GEOL 1601- FINAL

What does an angular unconformity imply?

Implies that the underlying rocks were folded/tilted AND eroded before the overlying layers were deposited.

Define a P-wave

Primary wave; travels through rock as a sequence of back-and-fourth vibrations PARALLEL to the direction of movement.

Define a S-wave

Secondary wave; travels through rock as a sequence of vibrations PERPENDICULAR to the direction of movement.

TRUE OR FALSE: Focus is the point beneath the surface where the earthquake occurs. And epicenter is the point on the surface directly above the focus

True

Antiforms, also called _______, are upfolds or ______ folds. The (oldest/youngest) rocks are in the middle.

Anticlines; convex; oldest

After a structure is subjected to directed pressure, it may strain. Strain is also called _______.

Deform

Oolitic Limestone (source to sink)

Well-rounded/sorted rock that is composed of calcite; can be found near shore

Coquina (source to sink)

Easily broken rock composed of calcite and shell fragments; can be found near beach environments

What does the Bowen Reaction Series tell us?

Explains the orderly sequence in which various minerals will crystallize from a natural magma

How is a Dip expressed?

Expressed in 2 digits

How is a strike expressed?

Expressed in degrees east or west of true north or true south (quadrant bearing); Also expressed as a 3 digit azimuth bearing in degrees between 000 and 360

TRUE OR FALSE: Do the descriptions below match these three types of waves? P-wave: Secondary wave- moves materials up and down in a shearing motion S-wave: travels along the earths surface likely to create damage Surface wave: Primary wave- compressional wave first to arrive

False

TRUE OR FALSE: A disconformity is where sediments deposit upon one another at an angle.

False

TRUE OR FALSE: A syncline has layers that dip downward from the center, with the youngest layer on top. The oldest layer will be directly in the center of the syncline.

False

TRUE OR FALSE: The law of superposition states that: in an undisturbed sequence, rocks at the top are oldest, and rocks at the bottom are youngest.

False

Faults

Faults in rock units are breaks along which movement has occurred

What does the Rule Vs determine?

Helps determine the general dip of a bed on a geologic map lacking strike and dip symbols

When synclines and basins are eroded, the beds exposed in the center are (older/younger) than the beds exposed away from the center.

Younger

When rocks slip past each other in faulting, the upper or overlying block along the fault plane is called the ______ ______; the block below is called the __________.

hanging wall; footwall

Love wave

horizontal shearing motion similar to the motion of a snake

Attitude

orientation of a rock unit or surface

A horizontal bed produces contacts that exactly _______ topographic contours.

parallel

Shear

smearing or tearing

On a geologic map, (older/younger) beds dip under, or toward, (older/younger) beds, unless they are overturned.

Older; Younger

Thrust faults generally place (older/younger) strata on top of (older/younger) strata.

Older; younger

Geologists can locate exposures, or _______, of bedrock by studying aerial photos to locate where the rock actually can be seen.

Outcrops

What are the three types of seismic waves?

P-waves, S-waves, and Surface waves.

Fossiliferous Limestone (source to sink)

Rock composed of calcite, containing clams and coral; can be found in reefs

Chert (source to sink)

Rock composed of mostly quartz that is broken with conchoidal fracture; can be found in deep marine environments

Coal (source to sink)

Rock made of organic carbon and coal; can be found in swamps

Left Lateral Fault

Rocks on opposite side of the fault appear to have moved to the left.

Block Diagram

Small #-D model of a portion of Earth's crust; combination of geologic map and cross section (geologic map on top and geologic cross section on each of its visible sides)

What types of matter can S-waves pass through?

Solids only

What types of matter can P-waves pass through?

Solids or liquids

Directed pressure on a structure is also called ______.

Stress

_______ is the forces that are applied to rocks, while ______ is the deformation resulting from the first blank.

Stress; Strain

Which type of seismic wave usually causes the most damage?

Surface waves

Synforms, also called _______, are down folds or ______ folds. The (oldest/youngest) rocks are in the middle.

Synclines; concave; youngest

What are the three kinds of stress in regard to faulting?

Tension, Compression, Shear

Sandstone (from source to sink)

well-rounded/sorted rock made up of mostly quartz; can be found in glaciers, channels, dunes, and lakes

Define a Surface wave

Travel ALONG THE SURFACE of earth as two types of waves; Love waves and rayleigh wave

Earthquake magnitude can be described by quantitative means such as total energy release, or by qualitative means such as the destructive effects an earthquake can have.

True

TRUE OR FALSE: A Nonconformity is: where younger sedimentary rocks are deposited on top of older igneous or metamorphic rocks.

True

TRUE OR FALSE: If beds are vertical, there is no V.

True

TRUE OR FALSE: The one exception to the Rule of Vs is: If beds dip down the valley, but at an angle less than the slope of the valley, the V points up-valley.

True

TRUE OR FALSE: Vertical Exaggeration is used for showing small changes in elevation over a large horizontal distance.

True

TRUE OR FALSE: A gradient is a change in elevation over a specified distance.

True

TRUE OR FALSE: An anticline has layers that dip downward from the center, with the youngest layer on top. The oldest layer will be directly in the center of the anticline.

True

TRUE OR FALSE: Normal Faulting is when the hanging wall falls relative to the footwall.

True

TRUE OR FALSE: Relative Geologic age indicates whether an event is recorded before and after another event, while Numeric Geologic Age indicates the exact geologic age.

True

State the Rule of Vs

Where a contact line crosses a valley, it forms a V that points in the direction of the dip of the contact between the two formations

As the dips become steeper, the Vs become _____ and _____.

Wider and shorter

A formation is.....

a mappable body of rock

Townships/Ranges cover an area of approximately: a. 6 miles b. 2 miles c. 5 miles d. 12 miles

a. 6 miles

Which of the following is true about contours? a. Contours that are closer together are indicating a rapid decrease or increase in elevation. b. They can split c. They can cross each other, or overlap

a. Contours that are closer together are indicating a rapid decrease or increase in elevation.

The _____ and ______ of deflection depend mainly on the dip of the beds.

amount; direction

Nonconformity

an erosion surface separating sedimentary rocks from older plutonic or massive metamorphic rocks (ie. crystalline rocks that are not layered)

Nonconformity

an unconformity between sedimentary rock/sediment and non-sedimentary (igneous or metamorphic) rock

Dip

angle between a horizontal plane and the inclined (tilted) stratum, fault, or fracture; dip direction is always perpendicular to the line bearing of the strike

Krantz (source to sink)

angular/poorly sorted rock composed of a variety of minerals; can be found in steep cliff environments

When plunging anticlines have been eroded, the contacts between beds, as seen in a map view, bend so as to point (toward/away from) the direction of plunge.

away from

In the field, if you noticed a large gap of time, between different layers of rock you would assume that this was: a. a Fault b. An unconformity c. Normal

b. An unconformity

Contacts

boundaries of formations that make it easy to separate from adjacent rock units.

How are Strike and Dip shown on maps?

by "T"-shaped symbols; Lone line (top of T) shows strike direction, and the short line shows dip direction; Short line of T points down dip

Which of the following is True about Radioactive Isotopes: a. Radioactive isotopes do not decay at a constant half life, therefore they are unreliable b. Decay rates are generally measures in quarter life's c. Different Isotopes decay at different rates, and therefore have different half-lives.

c. Different Isotopes decay at different rates, and therefore have different half-lives.

What does the passage of a P-wave cause?

causes alternate pushing (compression) and pulling (dilation) on particles in its path.

What does the passage of a S-wave cause?

causes particles to vibrate up and down or sideways.

Strike

compass bearing (direction) of a line formed by the intersection of a horizontal plane and an inclined layer of rock, fault, fracture, or other surface

Reverse Faults are caused by ______ when the hanging wall is pushed _______ in relation to the footwall block.

compression; upward

Shale (source to sink)

easily broken rock made of clay; can be found in deep marine environments, lakes, flood plains

Disconformity

either an erosion surface or a surface of non-depositional separating rocks whose layers are parallel; (an erosion surface is uneven and cuts laters of underlying rocks; a surface of non-deposition parallels underlying rocks)

angular unconformity

erosion surface separating rocks whose layers are not parallel; layers above and below meet at an angle

The outcrop width of a bed (increases/decreases) as the angle between the surface and the dip of the bed decreases.

increases

Basin

large circular structures formed when strata are warped downward, like a bowl

Dome

large circular structures formed when strata are warped upward like an upside down bowl

Gently dipping beds produce relatively _____ and _____ Vs.

long and narrow

Unconformity

may be a very irregular surface, because its usually a surface where erosion has occurred (before it was buried to form the unconformity)

Tension

pulling apart or lengthening

Compression

pushing together, compacting, shortening

Thrust Faults are _______ faults that develop at very (high/low) angles and may be difficult to recognize.

reverse; low

Chalk (source to sink)

rock composed of calcite and coccoliths; can be found in deep marine environments

Rayleigh wave

rolling up-and-down motion much like water waves.

Conglomerate (from source to sink)

rounded/poorly sorted rock composed of a variety of minerals; can be found in channels, glaciers, lakes, alluvial fan

Strike-Slip Faults (Lateral Faults) are caused by _____ stress and involve ______ motions of rock.

shear; horizontal

Geologic Cross Section

shows arrangement of formations and their contacts; drawing of a vertical slice through Earth, with the material in front of it removed (a cutaway view)

Geologic Map

shows distribution of rocks at Earth's surface; Shows topography, and contour lines (Made on basis of color, texture, or composition)

What is a depositional environment?

specific type of place in which sediments are deposited after going through a combination of physical, chemical, and biological processes.

In structural geology, a geologic structure may be subjected to ____________ (directed pressure) then it may _______ (deform)

stress; strain

Structural Geology involves deciphering ______ and ______ relationships.

stress; strain

Structural Geology

study of how geologic unites are arranged when first formed and how they are deformed afterward.

Unconformity

surface that represents a substantial gap in geologic record

Normal Faults are caused by _______ when the hanging wall moves ________ in relation to the footwall block.

tension; downward

Right Lateral Fault

the rocks on opposite side of the fault appear to have moved to the right

Angular Unconformity

unconformity between nonparallel strata (nonparallel layers in rocks above and below the unconformity)

Disconformity

unconformity between relatively parallel strata

Isotope

varieties of an element containing different numbers of neutrons in their nuclei

Normal, Reverse, and Thrust faults all involve _________ motions of rocks.

vertical

From high to low: Rank the velocity of the different types of seismic waves.

1. P-waves (primary waves) 2. S-waves (secondary waves) 3. Surface waves

When (plunging/non-plunging) folds have been eroded, the contacts between beds, as seen on a horizontal surface, are straight and parallel.

Non-plunging

When anticlines and domes are eroded, the beds exposed in the center are (older/younger) than the beds exposed away from the center.

Older