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Shock dynamics

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Shock Dynamics geology theory

Shock Dynamics geology is a theory of global tectonics on Earth that is quite different from Plate Tectonics theory, although its outcomes would lead to the appearance of Plate Tectonics activity today.

The account

It states that a protocontinent was split into the current arrangement of continents and islands in about 26 hours by the impact of a chondritic meteorite about 78 miles in diameter, striking north of Madagascar in what is today the West Somali Basin. All landmasses that moved (North America, South America, Antarctica, Australia, India, Southeast Asia) went directly away from this central point, leaving a trail of rifting and other features on the seafloor. At that point is an apparent central peak (Wilkes Rise, north of Aldabra Atoll) of a complex crater. The force of the impact impelled all of the surrounding continental crust away from the crater so that it is not easily discerned, although the Comoro Islands and Amirante Trench provide some definition.

The movement of landmasses produced the world’s mountain chains as the result of either impulse, collision, or friction with oceanic crust, according to the theory. The interaction of a surface shock wave with landmasses as far east of the impact as the Philippines and the Tonga Trench is given as the reason for the estimate of 26 hours for the duration of the event.

OutsideMounts.jpg

Origin

The Shock Dynamics geology theory was conceived by John Michael Fischer in 1986, published in the Creation Research Society Quarterly in 1992(Fischer), presented at the 3rd International Conference on Creationism in 1994(Fischer), and published on his website [1] in 2003.

From 1987 on, details of global seafloor topography were available on maps made using satellite altimetry data, which is sensitive to mass, and thus is influenced more by bedrock than by overlying sediment. By contrast, bathymetry measures sediment contours of the seafloor surface.

Unlike global tectonic theories that were inspired by the simple fit of South America to Africa and the Mid-Atlantic Ridge, Shock Dynamics was derived from the complex morphology of regions such as Southeast Asia, Australasia, the Bering Sea, and the Scotia Sea.

ETOPO1 Pacific poster snip.JPG

The visual evidence led the theory’s author to conclude that landmasses slid distances ranging from 3600 to 8000 miles at speeds ranging from 150 to 335 mph (the estimated speed of the surface wave) before coming to an abrupt stop. His force calculations show the explosive force of the giant meteorite was sufficient to propel the continental crust over a frictionless surface.[2] To account for the low friction, he applied the concept of acoustic fluidization to continental crust, which has shown characteristics of a Bingham fluid in its reaction to large meteorite impacts, seismic slip, and long-runout landslides.(Melosh) In the case of actual long-runout landslides, acoustic fluidization explains the movement of the mass over level ground up to 30 times the distance of a normal fall: a thick mass confines high vibrational energy to the base, lowering the coefficient of friction to near zero. When the overburden eventually spreads out and thins, particularly near the leading edge, energy is dissipated and normal friction brings the mass to a halt.(Campbell)[3]

Longrunout.jpg

Ejecta

Tektites are impact ejecta that range in size from tiny glass droplets (microtektites) to large, dark, layered objects. They are grouped into “strewnfields” that can be associated with particular impact craters chemically. The Australasian tektite strewnfield covers 15% of Earth’s surface and resulted from a single impact. To date, no source crater has found consensus with the scientific community.(Folco) Shock Dynamics claims that these tektites are the product of its giant meteorite impact. While microtektites would have been launched high into the atmosphere, the largest types, splash and Muong Nong (which are as much as 4 inches long and weigh up to 53 pounds), would have been launched ballistically from the crater.(Koeberl) In the Shock Dynamics reconstruction of the protocontinent, continental crust that became Southeast Asia, where the large Muong Nong-type tektites are found, lay only a short distance downrange from the impact.

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Appearance today

Shock dynamics attributes the appearance of Plate Tectonics motion today to an extremely slow driving force:

The Moon constantly slows Earth's rotation by pulling on Earth's tidal bulge. The approximately "2-3 degree tidal lag angle between the tidal bulge and the gravitational alignment between the Earth and Moon determines a permanent torque toward the 'west', opposite to the eastward rotation of the planet. This torque is considered responsible for the secular deceleration of the Earth, and acts directly on the lithosphere."(Riguzzi) "To conserve the angular momentum of the system, the Earth's deceleration is mostly compensated by the enlarging of the Moon's orbit, at a rate of 38.2 + 0.7 mm/yr."(Riguzzi)

The torque acts directly on Earth's outer shell, the lithosphere; less so on the mantle below the lithosphere. The result is that the lithosphere constantly drifts slightly to the west relative to the mantle; a differential rotation.(Smith) "The cumulative effect of this small horizontal motion... may well reach several centimeters (7-14) per year". "The advantage of this mechanism is to act contemporaneously all over the lithosphere."(Riguzzi) However, the force is distributed unevenly among the lithospheric plates, so they move at different rates.(Crespi)

While Shock Dynamics acknowledges that this force causes measurable plate motion, it also shows that all Plate Tectonics driving mechanisms are inadequate to raise mountain chains, split lithosphere, or initiate subduction.

Versus Plate Tectonics problems

Shock Dynamics claims to provide solutions to flaws in Plate Tectonics theory:

1. Raising mountain chains. The principal driving forces of Plate Tectonics are slab pull, ridge push, and basal drag, but they are too weak to raise mountain chains. In terms of bars (a unit of pressure), estimates for slab pull are 300–500;(Bird)(Meijer) 200–400 for ridge push;(Meijer) and 200 for basal drag,(Price) while the compressive force needed to push up mountain chains is estimated to be from 1500–2500 up to 4000–6000.(Price)(England) Shock Dynamics says that the momentum of landmasses sliding at up to 335 mph was sufficient to raise mountain chains by collision, as with the Himalayas, or by braking friction along the leading edge, as with the Andes and Rocky Mountains. The website shows calculated estimates of the dynamic forces involved.[4]

2. Orogeny past subduction zones. Compressive mountain building in Plate Tectonics theory should be limited to the edge of subduction zones because continental crust is attached to the lithosphere,(Burov) yet the mountains often extend far inland, such as the Tien Shan Mountains, which are 400-1000 miles beyond the collision front with India.

Shock Dynamics says that continental crust is already independent of the lithosphere below it, bounded by the Mohorovičić discontinuity at the base of continental crust, so compressive forces can extend beyond the collision zone.

3. Initiating one-sided subduction. Plate Tectonics theory is based on mantle convection. If subduction were to get started using convection, modeling shows that both sides of the surface layer would descend into the mantle.(Lowman) Yet this occurs nowhere on Earth; all subduction is one-sided.

Shock Dynamics says that subduction zones were initiated at the surface during the giant impact event by the compressive force of the leading edges of moving landmasses or by the final position of the shock wave in oceanic crust, both of these producing subhorizontal planar faults. This would also explain the observed lack of loose sediment that would be expected to have piled up where oceanic crust descended over millions of years.

4. Splitting lithosphere. There are a dozen or more lithospheric plates identified on Earth, including a number of “diffuse” plate boundaries spread over broad areas.(Anderson) However, like the other rocky planets in the solar system, it is unclear why the entire Earth is not covered by an unbroken shell of silicate rock, a “stagnant lid”, rather than many plates.(Korenaga) While the idea is plausible that weakness along a passive continental margin, such as the east coasts of North and South America, could lead to breaks in the lithosphere, it has not actually happened throughout the existence of the Atlantic Ocean, except at the small Carribean and Scotia arcs, so what was the mechanism?(Silver) Just splitting continental crust requires extraordinary force.

Shock Dynamics says that the faults in oceanic crust resulting from the giant impact continued to grow from the top down under the force of tidal drag between the Earth and Moon in the years since the event, producing Benioff zones and measured plate speed that varies with location but averages about 5 cm per year.(Scoppola)

Relevance to creationism

Plate Tectonics theory accepts 200 million years for the time from initial break-up to the present for its most recent supercontinent, Pangaea. This conflicts with those creationist timelines that require rapid protocontinent break-up. On a biblical timeline, Shock Dynamics suggests its rapid continental division occurred 530 years after the Noahic Flood (in the time of Peleg, Genesis 10:25, Septuagint text) in accord with biblical scholar Dr. Bernard E. Northrup.[5] It assigns the deposition of Cenozoic strata, with predominantly mammal fossils, to this event in contrast to the Paleozoic and Mesozoic strata deposited by the Noahic Flood and folded by compression during the Shock Dynamics event.

It finds other implications from a delay of 530 years between the end of the Noahic Flood and mountain building: Flood waters would have needed to rise only a few hundred feet to cover the highest hills; animal and human occupants of the Ark would not have had to descend over 13,000 feet down a volcanic mountain to a river basin in the rugged region there today; and all living things could have readily dispersed throughout the protocontinent before it was split apart by the Shock Dynamics event.

Obstacles

The Shock Dynamics meteorite impact site is not typical. Craters are often recognized by their crater walls, even when partially eroded. But according to Shock Dynamics, the enormous underground explosion penetrated the subcontinental lithospheric mantle and dispersed the surrounding continental crust, eliminating this feature. Only the Comoro Island arc and Amirante Trench delineate a partial boundary.

The sliding of continental crust is a deduction of Shock Dynamics theory from visual evidence, but it is counterintuitive; we don't see continents sliding. The applicability of acoustic fluidization at such a grand scale is unknown.

Could life on Earth survive an impact of the magnitude described by the Shock Dynamics geology theory?

On a biblical time scale, the Shock Dynamics impact occurred “in the days of Peleg” (Gen. 10:25), according to the theory. However, the meaning of this verse is disputed as to whether it was mainly land or people that were separated by water. Also, there is the question of why such a huge and consequential catastrophic event would not be described at length in the Old Testament, as the Noahic Flood is. On the other hand, there is a large difference in duration: Noah was on the Ark for a year; the Shock Dynamics event happened in one day. Also, none of the 190 meteorite craters in the Earth Impact Database[6] have a record in the Bible of their formation by impact.

Long half-life radiometric dating measures the ratios of parent and daughter elements in sample rocks. Reported dates for oceanic crust support Plate Tectonics’ idea of spreading lasting 200 million years. This problem must be addressed for creationist geology theories to be widely accepted.

References

  1. Fischer, J. Michael. 1994. A Giant Meteorite Impact and Rapid Continental Drift. in Proceedings of The Third International Conference on Creationism, Robert E. Walsh, editor, pp. 185–197
  2. Fischer, J. Michael. March 1992. Dividing the Earth. Creation Research Society Quarterly, Vol. 28, No. 4, pp. 166-169
  3. Melosh, H. Jay. 1979. Acoustic Fluidization: A New Geologic Process? Journal of Geophysical Research, Vol. 84, No. B13, pp. 7513-7520
  4. Campbell, Charles S. 1989. Self-lubrication for long runout landslides. The Journal of Geology, Vol. 97, No. 6, pp. 653-665
  5. Folco, L., B.P. Glass, M. D’Orazio, P. Rochette. 2018. Australasian microtektites: Impactor identification using Cr, Co and Ni ratios. Geochimica et Cosmochimica Acta, Vol. 222, pp. 550-568
  6. Koeberl, Christian. 1992. Geochemistry and origin of Muong Nong-type tektites. Geochimica et Cosmochimica Acta, Vol. 56, No. 3, pp. 1033-1064 DOI:10.1016/0016-7037(92)90046-L
  7. Riguzzi, Federica, Giuliano Panza, Peter Varga, Carlo Doglioni. 2010. Can Earth's rotation and tidal despinning drive plate tectonics? Tectonophysics, Vol. 484, pp. 60-73.
  8. Smith, Alan D., Charles Lewis. 1999. Differential rotation of lithosphere and mantle and the driving forces of plate tectonics. Geodynamics, Vol. 28, pp. 97-116
  9. Crespi, M., M. Cuffaro, C. Doglioni, F. Giannone, F. Riguzzi. 2007. Space geodesy validation of the global lithospheric flow. Geophysical Journal International, Vol. 168, pp. 491-506 DOI:10.1111/j.1365-246X.2006.03226.x
  10. Bird, Peter, Zhen Liu, William Kurt Rucker. 2008. Stresses that drive the plates from below: Definitions, computational path, model optimization, and error analysis. Journal of Geophysical Research, Vol. 113, B11406, pp. 1-32
  11. Meijer, P.Th., M.J.R. Wortel. July 30, 1992. The Dynamics of Motion of the South American Plate. Journal of Geophysical Research, Vol.97, No. B8, pp.11,915-11,931
  12. Price, Neville J. 2000. Major Impacts and Plate Tectonics - A model for the Phanerozoic evolution of the Earth's lithosphere. CRC Press, London. 368 pages
  13. England, Philip, Gregory Houseman. March 10, 1986. Finite Strain Calculations of Continental Deformation 2. Comparison With the India-Asia Collision Zone. Journal of Geophysical Research, Vol. 91, No. B3, pp.3664-3676
  14. Burov, Evgene B. 2011. Rheology and strength of the lithosphere. Marine and Petroleum Geology, Vol. 28, No. 8, pp. 1402 – 1443
  15. Lowman, Julian P. 2011. Mantle convection models featuring plate tectonic behavior: An overview of methods and progress. Tectonophysics, Vol. 510, pp. 1-16
  16. Anderson, Don L. 2002. How many plates? Geology, Vol. 30, No. 5, pp. 411–414
  17. Korenaga, Jun. 2007. Thermal cracking and the deep hydration of oceanic lithosphere: A key to the generation of plate tectonics? Journal of Geophysical Research Atmospheres, Vol. 112, B05408, 20 pages. DOI:10.1029/2006JB004502
  18. Silver, Paul G., Mark D. Behn. 4 January 2008. Intermittent Plate Tectonics? Science, Vol. 319, pp. 85-88
  19. Scoppola, B., D. Boccaletti, M. Bevis, E. Carminati, C. Doglioni. January/February 2006. The westward drift of the lithosphere: A rotational drag? GSA Bulletin, Vol. 118, No. 1/2, pp. 199-209

External links