CPG Stratigraphic Analysis & Sedimentology

Question 1

Which stratigraphic principle states that in undisturbed sedimentary sequences, older strata lie beneath younger strata?

Accepted Answer

Principle of superposition

Answer

The principle of superposition, formulated by Nicolas Steno, states that in undisturbed sequences younger layers are deposited above older layers.

Question 2

In sequence stratigraphy, a sequence boundary (SB) is most commonly characterized by which feature?

Accepted Answer

Subaerial exposure and incised valley formation during sea-level lowstand

Answer

Sequence boundaries form during relative sea-level falls when the shoreline migrates basinward, causing subaerial exposure, soil formation, and incised valley cutting.

Question 3

What sedimentary structure is most diagnostic of bidirectional tidal currents?

Accepted Answer

Herringbone cross-stratification

Answer

Herringbone cross-stratification forms from alternating flood and ebb tidal currents that deposit cross-beds in opposing directions, creating the characteristic V-shape pattern.

Question 4

In sequence stratigraphy, the maximum flooding surface (MFS) represents:

Accepted Answer

The deepest water conditions and maximum landward extent of marine transgression

Answer

The maximum flooding surface marks the time of greatest landward extent of marine conditions, typically rich in condensed pelagic sediment and organic matter.

Question 5

Which depositional environment most commonly produces a coarsening-upward (shallowing-upward) succession?

Accepted Answer

Prograding deltaic system

Answer

Prograding deltas build seaward over prodelta muds, producing a coarsening-upward succession from offshore silts to distributary mouth bar sands.

(CPG) Certified Petroleum Geologist Practice Test

(CPG) Certified Petroleum Geologist Practice Test

CPG Stratigraphic Analysis & Sedimentology