Earth Sciences (Sedimentary Rock 1)

Uplift

Tectonic compression uplifts pre-existing rock to create mountains through convergence

Weathering

the breakdown of rocks by physical(mechanical) or chemical (alteration) processes

Transportation of sediment

transports sediment across Earth'ssurface to adjacent basins where they are deposited

deposition

sediments come to rest and accumulate on Earth's surface

Lithification

the process of converting sediment intos edimentary rock by compaction and cementation

Clastic/Siliclastic Sedimentary Rock

Solid rock and mineral (mostly silicates) fragments derived from both mechanical and chemical weathering of existing rocks

Chemical Sedimentary Rock

Minerals that crystallize from percipitation of ions in solution in a bodies of water

Biogenic/biological Sedimentary Rock

Rock formed from remains of plants and water-dwelling organisms

Biogenic rock classification

Composition and Texture

What is limestone primarily formed from?

Calcite (CaCO3)

What type of limestone forms from the accumulation of calcite shells and skeleton fragments?

Biogenic limestone

Where can biogenic limestone accumulate?

Along beaches or in the deep ocean

What are some limestones, like chalk, primarily composed of?

Microscopic plankton shells

What is chert composed of?

Microcrystalline quartz (SiO2)

What types of plankton contribute to the formation of chert?

Diatoms and radiolarians

Where do the remains of plankton accumulate to form chert?

On the sea floor

Coal

a carbon-rich rock formed from the accumulation of a large proportion of plant matter in a swamp or marsh

Classification of chemical sedimentary rock

composition and mode of deposition

Evapories

chemical sedimentary rocks composed of minerals precipitated from saline water (lake or sea water) as a result of extensive or total evaporation of the water.

Rock salt

comprised of the mineral halite

Rock gypsum

comprised of the mineral gypsum

Sediment

unlithified material that has been transported and deposited

physical/mechanical weathering (Regolith)

the breaking apart of rock into smaller andsmaller pieces without changing the rock's mineral chemical composition

Abrasion/Eroison

Particles of hard minerals or rock fragments carried by wind, water, or ice collide with and wear rock away. Slow process

frost (ice) wedging

water works its way into cracks in rock and, onfreezing, expands and enlarges these openings

Unloading/exfoliation

When overlying weight is removed (could be eroded rock or melted glaciers), the outer portion expands more than the rock below, and splits into sheets - expansional splitting

Saltwater wedging

saltwater seeps into rocks and then evaporates on a hot sunny day, salt crystals grow within cracks and pores in the rock.

The growth of these crystals exerts pressure on the rock and can push grains apart, causing the rock to weaken and break

Hydraulic Action

the energetic force of moving water

Biologic weathering

Plant roots in search of nutrients and water grow into and expand fractures

Human weathering

Dissolution

Minerals dissolve into soluble ions in water

Hydrolysis

Minerals react with water to form clay minerals andrelease ions into water

Oxidation/Rusting

The process where Fe eleased from Fe-bearing silicates rreacts with oxygen to form iron oxide/hydroxide

chemical weathering (sapprolith)

dissolution of limestone can create underground caverns. Eventually these can create sinkholes and "karst" topography