Review of 'Phanerozoic Climate and Vertical Tectonic Cycles'

I am grateful to Professor Karl Karlstrom for having taken the time to read and review this short paper that has as its aim the assessment of whether the evidence of the Grand/Bryce Canyons support a previously proposed theoretical model suggesting there is a possible causal link between the onset of renewed pulses of sedimentation, following often long hiatuses in which either no sedimentation occurred and/or whatever sedimentation occurred had been eroded, and the onset of hot-house climatic conditions. The motivation for this short paper was an increasing realisation on the part of not just the author but also a widening community of geologists, that the current dominant model within the geologic sciences seriously fails to account for vertical tectonics, especially in zones remote from any recognised plate tectonic activity, such as the intra-cratonic areas of the Colorado Plateau. This view was reinforced at the recent Geological Society of London meeting¹ where the gathering of many of the world’s recognised pioneers of plate tectonics were challenged to provide credible explanations for the vertical tectonics at passive margins, where synchronous, kilometre scale burials and exhumations, occur over widely dispersed geographical areas at times that have little evident relationship with plate tectonic events¹. Based upon an extensive synthesis of AFTA, SLA and existing geological evidence any credible explanations of elevated passive continental margins (EPCMs), and it should be added intra-cratonic areas, it was suggested would need to satisfy “seven propositions^2,3, namely:

“1: EPCMs are not the inevitable consequence of rifting and breakup

2: Elevated topography at present-day EPCMs developed long after breakup

3: Similar EPCM landscapes at different margins suggest similar controlling

processes

4: EPCMs undergo episodic burial and exhumation rather than slow

monotonic denudation, both before rifting and after breakup

5: Post-breakup exhumation at continental margins is not restricted to

elevated onshore regions

6: Post-breakup burial and exhumation have affected low lying margins

as well as EPCMs

7: Exhumation events show a broad level of synchroneity across continents

and oceans and correlate with plate boundary events and changes in plate motions.”

For a period of many years the author has been grappling with closely related challenges and had developed an alternative narrative which has the potential to account for observed vertical tectonics at EPCMs as well as intra-cratonic areas^13,14 including possible satisfaction of the seven Green propositions. The written paper relating to reference (14) was rejected for publication by the GSL and there the matter would have probably rested had it not been for the author, in preparing for short talks to the UCL Science Society and Natural Science Club, coming across the report of the William Smith Meeting¹ and the important intervention of Paul Green et alia, also covered in References (2,3).

This alternative narrative is based upon surficial processes that have the potential to alter the geothermal heat flux. There is compelling evidence that long term alterations in the surficial distribution of water and ice can result in sufficient changes in geothermal heat flux, to cause long term changes in crustal thickness with associated isostatic adjustments that can start to explain the cyclical kilometre scale burials and exhumations of crust. And of course the fairly recent recognition that Earth has over at least the Phanerozoic (and very possibly well before) experienced at roughly 130Ma periodicity cycles of ice- and hot-house climate is potentially a major factor in determining the global distribution of ice and water. Incidentally, the author cannot understand why the reviewer suggests these long term cycles of climate are “unreferenced”. The works of Shaviv and Veizer (given as references 8 and 9 repeated below) are considered by the author as perhaps the most compelling in this regard in that they not only refer to the geological evidence of climate change but also relate these cycles to variations in the cosmic ray flux CRF resulting it is believed from the solar system’s motion through the spiral arms of the galaxy. Of course there are increasing numbers of other works alluding to these climate cycles but none in the author’s view as conclusive.

This geothermal flux interpretation of vertical tectonics predicts that an area experiencing long term transition from ice cover to sea water transgression, or even a long term transition from low lying continental crust to sea water transgression, will likely see the crust thinning and consequently subsiding even as sediments are added. In other words, the conditions required for the onset of sedimentation would according to this new theory be predicted to occur when Earth climate transitions from ice-house to hot-house. To look at the geological evidence from the rocks of the Grand Canyon and adjacent areas seemed a sensible way to test this theory since it is well documented by especially Sloss^6,7 that the patterns of sedimentation in this region display remarkable synchronicity with similar patterns of sedimentation over widely dispersed areas within not just N America but other continental locations. The reviewer suggests that it is perhaps stretching a point to claim that any correspondence between prediction and the evidence of just the Grand/Bryce Canyons is somehow confirmation of this new theoretical model. However, when the evidence of Sloss and so many others is taken into account then it follows that any correlation in the GC area is implicit confirmation that similar correlations would apply to widely dispersed areas across the globe. While he has not yet had the opportunity to do so it is certainly the aim of the author to look at other areas not already covered by Sloss et alia, such as the N Sea basin, the Paris basin, … to investigate whether the model works for other areas known to have been directly affected by ice- and hot-house cycles. That the ages of sediments immediately above the unconformities of Grand/Bryce Canyon areas support the prediction from this new theoretical model is surely a reasonably significant first step in suggesting “a causal relationship (might be) inferred from the proposed correlation”.

The author is criticised for using “out-of-date treatment of data from the Grand Canyon region”. He clearly defers to the reviewer’s considerably more detailed knowledge of the GC geology, but it would have been helpful to know what aspect of the data used would need to be revised by more recent studies. Since preparing the draft paper the author has superimposed the bar chart showing pulses of sedimentation upon a redrawn version of Sloss’s celebrated Fig 6⁶ showing the synchronous periods of deposition and non-deposition across N America. Perhaps the resulting Figure could be included in any redraft?

The author would be first to admit that many questions need to be more fully explored, such as “the durations of the different unconformities” why they “are very different, ranging from hundreds of million to just a few million years” and what are the “likely explanations for the preserved strata” and their “ages, durations, sedimentary character”. Clearly these and other important aspects will need to be thoroughly considered if a climate component is to be seen as part of the answer to global tectonics. Equally, it is conceded that a “lack of evaluation of alternate (or contributing) hypotheses, for example involving the supercontinent cycle and other tectonic forcings” and to relate very different “basinal successions” to possibly to plate tectonic interpretations involving concepts of “passive margin, to back arc basins, to interior seaway”, are areas that require consideration. However, others appear to have considered these interpretations and, as alluded to above, clearly found them wanting. Hence such matters were not considered to fall within the scope of what was intended to be a short contribution. It is the author’s intention to examine current hypotheses relating to vertical tectonics. For example, much of the work on back arc basins etc relies upon the “extensional basin” theory¹⁷. A further possible contribution to UCL Open Environment¹⁸ raises some fundamental questions about the veracity of this generally accepted and widely referenced theory.

It is of course very possible that this alternative theory may be demonstrated to be false. But the interesting correlation between its predictions and the evidence of the geology within the GC region make it at least worth serious consideration – especially in view of the widely recognised lack of an alternative.

References:

1. William Smith Meeting 2017: Plate Tectonics at 50, Geological Society London, 3 October, 2017. https://www.geolsoc.org.uk/wsmith17
2. Green, P et alia (2017) Kilometre-scale burial and exhumation of passive margins and continental interiors: an overlooked consequence of plate tectonics? Paper presented in session 8, William Smith Meeting 2017: Plate Tectonics at 50, Geological Society London, 3 October, 2017
3. Green, P et alia. Post-breakup burial and exhumation of passive continental margins: Seven propositions to inform geodynamic models, Gondwana Research, 53 (2018), 58–81.
4. Hutton, J (1795) Theory of the Earth, vol. 1, Edinburgh.
5. Sloss, LL, Krumbein, WC, Dapples, EC (1949) Integrated facies analysis, appearing in Longwell, CR, Sedimentary facies in geological history, GSA Bulletin, 39, 91-124.
6. Sloss, LL (1963) Sequences in the cratonic interior of North America, GSA Bulletin, 74, 93-114.
7. Sloss, LL (1964) Tectonic Cycles of the North American Craton, in Symposium on cyclic sedimentation: Kansas Geological Survey, ed. Merriam, D. F., Bulletin 169, 449-459.
8. Shaviv, N. J. and Veizer, J. (2003): Celestial driver of Phanerozoic climate? GSA Today, July, 4-10.
9. Shaviv, N. J. (2002): The spiral structure of the milky way, cosmic rays, and ice age epochs on Earth, New Astronomy, 8, 39-77.
10. Beus, S. S. and Morales, M. (ed) (2003) Grand Canyon geology, NY: Oxford University Press, 2^nd Edition, see contributions from Beus, S. S., Blakey, R. C. et alia.
11. Timmins, J. M. and Karlstrom, K. E. (ed) (2012) Grand Canyon geology: Two biion years of Earth’s history, GSA Special Paper 489, see contributions from Blakey, R. C., Middleton, L. T., Timmons, J. M., Karlstrom, K. E. et alia.
12. Sprinkel, D. A., Chidsey, D. C., Anderson, P. B. (ed) (2003) Geology of Utah’s parks and monuments. Utah Geological Association Publication 28, 2^nd Ed., see paper by Sprinkel, D. A.
13. Croll, J. G. A. (2007): A new hypothesis for Earth lithosphere evolution, New Concepts in Global tectonics, Newsletter, 45, December 34-51.
14. Croll, J. G. A. (2011) Some Comments on Lithosphere Evolution, paper presented at Frontiers Meeting, Geological Society London, 14 November, 2011.
15. Illis, B. (2009): Searching the Paleo Climate record for estimated correlations: temperature CO2 and sea level, see Kalenda et al..
16. Kalenda, P, Neumann et al. (2011) Tilts, global tectonics and earthquake prediction, research monograph, in press.
17. McKenzie, D. (1976) Some remarks on the development of sedimentary basins, Earth and Planetary Science Letters, 40 (1978) 25-32.
18. Croll, J. G. A. Some further remarks on the development of sedimentary basins, submitted to UCL Open Press Environment, August, 2019.

I am grateful to Professor Karl Karlstrom for having taken the time to read and review this short paper that has as its aim the assessment of whether the evidence of the Grand/Bryce Canyons support a previously proposed theoretical model suggesting there is a possible causal link between the onset of renewed pulses of sedimentation, following often long hiatuses in which either no sedimentation occurred and/or whatever sedimentation occurred had been eroded, and the onset of hot-house climatic conditions. The motivation for this short paper was an increasing realisation on the part of not just the author but also a widening community of geologists, that the current dominant model within the geologic sciences seriously fails to account for vertical tectonics, especially in zones remote from any recognised plate tectonic activity, such as the intra-cratonic areas of the Colorado Plateau. This view was reinforced at the recent Geological Society of London meeting¹ where the gathering of many of the world’s recognised pioneers of plate tectonics were challenged to provide credible explanations for the vertical tectonics at passive margins, where synchronous, kilometre scale burials and exhumations, occur over widely dispersed geographical areas at times that have little evident relationship with plate tectonic events¹. Based upon an extensive synthesis of AFTA, SLA and existing geological evidence any credible explanations of elevated passive continental margins (EPCMs), and it should be added intra-cratonic areas, it was suggested would need to satisfy “seven propositions^2,3, namely:

“1: EPCMs are not the inevitable consequence of rifting and breakup

2: Elevated topography at present-day EPCMs developed long after breakup

3: Similar EPCM landscapes at different margins suggest similar controlling

processes

4: EPCMs undergo episodic burial and exhumation rather than slow

monotonic denudation, both before rifting and after breakup

5: Post-breakup exhumation at continental margins is not restricted to

elevated onshore regions

6: Post-breakup burial and exhumation have affected low lying margins

as well as EPCMs

7: Exhumation events show a broad level of synchroneity across continents

and oceans and correlate with plate boundary events and changes in plate motions.”

For a period of many years the author has been grappling with closely related challenges and had developed an alternative narrative which has the potential to account for observed vertical tectonics at EPCMs as well as intra-cratonic areas^13,14 including possible satisfaction of the seven Green propositions. The written paper relating to reference (14) was rejected for publication by the GSL and there the matter would have probably rested had it not been for the author, in preparing for short talks to the UCL Science Society and Natural Science Club, coming across the report of the William Smith Meeting¹ and the important intervention of Paul Green et alia, also covered in References (2,3).

This alternative narrative is based upon surficial processes that have the potential to alter the geothermal heat flux. There is compelling evidence that long term alterations in the surficial distribution of water and ice can result in sufficient changes in geothermal heat flux, to cause long term changes in crustal thickness with associated isostatic adjustments that can start to explain the cyclical kilometre scale burials and exhumations of crust. And of course the fairly recent recognition that Earth has over at least the Phanerozoic (and very possibly well before) experienced at roughly 130Ma periodicity cycles of ice- and hot-house climate is potentially a major factor in determining the global distribution of ice and water. Incidentally, the author cannot understand why the reviewer suggests these long term cycles of climate are “unreferenced”. The works of Shaviv and Veizer (given as references 8 and 9 repeated below) are considered by the author as perhaps the most compelling in this regard in that they not only refer to the geological evidence of climate change but also relate these cycles to variations in the cosmic ray flux CRF resulting it is believed from the solar system’s motion through the spiral arms of the galaxy. Of course there are increasing numbers of other works alluding to these climate cycles but none in the author’s view as conclusive.

This geothermal flux interpretation of vertical tectonics predicts that an area experiencing long term transition from ice cover to sea water transgression, or even a long term transition from low lying continental crust to sea water transgression, will likely see the crust thinning and consequently subsiding even as sediments are added. In other words, the conditions required for the onset of sedimentation would according to this new theory be predicted to occur when Earth climate transitions from ice-house to hot-house. To look at the geological evidence from the rocks of the Grand Canyon and adjacent areas seemed a sensible way to test this theory since it is well documented by especially Sloss^6,7 that the patterns of sedimentation in this region display remarkable synchronicity with similar patterns of sedimentation over widely dispersed areas within not just N America but other continental locations. The reviewer suggests that it is perhaps stretching a point to claim that any correspondence between prediction and the evidence of just the Grand/Bryce Canyons is somehow confirmation of this new theoretical model. However, when the evidence of Sloss and so many others is taken into account then it follows that any correlation in the GC area is implicit confirmation that similar correlations would apply to widely dispersed areas across the globe. While he has not yet had the opportunity to do so it is certainly the aim of the author to look at other areas not already covered by Sloss et alia, such as the N Sea basin, the Paris basin, … to investigate whether the model works for other areas known to have been directly affected by ice- and hot-house cycles. That the ages of sediments immediately above the unconformities of Grand/Bryce Canyon areas support the prediction from this new theoretical model is surely a reasonably significant first step in suggesting “a causal relationship (might be) inferred from the proposed correlation”.

The author is criticised for using “out-of-date treatment of data from the Grand Canyon region”. He clearly defers to the reviewer’s considerably more detailed knowledge of the GC geology, but it would have been helpful to know what aspect of the data used would need to be revised by more recent studies. Since preparing the draft paper the author has superimposed the bar chart showing pulses of sedimentation upon a redrawn version of Sloss’s celebrated Fig 6⁶ showing the synchronous periods of deposition and non-deposition across N America. Perhaps the resulting Figure could be included in any redraft?

The author would be first to admit that many questions need to be more fully explored, such as “the durations of the different unconformities” why they “are very different, ranging from hundreds of million to just a few million years” and what are the “likely explanations for the preserved strata” and their “ages, durations, sedimentary character”. Clearly these and other important aspects will need to be thoroughly considered if a climate component is to be seen as part of the answer to global tectonics. Equally, it is conceded that a “lack of evaluation of alternate (or contributing) hypotheses, for example involving the supercontinent cycle and other tectonic forcings” and to relate very different “basinal successions” to possibly to plate tectonic interpretations involving concepts of “passive margin, to back arc basins, to interior seaway”, are areas that require consideration. However, others appear to have considered these interpretations and, as alluded to above, clearly found them wanting. Hence such matters were not considered to fall within the scope of what was intended to be a short contribution. It is the author’s intention to examine current hypotheses relating to vertical tectonics. For example, much of the work on back arc basins etc relies upon the “extensional basin” theory¹⁷. A further possible contribution to UCL Open Environment¹⁸ raises some fundamental questions about the veracity of this generally accepted and widely referenced theory.

It is of course very possible that this alternative theory may be demonstrated to be false. But the interesting correlation between its predictions and the evidence of the geology within the GC region make it at least worth serious consideration – especially in view of the widely recognised lack of an alternative.

References:

1. William Smith Meeting 2017: Plate Tectonics at 50, Geological Society London, 3 October, 2017. https://www.geolsoc.org.uk/wsmith17
2. Green, P et alia (2017) Kilometre-scale burial and exhumation of passive margins and continental interiors: an overlooked consequence of plate tectonics? Paper presented in session 8, William Smith Meeting 2017: Plate Tectonics at 50, Geological Society London, 3 October, 2017
3. Green, P et alia. Post-breakup burial and exhumation of passive continental margins: Seven propositions to inform geodynamic models, Gondwana Research, 53 (2018), 58–81.
4. Hutton, J (1795) Theory of the Earth, vol. 1, Edinburgh.
5. Sloss, LL, Krumbein, WC, Dapples, EC (1949) Integrated facies analysis, appearing in Longwell, CR, Sedimentary facies in geological history, GSA Bulletin, 39, 91-124.
6. Sloss, LL (1963) Sequences in the cratonic interior of North America, GSA Bulletin, 74, 93-114.
7. Sloss, LL (1964) Tectonic Cycles of the North American Craton, in Symposium on cyclic sedimentation: Kansas Geological Survey, ed. Merriam, D. F., Bulletin 169, 449-459.
8. Shaviv, N. J. and Veizer, J. (2003): Celestial driver of Phanerozoic climate? GSA Today, July, 4-10.
9. Shaviv, N. J. (2002): The spiral structure of the milky way, cosmic rays, and ice age epochs on Earth, New Astronomy, 8, 39-77.
10. Beus, S. S. and Morales, M. (ed) (2003) Grand Canyon geology, NY: Oxford University Press, 2^nd Edition, see contributions from Beus, S. S., Blakey, R. C. et alia.
11. Timmins, J. M. and Karlstrom, K. E. (ed) (2012) Grand Canyon geology: Two biion years of Earth’s history, GSA Special Paper 489, see contributions from Blakey, R. C., Middleton, L. T., Timmons, J. M., Karlstrom, K. E. et alia.
12. Sprinkel, D. A., Chidsey, D. C., Anderson, P. B. (ed) (2003) Geology of Utah’s parks and monuments. Utah Geological Association Publication 28, 2^nd Ed., see paper by Sprinkel, D. A.
13. Croll, J. G. A. (2007): A new hypothesis for Earth lithosphere evolution, New Concepts in Global tectonics, Newsletter, 45, December 34-51.
14. Croll, J. G. A. (2011) Some Comments on Lithosphere Evolution, paper presented at Frontiers Meeting, Geological Society London, 14 November, 2011.
15. Illis, B. (2009): Searching the Paleo Climate record for estimated correlations: temperature CO2 and sea level, see Kalenda et al..
16. Kalenda, P, Neumann et al. (2011) Tilts, global tectonics and earthquake prediction, research monograph, in press.
17. McKenzie, D. (1976) Some remarks on the development of sedimentary basins, Earth and Planetary Science Letters, 40 (1978) 25-32.
18. Croll, J. G. A. Some further remarks on the development of sedimentary basins, submitted to UCL Open Press Environment, August, 2019.