Chapter 6 Flashcards
Geologic Systems
a time-rock unit consisting of all the rocks that represent a geologic period
Stratigraphy
the study of stratified rocks, especially their geometric relations, compositions, origins, and age relations
Stratigraphic Units
a stratum or group of adjacent strata distinguished by some physical, chemical, or paleontological property, or the unit of time that is based on the age of such strata
Correlation
the procedure of demonstrating correspondence between geographically separated parts of a stratigraphic unit
Lithologic Correlation
correlation between stratigraphic units based on rock type
Temporal Correlation
demonstration that strata in two different geographic areas are the same age
Time-Rock Unit
a stratigraphic unit that includes all the strata in the world that were deposited during a particular interval of time
Time Unit
the interval during which a time-rock unit formed
Erathems
a time-rock unit consisting of all the rocks that represent a geologic era
Series
a time-rock unit consisting of all the rocks that represent a geologic epoch
Stages
the time-rock unit that ranks below a series and consists of all the rocks that represent a geologic age
Epochs
a division of geologic time shorter than a period
Ages
the division of geologic time smaller than an epoch
Boundary Stratotype
an outcrop where the boundary between two time-rock units is formally recognized
Biostratigraphic Units
a body of rock, such as a zone, defined on the basis of its fossil content and having approximately time-parallel upper and lower boundaries
Zone
a rock unit whose upper and lower boundaries are based on the ranges of one or more taxa-usually species-in the biostratigraphic record
Index Fossils/Guide Fossils
a species or genus whose fossils provide for especially precise correlation; an ideal index fossil is easily distinguished from other taxa, is geographically widespread, is common in many kinds of sedimentary rocks, and is restricted to a narrow stratigraphic interval
Magnetic Stratigraphy
the use of magnetic properties of rocks for correlation
Magnetic Field
the field of magnetism that results from motions of Earth’s iron-rich liquid outer core and which causes Earth to behave like a giant bar magnet, with a north and south pole
Chron
a formally recognized polarity time-rock unit
Polarity Time-Rock Unit
a time-rock unit in which the polarity of Earth’s magnetic field was either the same as it is today (a so-called normal interval) or the opposite of what it is today (a reversed interval)
Rock Units
a body of rock that is formally recognized as a formation, member, group, or supergroup
Lithology
the physical and chemical characteristics of rock
Stratigraphic Section
a local outcrop or series of adjacent outcrops that display a vertical sequence of strata
Type Section
a stratigraphic section at a particular locality that is designated to define a rock unit
Regression
a seaward migration of a marine shoreline and of nearby environments
Transgression
a landward migration of a marine shoreline and of nearby environments
Facies
the set of characteristics of a rock that represents a particular depositional environment
Radioactive Decay
the spontaneous breakdown of certain kinds of atoms into one or more atoms of different elements, accompanied by a release of energy and subatomic particles
Radiometric Dating
measurement of the amounts of naturally occurring radioactive isotopes present in rocks in relation to the amounts of their daughter isotopes (products of radioactive decay) to ascertain the ages of the rocks
Half-Life
the time required for a particular radioactive isotope to decay to half its original amount; that time is consistent for any isotope, regardless of the amount of that isotope present at the outset
Diagenesis
a wide array of postdepositional changes to sedimentary rocks, including lithification, petroleum generation, and the formation of low-temperature ore deposits
Radiocarbon Dating
radiometric dating by means of carbon 14, a radioactive isotope with a half-life so short that its decay can be used to date materials younger than about 70,000 years
Cosmogenic
of or relating to an elemental transformation resulting from cosmic ray bombardment
Thermoluminescence Dating
determination of the length of time since sedimentary materials have been buried close to the Earth’s surface by applying heat to drive out electrons that have remained trapped within crystalline materials after being dislodged by cosmic rays
Optical Dating
determination of the length of time since sedimentary materials have been buried close to Earth’s surface by employing light to drive out electrons that have remained trapped within crystalline materials after being dislodged by cosmic rays
Stable Isotope Stratigraphy
dating of a rock by identifying within it a change in the ratio of stable isotopes of an element that is know to occur on a global scale within the natural environment
Marker Bed
a distinctive bed that is useful for stratigraphic correlation
Seismic Stratigraphy
the study of sedimentary rocks by means of seismic reflections generated when artificially produced seismic waves bounce off physical discontinuities within buried sediments
Sequences
a large body of marine sediment deposited on a continent when the ocean rose in relation to the level of the continental surface and then receded again
Milankovitch Cycles
three types of regular changes in Earth’s rotation and orbit: the eccentricity cycle, the obliquity cycle, and the precession cycle
Positive Feedback
a result of a change that accelerates that change
Eonothem
a time-rock unit consisting of all the rocks that represent a geologic eon
Name the eons (from youngest to oldest)
1) Phanerozoic
2) Proterozoic
3) Archean
4) Hadean
HAPPY - Y (notice this is next to the youngest eon!) = HAPP (oldest to youngest)
Name the eras of the Phanerozoic eon (from youngest to oldest)
1) Cenozoic
2) Mesozoic
3) Paleozoic
Alphabetical order - CMP
Name the periods of the Phanerozoic eon of the Cenozoic era (from youngest to oldest)
1) Quaternary
2) Neogene
3) Paleogene
Can’t Quit Now Pal!
Ceno - Quat Neo Pal
Name the periods of the Phanerozoic eon of the Mesozoic era (from youngest to oldest)
1) Cretaceous (Late and Early)
2) Jurassic
3) Triassic
Monsters = dinosaurs in alphabetical order
Name the periods of the Phanerozoic eon of the Paleozoic era (from youngest to oldest)
1) Permian
2) Carboniferous (Late-Pennsylvanian and Early-Mississippian)
3) Devonian
4) Silurian
5) Ordovician
6) Cambrian
Pals - Please Count Dinosaurs Second On Category
Name the epoch of the Cenozoic era of the Quaternary period
1) Pleistocene
Name the epochs of the Cenozoic era of the Neogene period
1) Pliocene
2) Miocene
Night = Post Meridian (PM)
Name the epochs of the Cenozoic era of the Paleogene period
1) Oligocene
2) Eocene
3) Paleocene
POE = Poet
