. Early geophysical papers of the Society of Exploration Geophysicists. Petroleum; Prospecting. 68 L. D. LEET AND W. M. EWING ported behavior of granite stands out as an exception to the law demon- strated by Adams and Williamson "that at moderately high pressures the compressibility of a fresh holocrystalline rock is an additive function of the compressibility of its minerals", and resulted in their modifying it to apply only "provided the pressure is not too low". The following quotations sum- marize the evidence which Adams and Williamson had for this change and show the
. Early geophysical papers of the Society of Exploration Geophysicists. Petroleum; Prospecting. 68 L. D. LEET AND W. M. EWING ported behavior of granite stands out as an exception to the law demon- strated by Adams and Williamson "that at moderately high pressures the compressibility of a fresh holocrystalline rock is an additive function of the compressibility of its minerals", and resulted in their modifying it to apply only "provided the pressure is not too low". The following quotations sum- marize the evidence which Adams and Williamson had for this change and show the difficulty which they encountered in explaining it. In the discussion on page 523 of their report, accompanying the graph shown in Fig. 6 here, is the following statement: "The results of Adams and Coker for six different granites provide the basis for the estimate of the range. 4000 Pressure 10000 IZO00 6000 8000 in Megabars Fig. 6. Compressibility as a function of pressure, according to Adams and Williamson. The circle and dotted line have been added to their graph. of variation for granites, at low pressures. The corresponding variation for the gabbros at low pressures is admittedly a very rough estimate representing mainly the opinion of the ; Thus, the only evidence for the anomalous behavior of the compressi- bility of rocks at low pressures seems to be the results of Adams and Coker on six granites. Even a futile attempt to find a consistent explanation for the anomaly apparently did not lead Adams and Williamson to doubt the validity of the earlier results as average figures for low pressures. Porosity was looked upon as a possible cause, but after considering it at some length, they con- cluded: "None of the rocks has enough porosity to explain, on the basis of detached voids or channels, more than a few percent of increase of com- pressibility. . The granites, moreover, although containing less than one 212. Please note that these images are ex
Size: 1751px × 1427px
Photo credit: © The Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bo, bookcentury1900, booksubjectpetroleum, booksubjectprospecting
