Sediments and Sedimentary Rocks
Sediments are solid material that has settled from a state of suspension in a fluid (water, ice, or wind).
• When lithified (consolidated or cemented) becomes a sedimentary rock.
• Sediments are derived from weathering and erosion of pre-existing rocks.
• Sediments and sedimentary rocks can help tell the geologic history of an area (discussed in Chapter 5 about marine sediments).
• Sedimentary deposits are classified by grain size and source.
• Sedimentary deposits may contain fossils.
Sediments and sedimentary rocks cover much of the seafloor around the world. Most sedimentary rocks observed on land were deposited in ocean settings, along coastlines, or in shallow seaways that flooded onto the continents in the past. Sedimentary deposits and the fossils they contain have been important sources of information for resolving questions about Earth history and climate change.