ANTH 3-2 Flashcards
Stratigraphy
is the branch of geology that
studies rock layers (strata) and their
formation, composition, and relationships over time.
Are we able to find all the evidence
from the past? Why or why not?
No, because fossilization is rare, many remains degrade over time, and geological processes can destroy or bury evidence beyond our reach.
ite Formation Processes: WHAT DO WE SEE TODAY?
Time of species
the life span of species
Relative Dating techniques
Relative: How old something is in relation to something else
Lithostratigraphy (Tephrostratigraphy)
Biostratigraphy
Paleomagnetism
Absolute Dating techniques
Absolute (Chronometric): How old
something is in years before the present.
Techniques using radioactive
decay:
Potassium-argon (Argon-argon)
Radiocarbon (Dendochronology)
Uranium Series
Electron Trap Techniques:
Thermoluminescence
Optically Stimulated Luminescence
Lithostratigraphy
uses the correlation of rock units to estimate the relative age of different areas.
Tephrostratigraphy
is a type of lithostratigraphy that uses volcanic ash layers to match rock layers across different sites and determine their relative age.
Biostratigraphy
Based upon the principle of faunal
succession:
- There are predictable sequences of
fauna (species of animals) through
time associated with a particular
strata. This can help us date
geological layers.
Paleomagnetism
is the study of the Earth’s
past magnetic field recorded in rocks,
which helps date rock layers based on
changes in magnetic direction over time.
Potassium-Argon dating
measures the decay of potassium into argon in volcanic rock.
Radiocarbon dating
measures the decay of carbon-14 in once-living things
Dendrochronology
is the study of tree ring patterns to determine the age of trees and calibrate radiocarbon dates
Uranium series
dating measures the decay of uranium into other elements in materials like cave formations
Thermoluminescence:
Measures the last time a stone was exposed to high heat.
Optically stimulated Luminescence (OSL)
Measures the last time a grain of
sand was exposed to sunlight
Components of the Geological Timescale
*Eon
*Era
*Period
*Epochs
*Ages
BEFORE THE CENOZOIC
145 Ma - 201 Ma
a radiation of dinosaurs fills all the niches for large, terrestrial animals
Cynodonts:
Small, mammal-like reptiles evolve into the first true mammals
Cretaceous–Paleogene (K–Pg) extinction event
66Ma
brings us to the Cenozoic
Why do we call the Cenozoic the
“Age of Mammals”?
after the extinction of the dinosaurs, mammals diversified and became the dominant land animals on Earth.
