Normalized oxygen isotope composition in relation to a tectonically st

Shown here is the same oxygen isotope curve as above, over the past ~400,000 years. On a tectonically stable coast, such as Florida, the land is not uplifting and because the coast is a lower-energy one, wave-cut benches are not as common as in California. However, coral reef growth can take place in favorable locations and the tops of some coral reefs are found just a bit below sea level at the time of growth. Thus, past interglacial high-stands of sea are recorded as coral reef limestones, stacked one on top of the other (see diagram). Deeper limestones are progressively older and each successive reef is marked by a buried soil (paleosol) that formed during the intervening glacial period, when sea level was low.