Sedimentary Rocks The most common rocks on Earth’s surface!
rocks formed from the lithification (compaction + cementation) of previously existing sediments
Processes from the Rock Cycle lithification: to harden and form rock
crystallization: solidification of dissolved minerals from solution
Types of Sedimentary Rocks depends upon what they’re made of… 1.Clastic (LARGEST GROUP): fragments of other rocks 2.Chemical: dissolved minerals 3.Biochemical: parts from living things that weren’t actually alive (shells) 4.Organic: remains of once living things (plants, tissue, etc.)
Clastic Sediments= Fragments of pre-existing rock
Sediments from here
Sand Bar
Gravel Bar
Tallus Pile
Glacial Sediment
Classification of Clastic Sedimentary Rocks Classified 2 ways: 1.Sediment size larger the size, the more immature, shorter distance traveled 2.Sediment shape more jagged the shape, the more immature, shorter the distance traveled
Grain Size
Sorting of Sediments based upon the size and shape Very Poorly SortedVery Well Sorted
Are these well sorted or poorly sorted??
Common Clastic Rocks 1. Conglomerate 2. Breccia 3. Sandstone Siltstone 4. Shale Sediment
Jagged Clastic Sediments
Rounded Clastic Sediments
Conglomerate
Chemical Sedimentary Rocks water dissolves minerals in pre-existing rocks & then evaporates EXAMPLES: 1.rock salt 2.gypsum
Biochemical Rocks: non-living remains of plants and animals; EX- Coquina
Organic Rocks: remains of the living tissues of plants and animals; EX: Peat & Coal
Organic Sedimentary Rocks- Coal Swamp
Features of Sedimentary Rocks 1.Strata: sediment layers or beds 2.Geodes: hollow rock filled with silica from groundwater, forms crystals 3.Graded Bedding: deposits sorted according to size 4.Cross Bedding: movement of sand dunes 5.Ripple Marks: from water flow 6.Mud Cracks: rapid evaporation of clay 7.Fossils: remains from plants or animals
Geodes
Graded Bedding
Cross-Bedding Bedding Planes not Parallel
Ripple Marks Beach River
MudcracksMudcracks
Mud Cracks
Fossils: Molds
Fossils: Casts