Coquina – cemented aggregate of geologically modern shell fragments. Fossiliferous limestone – a cemented aggregate of original shell fragments, molds, and casts of ancient marine organisms. Note fossil mold of a shell in this specimen.
Peat, a mass of matted together plant material covered by H2O, which impedes decay. H2 and O2 are lost, concentrating carbon. Lignite, so called “brown coal”, a soft coal that forms when peat is compressed and aged, about 40% carbon.
Bituminous coal – soft coal formed when lignite is compacted and altered for millions of years, about 85% carbon, this coal is the most commonly mined and used for a fuel.
Sedimentary Rock Features • Features in sedimentary rock that reflect the sedimentary environment. • Not found in other rock types. • Features: • Stratification • Fossils • Ripple marks & crossbeds • Mud cracks • Nodules, concretions & geodes
Rock Stratification (layering) Bryce Canyon, UT Photo used with permission from Mike Jarvis, Naperville Central HS, Naperville, IL
Ripple marks caused by wave action on the sandy bottom of a shallow bay Almost identical ripple marks on the surface of a sandstone millions of years old.
Mud cracks in drying mud Mud cracks preserved on the bedding surface of a shale.
Geode Thunder Egg Groundwater dissolves hollow spaces in sedimentary rock, typically limestone, and mineral material is deposited inside the hollow with crystal points growing toward the center.
Cross-bedding at Checkerboard Mesa Zion National Park, UT Photo used with permission from Mike Jarvis, Naperville Central HS, Naperville, IL
Dinosaur skeleton preserved in sedimentary rock - China Photo used with permission from Mike Jarvis, Naperville Central HS, Naperville, IL