Module 2 Flashcards

Question

Oceanic crust is generally less than ________ years old, whereas some of the continental crust is _______ years old

Answer 1

200 million severel billions

Answer 2

Active Plate Boundaries: Volcanism and Earthquakes are ongoing along subduction zone . Passive Continental Margins: Volcanism and Earthquakes are really irrelevant now(non-active)

Answer 3

Hot Spot Volcansism: An unusual upflow of material from the mantle which stays in place while surface moves above it Hawaiian island chain formed when a lithospheric plate moved over a stationary “hot spot” in the mantle; provides explanation for occurrence of active volcanoes 1000’s km from plate boundaries (Figure 2.19)

Answer 4

came up with idea of Hot Spot Volcanism and transform vaults

Answer 5

transform faults joining segments of mid-oceanic ridges associated with horizontal motion

Answer 6

Geomorphology: from the Greek (gē: earth; morphē: form; and logos: discourse) refers to the study of the morphology of the surface of the Earth and the processes operating on it, in the present, past, and the future. (Alan S. Trenhaile 2013) Geomorphology seeks to: understand the sequence of landscape development understand the dynamics of physical, chemical, and biological processes that create landforms predict the nature of future change based on field observations, physical experiments, and numerical modelling -geomorphology is used in a wide spread of fields of knowledge

Answer 7

endogenic exogenic

Answer 8

1. Tension: lithospheric plates are pulled apart – divergent plate boundaries - dominated by normal faulting(rocks fail along a steeply inclined surface, typically sloping at an angle of between 45° and 70°) - these processes occur at mid-oceanic ridges (spreading centres) and contribute to seafloor spreading - rift valleys and grabens 2.Compression: lithospheric plates are pushed together – convergent plate boundaries -compression results in shortening of the lithosphere, a combination of folding and faulting, resulting in an increase in elevation and thickening of the lithosphere – creates orogenic mountain chains offshore, subduction of oceanic lithosphere creates deep, narrow depression in the seafloor – an oceanic trench 3.Lateral movement: lithospheric plates move horizontally past each other – transform plate boundaries.

Answer 9

rift valley graben

Answer 10

extrusive intrusive

Answer 11

1. Normal fault - high angle:one side sliding up while the other slides down - vertical displacement 2. Strike-slip fault - one side sliding in one direction and the other side sliding in the opposite direction - horizontal displacement 3. Reverse Faulting - low angle: one sliding up while the other slides down - vertical displacement - common in landscapes marked by compression

Answer 12

pillow newly formed oceanic lithosphere, composed largely of basalt and gabbro, moves away from the ridge crest e.g., Mid-Atlantic Ridge and Þingvellir Graben, East African Rift Valleys

Answer 13

new oceanic ridge is created by upwelling of basaltic magma along fractures beneath mid-oceanic ridges. The newly formed crust moves away from the ridge, forming the trailing edges of two oceans plates.

Answer 14

example in iceland of mid-oceanic ridges form where magma from the mantle rises and is erupted as pillow lavas forming broad ridges with a central rift valley where plates break apart and move apart

Answer 15

Ottawa-Bonnechere normal

Answer 16

intraplate

Answer 17

1. oceanic-continent collision - when they converge. the oceanic plate must subduct beneath the continental plate because the density of thick continental crust is too low to permit it to sink into the aestenosphere 2. oceanic-oceanic collision - when a convergent boundary forms between plates of oceanic lithosphere, the plate that is older, thicker, and denser subducts the less dense plate - can result in volcanic island arc like in Japan - example in phillipines 3.continent-continent collision -when subduction brings two continents together limited subduction may occur but the buoyancy of continental crust eventually stops the subduction. The contraction of crust in the collision zone doubles the thickness of continental crust and creates high mountains. Silvers of oceanic crust are commonly uplifted in the mountain range and record the basin consumed by subduction prior to collision of the continents Ex: india running into china and creating himilayas -no volcanism just earthquakes

Answer 18

Syncline-topographic depressions Anticlines- topographic relief

Answer 19

Features developed in landscapes marked by compression of rock units include folding and reverse (thrust) faulting. Folded terrain results from alternating of down-warped synclines and up-warped anticlines—often leading to the development of ridges (anticlines) and valleys (synclines). A cuesta is a ridge composed of sedimentary bedrock, where one side dips at a gentle angle and the opposite side forms a steep escarpment.

Answer 20

compression ``` .Reverse faults move rocks on the upper side of the fault (called the hanging wall) up and over those on the underside of the fault (the footwall). -Thrust faults are the most common class of reverse faults, involving movement over gently inclined surfaces. thrust-faulting is characteristic of compressive terrain associated with subduction zones. the major mountain chains of the eastern Canadian Cordillera, including the Richardson, Mackenzie, and Rocky mountains, are products of thrust-faulting from southwest to northeast, generated by plate tectonic activity. ```

Answer 21

Appalachians along the eastern seaboard

Answer 22

Gneiss- foliated(layered) texture developed from granite in metamorphic change

Answer 23

rock units are split horizontally by transform (or strike-slip) faults and displaced laterally. a sharp, clean break occasionally results, with essentially no difference in relief between the two blocks. More commonly, the moving blocks are forced into contact, fracturing rock faces and grinding the contact surface under high pressure. transform faults are most common on the ocean floor, but some occur on continents; e.g., San Andreas Fault in California, Queen Charlotte Fault west of Haida Gwaii (see Figures 2.12 and 2.15)

Answer 24

c=66 million to prsent day m=225 to 66 million pa=542 million to 225 pr=4.6 billion

Answer 25

Canadian Shield was created between 1.96 and 1.81 billion years ago through the collision and welding together of at least six ancient microcontinents .divided into structural provinces consisting largely of Archean granite (igneous) and gneiss (metamorphic) rocks, welded together by orogenic mountain belts consisting largely of Late Proterozoic volcanic (i.e., greenstones) and metamorphosed sedimentary rocks landform comprising the exposed part of the North American craton covered with younger sedimentary rocks in most of United States and Western Canada craton: refers to old continental crust preserved deep within the centres of continents North American craton large continent-sized block of Archean and Proterozoic rock stretching from Mexico to USA, Canada, and Greenland

Answer 26

igneous metamorphic

Answer 27

craton: refers to old continental crust preserved deep within the centres of continents

Answer 28

Grabens: faulting defines parts of the Shield boundary and it has brought different rock types into contact with each other within the Shield. Valley-like depressions, or grabens, have been created when a block subsides between two parallel faults.

Answer 29

rocks range in age from the Precambrian to the Mesozoic mountain building was associated with the opening and closing of the Iapetus Ocean closure of the Iapetus Ocean was associated with subduction of oceanic lithosphere and extensive volcanism; an ocean-continent collision closure was terminated by a continent-continent collision accompanied by folding, thrusting and metamorphism of sedimentary rocks along the continental margin in the Early Mesozoic continental rifting along the eastern border of this mountain system was associated with the creation of the Atlantic Ocean basin

Answer 30

this region includes the mountains of British Columbia, Alberta, Yukon, and Northwest Territories these mountain ranges have resulted from plate collision and crustal shortening the eruption of basaltic lavas, the construction of composite volcanoes, the intrusion of granite batholiths, and the folding and overthrusting of continental lithosphere have accompanied ocean-continent collision during the Mesozoic and Cenozoic

Answer 31

this region of Canada experienced rapid deposition of sedimentary rocks and continuous subsidence throughout the early Paleozoic (Cambrian-Devonian) orogeny in the Late Paleozoic (Devonian-Carboniferous) involved the eruption of basaltic lava and the folding and faulting of the overlying sedimentary rocks further uplift of the region was associated with the emplacement of granite batholiths (epeirogeny) subsequent weathering and erosion (Carboniferous-Cretaceous) heralded the return to rapid sedimentation and subsidence orogeny in the Early Paleogene involved the uplift, folding and faulting of the sedimentary rocks and the intrusion of igneous dykes.