Sediments and Sedimentary Rocks

Sedimentary Rocks Igneous Rocks Metamorphic Rocks Magma Sediment Pressure And Cementation Weathering/Erosion Heat and Pressure Cooling Heat Pressure Weathering Erosion

Sediments (soft) Material (such as gravel, sand, mud, and lime) that is transported by wind, water, ice, or gravity; Material that is precipitated from solution; Deposits of organic origin (such as coal and coral reefs). Sedimentary Rock (hard) Rock formed by the accumulation and consolidation of sediment.

Sediments - unconsolidated particles created by 1. The weathering of rock 2. The secretions of organisms or decomposition of organic matter 3. Chemical precipitation

Sedimentary Rocks Composed of lithified sediments - by compaction - by cementation Two (Textures) clastic (detrital) non-clastic

Types of Sediments Clastic Non-clastic 1. Biochemical 2. Chemical

1. Clastic 2. Non-clastic * Biochemical * Chemical 1. Phaneritic 2.Aphanitic * Glassy * Vesicular Igneous RocksSedimentary Rocks

1. Clastic – broken fragments of rock produced by weathering. Range in size from largest boulder to smallest clay particle. Classified according to size. Found everywhere on the Earth. Types of Sediments

Clastic Texture Texture - Size, shape, and distribution of particles that collectively make up a rock Size Rounding Sorting

Clastic Sediment Size

Clastic Texture Roundness – the shape of sediment grains. Related to the distance a sediment has been transported.

Roundness / Sphericity of Sediments

Size Rounding Sphericity Sorting

Clastic Sediments Sorting Sorting – separation of sediments by grain size and density. Poorly sorted – sediment with a wide range of grain sizes. Well sorted – sediment with a small range of grain sizes.

Sorting of Sediments

Sorting - a function of transported 1. Water 2. Wind 3. Glaciers

Texture and Transport Distance In general, as transport distance increases, rounding and sorting increase. Examples: Breccia – cemented close to source Conglomerate – transported then cemented

SourceDownstreamBeachOffshoreBasin Breccia Conglomerate Arkose Sandstone Swamp Lithic Sandstone Quartz Sandstone Reef Siltstone Shale Halite, Gypsum, Chert (Evaporites) (Playa Lake) Coal Limestone Clastic Sedimentary Rocks Smaller….Rounder…..Better Sorted Nonclastic Sedimentary Rocks Coquina Depositional Environments of Sedimentary Rocks

Transport by Water Saltation – particles move downstream in short jumps. Bed load – material transported by saltation Suspended load – material carried in water for long distances

Transport by Water

Sorting by Water Graded Beds

Fining up Graded Beds

Sorting by Wind

Cross Bedding – water or wind

Sorting by Glaciers

Clast Size / Rock Name Relationship Large ClastsSmall Clasts

Breccia - Formed at the source

Conglomerate – Formed near the source

Sandstone – Down stream to just off shore

Stream Deposit Tidal Flat Deposit

Off-Shore Environments

Strata Stratum Stratigraphy Stratigraphic - relating to layered sedimentary rocks

Bedding – Layering or stratification in sedimentary rock

2. Biochemical (non-clastic) – composed of remains of plants or animals. Types of Sediments

Biochemical Sediments (non-clastic) Corals - Large components of reefs. Bivalves, Gastropods, Foraminifers - Whole or partial skeletons form sand and gravels. Aglae, Crinoids, Echinoderms, Bryozoans - disintergrate to form some sand particles and lime mud. Diatoms, Radiolaria – Bedded chert SiO 2 Terestrial Sediments - mainly plant matter Marine Sediments - mainly carbonates

Coral (carbonate)

Foramanifera

Diatoms

3. Chemical (non-clastic) – formed by minerals precipitating from solution. - Inorganic process, no biological activity involved. Types of Sediments

Bonneville Salt Flats

Chemical Sediments (non-clastic) 1. Terestrial - Evaporites: Gypsum - CaSO 4. H 2 O Anhydrite - CaSO 4 Halite - NaCl 2. Marine - Carbonates - CaCO 3 (Whitings)

Clastic Rock – composed of fragments of preexisting rocks. Non-clastic Rock – composed of chemical precipitates or biogenic matter. Sedimentary Rocks

Ripple Marks

Mud Cracks

Burrows

Depositional Environments Where sedimentary rock live!

Delta building into lake. SE Alaska.

small fan emerging from a wineglass canyon. Death Valley, CA.

Ripples on tidal flat, SE Alaska

Son-Kul River, Tien Shan Mtns., Kyrgyzstan

Peanut Brittle Conglomerate in Southern Illinois