Science in Christian Perspective

Thermal Consequences of a 
Short Time Scale for Sea-Floor Spreading
Ross 0. Barnes 
Research Associate Professor of Marine Science 
Walla Walla College 
Anacortes, Washington 98221

From: JASA 32 (June1980): 123-125.

Introduction

The concepts of sea floor spreading, plate tectonics and continental drift have revolutionized and revitalized the geological sciences during the past 15 years. Stated simply, these concepts suggest that the earth's outer shell (lithosphere) consists of a number of relatively rigid plates that are moving with respect to each other as velocities on the order of a few cm/yr. Plates are moving away from each other along the crests of mid-ocean ridges; a series of branching, interconnected, underwater mountain ranges that extend for more than 40,000 miles through all the world's oceans. As these plates move away from each other at the ridges, new ocean crust is created between the plates by volcanic activity. If the earth's surface is not growing larger, then an amount of crust equal to that generated at the mid-ocean ridges must be consumed elsewhere. This occurs mainly at the ocean trenches surrounding the Pacific Ocean where one plate slides under another, creating a topographic depression (ocean trench) with accompanying volcanic and seismic activity. This process is called subduction. The continents are part of various lithospheric plates and move passively with the larger plate of which they are a part.

The purpose of this paper is not to explain these new ideas in detail or to critically examine the evidences pro and eon. Such publications are readily available.^1-5 Assuming that sea floor spreading may have occurred in the earth's history. I would like to examine some of the consequences of such activity from the viewpoint of a short time scale Flood geology model that assumes that most of the fossiliferous stratigraphic record was developed in a few years during the global Genesis Flood and its immediate aftereffects. Specifically I develop a simple model to examine the thermal consequences of creating the present ocean crust by magna injection and cooling this new crust to near its present temperatures all within a few years.

Time Constraints on Model

Geologists have suggested that the present phase of sea floor spreading began in the Late Triassic or Early Jurassic period and continues to the present day. This process broke up one or two large super-continents and created the Atlantic, Indian and Arctic ocean basins, at the expense of the Pacific Ocean.

The oldest known ocean basin sediments are Late Jurassic and are found in the northeast Pacific and the western North Atlantic Oceans at the greatest distances from ridge spreading centers in these two ocean basins. These sediments have been dated biostratigraphically from Deep Sea Drilling Project cores from these areas.^6-8 Ocean crust existing previous to this time plus a large amount of newer crust has been subducted at present and ancient trenches or lies buried beneath thick continental margin sediments in the Atlantic Ocean. The relative timing of this sea floor spreading is deduced from an examination of the sedimentary and tectonic history of the ocean basins and continental margins and from the polar wandering curve for the various continents determined from the remancnt geomagnetism of terrestrial volcanic rocks.^2,3,9,10

Based on these evidences, the correlation of sea floor spreading history to classical continental stratigraphic geology appears to be well established in its broad outlines. There are features of the earth's sedimentary and tectonic record that suggest episodes of sea floor spreading prior to the most recent break-up of the supercontinents in the Triassic. However, the primary evidence for such activity (the geomagnetic, tectonic, and sedimentary record of the appropriately aged ocean basin crust) has been lost presumably by subduction, relegating any pre-Mesozoic sea floor spreading to the realm of geological speculation at this time.

Under a short timescale Flood geology model, the constraints of historical and archeological chronology and of the presumed character of the ante-Diluvian earth suggest that most of the fossiliferous scdimeniary rocks from at least mid-Paleozoic up to Pliocene were deposited during the Noachian Flood and at most a few years after.¹¹ The Pleistocene "ice age" epoch commenced almost immediately after the waning of the Flood and lasted, at most, several hundred years until the start of the post Pleistocene archeological period.¹² Pleistocene and recent ocean floor is represented by a narrow strip about 100 km or less wide along the midocean ridges, only a few percent of the total ocean basin area.¹³

These chronologies, of sea floor spreading and of Flood geology, suggest that almost all of the present ocean floor was created during a few years at the time of the Flood, since the history of the ocean floor is correlated stratigraphically with the continental fossiliferous rock sequence as mentioned above.

In addition, a significant amount of ocean crust created during this time has already been subdueted. so that the total amount of sea floor created during sea-floor spreading is significantly greater than that presently in existence. If we assume that ocean crust equal in area to the present ocean basins was created by sea floor spreading during the Flood event, this should underestimate the total volume of crust produced.

Sea Floor Spreading Model

The model used for calculating the thermal consequences of a short chronology sea floor spreading event uses numerical data that are the best estimates or actual calculations, and can be considered reliable for the purposes of this paper. ¹⁴

Ocean crust averaging 6.5 km in thickness exclusive of sedimentary cover and equal in area to the present ocean basins is created in a period of a few years by intrusion and extrusion of rock magma at ocean ridge spreading centers. This rock it created at an assumed temperature of 1100°C and must cool to its present average temperature of 100'C within this same short period of a few years since there is no evidence of a significant warm thermal anomaly in Pleisotocene and recent sediments and fossils.

I am not considering a detailed calculation of the actual escape of heat from the newly created crust; this would he a complex and difficult calculation. Instead, assuming that the heat can be removed from the crust by some mechanism, I ask what are the consequences of this heat release to the ocean and atmosphere of the earth?

Our first calculation is the total heat released by cooling of this new ocean crust: Q_T =2.1 x 10²⁷ calories. We can compare this with the total radiant energy absorbed by the earth from the sun in one year: Q_T/ Q_S=2400, The first consequence of this heat release from the ocean crust would be to heat the oceans to the boiling point of water assuming one atmosphere of pressure at the ocean surface:

Q_B = 1.05 x 10²⁶ calories. The oceans will proceed to boil since the heat required is only 5% of the total heat released from the new crust. The excess crustal heat is sufficient to boil away all the water at the earth's surface 2.8 times.

The final consideration of this thermal model is the escape of this heat from the earth's atmosphere into space. The temperature structure of the present earth's atmosphere is in equilibrium with the present heat budget of the earth. The escape of thermal radiant energy from the earth's upper atmosphere balances the absorption of radiant energy from the sun. The present contribution of crustal heat to the atmospheric heat balance is insignificant ~1% of absorbed solar radiation).

The Stefan-Boltzmano Law states that the total radiant energy emitted by an ideal radiator is proportional to the fourth power of the absolute temperature. ihe effective radiation temperature of the earth's present atmosphere is about 218 K (-55° C). For our purposes, we can neglect compositional and structural changes in the atmosphere due to boiling of the oceans and simply calculate the effective radiant temperature needed to remove the heat of formation of the new ocean crust. The calculations are as follows: T (1 yr.)= 1252°C; T(10 yr,) = 585°C; T(l00 yr.)= 209°C; T(250 yr.) 110°C; T (1000 yr.) = -1.6°C.

The first two figures for 1 to 10 years would represent time periods of first choice for Flood geology. However, we can see that time periods in excess of 250 years are needed to lower the effective atmospheric radiating temperature to below 100^oC. Temperatures at the earth's surface would be even higher than these radiating temperatures because the atmospheric temperature must decrease with altitude until one reaches an atmospheric density where most of the emitted thermal radiation can escape directly into space (effective radiant temperature of the earth).

Discussion

From the viewpoint of Flood geology, one is forced to compress the warm thermal anomaly into a time span of a few years. (I) The Pleistocene epoch (ice ages) must have occupied most of the time between the waning of the Flood waters and the start of the historical period, but the existence of ice caps and the isotopic temperature record allow temperature variations of only a few degrees in this period.^15,16 (2) The generation of the Pleistocene ocean floor at ridge crests ('-'100 km wide strip) within a few hundred years would have added a yearly heat load to the atmosphere approximately equal to the energy presently absorbed from the sun with very significant thermal consequences for which there is no evidence (see item 1 above). (3) The time constant for cooling of the ocean crust is on the order of 105 to 106 years," but the present thermal and bathymetric structure of ocean basins does not suggest a recent episode of very fast sea-floor spreading. In fact, she thermal and bathymetric structure of ocean basins supports the current concepts of geological chronology.^{3, 18}

Acceptance of an intermediate chronology for Genesis history that allows "tens of thousands of years for combined pre- and post- Flood events" does little to alleviate the time problem for the seafloor spreading thermal anomaly. Flood events are still compressed into a few years and the "extra time" is used to accommodate the development of extensive ante-Diluvian fossiliferous sediments and to allow more time for post-Flood "ice ages" and archeological pre-history.

However, it is obvious that dissipation of ocean crustal heat within a few years produces thermal effects in the ocean and atmosphere that are not compatible with the continuity of organic life through the Flood event or with the hydraulic evidence for conditions prevailing during the deposition of the sedimentary rocks.

The model used for the calculations is somewhat crude in many respects but it is sufficient to show the magnitude of the thermal effects. More realistic (and complex) calculations would produce similar overall results.

The sea-floor spreading thermal problem can be resolved in three ways. (I) Sea-floor spreading has not occurred, or the fast Flood geology spreading proceeded by some unknown mechanism quite different from the "normal" slow spreading process currently envisaged by geologists. (2) Sea-floor spreading and the events producing the correlated sedimentary record from Mesozoic to Recent occurred over a period of time comparable to the presently accepted ideas of geological chronology. (3) Physical "laws" were suspended or altered in some way during the "Flood event" so that the purposes of God were accomplished but the environmental conditions remained within acceptable limits.

It is noteworthy that the application of simple physical principles so well defined "short-time scale geological events" often leads to alternatives similar to the three listed above. Two of these areas are radiometric geochronology and the thermal cooling history of batholiths or large intrusive bodies. ¹⁷ The latter problem was ignored in the present paper (how the heat was initially removed from the newly created ocean crust). The long geological ages calculated from radiometric dating are based on the assumed constancy of radioactive decay rates, an unprovable though reasonable assumption from a scientist's point of view. Thermal modeling on the other hand, simply assumes constancy in the physical interactions of matter and energy, and of atomic and molecular properties. It is significant that thermal modeling of the earth's crust leads to calculated ages comparable to radiometric geochronology. Considering alternative (3) above, the required "alterations" in the interactions of matter and energy during the "Flood event" extend beyond a mere change in radioactive decay rates and must include the laws of conductive, convective and radiant heat exchange and the atomic and molecular interactions of matter.

References

¹Marvin, V. B. (1973), Continental Drift: The Evolution of a Con cept. Washington, D. C. (Smithsonian Institution Press) 239 pp. Presents the historical development of modern concepts.
²Tarling, D. H., and M. Tarling(1971), Continental Drift, A Study of the Earth's Moving Surface. Garden City, N.Y. (Doubleday) 140 pp. A popular level exposition.
³Le Pichon, X., 3. Francheteau and J. Bonnin (1973), Plate Tectonics. Amsterdam (Elsevier) 300 pp. A more technical presentation.
⁴Kahle, C. F., ed. (1974), Plate Tectonics-assessments and Re assessments. American Assoc. of Petrol. Geologists Memoir #23. A collection of papers pro and con.
⁵The most prolific anti-drifter has been A. A. Meyerhoff. For an amazing array of anti-drift evidence (some good, some indifferent, some bad) see the series of articles by Meyerhoff and others (1970-1974) in: Journal of Geology 78; 1-51, 406-444; 79, 285-32 I; 80, 34-60, 663-692; American Assoc. of Petro leum Geologists, Bulletin 56, 269-336, 337-359; and in Kahlc, C. F., ed. op. cit.
⁶Ewing, J., C. Hollister, et a!. (1970), "Deep Sea Drilling Project: Leg II," Geotimes, /5, no. 7, 14-16.
⁷Heeren, B. C., I. D. MacGregor, et at. (1972), "Deep Sea Drilling Project; Leg 20," Geotimes, 17, no. 4, 10-14.
⁸Benson, W. E., R. E. Sheridan (1976), "In the North Atlantic: Deep Sea Drilling." Geotimes, 2/, no. 2, 23-26.
For more detail than above, see respective volumes of: Initial Reports of the Deep Sea Drilling Project, Washington, D. C. (U.S. Government Printing Office).
⁹Van der Voo, R., and R. B. French (1974), "Apparent Polar Wandering for the Atlantic-bordering Continents: Late Carboniferous to Eocene," Earth-Science Reviews, 10, 99-119.
¹⁰Jurdy, 0. M., and R. Van dcr Voo(1975),"True Polar Wandering Since the Early Cretaceous," Science, 187, 1193-1196.
¹¹Coffin, H. G. (1969), Creation-Accident or Design. Washington, D. C. (Review & Herald Publishing Assoc.) see Chapter 10. pp. 108-114.
¹²This "accordianed" chronology is necessitated by well accepted dating of the historical period to within a few hundred years of the Ussher date for the Genesis flood of 2350 B.C.
¹³See map by Pitman. W. C., R. L. Larson and E. M. Herron (l974) The age of the ocean basins, determined from magnetic anomaly lineations. Geological Society of America, map & chart series MC-G.
¹⁴The author will gladly supply information on the model and details of the calculations upon request.
¹⁵Savin, S. M., R. G. Douglas and F. G. Stehli (1975), "Tertiary Marine Paleotemperatures," Geological Society of America Bulletin, 86, 1499-1510.
¹⁶Emiliani, C. (1970), "Pleistocene Paleotemperatures," Science, 168, 822-825.
¹⁷Barnes, R. 0. (1971), "Time-and Earth's History," Spectrum, 3, No. I, 29-46 (see page 41).
¹⁸Morgan, W. J. (1974), "Heat Flow and Vertical Movements of the Crust." In: A. G. Fischer and S. Judson, eds., Petroleum and Global Tectonics, Princeton (Princeton University Press) 23-43.