Question 1

The rock sequences and mountainous topography of the northern portion of the Appalachian Mountains ________.
A)consist of up to six different accretionary sequences, plastered onto the eastern margin of North America during the closing of the Iapetus Ocean over several stages of tectonic convergence between the Cambrian and Carboniferous
B)was made up mainly of Late Proterozoic, passive margin sedimentary strata that weren't deformed until the break up of Pangaea in the Late Carboniferous
C)is made up of extinct composite volcanoes and massive intrusions formed above a Late Precambrian subduction zone
D)were barged across the Atlantic by homesick Scottish immigrants during the Highland Clearances

Accepted Answer

The northern portion of the Appalachian Mountains consists of multiple accretionary sequences that were added onto the eastern margin of North America during the closing of the Iapetus Ocean. This occurred over several stages of tectonic convergence between the Cambrian and Carboniferous periods.

Question 2

Intensely folded, thinly bedded, Paleozoic shales and carbonates cause this part of the Canadian Rockies to appear the most jagged and rough due to the easily-eroded shale interbeds.
A)Western Ranges
B)Main Ranges
C)Front Ranges
D)Foothills

Accepted Answer

The Western Ranges are the most jagged and rough part of the Canadian Rockies due to the easily-eroded shale interbeds in the intensely folded, thinly bedded, Paleozoic shales and carbonates.

Question 3

Between the original Proterozoic rifting of Rodinia and the Late Paleozoic rifting of Pangaea, how much "real estate" was added to the North American continent?
A)the entire width of the Appalachian Orogen, St.Lawrence Seaway through Nova Scotia, 600-800 kilometres
B)everything from Ontario to Alberta
C)only Newfoundland and Labrador
D)the width of Iapetus Ocean, thousands of kilometres

Accepted Answer

The Appalachian Orogen, St. Lawrence Seaway through Nova Scotia, which spans 600-800 kilometres, represents the significant addition to the North American continent between the Proterozoic rifting of Rodinia and the Late Paleozoic rifting of Pangaea. This addition was a result of tectonic activities and the closing of the Iapetus Ocean, leading to the formation of the supercontinent Pangaea.

Question 4

In general, which of the following statements about elevated, compressive orogens is true?
A)Crust was thickened by previous mountain building; as isostatic uplift and erosion proceed, the crust is gradually reduced in thickness.
B)Crust was thinned by extensional faulting in the past; isostatic uplift and erosion cause the crustal root to gradually thicken.
C)Crust is flattened by increased atmospheric pressure over mountain belts.
D)Crust is sucked into the mantle by increased convection under mountain belts.

Accepted Answer

Elevated, compressive orogens result from the thickening of the crust due to previous mountain building episodes. As isostatic uplift and erosion continue, the crust gradually reduces in thickness.

Question 5

During the Late Paleozoic (Devonian through Carboniferous), the tectonic and topographic configuration of the Appalachian region in eastern North America was most similar to the ________.
A)Himalayas and Tibetan Plateau
B)Andes
C)Afar Rift
D)western California

Accepted Answer

During the Late Paleozoic, the Appalachian region was part of the supercontinent Pangaea and was located near the southern edge of the continent. The collision of the North American plate with the African plate during this time period resulted in the formation of a mountain range that is often compared to the modern-day Himalayas and Tibetan Plateau because of its size and height.

Question 6

The Humber Zone (Valley and Ridge Province in USA)of the Appalachian Mountains is characterized by ________.
A)sedimentary strata folded in late Paleozoic time
B)deeply eroded, late Paleozoic, fault-block mountains and valleys
C)composite volcanoes above a volcanic arc
D)crustal stretching as Africa and Eurasia migrated away from North America

Accepted Answer

The Humber Zone of the Appalachian Mountains is characterized by sedimentary strata which are folded in late Paleozoic time.

Question 7

Under what terrane would you look to find the original rift zone tensional faults from the Proterozoic break up of Rodinia?
A)Humber Zone (Valley and Ridge Province in USA)of folded, sedimentary rocks on the eastern edge of the Appalachians
B)Dunnage Zone (Taconic phase)
C)Avalonia block (Acadian phase)
D)Meguma Zone

Accepted Answer

The Humber Zone, part of the Valley and Ridge Province in the USA, contains folded sedimentary rocks on the eastern edge of the Appalachians. This area is significant for its geological history, including evidence of the original rift zone tensional faults from the Proterozoic break-up of the supercontinent Rodinia. These faults are indicative of the extensional forces that pulled Rodinia apart, leading to the formation of new ocean basins and the initial stages of the Appalachian orogeny.

Question 8

Low elevation rounded mountains and hogbacks underlain by thrusts and folds in easily-eroded Mesozoic and Cenozoic strata are found in this part of the Rockies.
A)Foothills
B)Western Ranges
C)Main Ranges
D)Front Ranges

Accepted Answer

The description matches the characteristics of the Foothills region of the Rockies, which is known for its low elevation rounded mountains and hogbacks, often underlain by thrusts and folds in easily-eroded Mesozoic and Cenozoic strata.

Question 9

The ________ are a geologically old mountain range folded and deformed during the Paleozoic.
A)Cascades in the northwestern U.S.and southwestern B.C.
B)Canadian Rockies
C)Appalachians of eastern North America
D)Alps in Europe

Accepted Answer

The Appalachians of eastern North America are known as a geologically old mountain range that was folded and deformed during the Paleozoic. The Cascades in the northwestern U.S. and southwestern B.C., Canadian Rockies, and Alps in Europe are all relatively younger mountain ranges.

Question 10

Thick thrust sheets of massive Proterozoic and Paleozoic carbonates from glaciated peaks with steep cliffs on all sides like Castle Mountain in western Alberta are found in this part of the Rockies.
A)Main Ranges
B)Western Ranges
C)Front Ranges
D)Foothills

Accepted Answer

The Main Ranges of the Canadian Rockies, which include features like Castle Mountain in western Alberta, are characterized by thick thrust sheets of massive Proterozoic and Paleozoic carbonates, often with glaciated peaks and steep cliffs on all sides.

Question 11

What is the Meguma Zone in Nova Scotia (and similar rocks beneath the more southerly, continental shelf off the US eastern seaboard)thought to represent?
A)passive margin sequence from Gondwanaland as the Iapetus Ocean closed
B)passive margin sequence from Rodinia's rifted margin
C)Ordovician accretionary melange from the Taconic orogeny
D)Cretaceous and Tertiary shallow continental shelf deposits from North America's passive margin

Accepted Answer

The Meguma Zone in Nova Scotia and similar rocks beneath the continental shelf off the US eastern seaboard are thought to represent a passive margin sequence from Gondwanaland as the Iapetus Ocean closed. This interpretation is based on the geological history and the types of rocks found in this area, which are consistent with the processes and environments associated with the closing of an oceanic basin and the formation of a passive continental margin.

Question 12

The ________ of the Appalachian orogen consists of North American, continental shelf strata deposited prior to the late Paleozoic collision with Gondwanaland (Africa).
A)Humber Zone (Valley and Ridge in USA)of folded sedimentary rocks on the eastern edge
B)Dunnage Zone (Taconic phase)
C)Avalonia bock (Acadian phase)
D)Meguma Zone

Accepted Answer

The Humber Zone, also known as the Valley and Ridge in the USA, consists of folded sedimentary rocks that were part of the North American continental shelf strata before the late Paleozoic collision with Gondwanaland.

Question 13

What kind of crust was the Avalon Terrane prior to its accretion to the Appalachians in the Acadian Orogeny in the Silurian and Devonian?
A)microcontinental fragment rifted off Rodinia or Gondwanaland
B)supracrustal Iapetus seafloor sediments and Gondwanaland passive margin succession
C)ophiolite-Iapetus Ocean crustal sequence
D)island arc sequence

Accepted Answer

The Avalon Terrane is considered a microcontinental fragment that rifted off from larger landmasses like Rodinia or Gondwanaland before accreting to the Appalachians.

Question 14

What supercontinent drifted apart in the Proterozoic to form the first extensional phase of the Appalachian orogen?
A)Rodinia
B)Gondwanaland
C)Laurasia
D)Pangaea

Accepted Answer

The supercontinent Rodinia existed during the Proterozoic era before breaking apart, leading to the formation of the Appalachian Mountains.

Question 15

What ocean basin was destroyed and finally had its last sliver obducted to make the ophiolite between the Humber Zone and the Gander Terrane?
A)Iapetus
B)Atlantic
C)Arctic
D)Fundy

Accepted Answer

The Iapetus ocean basin was located between the ancient landmasses of Laurentia and Avalonia (which eventually collided to form what is now the Appalachian Mountains). It began closing during the Ordovician period and completely disappeared by the end of the Silurian period. The obduction of its last sliver (oceanic crust) between the Humber Zone and the Gander Terrane occurred during this process of closure, resulting in the formation of the ophiolite.

Question 16

Obducted ophiolite and island arc sequences are part of a ________ margin.
A)continent-ocean
B)continent-continent
C)ocean-ocean
D)divergent

Accepted Answer

Obducted ophiolite and island arc sequences are typically found at a convergent margin between a continent and an ocean.

Question 17

Which one of the following is an example of an isostatic movement?
A)stream downcutting following a drop in sea level
B)arching of strata at the centre of a dome
C)numerous aftershocks associated with deep-hypocentre earthquakes
D)uplift of areas recently covered by thick, continental ice sheets

Accepted Answer

Isostatic movement refers to the vertical movement of the Earth's crust in response to changes in the weight of overlying material. The uplift of areas recently covered by thick, continental ice sheets is an example of isostatic movement, as the removal of the weight of the ice causes the land underneath to rebound and rise.

Question 18

Well defined linear mountain ridges with southwesterly-dipping slopes, steep upturned bounding thrusts and intervening linear strike valleys are found in this part of the Rockies.
A)Front Ranges
B)Western Ranges
C)Main Ranges
D)Foothills

Accepted Answer

The Front Ranges of the Rockies are characterized by linear mountain ridges with southwesterly-dipping slopes, steep upturned bounding thrusts, and intervening linear strike valleys. The foothills are characterized by rolling terrain and are located at the base of the Front Ranges. The Main Ranges and Western Ranges do not have the same well-defined linear features as the Front Ranges.

Question 19

A ________ is a ridge of steeply inclined, resistant strata exposed along the edges of an uplifted block of older rock.
A)hogback
B)hoodoo
C)monotreme
D)shellback

Accepted Answer

A hogback is a geological feature that is formed by the edges of an uplifted block of older rock, exposing a ridge of steeply inclined, resistant strata. The name "hogback" comes from the resemblance of the ridge to the back of a hog. Hoodoo, monotreme, and shellback are not geological features related to this definition.

Question 20

The ________ is the global tectonic cycle that rifts supercontinents, developes extensive passive margins, opens ocean basins, closes ocean basins, creates new island arc or Andean crustal orogens, and finally builds new collisional mountain belts as the ocean completely closes to make a new supercontinent.
A)Convective Conga
B)Seafloor Shake Up
C)Wegnerian Break Up
D)Wilson Cycle

Accepted Answer

The Wilson Cycle is a well-established model that describes the global tectonic processes of the Earth in which we see the opening and closing of ocean basins and the formation and destruction of supercontinents over geologic time. The cycle begins with the rifting of a supercontinent, which creates a new passive margin and opens an ocean basin. This new ocean basin continues to widen as seafloor spreading occurs until it reaches a subduction zone where material is consumed, and where ultimately the ocean basin closes. Finally, the two continents collide, creating a new collisional mountain range, and a new supercontinent is formed. This cycle has been observed and documented multiple times throughout Earth's history, including the formation and breakup of Pangaea.

Quiz 13: Mountain Building and Continental Frameworks

The rock sequences and mountainous topography of the northern portion of the Appalachian Mountains ________.

Intensely folded, thinly bedded, Paleozoic shales and carbonates cause this part of the Canadian Rockies to appear the most jagged and rough due to the easily-eroded shale interbeds.

Between the original Proterozoic rifting of Rodinia and the Late Paleozoic rifting of Pangaea, how much "real estate" was added to the North American continent?

In general, which of the following statements about elevated, compressive orogens is true?

During the Late Paleozoic (Devonian through Carboniferous) , the tectonic and topographic configuration of the Appalachian region in eastern North America was most similar to the ________.

The Humber Zone (Valley and Ridge Province in USA) of the Appalachian Mountains is characterized by ________.

Under what terrane would you look to find the original rift zone tensional faults from the Proterozoic break up of Rodinia?

Low elevation rounded mountains and hogbacks underlain by thrusts and folds in easily-eroded Mesozoic and Cenozoic strata are found in this part of the Rockies.

The ________ are a geologically old mountain range folded and deformed during the Paleozoic.

Thick thrust sheets of massive Proterozoic and Paleozoic carbonates from glaciated peaks with steep cliffs on all sides like Castle Mountain in western Alberta are found in this part of the Rockies.

What is the Meguma Zone in Nova Scotia (and similar rocks beneath the more southerly, continental shelf off the US eastern seaboard) thought to represent?

The ________ of the Appalachian orogen consists of North American, continental shelf strata deposited prior to the late Paleozoic collision with Gondwanaland (Africa) .

What kind of crust was the Avalon Terrane prior to its accretion to the Appalachians in the Acadian Orogeny in the Silurian and Devonian?

What supercontinent drifted apart in the Proterozoic to form the first extensional phase of the Appalachian orogen?

What ocean basin was destroyed and finally had its last sliver obducted to make the ophiolite between the Humber Zone and the Gander Terrane?

Obducted ophiolite and island arc sequences are part of a ________ margin.

Which one of the following is an example of an isostatic movement?

Well defined linear mountain ridges with southwesterly-dipping slopes, steep upturned bounding thrusts and intervening linear strike valleys are found in this part of the Rockies.

A ________ is a ridge of steeply inclined, resistant strata exposed along the edges of an uplifted block of older rock.