BJU Earth Science Chapter 7

topography

variation of land surface elevations caused by different landforms

isostasy

geologists use the term _________ to describe the balance of the weights of rock, water, and ice, and the upward force of the mantle.

landforms

the shapes or structures on the earth's surface

orogeny

tectonic forces that geologists believe resulted in the making of mountains fall under the geologic term ___________. (geologic history)

mountain

a natural elevation of the earth's surface rising more or less abruptly to the a summit; applies to a hill too

summit

the highest point on a hill or mountain

height

the difference between mountains and hills is mostly _______, but it is also related to local customs in an area.

elevation

height of a mountain's peak above mean sea level - often expressed in meters or feet

actual height

the __________ __________ of a moutain is the height of its summit above the lowest elevation of the surrounding terrain, or its base

Mauna Kea

which mountain has the greatest actual height on earth?

relief

the difference in height between the highest and lowest elevations of the terrain in an area.

range

A series of mountain peaks in the same geographical area is a mountain _________.

system

a group of mountain ranges connected over a much larger area is a mountain __________.

relief map

a map that shows topography using thematic colors, shading, contour lines, or some other method. the most useful of this kind of map uses contour lines, which join points of equal elevation

The Mid-Atlantic Ridge

longest mountain system (found in the middle of the ocean)

fold mountains

mountains formed from folded rock strata. layers of softer, unsolidified materials can easily bend under a force.

anticline

an arch of rock layers. forces pushed the layers of rock into an upward fold.

syncline

a trough or downward fold or rock strata formed just like an anticline. certain kinds of folds seem to have been caused by horizontal forces pushing towards each other.

monocline

folded strata above a fault and often looks like a single step and can erode into cliffs.

subsidence zone

one plate goes under another

rift

most divergent zones lie between oceanic tectonic plates. a _______ is a series of steep-walled valleys lined w/ high cliffs rising from faults parallel to the valley. grabens in center

grabens

in the center of the rift are low areas where rocks are cracked and dropped downward. these are called _________. the long, faulted cliffs parallel to _________ are prominent features on the ocean bottom.

fault-block mountains

these are mountains set apart by one or more normal faults.

plateaus

broad regions of relatively undisturbed sedimentary deposits lifted by some tectonic processes.

dome

a landform w/ sedimentary strata that looks like an upside-down bowl.

basin

the opposite of a dome. most seem to have formed when a magma chamber deep underground emptied.

seamounts

extinct volcanoes in ocean basins.

erosional mountains

aka residual mts. mts that were carved out by extensive erosion, usually from a plateau. as erosion cut apart, or dissected a plateau, some parts of the plateau remained intact. these parts often contained erosion-resistant materials, such as hardened lava. in other cases, residual parts simply weren't washed away w/ the rest of the plateau

mesas

broad, flat-topped hills remaining from the erosion process. both these and buttes have steep, cliff like sides

buttes

smaller flat-topped hills remaining from the erosion process

f

t or f: the difference between mesas and buttes is well defined

talus

sloped piles of broken rock that collect at the base of the cliffs of buttes and mesas.

pinnacles

tall spires of rock that are all that remain of an eroded plateau. they can be found alone, in groups, or connected together in blade-like formations called fins. they typically are capped w/ an erosion resistant material that prevents the __________ from being eroded from the top down.

fins

pinnacles connected together in blade-like formations

monadnocks

erosional mts that are all that is left of an ancient magma chamber. long ago, molten rock pushed its way upward into sedimentary rocks and formed domed-chambers. later, the rock cooled to form very hard, erosion resistant masses. then the overlying softer sedimentary eroded away. the solidified magma is all that remains , forming domed rock "islands" standing out of a flat plain surrounding them. what are these distinctive lone mts called?

depositional mountains

the mts and landforms formed when sediments build up on land. these sediments can be carried by wind or glaciers or deposited by volcanoes.

glacial till

the resulting crushed materials when a glacier touches the underlying bedrock , breaking out chunks of rock and grinding it into pebbles, gravel, sand, and fine silt

moraines

rocks pushed by glaciers; long, relatively low ridges of glacial till that form mostly at the front and sides of glaciers.

eskers

sediment beds left by glaciers; winding deposits of till that followed meltwater streams as they flowed beneath the glacier

kames

debris washed into depressions; steep sided piles of till

drumlins

hills deposited by moving glaciers; long low hills that may have been formed as glaciers dragged over piles of till.

depositional

volcanoes are ____________ mts. they grow as various kinds of lava collect on their slopes. tectonic and ___________ landforms.

Mount Everest

Highest mountain in the world

Convergent boundaries

at which boundaries are fold mountains most formed at

Sierra Nevada

Classic example of fault-block mountains found in California

sediments or lava

what are most plateaus made of

plateaus or domes

types of landforms from uplifting

basins

type of landform from subsidence

volcanoes and seamounts

examples of volcanic landforms