DATING, EARTHQUAKE, FOSSILS

superposition

original horizontality

cross-cutting

faunal succession

techniques of relative dating

radiometric dating

dendrochronology

ice core dating

varve dating

techniques of absolute dating

radiometric dating

- based on decay of radioactive isotopes

- measures the time relapsed since the rock was formed or last altered.

- carbon 14, uranium-lead, potassium-argon

dendrochronology

- uses annual growth of tree rings to determine the age of wooden objects

ice core dating

- involves analyzing layers of ice to determine climate history and age of the ice

varve dating

- a method that uses layers of sediment in lakes and bodies of water to determine the age of deposits.

seismograph

instrument to detect and measure earthquake

richter scale

measures magnitude

modified mercalli scale

measures intensity

seismic waves

vibrations that travel through the Earth, generated by earthquakes or other geological activity.

primary or compressional waves (p-waves)

- compressing and expanding the SAME direction

- fastest seismic waves

secondary or shear waves (s-waves)

- shearing or displacing perpendicular to the direction

- slightly slower than p-waves

surface waves

- travel along the Earth's surface, causing most of the damage during an earthquake.

- 2 types: Rayleigh and Love waves.

- slowest

Rayleigh waves

- causes both vertical and horizontal ground movement, similar to ocean waves.

love waves

- side-to-side motion perpendicular to the direction of wave travel

clastic sedimentary rocks

- formed from accumulation and compaction of mineral/rock fragments

- ex: sandstone, shale, conglomerate

chemical sedimentary rocks

- formed from the precipitation of minerals from water.

- ex: limestone, rock salt, gypsum

organic sedimentary rocks

- formed from the accumulation of organic materials.

- ex: coal, some limestones.

foliated metamorphic rocks

- formed under high pressure, layered or banded appearance.

- Ex: schist, gneiss.

non-foliated metamorphic rocks

- formed under high temperature without pressure, lacking a layered appearance.

- Ex: marble, quartzite.