Exam 2 Flashcards
(48 cards)
What is the age of the earth?
4.6 billion
Term used for fossils of a particular kind of organism that was distributed widely but lived for only a relatively brief period of time
Index fossils
Term used for the identification and matching of sedimentary strata and other rocks of the same age in different areas and regions
Correlation
Longest to shortest divisions of geologic time scale
Eon, era, period, epoch
The principal that states that fossil organisms changed and evolved in a definite and progressive way. Strata of specific ages can be recognized by the fossils they contain
The principal of fossil succession
Term used for an Unconformity with tilted eroded rocks below an erosion surface and horizontal rocks above the erosion surface
Angular unconformity
Name for geologic era that means “ancient life”
Paleozoic
Who made the first clear statement of the law of superposition? When
Nicolas Steno, 17th century
What percentage of geologic time is represented by the Phanerozoic
The most recent 12%
Which mass wasting process has the fastest rate of movement
Rock falls/ rock avalanches
Which form of mass wasting occurs exclusively in permafrost regions?
Solifluction
How do freezing, thawing, wetting, and drying contribute to soil creep?
Soil expands and contracts, lifting particles and dropping them at a slight downslope.
What is the drop in elevation of a streams surface divided by the distance the water flows
(Stream) Gradient
What is the product of the average flow velocity and the area of the channel cross section. (Velocity X area)
Discharge
A dam and a reservoir a reconstructed on a graded river. What will Be the result?
Deposition upstream
Channel down cutting
What effect does water have on the cohesion of clay-bearing soils and regolith
The soil or regolith has less internal cohesion when wet than dry, causing it to collapse
During wet weather or snow melting, what sometimes happens to the toe of a slump
It becomes an earth flow
Which component generally constitutes the highest percentage of a streams load
Suspended load
Where is erosion concentrated along a meandering stream
On the outside banks of the meanders
In which drainage pattern developed in areas underlain by tilted or folded strata, do tributary streams flow along outcrop areas of the softer strata
Trellis
Where would a radial drainage pattern develop
Volcanos
At the head of the. Delta, the major river divides into numerous smaller channels. What are they called?
Distributaries
Which response best describes an aquifer
Permeable layer of saturated sediment or rock that contains groundwater
What accounts for the largest use of groundwater in the United States
Irrigation and Agriculture
