The increase in temperature with depth in the Earth, commonly in degrees Celsius per kilometer or degrees Fahrenheit per 100 feet. Gradients are sensitive to basal heat flow, lithology, circulating groundwater, and the cooling effect of drilling fluids. Worldwide average geothermal gradients are from 24 to 41°C/km (1.3-2.2°F/100 ft), with extremes outside this range.
- Peters, Kenneth E., David J. Curry, and Marek Kacewicz, 2012, An overview of basin and petroleum system modeling: Definitions and concepts, in Peters, Kenneth E., David J. Curry, and Marek Kacewicz, eds., Basin modeling: New horizons in research and applications: AAPG Hedberg Series no. 4, p. 1-16.