Changes

For these reasons, and also because of the possibility of fortuitous similarities between unrelated samples, gas chromatography seldom provides definitive positive correlations. It may, however, provide fairly definitive negative correlations. When used in conjunction with other correlation parameters, it can often be valuable for positive correlations as well, as demonstrated in the following two examples.

For these reasons, and also because of the possibility of fortuitous similarities between unrelated samples, gas chromatography seldom provides definitive positive correlations. It may, however, provide fairly definitive negative correlations. When used in conjunction with other correlation parameters, it can often be valuable for positive correlations as well, as demonstrated in the following two examples.

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file:oiloil-and-oilsource-rock-correlations_fig8-13.png|{{figure number|9}}Gas chromatograms of two oils from Wyoming. From Peters and Moldowan;<ref name=ch08r39>Peters, K., E., Moldowan, J., M., 1993, The Biomarker Guide—Interpreting [[Molecular fossils]] in Petroleum and Ancient Sediments: Englewood Cliffs, New Jersey, Prentice-Hall, 363 p.</ref> reprinted with permission from Prentice-Hall.

file:oiloil-and-oilsource-rock-correlations_fig8-13.png|{{figure number|9}}Gas chromatograms of two oils from Wyoming. From Peters and Moldowan;<ref name=ch08r39>Peters, K., E., Moldowan, J., M., 1993, The Biomarker Guide—Interpreting [[Molecular fossils]] in Petroleum and Ancient Sediments: Englewood Cliffs, New Jersey, Prentice-Hall, 363 p.</ref> reprinted with permission from Prentice-Hall.

file:oiloil-and-oilsource-rock-correlations_fig8-14.png|{{figure number|10}}Gas chromatograms of saturated hydrocarbons from an immature extract of coaly organic matter (top) and an oil with a fairly high wax content believed to have been sourced from a similar facies (bottom). Copyright: Unocal.

file:oiloil-and-oilsource-rock-correlations_fig8-14.png|{{figure number|10}}Gas chromatograms of saturated hydrocarbons from an immature extract of coaly organic matter (top) and an oil with a fairly high wax content believed to have been sourced from a similar facies (bottom). Copyright: Unocal.