Oceanic heat flow and thermal conductivity of sediments with lithology and depth.

摘要

The present study is three fold. The first part analyzes oceanic heat flow data for "pogo" (closely-spaced) measurements, to test if for regions where convection is the dominant mode of heat transfer, the measured heat flow values are more scattered and skewed to lower values, and for areas where conduction prevails, the values are normally (Gaussian) distributed and show less scatter, like previous studies suggest. Various descriptive statistics, test of the normality of the distribution, and the evolution of the scatter are used to this end and interpreted, for sites grouped according to geographic proximity.; The second part uses many more data compared to previous studies from the Ocean Drilling Program (ODP), Legs 101-128, to determine how porosity decreases with depth, to about 1 km below the seafloor, in different sedimentary environments. The goal is to determine which trend, either linear or exponential, best fits these data over this depth range. Some spatial trends of rate of porosity decrease are examined, and an attempt to predict porosity at depth is made for various tectonic settings.; Finally, the third part uses data from the Ocean Drilling Program, Legs 101-129, to determine how thermal conductivity increases with depth, to about 1 km below the seafloor, in different sedimentary environments. Again, the goal is to determine which trend, either linear or exponential, best fits these data over this depth range, and how it compares to the results of the geometric mean model of thermal conductivity as a function of porosity. The depth at which thermal conductivity starts to steadily increase is examined, and an attempt is made to predict thermal conductivity at depth for various tectonic settings. Finally, some spatial trends of rate of thermal conductivity increase in terms of lithologies and tectonic settings are observed as well.