Geo 200 - Chpt 13 (Intro to Landforms)
the most widespread oxides are those that combine with_______
iron - particularly hematite, magnetite, and limonite (all major sources of iron ore and are common rock-forming minerals
when lava on the surface cools, .....
it cools rapidly; therefore, producing a fine-grained texture
when magma cools beneath the surface, ...
it cools slowly; therefore, producing a coarse-grained texture
carbonates
light colored (or colorless) minerals that are common constituents of sedimentary rocks such as limestone (largely made of calcium carbonate in its mineral form, calcite). - carbonates are composed of one or more elements in combo w/ carbon & oxygen
________ are formed from skeletal remains of coral and other lime-secreting sea animals.
limestones
The "plates" in plate tectonics are in the ________.
lithosphere
magma vs lava
magma is molten rock beneath the surface, whereas lava is motion rock that flows out on, or is squeezed up onto, the surface
Mafic igneous rocks
magmas with relatively low amounts of silica generally cool into mafic igneous rocks, which contain large portions of dark-colored, magnesium and iron-rich silicate minerals such as olivine and pyroxene
An inner segment of the Earth which is rigid, dense, and solid and lies directly beneath the Moho is called the ________.
mantle
The thickest of Earth's interior layers is the ________.
mantle
classification of igneous rocks is based largely on ...
mineral composition and texture - which is determined by the "chemistry" of the magma, or particular combination of molten mineral material in the magma
organic sedimentary rocks
organically accumulated sedimentary rocks form from the compacted remains of dead plant material - lignite (soft brown coal) and bituminous coal (soft black coal)
The basic classification of rock types is based on their ________.
origin
examples of minerals that are native elements:
precious metals (gold, silver, platinum) - not combined chemically with another element
which are the most abundant of the silicate minerals?
quartz and feldspar - nonferromagnesian silicates (light)
drainage
refers to the movement of water (rainfall or snowmelt), either over Earth's surface or down into the soil and bedrock
structure of the landscape
refers to the nature, arrangement, and orientation of the materials (rocks) making up a landform.
tuff
rock made from volcanic ash or pyroclastic flow deposits
Detrital/Clastic Sedimentary Rocks
rocks composed of fragments of preexisting rocks in the form of cobbles, gravel, sand, silt, or clay
The most widely distributed type of metamorphic rock is ________.
schist
___________rocks accordingly constitute only a very small proportion (perhaps 4 percent) of the total volume of the crust.
sedimentary
on the continents, ___________rocks compose the most commonly exposed bedrock. - as much as 75%.
sedimentary
the combination of compaction and cementation consolidates and transforms sediments to __________
sedimentary rock
Mohorovicic discontinuity
the boundary between the earth's crust and the upper part of the Asthenosphere where there is a significant change in mineral composition; seismic waves change speed at this boundary
relief
the difference in elevation b/w the highest and lowest points in an area
slope of the landscape
the fundamental aspect of shape for any landform - the angular relationship reflects the balance b/w the structure and process at that time
sulfates mineral family
the group includes minerals such as gypsum that contain sulfur and oxygen in combo with some other element. - calcium is the principal coming element - usually light colored and found in sedimentary rocks
halides
the least widespread mineral family. - name derived from word meaning "salt" - minerals include halite (common table salt- NaCl) and fluorite
Diastrophism
the process of deformation of the Earth's crust which involves folding and faulting.
geomorphology
the study of the characteristics and development of landforms
petrology
the study of the origin and characteristics of rocks
topography
the surface configuration of Earth
lithosphere
the uppermost mantle zone together with the overlying oceanic or continental crust
pyroclastics
tiny pieces of solid volcanic rock, that have been explosively ejected onto the surface by a volcanic eruption and that "weld" to form some igneous rocks
Diastrophism is considered an internal geomorphic process.
true
Granite is a type of rock which has cooled from magma.
true
Plutonic rocks are the same thing as intrusive rocks.
true
although originally deposited and formed in horizontal orientation, the strata may later be uplifted, tilted, and deformed by pressures from within Earth.---- true or false.
true
basalt is a type of rock that has cooled from lava.
true
Organic material such as plants remains and algae remains can also become sedimentary rock. true or false
true - it accumulates over time alongside inorganic sediments.
just eight elements account for more than 98 percent of the mass of earth's crust --- true or false.
true - O and Si make up more than 75%
on magma can produce a number of quite different igneous rocks. True or false.
true - depending on whether the material cools below the surface, on the surface as lava flow, or on the surface as accumulation of pyroclastics.
the distribution of the three principal rock classes on Earth's surface is _______.
uneven - this is a consequence of processes operating on the surface and in the planet's interior
Most processes which shape topography are ________.
very slow
which igneous rocks have a fine-grained texture?
volcanic (extrusive) b/c they cool more rapidly
obsidian
volcanic glass
pumice
volcanic glass with frothy texture
Process of sedimentary rocks
weathering, erosion, deposition, compaction, cementation
the texture of an igneous rock is determined primarily by
where and how the molten material cools.
The most recent Era on the Earth is ________.
Cenozoic
what is the most common component of chemical sedimentary rocks? and was is the most widespread result?
calcium carbonate ; >>limestone
in addition to compaction, __________occurs in forming sedimentary rocks, in which process chemical agents - especially ______, ________, and ________ - precipitate from the water into the pore spaces between sediment grains.
chemical cementation ; silica, calcium carbonate, and iron oxide
chemical sedimentary rocks
chemically accumulated sedimentary rocks usually form by the precipitation of solids from ions in solution, but sometimes by more complicated chemical reactions.
minerals in granite
combination of light and dark quartz, plagioclase feldspar, potassium feldspar (light colored) and hornblende & biotite (dark colored)
sulfides
combo of reduced sulfur with one or more other elements. - many of the important ore minerals (galena-lead, sphalerite-zinc, and chalcopyrite-copper) are sulfides
over long periods of time, sedimentary deposits can build to a remarkable thickness, and the weight of this exerts enormous pressure, which causes individual particles of sediment to adhere to each other and tho interlock though________
compaction
process of the landscape
considers the actions that have combined to produce the landform. - geologic, hydrologic, atmospheric, and biotic - in some cases a landscape results from one process primarily (glaciation)
Earth is probably 14.6 billion years old.
false
Internal forces of the Earth tend to be better understood and more predictable than the external forces of the Earth.
false
Several organic minerals are found in nature.
false
Uniformitarianism is the study of the interior of the Earth.
false
Magma with relatively large amounts of silica generally cool into______ igneous rocks, which contain large portions of light-colored silicate minerals, such as quartz and feldspar.
felsic
bedding planes
flat surfaces separating one layer from the next
igneous rocks origin
formed by the cooling and solidification of molten rock
sediment
fragmented mineral material produced by disintegration caused by mechanical and chemical external processes operating on rocks
the most common plutonic rock is
granite
the bulk of the continents consist of __________, along with an unknown proportion of metamorphic rocks such as ________and _______
granite; gneiss and schist
the bulk of the crust is made up of _________ rocks.
igneous
The original rocks which cooled on the surface of the Earth could be classified as ________.
igneous extrusive
The ________ processes working on Earth's landscapes are energized by heat inside the Earth; they work without any regard to atmospheric influences.
internal
Earth's age is ________ billion years old.
4.6
With respect to minerals, which of the following is TRUE?
Fewer than 20 minerals make up 95% of the crust.
why exactly are silicates the most important mineral family
b/c they combine the two most abundant chemical elements in the lithosphere: oxygen and silicon
the ocean floor is composed almost entirely of ______ and ______
basalt and gabbro (the plutonic equivalent of basalt)
over most of Earth's surface, solid rock exists as a buried layer of ________
bedrock
Uniformitarianism
"the present is the key to the past." means that the processes that shape the landscape today are the same processes that formed the topography of the past - and are the same processes that will shape the topography of the future - James Hutton (1795)
the most common detrital (clastic) sedimentary rocks are:
- shale (or mudstone), which is composed o very fine silt and clay particles, and - sandstone, which is made up of compacted, sand size grains
what are the three sublayers of the mantle?
- upper mantle : thin, rigid and hard, layer under the crust (this plus the crust= lithosphere) - asthenosphere: risks are hot, "plastic" (deformable) - lower mantle: rocks are very hot but largely rigid b/c of higher pressures
The geographer's concern with Earth's interior is restricted primarily to its influence on________.
Earth surface features
The Pleistocene is a part of the ________ period.
Quaternary
rocks
a consolidated mixture of minerals
conglomerate rock
a detrital (clastic) rock composed of rounded, pebble-sized rock fragments
regolith
a layer of broken rock that covers bedrock
asthenosphere
a weak plastic layer of the mantle situated below the lithosphere; the rock within this zone is easily deformed b/c of the heat
oxide
an element combined with oxygen
landform
an individual topographic feature of any size
The proof for the long-doubted idea of drifting continents came in the form of ________.
analysis of magnetic and seismic patterns
Isostasy refers to the recognition that the ________ floats on the denser mantle.
crust
The ________ is a layer comprising less than 1% radius and 0.4% of Earth's mass.
crust
The ________ is the thinnest layer.
crust
ferromagnesian silicates are called _____ silicates.
dark - rich amounts of magnesium and iron.
When tectonic plates subduct it is because ocean crust is ________ than continental crust.
denser
three categories of sedimentary rocks based on how they formed:
detrital (clastic), chemical, and organic
why do most sedimentary rocks form in flat, horizontal layers called strata?
during transportation and disposition, sediments are sorted by size and composition - strata layers vary in thickness and composition
sial
silica and aluminum on the continental crust
the bulk of the crustal rocks are composed of what family of minerals?
silicate
The largest and most important mineral family consists of the ________.
silicates
what are the seven principle "families" of rock-forming minerals?
silicates oxides sulfides sulfates carbonates halides native elements
The rock type which results from metamorphosed shale is ________.
slate
In the formation of igneous rocks, large crystal size is closely related to ________.
slow cooling
when present, _______comprises the upper portion of the regolith
soil
outcrop
solid rock that is found right at the surface
four basic elements of the landscape
structure process slope drainage
what mineral family is pyrite?
sulfide - combo of iron and sulfur