Chapter 8 E2 Flashcards
father of modern geology
James Hutton, Theory of the Earth
James Hutton came up with the fundamental principle of geology that says
the present is the key to the past; uniformitarianism
determining when a geologic feature formed relative to other geologic features
relative age
determining when a geologic event occurred in exact units of time
radiometric or absolute age
law of superposition
oldest rocks are on the bottom
principle of original horizontality
sediment is deposited horizontally
principle of cross-cutting relationships
younger feature cuts through an older feature
one rock contained within another rock
inclusions
the rock containing the inclusions is
younger
a break in the rock rock record
unconformity
three types of unconformities
disconformity, angular unconformity, and nonconformity
missing time between horizontal SEDIMENTARY layers
disconformity
missing time between two sets of strata that are not parallel to each other
angular unconformity
unconformity between igneous or metamorphic rocks and younger sedimentary rocks
nonconformity
local unconformity
forms when a different rock unit is deposited within another relatively continuously deposited rock unit; find them in CHATANOOGA on the ancient river channel
matching rocks of similar age in different regions; often relies on fossils
correlation of rock layers
cavities and pores are filled with precipitated mineral matter
petrified fossils
cell material is removed and replaced with mineral matter
replacement
shell or other structure is buried and then dissolved by underground water
mold
hollow space of a mold is filled with mineral matter
cast
organic matter becomes a thin residue of carbon
carbonization
replica of the fossil’s surface preserved in fine grained sediment
impression
hardened resin of ancient trees surrounds an organism
preservation in amber
conditions favoring fossil preservation
rapid burial and possession of hard parts
______ fossils allow various sedimentary layers around the world to be correlated
index
variant of the same parent atom; different number of neutrons and mass number
isotope
spontaneous breaking apart (decay) of atomic nuclei
radioactivity
three types of radioactive decay
alpha emission, beta emission, and electron capture
lose an alpha particle
alpha emission
lose an electron
beta emission
gain an electron that changes into a neutron?
electron capture
the time for one half of a radioactive nuclei to decay
half life
carbon 14 is used for dating ____ events
recent
divisions of the geological calendar from biggest to smallest
eon
era
period
epoch
the era that is 88% of Earth’s history
precambrian era
