sedimentary rock notes09

Sedimentary Rocks

What are they?

3 types: Clastic or Terrigenous Biogenic Chemical

Clastic or Terrigenous sedimentary rocks WEDCC

Many depositional locations: Continental Shoreline Marine

Grain SizeName of Particle Size Range Loose Sediment Consolidated Rock

Boulder >256 mm Gravel

Conglomerate or Breccia (depends on rounding)

Cobble 64 - 256 mm Gravel

Pebble 2 - 64 mm Gravel

Sand 1/16 - 2mm Sand Sandstone

Silt 1/256 - 1/16 mm Silt Siltstone

Clay <1/256 mm Clay Claystone, mudstone, and shale

Texture Sorting- how uniform

the particle size is

Rounding- angular to rounded

Sedimentary structures

Bedding (stratification) Cross-bedding Ripples Fossils

Biogenic sedimentary rocks

Usually carbonate sediments

Classified by mineral composition

Created through biological processes

Limited depositional location

Chemical sedimentary rocks

precipitation of salts from solution Marine or non-marine Gypsum Halite

Education