lecture 16 volcanic and tectonic landforms

Question 1

___________ are directly produced by volcanic and tectonic activity (resulting landforms include volcanoes and lava flows, as well as rift valleys and elevated mountain blocks in zones of recent crustal deformation).

Answer 1

initial landforms

Question 2

Landforms, such as river valleys which are shaped by processes and agents of denudation, belong to the group of ________, which develop after the initial landforms have been create

Answer 2

sequential landforms

Question 3

A _______is a conical or dome-shaped initial landform built of lava and ash emitted from a constricted vent in the Earth’s surface. The magma rises in a narro_w, pipe-like conduit from a magma reservoir

Answer 3

volcano

Question 4

__________ lava is highly viscous; it is thick and sticky, and resists flow

Answer 4

felsic

Question 5

onsequently, volcanoes of felsic composition typically have _______ as the lava does not usually flow far from the vent

Answer 5

steep slopes

Question 6

The inter-layering of sluggish streams of felsic lava and eruptions of tephra produces________-

Answer 6

stratovolcanos

(sometimes referred to as composite volcanoes, or composite cones, since they are formed from layers of ash and lava

Question 7

Another important form of emission from explosive stratovolcanoes is a cloud of white-hot gases and fine ash. These intensely hot clouds, called nuéeardentesor ash flows (sometimes pyroclastic flows), travel rapidly down the flank of a volcanic cone, searing everything in its path.

Answer 7

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Question 8

One of the most catastrophic of natural phenomena is a volcanic explosion so violent that it destroys the entire central portion of the volcano. Vast quantities of ash and dust are emitted and fill the atmosphere for many hundreds of square kilometres around the volcano. A great central depression, named a _____, remains after the explosion

Answer 8

caldera

Question 9

mafic lava

Answer 9

has a low viscosity, and holds little gas. As a result, eruptions of basaltic lava are much less violent, with the lava often travelling long distances, spreading out in thin layers. Large basaltic volcanoes are typically broad rounded domes with gentle slopes; they are called shield volcanoes(Hawaiian volcanoes)

Question 10

Where hot rock material is near the Earth’s surface, it can heat nearby groundwater to high temperatures. When it reaches the surface, the heated groundwater provides

Answer 10

hotsprings

Question 11

At some places, jet-like emissions of steam and hot water, at temperatures not far below the boiling point, occur at intervals from small vents producin

Answer 11

geysers

Question 12

n____________is a motion of the ground surface, ranging from a faint tremor to a wild movement capable of shaking buildings apart. This type of movement can be produced by volcanic activity or when magma rises or recedes within a volcanic chamber, but most result from movements along the boundaries of lithospheric plates.

Answer 12

earthquake

Question 13

arthquakes produce four basic types of wav

Answer 13

P waves and S waves—travel deep within the Earth’s interior, and two of which — Rayleigh waves and Love waves — travel near the surfa

Question 14

The point on the Earth’s surface directly above the focus of an earthquake is referred to as

Answer 14

epicenter

Question 15

The faster of the two deep-seated wave types is called the

Answer 15

primary or P waves. The P waves propagate by alternately pushing and pulling the rock, and can travel through both solid and molten rock material, as well as the water of the oceans.

Question 16

s waves

Answer 16

create a transverse motion perpendicular to the direction of propagation. This can be a vertical or horizontal movement, either of which shears the rock at right angles to the direction of propagation

Question 17

n important environmental hazard often associated with a major earthquake centred on a subduction plate boundary is the

Answer 17

seismic sea wave, or tsunami

Question 18

dis defined as the condition that exists when the discharge of a river cannot be accommodated within its normal channel - as a result - the water spreads over the adjoining ground. Most rivers of humid climates have a flood plain, a broad belt of low, flat ground bordering the channel on one or both sides that is flooded periodicall

Answer 18

flood

Question 19

are characteristic of streams draining small watersheds with steep slopes

Answer 19

flash floods

Question 20

s a body of standing water found within continental margins that is enclosed on all sides by land

Answer 20

lake

Question 21

origins of lakes

Answer 21

tectonic activity creates rift valleys  meteorite impact and volcanic eruptions form craters that also may contain lake

Question 22

landforms shaped by running water are described as ______; they develop from the _____ of overland flow and stream flow

Answer 22

fluvial landforms, fluvial processes

Question 23

re sequential landforms, which because they are shaped by progressive removal of the bedrock mass, are also

Answer 23

erosional landforms

Question 24

ragments of soil, regolith, and bedrock are transported and deposited elsewhere to make an entirely different set of surface features, collectively referred to as ________

Answer 24

depositional landforms.

Question 25

is the progressive removal of mineral material from the floor and sides of the channel, whether bedrock or regolith

Answer 25

stream erosion

Question 26

consists of movement of the eroded particles dragged over the stream bed, suspended in the body of the stream, or held in solution as ions.

Answer 26

stream transportatio

Question 27

s the accumulation of transported particles on the stream bed and flood plain or on the floor of a lake, where it may be temporarily held until it is carried to the ocean

Answer 27

stream deposition

Question 28

three types of load in stream

Answer 28

. Dissolved load (solution): chemical solution 2. Suspended load: fine-grained particles 3. Bed load: coarser material

Question 29

natural levies

Answer 29

flood carries sediment - ability to carry ediment decreases with distance – coarsest material deposited near banks – banks build slowly through flood cycles so river can be deeper

Question 30

The geomorphic work of wind in terrestrial environments is collectively referred to as ________, and includes erosion, transport, and deposition of Earth material

Answer 30

aeolian processes

Question 31

The _____is a common type of sand dune that develops perpendicular to the wind. Once a sufficient mass of sand has formed, it begins to move downwind, taking on a distinctive crescent shape with the horns, or points, directed downwind. Upwind side - the sand slope is gentle and smoothly rounded – the downwind crescent side is the steep slip face.

Answer 31

barchan dune

Question 32

Marine erosion is caused in four general way

Answer 32

Materials dislodged through hydraulic action by the force of the waves alone or in combination with air trapped and compressed by the weight of the falling water. 2. Abrasion - when the waves pick up rock fragments and propel them against the shoreline

The rock fragments are gradually rounded and reduced in size through attrition as they grind against each other. 4.The weakly acidic nature of sea water can dissolve certain rocks, such as limestone and chalk, by corrosion (or solution).

Question 33

neutral coastline

Answer 33

develop when new land is built out into the ocean - deltacoasts form where sediment-laden rivers enter the sea. A rapid reduction in velocity of the current as it pushes out into the standing water allows the sediment to settle from the water. The coarser sand and silt particles are deposited first, while the fine clays continue out into deeper wate

Question 34

4/5/18 50 Glacier Systems and Permafrost Glacial ice accumulates when the average winter snowfall exceeds the amount of snow and ice lost in summer by ________-

Answer 34

ablation

ablation occurs through sublimation, melting, and evaporation. When winter snowfall exceeds summer ablation, a layer of snow is added each year to what has already accumulated.

Question 35

ypically, mountain glaciers are long and narrow because they occupy former stream valleys

Answer 35

alpine glaciers

Question 36

maller glaciers that persist in mountain basins are called

Answer 36

cirque claciersq

Question 37

end as icefalls when they no longer extend down to the main valley.

Answer 37

hanging glaciers

Question 38

regionally extensive ice accumulation in a mountain region that feeds several glaciers is known as a

Answer 38

icefield

Question 39

Debris carried in, on, or under the ice is eventually deposited as ridges or piles of rock. A lateral moraine

Answer 39

s a debris ridge formed along the edge of the ice adjacent to the trough wall

Question 40

Where two ice streams join, marginal debris is dragged as a narrow band on the ice surfac

Answer 40

medial moraine

Question 41

At the terminus of a glacier, rock debris accumulates in

Answer 41

terminal moraine

Question 42

s mark the positions where the snout of a receding glacier remained stationary long enough to produce a depositional ridge.

Answer 42

recessional moraines

Question 43

A valley is constantly deepened and widened as a glacier passes along it. After the ice has disappeared, ____________

Answer 43

a deep, steep walled glacial trough remains

Question 44

The trough typically has a U-shaped cross-profile. In coastal areas, deeply excavated glacial troughs are usually flooded with sea water as the ice recedes, creating-______

Answer 44

fjords.

Question 45

term ________ includes all varieties of rock debris deposited as a result of continental glaciation.

Answer 45

glacial drift

Question 46

Two major types of drift are distinguished according to the degree of sorting and layering that occurred during depositio

Answer 46

Tillor non-stratified drift is made up of a mixture of rock fragments, ranging in size from clay to boulders, that is deposited directly from the ice without subsequent water transport. Stratified driftconsists of layers of clays, silts, sands, or gravels that were deposited by meltwater streams or settled out in bodies of water adjacent to the ice

Question 47

a __________is another common feature formed from glacial till; these smoothly rounded, oval hills have the general shape of an inverted spoon. _______invariably lie in a zone behind the terminal moraine. The long axis of each _____________-parallels the direction of ice movement, with the steeper, broader end facing the oncoming ice

Answer 47

drumlin(s)

Question 48

Ground with temperatures perennially below 0 °C is called

Answer 48

permafrost

Question 49

while the ice that is commonly present in pore spaces or as lenses is known as

Answer 49

ground ice

Question 50

A distinctive feature of permafrost terrain is the shallow surface layer, called the active layer, which freezes and thaws each year

Answer 50

active layer

Question 51

Four permafrost zones are recognized in the northern hemisphere

Answer 51

Continuous permafrost zone, Discontinuous permafrost, Sub-sea permafrost Alpine permafro

Question 52

The growth of ice lenses usually causes stones to move upward or sideways within the soil profile through a process of

Answer 52

cyroturbation

Question 53

The growth of ice lenses usually causes stones to move upward or sideways within the soil profile through a process of cryoturbation. In arctic environments, cryoturbation can produce regular surface forms, such as circles, polygons, and nets of stones, or fields of low mounds of soil. These features are collectively known as ______________. Circles, polygons, and nets are common features of permafrost terrain on flat or gentle slopes, but often become elongated into stripes on steeper slope

Answer 53

patterned ground

Question 54

A special type of earth flow characteristic of cold regions is _____________

Answer 54

solifluction

This occurs in late summer, when the ice-rich layer at the bottom of the saturated active layer melts to form mud. The active layer above then moves downslope as a single mass.

Question 55

Energy transformations in an ecosystem occur through a series of _________, or feeding levels, that are collectively referred to as a food chainor food web

Answer 55

trophic levels

Question 56

The plants and algae in a food web are the ___________and make up the first trophic leve

Answer 56

primary producers

Question 57

he primary producers support the _________— organisms that ingest other organisms as their food source

Answer 57

consumers

Question 58

The __________or herbivores are the lowest level of consumers. ________ or carnivores feed on the primary consumers. Some animals are ________and can feed on both plant and animal materials - ________use ______, or decaying organic matter, derived from all feeding level

Answer 58

primary consumers

Secondary consumers

omnivores

decomposers, detritus

Question 59

________is the production of carbohydrate — a general term for a class of organic compounds consisting of the elements carbon (C), hydrogen (H), and oxygen (O) with the general molecular formula CH2O (sugar or sucrose (C12H22O11)).

Answer 59

Photosynthesis

Question 60

s the opposite of photosynthesis in that carbohydrate is broken down and combined with oxygen to yield CO2 and water.

Answer 60

respiration

Question 61

Matter moves through ecosystems under the influence of both physical and biological processes. Each substance follows a specific biogeochemical cycle(material cycle or nutrient cycle) that consists of various pools interconnected by flow pathways

Answer 61

biogeochemical cycle

Question 62

A pool refers to any area or location of material concentration. There are two types of pool

Answer 62

active pools, where materials are in forms and places easily accessible to life processes, and storage pools, where materials are more or less inaccessible to living systems

Question 63

Biogeochemical cycles exists in two form

Answer 63

n a gaseous cycle, the element or compound can be converted directly into a gas - the primary constituents of living matter —carbon, hydrogen, oxygen, and nitrogen—all move through gaseous cycles. In a sedimentary cycle, weathering releases the compound or element from rock - the cycle is completed when the rock is uplifted and exposed to weathering.

Question 64

carbon cycle

Answer 64

The movements of carbon through the life layer are of great importance because all life is composed of carbon compounds of one form or another. Of the total carbon available, most lies in storage pools as carbonate sediments below the Earth’s surface. Only about 0.2 percent is readily available to organisms as CO2 or as decaying biomass in active pools.

Question 65

nitrogen cycle

Answer 65

Nitrogen moves through the biosphere in the gaseous nitrogen cycle in which the atmosphere acts as a vast storage pool. Nitrogen in the atmosphere, in the form N2, is an inert gas, and most plants or animals cannot assimilate it directly. The process by which nitrogen is converted into nitrogen compounds, such as ammonia (NH3) and nitrates (NO3-), is called nitrogen fixation - only certain microorganisms possess the ability to use nitrogen directly. In these forms, nitrogen is then available for various biochemical processe

Question 66

The_________ lie for the most part between the Tropics of Cancer and Capricorn and represent about 50 percent of Earth’s surfac

Answer 66

low-latitude climates

Question 67

The ____occurs in areas where the ITCZ is nearby for most of the year. This climate is dominated by warm, moist maritime equatorial (mE) and maritime tropical (mT) air masses that yield heavy convectional rainfall. The wet equatorial climate is found in the latitude range 10° N to 10° S.

Answer 67

wet equatorial climate

Question 68

are cool to cold, usually moist, climates that are associated with mountainous regions and high plateaus (closely associated with the climate of the surrounding lowlands). Generally, the higher the location, the colder and wetter is its climate. Temperatures are lower since air temperatures in the atmosphere normally decrease with altitude. Rainfall increases because orographic precipitation tends to be induced when air masses ascend to higher elevations, especially on windward slopes

Answer 68

highland cimates