Historical Geology

Question 1

What Marine Facies do we have depending on the sedimentary environment?

Answer 1

• Coastal: Detrital sands with organic remains.
• Platform: Silts, clays, marls, carbonates (including evaporites and limestones).
• Reef: Built by corals/rudists, possibly dolomitized.
• Slope: Flysch/turbidites.
• Sea bed: Clayey sediments and pelagic marls.

Question 2

What is the main focus of historical geology?

Answer 2

Reconstructing Earth’s geological history using stratigraphy and paleontology

Question 3

Which environments best record Earth’s geological history?

Answer 3

Sedimentary environments

Question 4

What does stratigraphy study?

Answer 4

Rock layers (strata), their sequence, composition, and spatial relationships

Question 5

What does paleontology study?

Answer 5

Fossils and ancient life forms and their relationship with past environments

Question 6

What is a stratum?

Answer 6

A sedimentary rock layer bounded by stratification planes

Question 7

What defines a stratigraphic series?

Answer 7

A sequence of strata representing a chronological unit based on lithology and fossils

Question 8

What are sedimentary structures used for in stratigraphy?

Answer 8

To infer the sedimentary environment and paleogeography

Question 9

What is the goal of correlating stratigraphic series?

Answer 9

To reconstruct past environments and events

Question 10

What is an index fossil?

Answer 10

A fossil used to define and identify geological periods

Question 11

What are the characteristics of a good index fossil?

Answer 11

Short geologic range, wide distribution, easily fossilized

Question 12

What are ichnofossils?

Answer 12

Trace fossils indicating the activity of ancient organisms

Question 13

What is the purpose of biostratigraphy?

Answer 13

To correlate and date rock layers using fossil content

Question 14

What is a facies?

Answer 14

A set of characteristics in strata that reflect a specific depositional environment

Question 15

What are descriptive facies based on?

Answer 15

Lithology and fossil content

Question 16

What do determinative facies help interpret?

Answer 16

The environment of formation

Question 17

What are the typical characteristics of coastal facies?

Answer 17

Detrital sands with shell fragments

Question 18

What is a platform facies?

Answer 18

Marine facies with clays, marls, and carbonates

Question 19

What characterizes reef facies?

Answer 19

Carbonates formed by coral and rudist builders

Question 20

What are flysch deposits?

Answer 20

Alternating layers of sandstones and clays typical of slope facies

Question 21

What causes lateral facies changes?

Answer 21

Environmental changes across space during sedimentation

Question 22

What law explains vertical and lateral facies variation?

Answer 22

Walther’s Law

Question 23

What is a transgression?

Answer 23

Advance of the sea over land, leading to finer sediment deposition

Question 24

What is a regression?

Answer 24

Retreat of the sea, causing coarser sediment deposition

Question 25

What is relative dating?

Answer 25

Determining the order of geological events without exact ages

Question 26

Name one principle of relative dating.

Answer 26

Law of Superposition

Question 27

What is absolute dating based on?

Answer 27

Radioactive decay of isotopes

Question 28

What does a half-life represent?

Answer 28

Time it takes for half of a radioactive isotope to decay

Question 29

Which isotope is used for dating recent organic remains?

Answer 29

Carbon-14

Question 30

Which isotope system is used to date ancient rocks?

Answer 30

Uranium-238 to Lead-206

Question 31

What is geochronology?

Answer 31

Dating geological events in time using absolute or relative methods

Question 32

What are the two eons in the geologic time scale?

Answer 32

Precambrian and Phanerozoic

Question 33

What are the three eras of the Phanerozoic?

Answer 33

Paleozoic, Mesozoic, Cenozoic

Question 34

Which periods belong to the Paleozoic?

Answer 34

Cambrian, Ordovician, Silurian, Devonian, Carboniferous, Permian

Question 35

What periods are in the Mesozoic era?

Answer 35

Triassic, Jurassic, Cretaceous

Question 36

Which periods make up the Cenozoic?

Answer 36

Paleogene and Neogene

Question 37

What is a GSSP?

Answer 37

Global Boundary Stratotype Section and Point defining geologic time boundaries

Question 38

What orogeny shaped the Iberian Peninsula during the Paleozoic?

Answer 38

Hercynian (Variscan) orogeny

Question 39

What massif formed during the Hercynian cycle?

Answer 39

Iberian (or Hesperic) Massif

Question 40

What cycle followed the Hercynian?

Answer 40

Alpine cycle

Question 41

What mountain range is a key result of the Alpine orogeny?

Answer 41

The Pyrenees

Question 42

What caused the formation of the Pyrenees?

Answer 42

Collision between the Iberian and Eurasian plates

Question 43

What materials form the Pyrenees' basement?

Answer 43

Paleozoic metamorphic rocks deformed during the Hercynian

Question 44

What are post-Alpine basins?

Answer 44

Basins formed by extension after the Alpine compression phase

Question 45

What are intermountain basins?

Answer 45

Depressions between mountains filled with sediment

Question 46

Name two foreland basins in the Iberian Peninsula.

Answer 46

Ebro and Guadalquivir basins

Question 47

What are rift-type basins?

Answer 47

Elongated basins formed by post-orogenic extension

Question 48

Where is volcanism found in rift basins?

Answer 48

Olot, Murcia, Campo de Calatrava, etc.

Question 49

What is paleogeography?

Answer 49

Reconstruction of past geographic environments based on geological data

Question 50

What is the difference between stratigraphy and historical geology?

Answer 50

Stratigraphy focuses on spatial relationships, historical geology on temporal sequence