The relationship between depth and age and heat flow and age in the western North Atlantic

Abstract

Abstract There are two simple models, compatible with the theory of plate tectonics, that can account for the observed relations between depth and age and between heat flow and age for oceanic crust. The first is the cooling plate model (Langseth and others, 1966; McKenzie, 1967; Sclater and others, 1971), which has been best matched to the depth and heat flow observations by Parsons and Sclater (1977). The second is that of a growing boundary layer (Turcotte and Oxburgh, 1967; Parker and Oldenburg, 1973) that has been matched to the depth and heat flow data by Davis and Lister (1974) and Lister (1977). Both models give good agreement with observations in the range 0–80 Ma. At greater ages the observations of average depth and mean heat flow are best matched by the plate model. The models are similar in that thermal cooling is the dominant mechanism. The difference between them results from concentrating on two different aspects of the observations. In the plate model, emphasis is placed on matching the exponential decay of heat flow and depth at older ages, whereas the boundary layer model was developed to explain the relation between subsidence and the square root of time on young ocean floor. Though the predictions of the plate model best match the average observations there is a problem with this model in that the constant temperature bottom boundary condition is physically unrealistic. Parsons and McKenzie (1978) have reconciled the two models and also developed