Reading Check 1 Mod 19-20

list 4 steps how earth formed

1. cosmic duct

2. hot molten sphere

3. cooled elements layered by mass

4. stabilized

core

• innermost zone

• iron and nickel

• outer liquid, solid inner

mantle

• layer above core

• magma, asthenosphere, solid upper mantle

magma

molten rock

asthenosphere

• layer in outer mantle, made of semi-molten rock

lithosphere

• outermost layer, solid upper mantle + crust, soil for life

plate tectonics theory

lithosphere of Earth is divided into plates, most of which are in constant motion, proposed by Alfred Wegener 1912

evidence of plate tectonics theory

1. identical rock formations on both Atlantic sides → supercontinent broke up

2. fossils of same species on diff. lands

3. geologic activity = moving plates

earthquake

sudden movement of Earth’s crust caused by a release of potential energy tectonic plates moving

Richter scale

measures magnitude of earthquake and large ground movement (logarithmic scale)

hot spot

place where molten material from mantle reaches lithosphere., caused by plumes of heat

volcano

vent in the surface that emits ash, gases, or molten lava

volcano chains

plate moves over hot spot → heat from the rising mantle plume melts the crust

tsunami

series waves in ocean caused by seismic activity or undersea volcano causing a huge displacement of water

oceanic crusts

denser, iron, under ocean

continental

lighter, silicon oxide, under landmass

divergent boundary

area below the ocean; tectonic plates move away from each other

seafloor spreading

rising magma forms new ocean crust on the seafloor at the boundaries between plates

3 types of divergent boundaries

• volcanoes, earthquakes, rift valleys → ex: The Great Rift Valley in Africa

convergent boundary

area where one plate moves toward another plate and collides; subduction or collision zone

subduction

edge of an oceanic plate moves down beneath the continental plate and pushed toward Earth’s center

island arcs

chain of islands formed by volcanoes due to two tectonic plates doing subduction

collision zone

area where two continental plates are pushed together and the forces push up crust to a mountain range → Himalayas

transform boundary

area where tectonic plates move sideways past each other

fault

fracture in rock caused by a movement of Earth’s crust

consequences of plate movement on biodiversity

plates move → continents move → climate changes, geographic barriers add/removed

species evolve or die out

allopatric speciation

allopatric speciation

different evolutionary paths and over time evolve into two or more separate species, determined thru fossil record

impacts of earthquakes 7

• destroy buildings, fire, water, dams, death (bc close to epicenter, not magnitude)

• precaution w radioactive materials

impacts of volcanoes 8

• eject cinder, ash, dust, rock, lava

• death, habitat destruction, bad air quality, etc.

igneous rocks

formed directly from magma (heat)

brings rare elements up

basaltic rock

• dark rock, high iron magnesium calcium

• fertile soil

granitic rock

• light rock, quarts silicon aluminum potassium (crusts)

  • breaks down to sand

  • more permeable

  • fertile soil

fractures and veins

cracks when rocks cool → mineral-filled deposits in fractures, gold silver

sedimentary rocks

sediments such as muds, sands, or gravels are compressed by overlying sediments (pressure)

give 4 facts abt sedimentary rocks

• long time

• dunes, mudflats, landslide areas r buried, pressure created

• uniform composition, i.e. sandstone, or heterogenous, i.e. gravel/sand

• fossil records

metamorphic rocks

sedimentary, igneous, or other metamorphic rock is subjected to high temperature and pressure (heat and pressure)

3 facts abt metamaorphic rocks

• big physical chemical changes

• pressure from overlying rocks or tectonic processes like collisions

• humans love bc super strong and cute

rock cycle

controls constant formation, change, and destruction of rock material by tectonics, weathering, and erosion

steps of rock cycle (5)

1. Rock (igneous) forms when magma reaches surface, cools, hardens

2. Rocks broken, moved, and deposited thru weathering and erosion

3. Sedimentary rock can form from deposited material if pressure; heat and pressure would form metamorphic rock from deposited shi

4. Rock is subducted into mantle and becomes magma

5. Repeat

physical weathering

mechanical breakdown of rocks and minerals by water, wind or temp

effect of physical weathering

exposes more surface area, more vulnerable for more degradation and chemical weathering

chemical weathering

breakdown of rocks/minerals by reactions, the dissolving of chemical elements from rocks, or both

3 facts abt chemical weathering

• releases nutrients from rocks

• occurs fastest on newly exposed materials → primary → secondary → ions

• easily dissolvable rocks (CaCO3) go fast

acid precipitation

Precipitation high in sulfuric acid and nitric acid, caused by human activity emissions

erosion

physical removal of rock fragments from a landscape or ecosystem

2 mechanisms of erosion

• wind, water, ice move materials down a slope w gravity

• living organisms that burrow

what accelerates erosion

deforestation, overgrazing

4 functions of soil

• plant growth medium

• water filter

• biodiversity → provides habitats

• filter some pollution

how is soil formed briefly

physical + chemical weathering + accumulation of detritus from biosphere

where do soil properties come from

parent rock type, time, biotic and abiotic compounds

steps of soil formation process (2)

1. weathering rocks and primary minerals gives raw material for soil

2. deposition of organic matter and waste does soil formation above

5 things that affect soil

parent material, climate, topography, organisms, time

parent material

underlying rock material from which the inorganic components of a soil are derived; ex calcium carbonate → calcium ion supply

how does climate affect soil

temp, humidity, water

• too cold → slow decomposition and water

• humid → fast weathering, nutrients, decomposition

• detritus

how does topography affect soil

• steep slope soils have more erosion

• bottom of steep slope → material from higher → deeper

how do organisms affect soil

• plants take nutrients and add acids

• burrowing animals mix organic and mineral materials

how does time affect soil

US old soils support most agriculture bc constant organic input

other old soils r less productive bc maybe more water

horizons

horizontal layer in a soil defined by distinctive physical features such as color and texture

list horizons in order

O, A, (E), B, C

O horizon

organic horizon at surface, organic detritus in various stages of decomposition

humus

most fully decomposed organic matter in the lowest section of the O horizon

A horizon/topsoil

Frequently the top layer of soil, zone of organic material and minerals that have been mixed together

E horizon

zone of leaching, or eluviation, found in some acidic soils under the O horizon or, less often, the A horizon

• iron from E to B

B horizon

subsoil, soil horizon primarily of mineral material with very little organic matter, nutrients

C horizon

least-weathered soil horizon, always beneath the B horizon and is similar to the parent material

how does human activities impact the effect of water on erosion (3)

no vegetation or logging on steep → no plant roots to hold onto soil particles → rainstorms remove a lot of soil

massive landslides

topsoil loss very bad

how does human activities impact the effect of wind on erosion (3)

• wheat stems removed → bare soil exposed to wind

• drought → less crops → wind picked up more soil

• Dust Bowl

4 physical properties of soil

porosity, size/mass, water holding capacity, permeability

porosity

size of the air spaces between particles

• (small-large) clay, silt, sand

how are soils organized

percentage of clay, silt, sand → balance = loam, perfect

water holding capacity

amount of water a soil can hold against the draining force of gravity

permeability

ability of water to move through the soil

2 chemical properties of soil

cation exchange capacity

base saturation

cation exchange capacity

ability of a particular soil to adsorb and release cations

• high → gives cations to plants, but tm clay overburdens plant w water

base saturation

proportion of soil bases to soil acids, expressed as a percentage

• balance bases for growth, acids for nutrition

biological properties of soil

fungi, bacteria, protozoans

snails, slugs, insects, earthworms, rodents

most soil organisms are detritivores