Geology Final Exam

What geologic event(s) caused the mass extinction at the end of the Permian Period? At the end of the Cretaceous?

Flood Basalt caused mass extinction at the end of the Permian Period, and an Asteroid Impact caused mass extinction at the end of the Cretaceous Period.

What is groundwater?

Groundwater is water that resides under the surface of the Earth, mostly in pores or cracks of rock or sediment. Groundwater is stored mostly under the surface of the Earth.

What is a half-life?

Half-Life: Time required for 1/2 of a radioactive parent isotope to decay into its stable daughter. They are constant and cannot be altered.

When did life first begin to evolve onto the land (out of the oceans)?

Life began to evolve onto the land in the Silurian period.

How were the different divisions (Eons, Eras, Periods) of the geologic time scale originally devised? What are the different divisions? Make sure that you know each of the subdivisions of the geologic time scale, and the major numeric boundaries that you were given in class.

Look in Notes

What is Porosity? Permeability?

Permeability is the degree to which a material allows fluids to pass through it via an interconnected network of pores and cracks. Porosity is the space between solid grains or crystals immediately after rockor sediment forms.

What is the 'Principle of Uniformitarianism'? Who proposed it?

Principle of Uniformitarianism is that the thought that the same processes that had operated in the past will be the same process that operates in the future. It was proposed by James Hutton.

What are the various principles covered in class? (6 Principles Total)

Steno's Laws for Relative Age Dating: 1. Principle of Original Horizontally - Sedimentary rock layers are originally horizontal. 2. Principle of Superposition - Sedimentary Layers in a sequence are oldest in bottom, youngest on top. 3. Principle of Unconformities - There may be a gap in Geologic time (missing Geologic History) due to erosional events. There are 3 types of Unconformities we have to deal with: A. Angular Unconformity: Rock layers above and below are not parallel. B. Disconformity: Missing layers between parallel layers. C. Nonconformity: Sedimentary rocks form at the surface, while Phaneritic Igneous rock form deep below the surface, and lastly there must be some type of erosion that happened in the middle. 4. Principle of Cross Culture Relation - Reverse fault (/). Fault occurred after Q, before M. 5. Principle of Continuity - Sedimentary rock layers, at the time of deposition, end by thinning, by butting up against a barrier, or by gradually changing a new rock type (which we refer to as a Facies change). Basically, with seal level rising, the sedimentary rocks will transfer up. 6. Principle of Faunal Succession - Fossil species succeed one another in the rock record, and do so in a regular and recognizable pattern. Proposed by William smith. Fossil Species succeed one another in a regular and recognizable pattern. Only thing you find in the old rocks on the planet is: Invertebrates -> Fish(Younger) ->Amphibians -> Reptiles -> (Split into two) Mammals & Dinosaurs and from Dinosaurs -> Birds

What is meant by mass wasting? Landslides?

The downhill movement of bedrock, rock debris, or soil due to the pull of gravity. Landslides are a general term of the slow to very rapid descent of rock or soil.

What is the angle of repose? What are the different factors which control this angle?

The steepest angle at which the debris remains stable. 1. Size of the material 2. Shape of the material 3. Moisture content

When did 'visible' life first appear on planet Earth?

Visible life first appeared on planet Earth 3.85 billion years ago.

What is meant by Relative Age Dating? Radiometric Age Dating?

We measure Geologic Time using Two Methods: Relative Age Dating: Looking at relationships between rocks and rock units to determine a relative age. Example: Rock A is older than Rock B. With Relative Age Dating, we use a set of very simple, common sense principles, known as Steno's laws. Radiometric Age Dating: Also know as "Absolute Age Dating" or "Numeric Age Dating" - Using radioactive Isotopes to accurately determine the age, in years, of a rock or Geologic event.

Make sure you know how to calculate the age of a given rock, or geologic event given the proper isotopic information.

You can calculate the age of a given rock by looking at its radioactive decay, and determining how many half-lives the element went through. For example, lets say a parent has 100% parent Isotope. After "half-life" the parent isotope is 50% parent and 50% daughter. After the second half life, the parent is 25% and the daughter is 75%. We NEVER use a parent/daughter half-life past 5.

How are Geysers and Hot Springs formed? How is geothermal energy produced?

...

How do caves form?

...

How do springs form?

...

How does a confined aquifer differ from an unconfined aquifer?

...

How does water enter into the subsurface?

...

How is groundwater contaminated?

...

How is water distributed on the planet?

...

How is water withdrawn from the subsurface?

...

What are losing streams and gaining streams?

...

What are some of the effects of excessive groundwater withdrawal?

...

What is Karst Topography?

...

What is a 'perched' water table?

...

What is an Aquifer? An Aquiclude? An Aquitard?

...

What is an Artesian Well?

...

What is the major consumer of groundwater?

...

What is the water table? The Vadose Zone? The Phreatic (Saturated) Zone? The Capillary Fringe?

...

What are the different mass wasting events and how do they differ?

1. Fall: -Moves: free fall -Speed: Very Fast 2. Flow: -Moves: Down-slope movement of unconsolidated material in which particles mix and move down-slope. -Can be avalanche speeds -Speed: Fast 3. Slide/Transitional Slide: -Moves: A coherent block moving along a slip-plane (/) -Speed: Medium *FASTEST and most DESTRUCTIVE mass wasting event 4. Slump/Rotational Slide: -Moves: Rock or soil sliding along a curved slip-plane ) -Speed: Slow *Rotates while slipping/sliding, deeper in earth, creates "benches" 5. Creep: -Moves: downwards slowly -Speed: Extremely slow, slower than the growth of trees -Bends rock layers -Curved tree trunks, deformed roads, titled posts -Caused by expansion and contraction of soils and rocks -Freezing & Thawing

How are the different mass wasting events subdivided?

1. Rate of Movement: how fast does the material move downhill? Is it slow (cm/yr) or rapid? 2. Type of Material: what sort of material is moving downhill? Is it bedrock or unconsolidated material? Unconsolidated material is generally referred to as soil. Soil can be considered debris (coarse-grained), earth (fine-grained) or mud (lots of water). 3. Type of Movement: how did that material move downhill? Did it fall, slide, or flow? And there are 2 types of slides: translational and rotational.

What are the possible triggers of mass wasting events?

A sudden event may trigger the mass wasting of a hillside that is unstable. These include: - Earthquakes: commonly cause landslides - Heavy Rainfall: the sudden influx of water quickly reduces the angle of repose - Construction: the extra weight of buildings or bulldozing the base of a slope (cutting the toe)

When was the Age of Fish? The Age of Reptiles? Age of Mammals?

Age of Fish: Paleozoic Age of Reptiles: Mesozoic Age of Mammals: Cenozoic

Scientific Equation:

Age(Time) = Amount of Change divided into Rate of Change

What is a parent isotope? A daughter?

All Radioactive substances -over time break. 1. Parent Isotope: Starting point of an element which decays into another element. 2. Daughter Isotope: Element that was decayed into by the parent isotope.