Student Concept Map Sedimentary Rocks Dr David Steer

Student Concept Map

Sedimentary Rocks Dr. David Steer

Rock Cycle

Group discussion time v Given: v Bag of sedimentary rocks Group these rocks in some manner.

Grouping items v Remember this exercise?

Grouping items v Group these objects in some logical way.

Depositional setting (3) Texture Grouping items v Group these objects in some logical way. Throw Target Use only hands Hit with a stick Kick

Sedimentary Rocks: Deposition v Clastic (detrital) sedimentary rocks – v v Chemical sedimentary rocks v v composed of sediments, rock and mineral fragments formed when rocks disintegrate at or near the earth's surface. precipitated from a solution (e. g. sea-water) as the result of changing physical conditions (e. g. evaporation). Biochemical sedimentary rocks – v formed by the actions of living organisms or composed of the remains of dead organisms.

Clastic or Detrital Sedimentary Rocks v Clastic v sediments Classified based on: coarse grain size particles v (gravel, v medium includes pebbles, cobbles and boulders), grain size v (sand) v fine grain size v (silt) v very May appear layered gritty feel of sample fine sediment v (clay) too fine to see

Clastic Rocks Classified Sediment Grain Size (diameter) Sedimentary Rocks Shale, Mudstone Clay less than 0. 0039 mm Silt 0. 0039 to 0. 0625 mm Siltstone Sand 0. 0625 to 2 mm Sandstone Gravel more than 2 mm Conglomerate

Review v Which rock is most likely sedimentary? Temperature when formed A B Depth C D E

Examples of clastic sedimentary rocks v Mudstone v Fine grained low energy v. Sandstone v. Medium grained moderate energy v. Individual grains visible in samples v. Conglomerate v. Medium to coarse grained high energy

Chemical Sedimentary Rocks v Chemical sedimentary rocks – v precipitated from a solution (e. g. sea-water) as a result of changing physical conditions (e. g. evaporation). v May be difficult to see layers v Biochemical v formed sedimentary rocks – by the actions of living organisms or composed of the remains of dead organisms. v Fossils usually apparent

Examples of Biochemical Sedimentary Rocks v Limestones v form when marine organisms die and their skeletons accumulate. v. Coal vforms when land plants die and their organic tissue accumulate.

Concept Map v Construct a concept map that guides you through classifying a sedimentary rock. Classify these rocks.