ASBOG Paleontology and Geochronology 3

Question 1

The Permian-Triassic boundary (~252 Ma) marks the transition between which two geologic eras?

Accepted Answer

Paleozoic Era to Mesozoic Era

Answer

The Permian-Triassic boundary at ~252 Ma marks the end of the Paleozoic Era (with the Permian Period) and the beginning of the Mesozoic Era (with the Triassic Period), coinciding with the largest mass extinction in Earth history.

Question 2

Trilobites are most characteristic of which geologic era and are used to zone strata within it?

Accepted Answer

Paleozoic Era

Answer

Trilobites (extinct marine arthropods) existed from the early Cambrian through the end of the Permian (~521–252 Ma), making them important zone fossils throughout the Paleozoic Era.

Question 3

The study of fossil pollen grains and spores to interpret past vegetation and climate is called:

Accepted Answer

Palynology

Answer

Palynology is the study of pollen, spores, and other acid-resistant microfossils; it is used to reconstruct past vegetation, climate conditions, and correlate continental sedimentary sequences.

Question 4

Chemostratigraphy correlates rock units using changes in:

Accepted Answer

Isotopic and elemental geochemical signals (e.g., δ¹³C, δ¹⁸O)

Answer

Chemostratigraphy uses systematic changes in stable isotope ratios (such as carbon, oxygen, or strontium) and trace element concentrations to correlate sedimentary sequences and identify major oceanographic or environmental events.

Question 5

The Holocene Epoch, the current epoch of geologic time, began approximately:

Accepted Answer

11,700 years ago at the end of the last glacial maximum

Answer

The Holocene began ~11,700 years ago (11.7 ka), defined by the rapid warming that ended the last glacial stage (Younger Dryas) of the Pleistocene, as recorded in Greenland ice cores.

ASBOG - Association of State Boards of Geology Practice Test

ASBOG - Association of State Boards of Geology Practice Test

ASBOG Paleontology and Geochronology 3