Map And Cross Section Interpretation Flashcards
Blind thrust
A thrust fault that does not reach the ground surface.
Detachment fault
A low angle normal fault associated with refional movement.
Dip-slip fault
A fault in whoch the movement isnparallel to the dip of the failt place. Known as a normal, reverse, or listric fault.
Fenster
This is an erosional opening or a window where thr underlying rocks are exposed. This process is normally caused by erosion or normal faulting of a thrust system.
Footwall block
The underlying block of a fault that has an inclined fault plane. This underlies a non-vertical fault.
What does ‘Ga’ stand for?
This is an abbreviation for Giga-annum which is one billion years.
What is GIS?
An abbreviation for geographic information system. This is a computer based tool that is used for mapping, analysing, and visualizing geographically refererenced data.
What is GPS?
This is an abbreviation for global positioning system. This is a radio navigation system that determines the exact location, time, and velocity and determined by triangulation.
What is a growth fault?
This is a fault that forms at the same time as deposition in sedimentary rock.
The throw [define] increases with depth and thr sedimentary units on the downthrown side are thicker than the corresponding units on the up thrown side.
Define a hanging wall block.
This is the block that overlies a non-vertical fault.
Define heave
This is the amount of horizontal displacement on a fault.
What does ‘Ka’ represent?
This is the abreviation for Kilo-annum which means one thousand years.
Define
klippe.
This is an outlier of a thrust sheet that is completely surrounded by the exposed foot wall.
What are key beds?
These are well-defined, easily identified strata that is distinctive enough to be useful in correlation in mapping.
What is a listric fault?
This is a fault woth a curved fault plane.
Near the surface the fault plane is steeply dipping, but becomes flatter with depth. These faults can be either normal or reverse.
What does ‘Ma’ stand for?
This is an abbreviation for Mega-annum which means one millions years.
What is magnetic declination?
This is the angle that is between true North and magnetic North.
Define nappe.
This is a sheet-like rock unit that has moved over other rocks (allochthonous) on a predominately horizontal surface.
Define net slip.
This is the distwnce between two formerly adjacent points on either side of the fault, measured on the fault surface.
Define nonconformity.
This is an unconformity that is formed by older igneous rocks in contact with younger sediments, which indicates a missing time after the igneous intrusion.
Define normal fault.
This is a dip-slip fault in which the hanging wall has moved down relative to the foot wall.
The dip of the fault is between 45 and 90 degrees.
Define an oblique slip fault.
This is a fault in which movement is not parallel to the strike or dip of the fault plane.
Define offset.
The horizontal component of displacement measured perpendicular to the strike of the disrupted unit.
Define reverse fault.
A dip slip fault in which the hanging wall has moved up relative to the footwall. The dip of the fault is between 45 and 90 degrees.
What is the rule of V’s?
This rule states that the outcrop pattern of a formation as it crosses a valley forms a V shape (map view). The V points in the direction that the formation underlies the valley.
What is the state plane coordinate system?
This is a two dimensional coordinate system that was developed by the National Geodetic Survey for use in states and counties.
Define strike separation.
The horizontal distance between a stratigraphic unit offset by a fault, measured along the strike of the fault. It is an apparent displacement.
Define strike-slip fault.
A fault in which movement is parallel to the strike of the fault plane.
Define throw.
This is the amount of vertical displacement on a fault, also, the vertical component of net slip.
Define thrust fault.
This is a reverse fault in which the fault plane dips less than 45 degrees.
Define unconformity.
This is a gap in the geologic record which signals an interruption in the depositional sequence that implies uplift and erosion have removed part of the geologic record or non- deposition has occurred.
Name the four Eons.
List youngest to oldest.
Phanerozoic
Proterozoic
Archaen
Hadean
What is the law of initial horizontality.
This law assumes that the sequence of layers were deposited horizontally or nearly so.
The oldest layer is therefore on the bottom and the youngest layer is on top.
In dissected topography, the youngest layers will form hill tops.
What does the law of superposition state?
States that the oldest layer is on the bottom and the youngest layer is on the top and assumes that layers have not been overturned during formation.
This law can be applied to any layered rock sequence such as sedimentary units or extrusive igneous rocks.
Define cross cutting relationships.
These are useful in determining relative ages because cross cutting is so common.
This implies that the feature that is cut is older than the feature that cuts across it and is cut by either intrusion, faulting, unconformities, or mineral replacement.
Define the principal of lateral continuity.
This implies there are sedimentary layers that when deposited covered a large area extending laterally in all directions.
Rocks are considered to be laterally continuous even though they may now be separated by uplift or erosion.
How can faunal and floral succession be used to determine ages?
By looking at the evolutionary decelopment of fossils, a sequence of age can be deceloped.
Older and more primitive fossils are usually found below younger fossils.
Extinctons may break the pattern and new patterns emerge. Fossils may show distinct evolutionary trends which may be used to correlate with stratigraphic sequences in other areas.
What is the law of inclusions?
This states that inclusions in a rock signify that the inclusions are older than the rocks in which they are included.
Inclusioks may also provide clues of the provenance [define] at the time of formation.
How can metamorphosed beds be used to determine age?
Imply that the metamorphosed beds are younger than the rock as it existed before metamorphism.
Metamorphism occurs at the same time with igneous intrusion or tectonism that produced the metamorphism.
Name the Periods from youngest to oldest.
Quarternary Tertiary Cretaceous Jurassic Triassic Permian Carboniferous Devonian Silurian Ordovician Cambrian
Name the subperiods and the periods they are apart of.
Neogene and paleogene - tertiary
Pennaylvanian and Mississippian - carboniferous
Name the Epochs and the Periods theyre apart of.
Holocene, Pleistocene - quarternary
Pliocene, Miocene - neogene
Oligiocene, Eocene, Paleocene - paleogene
Name the Eras
Cenozoic
Mesozoic
Paeozoic
Name the feature.
Graded bedding
Name the feature.
Truncated cross-bedding
Namw the feature.
Ripple marks
Name the feature.
Sole marks
Name the feature.
Basal conglomerates
Name the feature.
Rip-up clasts
Name the feature.
Scouring or channeling
Name the feature.
Mud cracks
Name the feature.
Solution surfaces.
Name the feature.
Pebble dents
Name the feature.
Brqchiopod shells encrusted with barnacles.
Name the feature.
Coral
Name the feature.
Disjointed pelecypod shells
Name the feature.
Worm tails
Name the feature.
Burrows
Name the feature.
Baked zone under lava flow
Name the feature.
Vesicular lava flow
Name the feature.
Pillow lavas
