My science/technology-related thoughts, sometimes controversial, sometimes can be based on limited knowledge base, logic can be non-perfect as well. I develop my vision in iterations. Don't take this blog as an attempt to convince anybody in anything.
Each post in this blog reflects my level of understanding of Tectonics of the Earth at the time the post was written; so, some posts may not necessarily be correct now.

12 May, 2013

Pacific basin reconstruction. The Active Fracture Tectonics approach.

400+ years ago. A concept was needed.
The Americas were "torn away from Europe and Africa . . . by earthquakes and floods"? That was the suggestion by Abraham Ortelius. (Kious, W.J.; Tilling, R.I.; USGS, This Dynamic Earth: the Story of Plate Tectonics. Retrieved 2013-04-02 <http://pubs.usgs.gov/gip/dynamic/dynamic.pdf>). 

Since then 400+ years passed. Do these centuries add to our scientific experience to allow us to advance in the Abraham Ortelius' approach to suggest the mechanism behind the observed phenomena? I think, yes. Missed was the step to develop a concept from the observation and then to check the concept over the full possible scope, that is over the entire Earth.

Observed fact is:
- Proto-Americas moved westwards off proto-Africa and proto-Europe.

Abstracted  from the observed fact the concept is:
- Continents could be torn into chunks, and the chunks could be sent west-eastwards.

The scope is The Earth. Parts left to be examined are:
- Proto-Americas' western border
- Proto-Asia's eastern border.

Checking the concept over the two borders naturally raises two questions:
- Why not proto-Americas' western chunks to be torn westwards?
- Why not proto-Asia's eastern chunks to be torn eastwards?

The scenario for Pacific basin reconstruction. Why not proto-Americas' western chunks to be torn westwards?
South Pacific. 
The concept of South Pacific "plate" reconstruction (New Zealand and Australia) was suggested by me almost 2 years ago in my posts:
"Porphyry Copper. More On Reshaping Pangaea (Gondwana)", 22-July-2011,
< http://divergent-boundaries.blogspot.com/2011/07/porphyry-copper-more-on-reshaping.html >
"Reshaping Pangaea", 12-July-2011,
< http://divergent-boundaries.blogspot.com/2011/07/reshaping-pangaea.html >

Central and North Pacific. Objects are:
- Western proto-Americas.
- South-West of proto-Europe. At the very beginning of Pangaea break-up, the mid-Atlantic divergent ridge should had started spreading out proto-Pacific-Jurassic-Quiet-Zone (proto-JQZ), the zone between proto-Americas and proto-India..
- Proto-India on the north of Australia between western margins of proto-South-America and proto-North-America, on the West of proto-Europe.
- Proto-China on the North of proto-India close to western margin of proto-North-America.
- Proto-Mongolia on the North of proto-China close to western margin of proto-North-America.

The scenario for Pacific basin reconstruction:
Pacific-Jurassic-Quiet-Zone (JQZ)
- the spreading of proto-JQZ started on Pangaea break-up.
- A number of divergent zones have been spreading the oceanic crust.
- The zones that spread crust in east-west direction were active as they developed the force to move the crust towards proto-Asia. These zones should feature magnetic lineations as the differentiation under compressional stress in divergent zone would pop-up stronger material.  See my "Hawaii Convergent, Part 3. The Moat And Arch Of Hawaii. Now: Active Fracture Tectonics." < http://divergent-boundaries.blogspot.com/2012/10/hawaii-convergent-part-3-moat-and-arch.html >.
- The zones that spread crust in south-north direction were passive. They developed due to forced opening of the area. Such zones pop-ups material that is less dense and is of lower melting temperature. These zones should not feature magnetic lineations.
- The divergent zone between JQZ and Americas moved JQZ westward.

India
The westward moving JQZ spread Proto-India even farther to the West.

China and Mongolia
A divergent boundary broke proto-North America. Western parts of proto-North America ( Proto-China and proto-Mongolia) started   their way westward. The proto-Marsupial land  ( Proto-China and proto-Mongolia)  reached probably too close to North Pole on its way leaving no choice to survive for Marsupials. The northwest direction could be explained by the divergent processes within the Pacific basin in the North-South direction .  

Some facts to look for to backup the Active Fracture Tectonics concept of Pacific basin reconstruction.
Compare to other reconstructions of Pacific Plate.
The proposed Pacific basin reconstruction does not place the proto-JQZ divergent triangle in the middle of Pacific. Instead, the proto-JQZ is the product of opening between proto-Americas and proto-India. There is no need to find an explanation how the triangle divergent hole started in the middle of the Pacific.
The combination of active/passive divergent zones within JQZ makes its chemical composition be somewhat closer to the composition of continental crust (say, the one between Ural and Putorana in Siberia. See my, Sergey D. Sukhotinsky's post "Ural-Putorana Diverged, Suggesting The Global Mechanism Behind The Event." < http://divergent-boundaries.blogspot.com/2011/08/ural-putorana-diverged-suggesting.html >).

Fossil Evidences.
Fossil evidences to tie South America (Chile & Patagonia), New Zealand, Australia, New Guinea, and New Caledonia are numerous (Nothofagus to name one). Also, history of marsupials connects all the discussed objects of the Pacific basin reconstruction (currently except for JQZ). Moreover, at least one marsupial from Argentina and Chile (monito del monte) is more genetically similar to Australian marsupials than it is to the American marsupials, - we don't need the poor monito del monte to travel through Antarctica to explain the similarity.

Geological evidence.
See my "Porphyry Copper. More On Reshaping Pangaea (Gondwana)" < http://divergent-boundaries.blogspot.com/2011/07/porphyry-copper-more-on-reshaping.html >.
Geological evidence for China and Mongolia yet to be found.

Geomorphological evidence.
Active and passive divergent zones produce different types of crust. Active divergent zone produce dense (oceanic) crust. The crust then subducts down into mantle. See my "Hawaii Convergent, Part 3. The Moat And Arch Of Hawaii. Now: Active Fracture Tectonics." < http://divergent-boundaries.blogspot.com/2012/10/hawaii-convergent-part-3-moat-and-arch.html >.
Passive divergent zones produce less dense, more buyoant crust that just can't sink in the mantle. The enormous amount of crust produced by passive divergent zones was broken into pieces under the pressure of the force developed by active divergent zones. The pieces rotated almost vertically and formed Himalaya and some other mountain systems in the region. I called the process "Green process of mountain formation" in my previous posts because it does not require "great" force, neither it requires "enormous" energy needed for "collisional" type of mountain formation.  

Why not proto-Asia's eastern chunks to be torn eastwards?
As far as I understand, Pacific basin's crustal age estimated by magnetic lineations left no time-gap for Asia's crust to move eastward up to America.

Back to suggestion of mechanism to get the Americas  "torn away from Europe and Africa ".
If suggested above the Pacific basin reconstruction is adequate,  neither "by earthquakes and floods" mechanism, nor by mantle convection mechanism looked capable of providing almost around the World trip for western proto-Americas land.

Sergey D. Sukhotinsky.
http://divergent-boundaries.blogspot.com/
http://weblogs.asp.net/SergeyS

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Message-ID: <DUB119-W19015BD2F45EBCA7BA4EB6DBA60@phx.gbl>
From: Sergey Sukhotinsky <sukhotinsky@live.com>
To: Sergey Sukhotinsky <cognitive.walkthrough@gmail.com>
Subject: Pacific basin reconstruction. The Active Fracture Tectonics approach.
Date: Sun, 12 May 2013 01:28:27 +0300
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