4/23 sci vocab

Uniformitarianism

Principle stating that current geological processes also occurred in the past

Erosion

Process of wearing down and carrying away rocks

Weathering

Process breaking down rock and other substances

Mechanical weathering

Physically breaking rock into smaller pieces

Chemical weathering

Chemical changes breaking down rock (e.g., acid rain)

Permeable

Material with tiny air spaces allowing water seepage

Soil

Loose, weathered material supporting plant growth

Bedrock

Solid rock layer beneath the soil

Humus

Decayed organic material in soil

Fertility

Measure of soil's ability to support plant growth

Loam

Soil with equal parts of sand, silt, and clay

Horizon

Soil layer differing in color, texture, and composition

Decomposer

Organism breaking down dead matter

Natural resource

Environmental element used by humans

Contour plowing

Farming along slope curves

Conservation plowing

dead weeds and stalks of the previous years crop are plowed into the ground to help return soil nutrients, retain moisture, and hold soil in place.

Crop rotation

Planting different crops yearly

Fossil

Preserved remains or traces of living things

Relative age

Rock's age compared to others

Absolute age

Number of years since rock formation

Strata

Layers of rock

Index fossil

Fossils aiding in matching rock layers

Unconformity

Gap in geologic records

Half-life

Time for half of radioactive atoms to decay

Geological time scale

Record of geologic events and life evolution

Eras

Earth's history divided into 4 eras

Periods

Rows of chemical elements

Precambrian

Time period before Paleozoic era,  technically not an era referred to as a time

Paleozoic

Era of ancient life

Mesozoic

Era in geologic time

Cenozoic

Era of recent life

O horizion

A horizion

topsoil mostly minerals from parent material with organic matter incorporated.

B horizon

subsoil rich in minerals that leached from the A horizon lower limit of plant roots and burrowing animals

C horizion

weathered /aged parent material, resembles parent material 

Compression fossil-

two-dimensional organic remains.

impression fossil

two-dimensional but do not contain any organic matter

petrified

turned to rock minerals replace the organism in the fossils.

Principle of superposition-

younger strata are on top, while old strata on bottom