Nils Axel Morner: Neotectonics and the recent ice ages

Posted: December 8, 2012 by tallbloke in Analysis, climate, Earthquakes, general circulation, Geology, Ice ages

My thanks to Hans Jelbring, who has sent me a copy of a paper by Nils Axel Morner. The paper introduces the concept of ‘Neotectonics’ and defines the epoch as beginning around 3M years ago, when we entered the current run of glacial interglacial cycles. Nils proposes the hypothesis that movements of the tectonic plates, especially in the uplift of mountainous plateaux and the closing of the strait between South america and Antarctica, amplified the effects of Milankovitch orbital cycles and resulted in a fall in Earth’s average surface temperature. I’ve provided a few excerpts here, but be sure to download and read the whole paper, it reads easily and isn’t too long.

Neotectonics, the new global tectonic regime during the last 3 ma and the initiation of ice ages
NILS -AXEL MÖRNER

Paleogeophysics & Geodynamics, S-10691 Stockholm, Sweden

Abstract
It recently became evident that the globe experienced a significantly changed tectonic
regiment from about 3.0 Ma onwards. This puts the term “neotectonics” in quite a new
perspective. We are now able to identify the last 3 Ma as characterized by generally
intensified tectonic activity. This period may hence be looked upon as a special
“neotectonic period”. Large areas were rapidly uplifted between 3.0 and 2.5 Ma. This led
to a seemingly more general lowering of the ocean floor due to an adjustment of the
geoid-oceanoid level. The tectonic reorganization 3.0-2.5 Ma ago led to the initiation of
global ice ages, the first one of which occurred at about 2.3 Ma.

neotectonics


Introduction
The term “neotectonics” originates from Russina nomenclature (Mescherikov, 1968;
Fairbridge, 1981), where it was used to denote crustal movements during the Neogene
and Quaternary periods (i.e. from the Miocene onwards). In the rest of the world the
term has been used to denote upper Cenozoic young and on-going tectonics (Mörner,
1989; INQUA 1978–1993; Vita-Finzi, 1986), or the period when tectonic conditions of
present-day-typ began (Mörner, 1989). In most cases, there were no real grounds for
separating a general lower boundary at which “neotectonics” could be said to have
commenced globally. In the Mediterranian region, however, a new prevailing tectonic
regiment seemed to have begun at about 3.0-2.5 Ma ago when the northward push of the

African plate seemed to have been significantly intensified inducing new tectonic
conditions not only within the Mediteranian region but also far up in northern Europe
(Mörner, 1989, 1986, 1987a). In a global context, the time base for a meaningful
application of the term “neotectonics” seemed to vary greatly over the globe and rather be
of local to regional character.

In recent years, the picture has changed rapidly and significantly. We are now able to
identify a thoroughly revised senario which puts the term “neotectonics” in quite new
perspectives.

Download and read the full paper.

Comments
  1. Lance Wallace says:

    The paper appears to have been written about 20 years ago (no refs after 1992). Also not the final published version apparently. (If it is final, too bad about “regiment” (for regimen), “bagun” (for begun) multiple other typos).

    An interesting paper nonetheless. But it would be interesting to hear whether 20 additional years of work has confirmed or altered the hypotheses presented.

    [Reply] The age is one of the reasons I published it here. Typos: He’s not English, but I found his writing legible and lucid.

  2. Paul Vaughan says:

    Related: I recommend paying careful attention to the comments & illustrations of Bill Illis at WUWT — e.g. http://img844.imageshack.us/img844/6939/tempgeog45mlr.png . He understands the powerful impact of the spatial dimensions on time series (sampling dramatically altered by qualitative shift of circulatory morphology).

  3. Entropic man says:

    This is not unfamiliar. The movement of the North America, Asia and North America into their present positions are thought to play a major role in the onset of Ice Age conditions.
    These restricted water exchange between the Arctic Ocean, and its neighbours. This allowed the ocean to cool enough to form a permanent Arctic ice pack, and cool surrounding areas enough for ice sheets to develop down to 50N latitude.
    These conditions only mitigate when changes in Earth’s orbit maximise Winter insolation in the Arctic and cause a temporary interstadial like the one we enjoy at present.

  4. Tim Cullen says:

    The quarterly “New Concepts in Global Tectonics” newsletter is also an interesting read.

    PDF versions going back to December 1996: http://www.ncgt.org/newsletter.php

  5. Hans Jelbring says:

    Paul Vaughan says: December 8, 2012 at 6:22 pm

    Thanks for pointing to this interesting graph Paul. It should be noted that 18O is not necessary equivalent to temperature and the interpretation has to be very careful. It was (is?) also a proxy for ice accumulation. Is the O18 from foraminifera or from other minerals? In the former case is it from surface or bottom living foraminifera? Having said that it would be interesting to see three similar graphs from drill cores from north polar areas, equatorial areas and south polar areas.

    The major reason for my wish is to know if the beginning of the GIN Sea (Greenland, Iceland and Norwegian Seas) as a major planetary cooler would be easy to spot in such graphs. The circulation of atmosphere and currents are and is heavily influencing climate change on earth at all time scales.

    The onset of cold water production in GIN Sea is shown by accumulation of so called “drifts” north of Ireland and at similar latitudes. These are enormous “mountains” of eroded bottom sediments transported by cold bottom flowing water masses originating from the GIN Sea. They started to accumulate about 5 million years ago and had a peak about 3 million years ago if I remember correctly. Anyway, the information can be found in an excellent work: Wold, Christopher N., Cenocoic sediment accumulation on drifts in northern North Atlantic, Paleoceanography, 9, 917-941, 1994.

  6. Paul Vaughan says:

    Hans Jelbring,

    I am sure that Bill Illis will be willing & able to concisely address your questions. I can suggest keeping an eye out for his contributions at WUWT and then asking when he appears.

    A more general comment: You appear to have proper appreciation for wind’s vicious coupling with the sea. Please consider volunteering a super-refined & super-concise guest post on this topic. I volunteer to help with refinement & super-conciseness behind the scenes if you can find time. It would be of great value to have a super-concise article to which to point, as so many do not seem to realize wind’s simple & basic effects on ocean surface currents, evaporation, heat transfer, downwelling/upwelling. Perhaps they have not spent much time at sea to realize just how vicious is the coupling. Perhaps they have never been swept away by an ice flow. Perhaps they have never fallen through the ice. Perhaps they have never had ice freeze on their face from a severe wind chill during an extreme blizzard. Something else to consider: We need to find someone who can write a similarly refined & concise article on the concept thermal wind. I will be greatly indebted if anyone can do a super-concise job at this. My time is overstrained. I find it necessary to reach out for help. Deep, sincere thanks to any strong, good people who are able to help with crucial communications.

  7. Paul Vaughan says:

    “[Moderation note] Replaced ‘vicious’ with ‘viscous’. When spell checkers bite….”

    Vicious was written & intended.

    [Reply] Apologies, reverted.

  8. Brian H says:

    RU sure this isn’t paleoneotectonics? Mikey may already have a copyright.

  9. Bill McIntyre says:

    may be part of the 150,000,000 year problem?

    See : page 11 of http://rsp.com/

    Our galaxy’s inner core is like a party sparkle stick – lit at both ends and rotating like a two bladed fan.

    I think of the inner core as two massive black holes in orbit.

    At present, they are in a super critical state. The outer portions (the ends of the “barrel”) go super-critical first because of some centrifugal force assist. This results in an explosion and a compression (like Ram Jet Propulsion). This action is a bit self-sustaining so that the masses are below a critical state when they have to stop and wait for their “ingestion” to catch up. EG: While the the “sparks” are emitted in all directions, only those emitted from the leading edges of the “stick” at a certain point and angle may attain escape velocity (trajectory??). All other “sparks” are failures and are “re-ingested”. The “breaks” dividing the “arms” of the galaxy into sections (creating new arms) are obvious times when the inner core would be busy “re-ingesting”

    I suggest that the 150,000,000 year timing of the cool periods are caused by some wave form(s). that would be “laid down” in spirals (as the galactic arms but not contained to / therein)

  10. Hans Jelbring says:

    Paul Vaughan says: December 9, 2012 at 1:58 pm

    The Mörner article has been published and hopefully spell checked in:
    Ann. Brazilian Acad. Sci., (1993) 65 (Supl. 2): 295-301.

    Many thanks for your offer which I will consider carefully. Since I have written a thesis named “Wind Controlled Climate” and seen little official impact of that thesis (except hostility) I have second thoughts of what good writing articles might do. On the other hand there are some people reading posts at Tallbloke who have shown a sincere interest and you and I seem to appreciate the importance of flowing matter in relation to climate change. Your reference to the chilling factor of blowing wind hitting the face is for certain true. Obviously, you can easily imagine that stronger winds over the oceans would lead to a cooler world.

    If you send your email adress to Tallbloke for further transfer we could discuss this topic.