Rocks III.Sedimentary rocks form from earlier rocks A.Some rocks form from rock particles 1.Sedimentary rock forms from small particles of rock getting naturally cemented together 2.Sediment are materials that settle from water or air a.Rocks and minerals b.Plant and animal remains 3.Sedimentary rock can form under water or on land from layers of sediment 4.Forming and transporting rock particles a.Wind and water remove loose particles and carry them downhill b.As the current slows down the particles start to settle, larger first

Rocks 5.Forming loose sediments into rocks a.It’s like building a road b.Loose layers of dirt and gravel are laid down c.Each layer is packed hard onto the layer below d.Each layer of sediment presses down and compacts the previous layer e.The layers may turn to rock just under pressure f.Other layers of rock are held together by minerals forming between the particles

B.Some rocks form from plants or shells 1.Coal a.Unusual sedimentary rock b.You can sometimes see forms of wood or leaves in coal because it use to be plants c.Formation is similar to particles of rock, as plants die they end up on top of other plants and pressure builds d.Scientists THINK that this process took millions of years 2.Limestone a.Made of carbonate materials, such as shells and skeletons b.Pieces of shell and bone eventually breakdown and blend into the surrounding rock and minerals c.White cliffs of Dover, England are made of chalk d.Coral is an example of natural limestone that comes from Coral organisms rebuilding layer upon layer over ole “homes” Minerals

C.Some rocks form when dissolved minerals re- form from water 1.Dissolved minerals recrystallize as water evaporates 2.Comes from water in cracks or filtering through cave walls. D.Sedimentary rocks show the action of wind and water 1.Sedimentary rocks are layered, oldest rock on bottom 2.Fossils tell some of the story 3.The types of rock in the layers also speak about what was going on at different times 4.Tilted lines=wind, ripples=moving water, cracks=standing water Minerals