Earth Science, Tarbuck Chapter 11 Flashcards
What is the Principle of Uniformitarianism
the physical, chemical, and biological laws that operate
today have also operated in the geologic past
What is the Principle of Superposition
in an undeformed sequence of sedimentary rocks, each bed is
older than the one above and younger than the one below.
What is Principle of Lateral Continuity
sedimentary beds originate as continuous layers that
extend in all directions until they eventually grade into
a different type of sediment or until they thin out at the
edge of the basin of deposition
What is principle of Original Horizontality
states that layers of sediment are generally
deposited in a horizontal position. Thus, if we observe rock
layers that are flat, we know that they have not been disturbed and still have their original horizontality
What is Principle of Cross-Cutting Relationships
states that geologic features that cut across rocks
must have formed after the rocks they cut through.
What is Principle of Inclusions
The rock mass adjacent to the one containing the inclusions must have been there first in order to provide the rock fragments.
What are Sediment layers that are conformable
layers of rock that have been deposited essentially without interruption,
What are unconformities
breaks in the rock record where deposition ceased, erosion removed previously formed rocks, and then deposition resumed
What is an Angular Unconformity
consists of tilted or folded sedimentary rocks that are
overlain by younger, more flat-lying strata
What is a disconformity
a gap in the rock record that represents a period during which erosion rather than deposition occurred.
What is a Nonconformity
younger sedimentary strata overlie older metamorphic or intrusive igneous rocks following erosion and uplift.
What is Permineralization fossilization
When mineral-rich groundwater gets into porous tissue such as bone or wood, minerals precipitate out of solution and fill pores and empty spaces
What is Mold Fossilization
When a shell or another structure is buried in sediment and then dissolved by underground water,
What is Cast Fossilization
When a mold is filled with mineral matter and hardens to form a cast
What is Carbonization Fossilization
fine sediment encases the remains of an organism. As time passes, pressure squeezes out the liquid and gaseous components and leaves behind a thin residue of carbon
What is Amber Fossilization
Tree Resin seals off the organism from the atmosphere and protected the remains from damage by water and air.
What are Trace Fossils
traces of prehistoric life
What are Tracks Trace Fossils
animal footprints made in soft sediment that later turned into sedimentary rock.
What are Burrows Trace Fossils
tubes in sediment, wood, or rock made by an animal. These holes may later become filled with mineral matter and preserved. Some of the oldest-known fossils are believed to be worm burrows.
What are Coprolites Trace Fossils
Fossilized Dung
What are Gastroliths Trace Fossils
highly polished stomach stones that were used in the grinding of food by some dinosaurs and other organisms.
What special Conditions favor fossilization
rapid burial and the possession of hard parts
What is Principle of Fossil Succession
Fossil organisms succeed
one another in a definite and determinable order, and
therefore any time period can be recognized by its fossil content.
What are Index Fossils
widespread geographically but limited to a short span
of geologic time, so their presence provides an important method of matching rocks of the same age
What does a neutron turn into during radioactive decay
1 Proton and 1 Electron
What are the 3 ways radioactive decay can happen
Alpha Particle release, electron release, and electron capture
How does alpha particle release radioactive decay happen
When an alpha particle(2 protons and 2 neutrons) is released from the atom, atomic mass is lowered by 4 and atomic number is lowered by 2
How does electron release radioactive decay happen
When an electron escapes from the atom, a neutron will decay to get 1 proton and the electron it lost. This means atomic number increases by 1 and mass stays the same
How does electron capture radioactive decay happen
Electron that is captured combines with proton to form a new neutron, atom mass stays the same, atomic number is lowered by 1
Isotope used to find geologic events that occurred very recently
Carbon-14
Rate of Half life of carbon-14
5730 years
What are the 2 eons that precede the Cambrian
Archean and Proterozoic
