Geologic Distillation Of Petroleum

IN 1882, Peckham put forward a provisional hypothesis to account .or the distillation of petroleum.1 He did not formally state the hypothesis, but in a discussion of facts drawn from many fields he made it clear that he regarded petroleum, and especially the petroleum of the Pennsylvania fields, as a "fractional distillate produced under high pressure and consequently at a comparatively high temperature.?2 He quotes James Hall on the geology of the Appalachians and says:3 It is not necessary here to discuss the nature or origin of metamorphic action. It is sufficient for our purpose to know that from the upper Silurian to the close of the Carboniferous periods the currents of the primeval ocean were transporting sediments, sorting them into gravel, sand, and clay, forming gravel bars and great sand beds beneath the riffles and clay banks in still water, burying vast accumulations of sea weeds and sea animals far beneath the surface. The alteration, due to the combined action of heat, steam, and pressure, of the formations of the Appalachian system from Point Gaspe in Canada to Lookout mountain in Tennessee, involving the Carboniferous and earlier strata, distorting and folding them, and converting the coal into anthracite and the clays into schists along their eastern border, could not have ceased to act westward along an arbitrary line, but must have gradually died out farther and farther from the surface (source?). The great beds of shale and limestone containing fucoids, animal remains, and even indigenous petroleum must have been invaded by this heat action to a greater or less degree, and that "chronic evaporation" of Prof. Lesley must have been the inevitable consequence. From an investigation of the relations between coal and petroleum, White has" more recently concluded as follows: (1) Petroleum is a product generated in the course of the geodynamic alteration of deposits of organic debris of certain types buried in the sedimentary strata. (2) The quantity and characters of the oils generated are determined by: (a) the composition of the organic deposit at the beginning of its dynamo-chemical alteration; (b) by the stage in the progress of the dynamo-chemical alteration of the organic substances; (c) by the elimination, under certain conditions, of the heavier and more' viscous hydrocarbons through filtration incident to migration.