Sedimentary Rocks and WES (Weathering, Erosion, Soil)

what is a Clastic sedimentary Rock?

Rock made of sediments of pre-existing rock, we can further classify by sediment size

what are the two categories of sedimentary rock?

Clastic and non clastic

Chemical sedimentary rock (non-clastic)

made from dissolved sediments that precipitate out of water, mostly inorganic, Ex: chemical limestone, chalk

biological (organic) sedimentary rock (non-clastic)

Rocks formed from biological (living) sources, such as stratified remains of plant material or carbonate shelled organisms, Ex: coal is from swamp plants and coquina is from shells

weathering

breaking of rock into smaller pieces (sediments)

Erosion

movement of sediment

deposition

dropping sediments

mechanical weathering

Breaking down of rock into smaller pieces without changing the chemistry of the rock

Chemical Weathering

Chemical reactions cause rock to break down, the chemistry of the rock has changed (physical weathering)

what are some examples of chemical weathering?

Oxidation (iron rusting), acid rain, carbonation (caves/caverns), Lichens (can grow on rocks and release enzymes to break them down)

what is deposition?

sorting is a common natural occurrence, when the force that causes erosion stops or eases large/dense sediments are dropped first, small sediments can stay suspended

how does a river erode the land

river erode the banks, over time a river bend more and more,

Oxbow lake

a lake that was a river but the loops got cut off from the main river

what are some examples of river deposits?

flood plain, delta, alluvial fan

flood plain

areas on banks of river that get flooded

delta

fan/triangle shaped deposit at mouth of river

alluvial fan

fan shaped deposited at base of mountain

Glaciers

as glacier moves the surface is scratched and rocks can be moved large distances

ocean waves

when ocean waves hit the land it causes weathering, erosion, and deposition

wind

sand dunes are in areas of high wind erosion, dunes can changed shape

mass movement

gravity causes this, Ex: landslides/mudslides, avalanches, creep (when the ground settles into new position)

what is soil?

soil is a product of weathering, erosion and deposition, soil contains sediments, organic material called humus, water, air, soil sits on top of bedrock

what is the succession of soil

soil is created over time as solid bedrock is exposed to weathering forces, as bedrock breaks down more and more living things come and add varying organic matter, soil is constantly changing

what is the order of soil horizons

o,a,b,c,d

Horizon O

organic matter/humus

Horizon A

topsoil, rich dark and at surface

Horizon B

subsoil, clay, that fell from above layer

Horizon C

partially weathered bedrock

Horizon D

solid bedrock, parent material

where are there different types of soil

not all areas have the same soil, soil is determined by parent material, time, climate, organisms, slop, warm and wet environments have high decomposition

what is a soil texture pyramid

texture of any soil can be represented by point in diagram

what are some causes of soil erosion?

Agriculture and overgrazing, construction, logging and mining

what are solution to soil erosion

windbreaks, contour faming, strip framing, no till farming

Igneous rock

cool/hardening of lava

Sedimentary Rock

weathering/erosion to sediments to compaction/cementing

metamorphic rock

heat + pressure

Pressure unloading

when top layer of rock is scraped off it relieves pressure