Sed Strat Test #3

Superposition

old rocks exist below younger ones

Inclusion

a feature which is present entirely within another is older

Cross-Cutting

a cut across multiple features is younger than all of those features

Faunal Succession

in similarly-aged rocks, fossils succeed each other in the same order

Lithostratigraphic Heirarchy

supergroup - group - formation - member - band

Type Locality

a location where a geologic unit is well exposed and displays the characteristics and variability of said unit

Walthers Principle of Facies

states that in an unbroken sequence, laterally adjacent facies can be superimposed vertically in a stratigraphic section as the environment shifts

Conformable Boundaries

a geologic boundary where the change is gradual and continuous

Graduational Boundary

a type of conformable boundary which is gradual and implies slow and continuous change in the nature of deposition

Intercalated Boundary

a type of conformable boundary where each rock layer is interbedded, with one bed becoming more thick and frequent until the boundary ends

Non-Conformities

a sedimentary rock unit overlying an unconformity which itself overlies igneous or metamorphic rocks (which are unstratified)

Disconformities

Two sedimentary rock units with an unconformity between them

Angular Unconformities

a flat sedimentary rock unit overlying an older / folded sedimentary rock unit

Eustatic Sea Level Change

worldwide change in sea level

Biozone

fundamental unit of biostratigraphy, marked by the first and/or last appearances of different fossils

Index Fossils

specific fossils which due to their larger geographic range, constrained time period, or relative abundance can reliably estimate and constrain the age of a rock

Magnetostratigraphy

the element of stratigraphy that deals with the magnetic properties of rocks, particularly the rock’s polarity

Curie Point

The temperature at which a rock loses its internal magnetism and realigns to the Earth’s magnetism

Remanent Magnetism

The internal alignment of magnetic minerals in a rock

Thermal Remanent Magnetism

created by cooling below the Curie Point, can change if the rock is reheated

Detrital Remanent Magnetism

created as fine-grain magnetic particles align with the magnetic field as they settle in water and form sedimentary rocks, requires unique and undisturbed physical conditions

Chemical Remanent Magnetism

created during the precipitation of magnetic minerals in solution, coincides with the precipitation of magnetic minerals (which may occur later than the initial rock formation)

Polarity Zone

fundamental unit of magnetopolarity

Epoch

The old magnetostratigraphic terminology describing long periods of time where magnetism was relatively the same

Event

smaller moments of pole reversal within an epoch

Seismic Stratigraphy

a method of interpreting the stratigraphy of Earth’s subsurface utilizing seismic signals

Wilson Cycle

a geologic model describing how ocean basins can open and close over as little as two paleozoic periods

Rift Systems

created by a variety of geologic processes (including hotspots), and can create divergent boundaries or pathways for hydrologic features