Final Exam Prep

Question 1

Main orogenic event in N. America during the Devonian Period?

Answer 1

Antler Orogeny

Question 2

What occurred during the Roberts mountain thrust?

Answer 2

Thrusts deep water shale over coeval shallow water limestone

Question 3

What where the major changes of the Devonian-Silurian life?

Answer 3

Major changes include:

• advanced predators (includes jawed fish)
• initial colonization of land by plants and invertebrates

Question 4

Evidence of the Ordovician extinction event spurred a diverse recovery in the Silurian and Devonian?

Answer 4

• superior reef builders
• swimming predators
• aquatic recovery of articulate brachiopods, bryozoans, crinoids, rugose coral, and graptolites

Question 5

Reef builders and differences between the Silurian-Devonian period?

Answer 5

• tabulate corals
• colonial rugose coral
• stromatoporoids
• often bound together by encrusting calcareous algae.

Silurian- reefs up to 10m high

Devonian- true reefs with a rigid framework much like modern reefs however the organisms where different.

Question 6

Devonian canning basin?

Answer 6

• 100m high
• consists of corals, stromatoporoids, and calcareous algae
• forms a forereef consisting of the reef front talus (high energy)
• forms a backreef lagoon consisting of horizontal stratified layers. (High energy and diverse fauna)

Question 7

Two types of land plants and how do they differ?

Answer 7

Nonvascular- primitive, lived in low lying wet environments. Has no specialized cells for moving water or nutrients through plant.

Vascular- have well developed tissue system with cells to move water and nutrients. Allows them to grow bigger and are able to evolve into true terrestrial environments

Question 8

What is the oldest evidence for vascular plants?

Answer 8

Spores found in Ordovician rocks from Libya

Question 9

What is the earliest known vascular plant?

Answer 9

Cooksonia from the mid Silurian period found in Whales and Ireland.

Question 10

What is the importance of the plant life of the Devonian period?

Answer 10

Wide spread colonization of land (prior to this soils where only weathered rock). This creates a food web for land dwelling animals. The arrival of vascular plants was ~80m.y. earlier than the first known amphibians (L. Dev).

Question 11

Agnatha

Answer 11

Part of Ostracoderms- jawless primitive fish (Cam-Ord.)

Question 12

Acanthodians

Answer 12

First jawed fish from the early Silurian to Permian. Elongated fish with paired fins, jaws, large spines/scales, and plates.

Question 13

Placoderms

Answer 13

Diverse bottom dwellers and larger predators up to 12m long from the middle Silurian to Permian.
-Dunkleosteus

Question 14

Cartilagendous fish

Answer 14

Sharks, rays, and skates from the middle Devonian to recent.

Question 15

Bony fish

Answer 15

Ray finned and lobe finned that give rise to modern fish

Question 16

3 orders of lobe finned fish

Answer 16

• coelacanths
• lungfish
• crossopterygians

Question 17

Crossopterygians

Answer 17

Most likely a relative of amphibians. Fresh water predators up to 2m long, muscular finned, and elongated body for rapid swimming. (had everything required to live on land)

Question 18

Labyrinthodont

Answer 18

First amphibians

Question 19

Labyrinthodont vs. crossopterygians

Answer 19

• skull structure
• limb bones (fins vs. lobe fins)
• tooth structure

Question 20

What where the first vertebrates on land and what where required of them to live on land?

Answer 20

Amphibians where first vertebrates on land preceded by insects, arthropods, spiders, and snails.
Required:
- skeletal structure unsupported by water
- lungs
-limbs to move

Question 21

What was the transition between crossopterygians and labyrinthodonts?

Answer 21

Tiktaalik found in 2006 and had gills, scales, lungs, flexible neck, forelimbs with wrist bones, and five digits.

Question 22

Late Paleozoic environment (Permian, Pennsylvanian, and Mississippian)

Answer 22

Carboniferous- coal bearing strata formed from large swamps and giant spore bearing trees found in eastern North America and Western Europe

Question 23

Gondwana environment (all southern continents)

Answer 23

Large scale glaciation and numerous large scale sea level oscillations that eventually collides with Laurasia (northern continents) to form Pangea.

Question 24

What 4 mountain belts where formed at suture points during the formation of Pangea?

Answer 24

• Marathon- Ouachita belt (Gulf Coast)
• Appalachian (East Margin)
• Hercynian (North Africa)
• Caledonian ( British Isles)

Question 25

San Rafael Group

Answer 25

• arid climate

- small scale transgressions and regressions

Question 26

Mississippian deposition

Answer 26

• Kaskaskia sequence (sloss)
• vast shallow epeiric sea consisting of crinoidal and oolitic limestone (all cross-stratified and rippled formed by a high energy and shallow water environment)
  e.g. Leadville limestone- Colorado
  Redwall limestone- Western Colorado

Question 27

Pennsylvanian deposition

Answer 27

Worldwide cyclical nature of deposition called cyclothems on a ~200,000 year cycle. Cyclothems caused numerous alterations of non-marine and shallow marine facies controlled by sea level cause by glaciation/deglaciation in the southern polar regions.

Question 28

Single cycle- idealized cycle

Answer 28

• fluvial sandstone
• nearshore sandy shale (may be eroded)
• fossiliferous limestone (may be eroded)
• deep water shake (may be eroded)
• fossiliferous limestone
• nearshore shale
• coal deltaic swamp
• underclay
• non-marine sandstone (fluvial)

Question 29

Cause of the cyclical glaciation/deglaciation?

Answer 29

Milankovitch cycle.

• variations in eccentricity of orbit. (100,000 year cycle)
• obliquity (tilt of orbit) (41,000 years combined)
• precession (22,000 years)

Question 30

What formations make up the Central Colorado trough?

Answer 30

• Belden (black shale, limestone, coarse sandstone)
• Gothic/Minturn (shallow marine conglomerate, siltstone, sandstone, limestone)
• Eagle Valley Evaporites
• Maroon (fluvial sandstone, siltstone, conglomerate, minor thin limestone)
• Weber (aeolian dune field)

Question 31

Gothic/Minturn cyclicity

Answer 31

• conglomerate
• sandstone
• siltstone
• limestone (commonly sandy)
• siltstone
• sandstone
• conglomerate

Question 32

What is the Permian extinction event and what caused it?

Answer 32

Extinction that caused 90-95% of all marine species to die out. Some of the species effected where brachiopods, trilobites (went completely extinct), bryozoans, tabulate and rugose corals. The cause of this event happens in two stages spread out over 2 m.y. during the Permian. Some species went extinct when a global cooling event (glacial related) however, some species adapted to cooler climates. Then a rapid warming event occurred which caused severe stress on the newly adapted fauna eventually causing death. (In 2012 a new theory purposes that the warm climate likely caused from volcanism led to an increase in CO2 which formed a weak acid in the marine environment causing the death of the marine fauna)

Question 33

Triassic tectonics

Answer 33

It was globally dominated by extension when Pangea begins to break up caused by the continental rift phase of the Wilson Cycle. The evidence for this is the continental rift basins along the east coast of North America forming coarse-grained fluvial and lacustrine deposits (lake deposits). As Pangea begins to break up this opens up the Tethys sea near the southern portion of Pangea that eventually formed thick evaporate deposits in the Gulf of Mexico and western North America.

Question 34

What was the major orogenic event that occurred during the Permian/Triassic period and how did it form?

Answer 34

The Sonoma orogeny that was caused by the collision of Golconda island arc and the microcontinent Sonomia which now makes up Southeast Oregon, Northern California, and western Nevada.