9 - Unravelling the Thermal History of Sedimentary Basins
Published online by Cambridge University Press: 10 May 2010
Summary
We cannot explore the sub-oceanic crust, and do not know from direct evidence whether it has been compressed, as we know has happened to the continental areas. Many geologists feel assured that the oceanic areas have always been oceanic, and that they have never interchanged places with the continents. If that be the case they have never been compressed and elevated.
Physics of the Earth's Crust – Rev. Osmond Fisher, 1881, p. 282.By this point, the task of recreating the thermal history of a prospective petroleum exploration province probably seems fraught with uncertainty and complicated mathematics. Not only do we require estimates of such tenuous parameters as the thickness, temperature and thermal properties of the lithosphere, crust and sediments, but we must also interpret often-ambiguous geological evidence for stretching factor, extension rate, age, subsidence and magmatic underplating. Even then, all of these parameters intelligently and carefully chosen only provide a history of heat flow to be superimposed over a background value, which is, itself, often a matter of some conjecture.
With good-quality data, however, most of these complications can be largely overcome. The discussions in Chapter 7 focussed on forward modelling of heat flow history – estimating what the heat flow history of a basin should have been based on its general tectonic age and style. The alternative is to reverse model the thermal history – use physical data from the basin to deduce what the heat flow history must have been. This chapter details the steps for such a procedure.
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- Crustal Heat FlowA Guide to Measurement and Modelling, pp. 293 - 302Publisher: Cambridge University PressPrint publication year: 2001