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.

15 April, 2013

How to spot a Geo-science talent

I posted a message "How to spot a Geo-science talent" to GEO-TECTONICS List a few days ago. I tried to show how a talented kid would approach one of the basic Plate Tectonics puzzles, - How could an oceanic plate be more dense than the underlying layer of mantle?

Being not under the pressure of need to play the "Science" game, the talented kid, would probably think simple:
- With time the oceanic plate can't get from bottom the denser material than the upper mantle itself, as the the denser material would just sink on solidifying.
- With time the oceanic plate gets thicker, not denser (roughly) as the upper and bottom temperatures are fixed, the average temperature roughly remains the same. The plate's material thermal expansion coefficient is quite low, hence the plate's average density doesn't change considerably with time.
 - So, what's the reason an oceanic plate exposes denser layers on de-lamination on subduction? Why not to suggest that the very mechanism of the plate generation produce the denser layer within the oceanic plate? That's it.
 
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My post to GEO-TECTONICS List (Tectonics & structural geology discussion list ).
title How to spot a Geo-science talent.
pubDate Fri, 12 Apr 2013 14:05:03 +0300
guid
https://www.jiscmail.ac.uk:443/cgi-bin/webadmin?A2=geo-tectonics;24cc7655.1304

Gmail posting:
date: Fri, 12 Apr 2013 14:05:03 +0300
message-ID: <
CAMETt9Vurk2XGbm6ZY=Y_3+oUyr+NyrtEmfbCky6bVjGsSj4Xg@mail.gmail.com>

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The great thing about NSF is that they are not "fixed" in some way, they publish articles not only to answer questions, but at times also to raise some: "The researchers are now trying to find the source that supplies the magma in the newly discovered layer."  from:
< http://nsf.gov/news/news_summ.jsp?cntn_id=127315 > March 20, 2013, NSF, Press Release 13-045, Scientists Discover Layer of Liquified Molten Rock in Earth's Mantle. Hidden magma layer could play role in shaping the geologic face of our planet. Why not to redirect the puzzle about the source of the magma to kids? The puzzle could sound the next way:

Facts:
- There is an incoming plate that bends and subducts under the continent.
- The plate constantly is being spread out at some oceanic ridge some thousands km away.
- The density of the plate is known to be greater than the average density of the underlying mantle.
- NSF says "Scientists have discovered a layer of liquified molten rock in Earth's mantle that may be responsible for the sliding motions of the planet's massive tectonic plates." (see the link above)

Question (by NSF):
What's the source that supplies the magma in the newly discovered layer?

Select the answers that follow the next pattern:
- The greater density can't be due to just cooling because on the transition from ductile to rigid state the elementary volumes of more dense material would just sink down. The body of the Earth vibrates and the vibration would assist the process greatly.
- So, there should exist some mechanism that differentiate the mantle material at the oceanic ridge. The denser fraction of Earth's mantle builds up the plate, the less dense fraction of it has no choice other than to find its way down.
- The less dense fraction happens to be of lower melting temperature, hence the molten layer beneath the plate. Besides, as the process involves oceanic water, the less dense fraction and high temperature, it would only be natural to expect the layer to be related to
a) abiotic hydrocarbons generation (the less dense fraction accumulates under the bent as it can't follow the plate under the continent)
b) earthquakes, as the less dense fraction tends to find its way up and, also, the molten layer serves as the lubricant for plate movement.

Spot the kids with the answers that followed the pattern and have them to rule the Geo-science :-)

Thank you.
Sergey D. Sukhotinsky.
http://divergent-boundaries.blogspot.com/
http://weblogs.asp.net/SergeyS
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Message-ID: <DUB119-W18F03EF85D55A7A8F9D99CDBCC0@phx.gbl>
From: Sergey Sukhotinsky <sukhotinsky@live.com>
To: Sergey Sukhotinsky <cognitive.walkthrough@gmail.com>
Subject: How to spot a Geo-science talent
Date: Mon, 15 Apr 2013 08:48:37 +0300
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