Chapter 8 Flashcards
Taphonomy
The study of the deposition of plant or animal remains and the environmental conditions affecting their preservation
Sedimentary
Rock formed when the deposition creates distinct layers, or strata
Eras
Major divisions of geologic time that are divided into periods and further subdivided into epochs
Epochs
Divsions of periods (Which are the major divisions of eras) in geologic time
Pangea
A hypotheitcal landmass in which all the continents were joined , approximately 300-200 mya
Tectonic
Refers to varous structures on Earth’s surface, such as the continental plates
Steno’s Law of Superposition
The principle that the lower the stratum or layer, the older its age; the oldest layers are at the bottom, and the youngest are ath the top
Stratigraphic Correlation
The process of matching up strata from several sites through the analysis of chemical, physical, and other properties
Fluorine dating
A relative (chemical) dating method that compares the accumulation of fluorine in animal and human bones from the same site
Chemical dating
dating methods that use predictable chemical changes that occur over time
Index fossils
fossils that are from specified time ranges, are found in multiple locatoins, and can be used to determine the age of associated strata
Cultural Dating
Relative dating methods that are based on material remains’ in time spans
Pebble tools
The earliest stone tools, in which simple flakes were knocked off to produce an edge used for cutting and scraping
Dendrochronology
A chronometric dating method that uses a tree-ring count to determine numerical age
Radiocarbon dating
The radiometric dating method in which the ration of 14C to 12 C is measured to porivde an absolute date for a material younger than 50,000 years
Isotopes
Two or more forms of a chemical element that vary in the number of neutrons in the nucleus and by the atomic mass
Half-life
The time it take for half of the radioisotipes in a substance to decay; used in various radiometric dating methods
Igneous
Rock formed from the crystallization of molten magma, which contains the radioisotope 40K used in potassium-argon dating
Radio potassium Dating
The radiometric dating method in which the ratio of 40 K to 40 Ar is measured to provide an absolute date for a material older than 200,000 years.
Fission track dating
An Absolute dating method basid on the measurement of the number of tracks left by the decay of uranium-238
Amino acid Dating
An absolute dating method for organic remains such as bone or shell in which the amount of change in the amino acid structure is measured
Polarized light
a kind of light used in amino acid dating because it allows amino acid changes to be observed and measured
Recemization
The chemical reaction resulting in the conversion of L amino acids to D amino acids for amino acid dating
Paleomagnetic dating
An absolute dating method based on the reversals of Earth’s magnetic field
Electron Spin Resonance dating
An absolute dating method based on the reversals of Earth’s magnetic field
Election Spin Resonance dating
An absolute dating method that uses microwave spectroscopy to measure electons’ spins in various materials
Thermoluminescence Dating
A relative dating method in which the energy trapped in a merterial is measured when the object is heated
Foraminifera
Marine protozoans that have variably shaped shells with small holes
C3 Plants
Plants that take in carbon through C3 photosynthesis, which changes carbon dioxide into a compound having three carbon atoms, Thending to be from more temperature regions, these plants include wheat, sugar beets, peas, and a range of hardwood trees
C4 Plants
Plants that take in carbon through c4 photosynthesis, which changes carbon dioxide into a compound with four carbon atoms. These plants tend to be from warmer regions with low humidity and include corn, sugarcane, millet, and prickly pear
