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      Phanerozoic Climate and Vertical Tectonic Cycles

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        , 1

      UCL Press

      climate, erosion, geodynamics, geothermal, hot-house, ice-house, sedimentation, subsidence, uplift, tectonics, Climate

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          Summary

          Plate tectonics appears to have no accepted explanation for the widely recognised cycles of kilometre scale uplift and subsidence - why they appear to have such regular periodicity measured in many 10’s million years, why they seem to occur synchronically over widely dispersed geographic domains, and why they so often occur at locations where plate tectonics suggests passive tectonic activity. This short paper reconsiders these cycles of uplift and subsidence so strongly in evidence within the Grand Canyon area, and especially the timing of the onset of new pulses of sedimentation as revealed by the dates of strata immediately above the major unconformities. This suggests that commencement of new pulses of marine sedimentation initiating continuous kilometre scales of burial have a strong periodic signature of circa 130Ma. It is demonstrated that these recommencements of burial of often mega sequences of sediment occur when earth climate is emerging from ice-house to hot-house conditions. Furthermore, it is pointed out that recognised periods of mountain building have similar 130Ma periodicity with phasing closely aligned with periods when earth is experiencing ice-house conditions. Tentative explanations as to why changes in climatic conditions could account for these kilometre scales of uplift and subsidence focus on the associated changes in the surficial disposition of ice and water associated with ice- and hot-house conditions and how this effects the geothermal flux. Changes in geothermal flux will as a result of phase changes at the lower crustal boundary produce changes in crustal thickness and hence crustal buoyancy, accounting for both the massive cycles of burial and those of exhumation.

          Abstract

          Evidence of kilometre scale uplift and subsidence at locations remote from any recognised plate boundaries, the existence of mega-sequences of post-rift marine sediments over widespread intra-cratonic areas, and the consideration that pulses of deposition display a clear periodicity and synchronicity over widely dispersed spatial domains, remain largely unresolved issues within current geological theory. While the exact timing of uplift and erosion associated with major unconformities are difficult to assess, the age of sediments immediately above provide vital temporal markers for the onset of subsidence and associated sea level rise. By reconsidering the much studied sedimentary sequences of the Grand and Bryce Canyon areas the following will show that the at least over the Phanerozoic eon the initiation of new pulses of deposition occur at times when earth climate is emerging from ice-house to hot-house conditions. Furthermore, the recorded periods in which global occurrences of epeirogeny have occurred will be shown to correlate closely with the end of hot-house periods and the onset of ice-house global climate conditions. Finally, some tentative thermo-geodynamic explanations for this apparent causal link between global climate and vertical tectonics will be suggested.

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          Most cited references 2

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          Sequences in the Cratonic Interior of North America

           L Sloss (1963)
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            Post-breakup burial and exhumation of passive continental margins: Seven propositions to inform geodynamic models

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              Author and article information

              Journal
              UCL Press
              1 February 2019
              Affiliations
              [1 ] University College London
              Article
              10.14324/111.444/000009.v1

              This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY) 4.0 https://creativecommons.org/licenses/by/4.0/, which permits unrestricted use, distribution and reproduction in any medium, provided the original author and source are credited.

              Geosciences

              geodynamics, geothermal, hot-house, ice-house, sedimentation, subsidence, uplift, tectonics, Climate, climate

              Comments

              Decision date: 17/9/2020

              Handling Editor: Dan Osborn

              The article is no longer under consideration for peer review in UCL Open: Environment. The authors are free to submit this manuscript to any other relevant journal. If the author wishes to re-submit this article to the journal, all the points previously raised by the reviewers and the Editor-in-Chief should be addressed.

              2020-09-17 08:45 UTC
              +1

              Decision of the handling editor after review

              This manuscript requires substantial revisions before it can be published. Once the author has revised the manuscript it shall need to undergo further peer-review. In its present form, the manuscript is missing:

              • A thorough engagement with the exiting published literature on the topic
              • An adequate description of the geology of both Grand and Bryce Canyons, which fully considers their nuances
              • Time series analysis between the local geology and the global climate
              • Theoretical justification for the proposed causal relation between climate and vertical motion
              • Discussion of possible confounding factors
              • Analysis of other locations to assess whether the proposed relation is global
              • Up-to-date and publication-quality figures
              2019-08-23 16:10 UTC
              +1
              wrote:

              Dear Chris, sorry to have missed your comments but over the last 8 months I have been preoccupied with other rather important health matters and unable to come back to what was intended to be just a short note. The aim was to highlight what is pretty well accepted evidence from the Grand Canyon area that seems to support predictions of an earlier theoretical model of what could be the cause of many forms of vertical tectonics. You will appreciate that although having had a longstanding interest in geology (going back 60 years to one of my first jobs working on the Wairakei geothermal power plant in New Zealand), my professional activities have been elsewhere. But that fresh thinking is needed to explain vertical tectonics is I think rather widely acknowledged. This is especially true of the rises and falls of oceanic and continental crust remote from any plate tectonically active areas – including the cratonic interior of N America. My own thinking on the subject explored in some earlier papers may well be off the wall but it is just possible it might help to explain processes that are widely recognised as being poorly understood. Let me respond to your various points below and then follow that with some comments on what I thought were the problems that this new publication initiative of the UCL Open press is trying to address:

              Decision of the handling editor after review (my reactions in italics)

              This manuscript requires substantial revisions before it can be published. Once the author has revised the manuscript it shall need to undergo further peer-review. In its present form, the manuscript is missing:

              • A thorough engagement with the exiting published literature on the topic
              1. presume you mean “exciting literature” which I thought I had addressed? To me the most exciting recent literature on the subject is that highlighted by Paul Green (a highly respected geologist) and his colleagues. Why is this exciting? Because they make it very clear that current models of vertical tectonics fail to account for the kilometre scale burials and exhumations of sedimentary mega-sequences, why they exhibit cyclic patterns and why these cyclic patterns are shared across very wide and seemingly unconnected geographic domains. These challenging and exciting observations have been repeatedly made since the seminal work of Sloss focused on the geology of the Grand Canyon area. But as I report in the opening paragraphs of the note the recent meeting bringing together the great and the good of the PT world were unable to provide a satisfactory response to the challenge laid down by Paul Green. The purpose of my little note was not to discuss what are in my view the various less than satisfactory theories advanced in the past 50 or so years; this I intend to do in future short notes. The aim was to simply note the interesting and potentially significant correlation between the onset of new mega-sedimentary sequences after long hiatuses and long term climate cycles – with just a hint of a possible rational model to explain this correspondence.
              • An adequate description of the geology of both Grand and Bryce Canyons, which fully considers their nuances
              1. focus of this short note is the patterns exhibited by long term sedimentary cycles – those in the 10s to 100s Ma range that are responsible for the most significant missing times at the well documented unconformities. These are fairly well documented and surely do not need repetition in this context? The various shorter term cycles are also well documented and of course will critically influence the nuances of the sedimentary sequences - if by nuances you mean the patterns reflecting shorter period cycles, then this is not the focus of the short note and would be inappropriate to its aims.
              • Time series analysis between the local geology and the global climate
              1. the relevant time scales I thought I had covered this. But I have taken on board the comments of the reviewer that perhaps I should be rather less reliant on the work of Shaviv and Viezer given their involvement in the debate as to whether CO2 is also the primary driver of short period climate change – given that their work had shown it to be an unlikely primary driver of climate change at 100Ma plus time scales. For this reason, in any revision of the short note I will make sure to reference the important work of Frakes, Crowell et alia which relies upon different climate proxies but is broadly in line with the important work of Viezer. I think the relationship between sedimentary sequences and climate at shorter (10s to 100s Ka) time scales are now fairly widely accepted; these are not the focus of this intended short note.
              • Theoretical justification for the proposed causal relation between climate and vertical motion

              This was not the aim of the short note which is why a brief summary only was provided in the appendix B. My intention is to publish a stand-alone paper addressing the theoretical model which will be an updated version of the brief account provided in the referenced, but unpublished except in ResearchGate, paper presented to the Geological Society London meeting back in 2012. Other intended papers will also demonstrate that periods of geographically widespread synchronous epeirogeny also have a very strong correlation with these long term climate cycles. These intended papers will also draw attention to some possible serious inadequacies of current thinking about mountain building, orogeny, etc

              • Discussion of possible confounding factors

              I was of course hoping that these might be revealed in the open discussion of the paper.

              • Analysis of other locations to assess whether the proposed relation is g;obal.                                                                                                      I am not sure my projected life span will allow this but surely it is not needed? Sloss, many of his contemporaries and the legions of subsequent followers have already done this very effectively. Even if I could there would appear to be no reason for me to repeat this work. What this past body of work has shown is that periods of deposition and hiatuses in deposition display synchronicity over widely dispersed geographic domains of N America and other continental areas. It follows that if the sequences within the Colorado Plateau exhibit a close relationship between the times at which new pulses of deposition begin and those when earth climate is emerging from ice-house periods, then at a similar synchronicity will exist at widely dispersed geographic domains.
              • Up-to-date and publication-quality figures

              Yes, I agree. A few of the figures were not of publication standard. In any revision these will to the best of my ability (as a pre-computer graphics fossil) be brought up to expected standards.

               

              It will I believe be a regrettable derogation of the very laudable aims of this new UCL Open publication initiative if genuinely open debate of new ideas should be repressed by the damp hand of the refereeing system. To my knowledge the work described in the short note is novel. It addresses problems in geological science that are widely recognised as being of a fundamental nature but remain inadequately explained. While it is possible that this new line of thinking may lead to a dead end it is also possible it might open up new ways of explaining some of these unresolved problems. It is noticeable that the reviews of what is just a short note have concentrated on process rather than the substantial ideas and the underlying arguments. It would be great to have the chance of discussing openly these important issues and underlying arguments.

               

              2020-03-04 11:44 UTC

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