Radiometric age dating geology
Despite seeming like a relatively stable place, the Earth's surface has changed dramatically over the past 4.6 billion years.
Mountains have been built and eroded, continents and oceans have moved great distances, and the Earth has fluctuated from being extremely cold and almost completely covered with ice to being very warm and ice-free.
We label the Sphinx geological layers Member I, Member II, and Member III after the work of geologist K. Most of the Sphinx body is cut into Member II, seven layers that alternate softer and harder as they rise in elevation.As we pointed out in these two articles, radiometric dates are based on known rates of radioactivity, a phenomenon that is rooted in fundamental laws of physics and follows simple mathematical formulas.Dating schemes based on rates of radioactivity have been refined and scrutinized for several decades.Here is one example of an isochron, based on measurements of basaltic meteorites (in this case the resulting date is 4.4 billion years) [Basaltic1981, pg. Skeptics of old-earth geology make great hay of these examples.For example, creationist writer Henry Morris [Morris2000, pg.