The Proceedings of the Eighth International Conference on Creationism (2018)

Worraker, W.J., and R. Ward. 2018. Modeling of Flood and post-Flood ocean floor cooling. In Proceedings of the Eighth International Conference on Creationism , ed. J.H. Whitmore, pp. 673–682. Pittsburgh, Pennsylvania: Creation Science Fellowship. MODELING OF FLOOD AND POST-FLOOD OCEAN FLOOR COOLING William J. Worraker , Biblical Creation Trust, P.O. Box 325, Ely, CB7 5YH, United Kingdom, wworraker@gmail.com Richard Ward , Biblical Creation Trust, P.O. Box 325, Ely, CB7 5YH, United Kingdom, richard.ward@cantab.net ABSTRACT Given that the earth’s ocean basins are geologically young, few areas being older than early Jurassic, and that most creation scientists regard Jurassic rocks as Flood deposits, these basins must have formed during and since the Flood, i.e. within no more than 4500 years. This paper represents a first attempt at modeling ocean basin formation by the separation of the continents and cooling of mantle material emplaced at spreading centres well within that limited time. We use a spreadsheet-based finite difference solution of the heat diffusion equation applied to a simple widely- used plate model of ocean lithosphere formation. Having verified our model by reproducing in detail the results of published uniformitarian calculations, we use it to demonstrate the effects of enhanced heat conduction and of a variety of heat sinks, both uniform and tailored in space and time, within a biblical time scale. Enhanced heat conduction is physically unrealistic and delivers an overwhelming heat load to the oceans, thus requiring two extraordinary changes to normal physics. A tailored heat sink reproduces surface heat flux and bathymetry profiles of the observed general forms, but predicted heat fluxes in the broad near-ridge region are far too high, and ridge profiles are too sharp. These problems stem from the presence of an apparently unavoidable near-surface thermal boundary layer. Including more realistic initial conditions and taking account of hitherto neglected geophysical processes (e.g. phase changes during magma depressurization, water production and fluid convection) to construct more sophisticated models are suggested as possible ways forward from this impasse. KEY WORDS Ocean floor; Jurassic; lithosphere; conduction; heat flow; spreading rate; modeling Copyright 2018 Creation Science Fellowship, Inc., Pittsburgh, Pennsylvania, USA www.creationicc.org 673 INTRODUCTION Today’s ocean floors are geologically young, few areas being older than early Jurassic. In uniformitarian terms this is about 200 million years old at most (Müller et al. 2008). Oceanic lithosphere consists mainly of cooling mantle material emplaced at mid-ocean ridges and spreading centres, with an overlying layer of sediment. Most of this sediment is less than 5 km thick over the larger central parts of the Atlantic and Pacific oceans (Whittaker et al. 2013). In thermal modeling oceanic lithosphere is typically taken to be about 100 km thick, although its bottom boundary is not precisely defined (McKenzie et al. 2005, Crosby et al. 2006). Both sediment and lithosphere thicken progressively away from spreading centres. Ocean tectonic plates are currently moving at half spreading rates of a few centimetres per year, e.g. ~2 cm/year in the North Atlantic, ~10 cm/year around the East Pacific Rise (Müller et al. 2008). Although these present day rates are based on data such as GPS and space geodesy measurements, accepted plate tectonic histories of ocean basins are deduced mainly from the uniformitarian ages of magnetic anomaly patterns (Müller et al. 2008, Seton et al. 2012). The total upward heat flow into the oceans is 32 TW (terawatts), which implies an average oceanic heat flux of 105 mWm -2 (milliwatts per square metre; see Davies and Davies 2010). The minimum heat flux (for the oldest ocean floor) is approximately 48 mWm -2 (Stein and Stein 1992), while the maximum, which occurs at mid-ocean ridges, is approximately 450 mWm -2 (Davies and Davies 2010); even higher heat fluxes may occur at volcanic hot-spots, but these cannot be accounted for in the global average models considered here. However the above figures serve as observational checks against our model predictions. Given that most creation scientists regard Jurassic rocks as Flood deposits, the ocean basins must have formed during and since the Flood, and most oceanic lithosphere must have cooled to its present state within that time, i.e. in no more than 4500 years, probably far less. Considerable heat is deposited by the material surfacing at spreading centres: Furlong and Chapman (2013) estimate a total heat load of ~3.9×10 14 joules per square metre of fresh ocean lithosphere, more than 30 times enough to boil off the oceans if deposited very rapidly. The associated “heat problem” is to determine how the cooling was accomplished in a short time (Barnes 1980), given that sea-floor climate proxies (notably oxygen-18 levels in marine fossil shells, quoted as δ 18 O values) do not exhibit high-temperature excursions above about 12°C as seen in the Paleocene-Eocene Thermal Maximum (Zachos et al. 2001, Cramer et al. 2009, Mudelsee et al. 2014). The approach taken here is to undertake a spreadsheet analysis of a plate cooling model based on those considered by Parsons and Sclater (1977) and by Stein and Stein (1992). Although plate models embody a drastic simplification of the physics of lithosphere formation by cooling (Crosby et al. 2006), they have been widely used and for many purposes give useful results for comparison with field data. Furthermore, since we are considering time scales several orders of magnitude shorter than those assumed in the secular literature, secondary effects such as near-surface hydrothermal cooling, latent heat effects related to partial melting of magma, or nonuniform convective motion in the underlying mantle, can justifiably be neglected in the first instance. We first analyse the model of Stein and Stein (1992) on the assumption of uniformitarian time scales in order to verify by comparison with their results that our spreadsheet is correctly set up. We then consider variations on our basic model involving (1) extremely high thermal conductivity, and (2) various spatial