Hypothesis

A falsifiable explanation of current data

Theory

a robust widely accepted explanation of a mechanism.

Good data should be:

Objective and subjective

William Smith

Created the first geological map

Bishop Ussher

estimated Earth to be about 6,000 years old

James Hutton

Argued that modern processes help explain rocks and that earth is very old

Charles Lyell

important geology textbook

Alfred Wegner

proposed continental drift

Evidence for continental drift

1. puzzle-like fit of continents 2. fossils 3. coal seams/ field 4. mountain ranges

Problem with Wegner's ideas

He didn't have a mechanism for how the continents moved

Mid-oceanic ridges

Really high Made of rocks that are different than terrestrial ridges

Central rift valley

When plates pull apart (divergence) the lowland between the plates is the central rift valley.

Sea floor held the keys

Mid-oceanic ridges- made out of basalt Central rift valley High heat Near mid-oceanic ridges sediment is much thinner getting thicker as they go farther out.

Magnetic Field

Earths magnetic field has changed/reversed over time Rocks on the sea floor record these magnetic reversals The patten of the magnetic stripes supports seafloor spreading

Divergent (divergence)

Plates move apart Common at mic ocean ridges and continental rifts

Convergent/ Convergence

Move towards each other

Convergent: Oceanic to continental

Oceanic plates subject beneath continental plate. Produces: Deep ocean trench Volcanism Earthquakes Wadati-Benioff Zone

Convergent: Oceanic to Oceanic

Older Oceanic plate generally subducts below the younger oceanic crust. Creates: Tenches and Volcanic Island arcs

Convergent: Continental- continental

Continents collide Produces large mountain ranges Ex. Himalayas

Transform

Plates move past each other horizontally Earthquakes are common Connects other plate boundaries

Chemical Layers: Crust

Continental Crust- Granitic ( Ground) Thicker Oceanic Crust- basaltic ( Bottom/baseline) Thinner

Chemical Layers: Mantle

Rich in Iron and Magnesium Major Rock - Peridotite (period- red magma)

Chemical Layers: Core

Mostly Iron and Nickel Outer core- liquid Inner core- solid

Physical/ Mechanical Layers: Lithosphere

Crust+ Uppermost mantle Broken into tectonic plates Oceanic lithosphere is thinner

Physical / Mechanical Layers: Asthenosphere

Mechanically weaker part of the Mantle Allows plates to move

Physical/ Mechanical Layers: Mesosphere

Lower Mantle: More Ridged: than asthenosphere

A mineral is:

Naturally occuring Inorganic Solid Has a known chemical compositionn Has an ordered atomic structure

Proton

Positive charge

Neutron

No charge

Electron

Negative charge

Atomic number

Number of protons

Atomic Mass

protons+ neutrons

Valance electrons

Electrons in the outermost energy shell. Atoms tend to become more stable when their outer shell is full

Ionic Bond

Electrons are transferred

Covalent Bond

Electrons are shared

Silicates

Built from Si-O tetrahedra Major mineral group

Carbonates

Contains the CO group example calcite

Oxides

Contains Oxygen Example category affected by chemical weathering

Sulfides

pyrite galena

Sulfates

made of a single element Gold/ Copper

Critical Zone

Upper part of Earth that include: Unconsolidated rock soil minerals plants

Critical zone pt 2

Biosphere, atmosphere, geosphere, hydrosphere

Chemical Weathering

chemical reactions break down minerals

Chemical Weathering: Dissolution

Minerals dissolve in water/ acid Example: Limestone/ calcite

Chemical Weathering: Oxidation

Oxygen attaches to minerals/ crystal structures

Chemical Weathering: Hydrolysis

Reaction involving water/ carbonic acid Example: Feldspar to clay

Erosion

transport of consolidated material such as: Rock soil and sediment

Agents of erosion:

Water Wind Dissolution Gravity

Controls of the critical zone

Climate Organisms Relief/topogrophy Parent material Time

Soil Profiles

O Horizon A Horizon B Horizon C Horizon R Horizon

O Horizon

Topsoil/ organic material

A Horizon

Top Soil

B Horizon

Zone of accumulation ( Illuviation) part recorded as a paleosol

C Horizon

lots of parent material, little organic matter

R Horizon

parent rock

Surface water

Streams and rivers

Water table

Upper the surface of the saturated zone

Saturated Zone

Ground where pore spaces are filled with water

Vadose Zone

Zone above the water table

Spring

Ground water reaching the surface

Aquifer

subsurface water- bearing unit that supplies a usable amount of water

Confined aquifer

aquifer trapped between less permeable layers