ASBOG Sedimentology and Stratigraphy 4

Question 1

Which cement type in sandstone forms early in shallow burial and is commonly dissolved during deeper burial to create secondary porosity?

Accepted Answer

Calcite cement

Answer

Calcite cement precipitates early in sandstone diagenesis and is readily dissolved by acidic fluids during burial, creating significant secondary porosity.

Question 2

The ASBOG Fundamentals of Geology exam emphasizes which stratigraphic principle when establishing the relative age of an intrusive igneous body?

Accepted Answer

Cross-cutting relationships

Answer

The principle of cross-cutting relationships states that an igneous intrusion is younger than the rocks it cuts, establishing relative age.

Question 3

Which paleoenvironment is indicated by the co-occurrence of coal seams, seat earths (underclays), and freshwater limestones in a cyclothem?

Accepted Answer

Coastal swamp / paralic environment

Answer

Cyclothems with coal (peat swamp), seat earth (paleosol), and freshwater limestone record repeated coastal swamp (paralic) cycles driven by sea-level fluctuations.

Question 4

Graded bedding where grain size decreases upward in a single bed is described as:

Accepted Answer

Normal grading

Answer

Normal grading (coarse-to-fine upward) records waning flow energy, where heavy grains settle first and finer grains settle last from suspension.

Question 5

When correlated globally, the base of the Cambrian System is defined by the first appearance of which fossil?

Accepted Answer

Treptichnus pedum (ichnofossil)

Answer

The base of the Cambrian (GSSP at Fortune Head, Newfoundland) is defined by the first appearance of the trace fossil Treptichnus pedum.

ASBOG - Association of State Boards of Geology Practice Test

ASBOG - Association of State Boards of Geology Practice Test

ASBOG Sedimentology and Stratigraphy 4