4-3 Sedimentary Rock—usually forms under water notice the layers (stratification)

From Sediment to Rock Formed from sediments=small, loose solid pieces of material that come from weathered rock or living material formed in layers (may not be visible) May contain fossils examples of sediments: shells, bones mud, gravel sand, clay

How do sediments build up? Observe how sediments are deposited (website)

Sediments accumulate in layers at the bottoms of lakes or oceans (called deposition)

(examples—not to memorize) sand becomes……………sandstone gravel becomes………….conglomerate mud & clay becomes…….shale

2 forces that make the sediments into rocks (can take millions of years) 2--Cementation dissolved minerals crystallize and glue particles together (natural glue) (GLUED TOGETHER) 1--Compaction press sediment together and squeezes out the water (PRESSURE)

PERFORMANCE TASK #4

Texture of Sedimentary Rocks

3 types of sedimentary rocks (look at the type of sediment) 1--clastic 2--organic 3--chemical

Clastic=broken pieces glued together (need to look at size of pieces) Shale tiny pieces of clay thin, flat layers feels smooth due to compaction Sandstone forms on beaches, ocean floors, in riverbeds, or sand dunes fairly small pieces of sediment due to compaction & cementation Conglomerate and Breccia variety of particle sizes conglomerate=round breccia= sharp edges

2 other types of sedimentary rocks Organic-from ancient plants and animals {many extinct-may have fossils} coal=remains of swamp plants (over millions of years old) limestone=from shells and skeletons of ancient sea animals, which contain calcite (coral, clams, oysters, snails) Chemical Rocks limestone forms when dissolved calcite comes out of solution and forms crystals rock salt and gypsum form from evaporation (in dry climates)

Performance Tasks Number FIVE and EIGHT… Can now be completed Make sure you completed 5 & 8!

Questions What natural activities work to break down rock? weathering What do sand and mud become when they form sedimentary rock? Sandstone, shale and mudstone In what type of rock would paleontologists look for fossils? (organic) sedimentary –like limestone

Question--{enrich} A layer of a sedimentary rock is 2 meters (2000 mm) thick. How many years did it take for this layer to form if an average of 4mm of sediment accumulated each year? >> 500 years