Embedded Files
Geologic Time
Geologic time video link: http://www.ucmp.berkeley.edu/education/explorations/tours/geotime/gtpage1.html
Expected outcomes:
Vocabulary:
uniformitarianism
paleontologist
contacts
formation
superposition
original horizons
truncated
cross-cutting relationships
paleo, meso, ceno, zoic
physical continuity
correlation
dendrochronology, varve
fossil
half-life
radioactive decay
isotope
era, period, epoch
revolution, disturbance
relative time, numeric time
shield
Concepts:
The divisions of geologic time - four eras and periods of each
Principles used to determine relative age (separate regions(3) and same region(3))
Principles used to determine numeric age
Five types of fossils
Label diagram of relative time principles
Major events of geologic periods
NOTES
Geologic Time - Study of physical history of earth
Geologic time scale - calendar of events
divided using eras - major portions and periods - smaller portions
ears divided by revolutions - times of extensive changes, and disturbances - smaller less significant change
Relative time - putting events in order according to sequence
uniformitarianism - the present is the key to the past - the way things happen today, happened the same way in the past
contacts - the surface that separates two different rock layers
formation - bodies of rock with distinct characteristics that make it distinguishable (Ex: Bar Harbor Formation - pink granite)
Principles of relative time - determines events in a specific region
Original horizontality - sediments deposited in water will form horizontal layers
Law of superposition - oldest layer is on bottom
Cross-cutting - disrupted is older than the disruption (dykes, sills, truncated(cut off))
Principles of relative time - sequence in different areas
correlation - determining age relationships in different areas
physical continuity - trace a course of rock
similarity of rock types - similar rock types in two different areas, follows superposition
fossils - organisms in sediments in one area match in different area - different continents
Fossils - recognizable remain of past life - help solve mysteries of earth's past
in order to form:
must be protected from bacteria and scavengers
covered quickly
needs hard parts
Five types of fossils
1 - petrified - rocklike, original replaced with minerals
2 - carbonaceous - pressure and heat forces out carbon leaving outline of figure
3 - molds/casts - cavity in rock where shell fell then dissolves
4 - original - ice
5 - trace - tracks and prints
Paleontologist - scientist studies fossils
Numeric Time - giving an actual age to events
dendrochronology - using tree rings - climate conditions, physical conditions - 3000 to 4000 years
varve analysis - study of sediment beds in water (varves), rate at which sediments deposit
radiometric dating - using isotopes to determine age
half-life - the time it takes for half of isotope to breakdown or decay(set rate-carbon14 takes 5730 years)
Geologic Time Scale - calendar used to put events in order
zoic - animal life
paleo - ancient
meso - middle
ceno - recent
Precambrian era - longest 4 billion years
Paleozoic era
cambrian, ordovician, devonian, carboniferous, permian periods
Mesozoic era
triassic, jurassic, cretaceous periods
Cenozoic era
tertiary and quaternary periods
Page updated
Google Sites
Report abuse