vaalbara being the first supercontinent. Bettymnz4 (talk) 21:08, 7 March 2010 (UTC)

This article's primary source in its introduction is not a reliable source. We should probably rectify that; starting off by citing enotes rather than some scientific papers is pretty sketchy. Titanium Dragon (talk) 23:36, 22 June 2014 (UTC)

It seems that neither Ur nor Vaalbara is 100% confirmed, so either or neither might have actually existed. 2601:441:467F:9E00:F907:6112:FCDE:50 (talk) 19:18, 30 March 2020 (UTC)

Reversal of SmartBot's efforts. Bettymnz4 (talk) 02:26, 6 March 2010 (UTC)

As I was working on my Saganagan Orogeny article, I wrote quite a bit about Vaalbara. I then decided that Vaalbara really didn't have anything to do with Saganagan (even though I wanted to "flesh" that article out).

I added my hyperlinks to the Saganagan article and was shocked to see that Vaalbara was not a red link. I was planning to copy and paste my information into a new article 'Vaalbara'.

Anyway, I did copy and paste my information into the existing 'Vaalbara' and then printed it out so I could work on combining the two articles.

SmartBot beat me to it!!!

I need to do more work on this.

Based on comments for my article "Rove region", to be moved to "Rove Formation", I need to do more work with citations especially.

I see in the comments for the special page intro, that a diagram of some sort is desired. I haven't found anything. Would a map of current-day South African Kaapvaal craton and/or of Western Australian Pilbara craton work? Bettymnz4 (talk) 18:47, 6 March 2010 (UTC)

I am finished.

I will apply a for peer review. Bettymnz4 (talk) 20:51, 7 March 2010 (UTC)

No, I won't apply for a peer review. After reading the information in the project box at the top of the page, it probably wouldn't get anywhere.

Today as I was adding my references to what someone else had written, it appeared that the copy had been copy-and-pasted directly from the websites without attribution. Perhaps they were worded that way in the non-footnoted references supplied by the orginal author of this piece? (I did reword them; are they reworded enough?)

I don't know if there is much more information available, as this is a theory. As it is soooo early in the Earth's history, there probably aren't maps available.

I will check in the library to see if I can find additional information.

Should I do anything with what has been presented so far?

Thank you for any and all help. Bettymnz4 (talk) 21:05, 7 March 2010 (UTC)

Supercontinent [in]formation

I removed the following off-topic content from the article. --Fama Clamosa (talk) 10:45, 17 April 2016 (UTC)

Continental plates have periodically collided and assembled in geologic periods of orogenesis (mountain building) to form supercontinents. The cycle of supercontinent formation, breakup, dispersal and reformation by plate tectonics occurs every 450 million years or so.

Supercontinent formation

Cratons are the masses of rock composing the basic, initial structure of continents; they have remained stable for billions of years throughout the process of the ocean crust being continually created and destroyed.<ref name=enotes/> Continental plates, containing the ancient cratons, have periodically collided and assembled in geologic periods of orogenesis (mountain building) to form supercontinents.<ref name=enotes>{{cite web |url=http://www.enotes.com/earth-science/supercontinents|title=Supercontinents|publisher=enotes.com Science|pages=1–2|accessdate=February 28, 2010 }}</ref> A supercontinent is a landmass composed of more than one craton.

Mechanism for breakup of supercontinents

Supercontinents act as thermal lids, blocking the escape of Earth's internal heat, so the asthenosphere overheats.<ref name=enotes/> Eventually the lithosphere begins to dome upward, it cracks, magma wells upward and fragments of the supercontinent slide off the overswell. The East African Rift valleys are a modern-day example of this breaking apart.<ref>{{Harvnb|Tarney|1998}}</ref> This cycle – the Wilson Cycle – of supercontinent formation, breakup, and dispersal, followed by convergence and patching, through plate tectonics occurs every 450 million years or so.<ref name=crater>{{Harvnb|Erickson|1993}}</ref>{{rp|90}}

• Tarney, J. (1998). "Plate Tectonics: Lecture 3, The Wilson Cycle: Rifting and the Development of Ocean Basins". University of Leicester. Retrieved April 2016. {{cite web}}: Check date values in: |accessdate= (help)

Is it possible?

Is it possible that Vaalbara looked like this? http://i.imgur.com/yGdP6rV.png — Preceding unsigned comment added by 2601:645:4000:7A80:B544:171A:1107:8AE9 (talk) 22:33, 26 April 2016 (UTC)

Why "Supercontinent"?

Why is Vaalbara called a supercontinent? It was smaller than Australia. 2601:441:467F:9E00:F907:6112:FCDE:50 (talk) 19:16, 30 March 2020 (UTC)

@2601:441:467F:9E00:F907:6112:FCDE:50 A supercontinent is a landmass consisting of almost all the land on the world. There wasn't any other land on the world during that time, so it is a supercontinent. Wikifan153 (talk) 12:20, 18 March 2023 (UTC)