Sedimentary Rocks A sedimentary rock is made up of pieces or fragments of other rocks. Rocks can be broken up through the process of Weathering and or Erosion. Once broken down into fragments or sediments, those fragments need to be buried, compacted and cemented together.
Parts of Sedimentary Rocks Sediments Fragments of any types of rocks formed by the process of weathering – transported by erosion Weathering is the breaking down of rocks into fragments while Erosion is the removal of those fragments by wind, water, ice and gravity Water can transport sediments down stream (as shown in this animation – click) and they are deposited according to size. The smallest sediments travel the furthest.
ESRT Page 6 – shows how much stream velocity is required to move different size particles
Process of Weathering Types of weathering Chemical Where the end product has been changed. Can’t get it back to it’s original form. Mechanical Changing size, color and or shape of rocks, but NOT changing its composition
Types of sedimentary Rocks Clastic rocks – made up of fragments of other rocks Sandstone – made from particles of sand Types – sandstone, siltstone, shale, conglomerate Bioclastic – made up of fragments of once living things. Coquina – Types –Limestone – Bituminousmade from sea shells Coal Chemical – formed from minerals that precipitate or evaporate out of solution. Types – Rock salt, Gypsum, Dolostone
Key Features of SedimentaryRocks Fossils Ripple marks Geode Mud cracks
Metamorphic Rocks Formed through the process of Heat and or Pressure. Click !! Minerals may be enlarged, recrystalized or new minerals may appear.There are two areas where heat and or pressure are common occurrences Contact metamorphism Formed when magma underground heats up the rocks (but doesn’t melt them) in direct contact with the heat source. Regional metamorphism Wide scale area usually associated with plate collisions
Features of Meta Rx Foliation Mineral Alignment When minerals align themselves through the process of metamorphism. Parent Rock Where the original rock came from For example Gneiss was Granite Quartzite was sandstone