Figure 13.13

Depositional environments of the most common sedimentary rocks. (A) Deposits of clay in estuaries, lakes, and on the seafloor lithify into shale. This shale, called Utica shale, near Fort Plain, New York, is 450 million years old. (B) Sand dunes form in desert and coastal beach environments. These lithified dunes, which formed about 170 million years ago, are part of the Navajo sandstone formation in Zion National Park, Utah. (C) There are many kinds of limestone, but all are at least 50% calcite. Most limestone is formed as minerals dissolved in water precipitate out as a solid. These limestone rocks, which formed about 260 million years ago, are part of the Kaibab Formation in the Grand Canyon in northern Arizona.

(A. © Ron Erwin/All Canada Photos/Getty Images; Michael C. Rygel via Wikimedia Commons; B. © Witold Skrypczak/Lonely Planet/Images Getty Images; Bruce Gervais; C. © Tobias Bernhard/Oxford Scientific/Getty Images; Bruce Gervais)