Geology 101 Test 1

What phrase is given to the formation of new sea floor?

sea floor spreading

A volcano built of thin flows of fluid lava (low viscosity lava) is a:

shield volcano

HEMATITE 2

specular variety, with metallic luster. Composition: Fe2O3 Streak: reddish-brown Luster: metallic

Paloemagnentic studies shows what?

the fact that when iron bearing minerals crystalize they align themselves parallel to the earths magnentic field.

GYPSUM

variety "rock gypsum" occurs in granular masses. Composition: CaSO4·2H2O Color: light colored or transparent Hardness: 2 (can be scratched with fingernail) Occurrence: commonly found in sedimentary rocks; formed under evaporitic conditions. Use: Plaster of Paris, gypsum lath, fertilizer, ornamental (variety called alabaster).

What causes explosive volcanoes?

viscus lava, the runnier it is the less explosive

vander waals bonding

weakest type of bonding a weak electrostatic attraction arises because certain atoms and ions are distorted

LIMONITE

yellow ocher Composition: Fe2O3·nH2O Streak: yellow-brown (Other properties vary widely.) Occurrence:formed by alteration of previously existing iron minerals. Use: pigment, minor source of iron

Oxygen comprises about what % of the earth's crust by volume?

94%

Why are convergent plate boundary volcanoes more explosive?

Because they have more viscous lava

What is the tendency for minerals to break along flat planes called?

Cleavage

CALCITE

Composition: CaCO3 Color: usually colorless to white, but other colors occur. Hardness: 3 Cleavage: good along three inclined planes. Chemical test: effervesces freely in cold, dilute hydrochloric acid. Occurrence: chief constituent of limestone, chalk, and marble. Use: chiefly in manufacture of cement, also decorative, and in optical instruments.

CHALCOPYRITE

Composition: CuFeS2 Color: brass yellow, but often tarnished to bronze or iridescent. Hardness: 3.5 to 4 (less than pyrite). Streak: greenish-black Crystal form: usually massive, crystals not observed. Occurrence: usually found in veins in igneous rocks. Use:the most widely occurring copper mineral and one of the most important sources of copper.

ORTHOCLASE FELDSPAR

Composition: KAlSi3O8 Hardness: 6 Color: usually pink or white Luster: vitreous Cleavage: two good at 90° Occurrence:orthoclase and the other feldspars are the most abundant minerals in the Earth's crust; found in all three kinds of rocks but most commonly in igneous rocks. Use: in manufacture of porcelain.

HALITE

Composition: NaCl Hardness: 2.5 Cleavage: cubic Taste: salty Feel: "damp" Soluble in water Occurrence:precipitated from sea water under evaporitic conditions and found in sedimentary rocks. Use: common table salt; source of sodium. Name: from the Greek word meaning salt. Effervescence: Fizzing of calcite in hydrochloric acid.

Nucleus

Dense area in the center of the atom

HEMATITE

Earthy variety called "red ocher" Composition: Fe2O3 Streak: reddish-brown Luster: earthy

T/F A mineral with chemical composition of CaSO4.2H2O and hardness of 2 is called corundum.

False

T/F Orthoclase is a rock-forming nonsilicate mineral.

False

T/F The mineral halite is composed of equal numbers of sodium and olivine atoms.

False

T/F rift valleys are asscoaited with converging plates

False

T/F A specific gravity of 7 means that a substance has the same hardness as quartz.

False Hardness does not relate to specific gravity

T/F Diamond and quartz are both minerals composed of a single element.

False Quartz is made of 2 Diamond only one

T/F Biotite is dark and muscovite is colorless. Both belong to a group of silicate minerals called mica.

False, Biotite belongs to the ferromagnesian mineral group

T/F In ions, the number of electrons are usually equal to the number of protons.

False, In ion is when there is an imbalance in electrons and protons, if there is the same number it is an atom

Basaltic magma

Mafic, exists through partial melting of the athenosphere, mid ocean ridges and hot spits creates rocks basalt and gabbro

Is oil a mineral?

No!, Neither is coal

granitic magma

felsiic, exists through melting of sedimentary rocks and lower portion of the continental crust. Creates granite and rhyolite.

T/F The process of partial melting produces most, if not all, magma.

true

When did pangea start to drift?

200 million years ago

Silica tetrahedron a. contains 4 oxygen atoms and one silicon atom b. contains 1 oxygen atom and 4 silicon atoms c. has the shape of a cube d. usually contains as much calcium as silicon

A

What is a possible driving force for plate movement?

A possible driving force for plate motion is convection in the asthenosphere.

dike

A tabular body of igneous rock that cuts across the structure of adjacent rock or cute massive rocks.

Who came up with the theory of continental drift?

Alfred Wegener

Where are andesitic volcanoes found?

Along converging zones

Where are basaltic volcanoes found?

Along spreading centers

What is a corundum?

An extremely hard mineral, a form of aluminum oxide with the chemical formula Al2O3, that occurs in the form of the gemstones sapphire and ruby; with a hardness of 9

How does an ion form?

An ion is an atom or group of atoms that have a net electrical charge. An ion is formed when electrons or protons are gained or lost by an atom.

Which group below lists only members of the ferromagnesian silicate minerals? a. magnesium, iron, fertilizer b. olivine, biotite, augite c. muscovite, quartz, orthoclase d. limestone, dolomite, olivine

B

Which group of minerals below lists only silicate minerals a. hematite, sphalerite, limonite b. orthoclase, muscovite, plagioclase c. quartz. gypsum, pyrite d. augite, hornblende, galena

B

OLIVINE

Composition: (Mg, Fe)2SiO4 Color: olive green to black Hardness: (of individual, separate grains) 6.5 to 7. Luster: vitreous Occurrence: found mainly in igneous rocks. Use: as the gem peridot.

GALENA

Composition: PbS (almost always contains silver. Color: lead gray Hardness: 2.5 Specific gravity: 7.5 (heavy) Luster: metallic Cleavage: cubic Occurrence:in igneous rocks and in veins in limestone, associated with sphalerite and fluorite. Use: practically the only source of lead and an important ore of silver.

QUARTZ

Composition: SiO2 Hardness: 7 Luster: glassy Conchoidal fracture (no cleavage) (May or may not occur as crystals.) Occurrence:next to feldspar, the most abundant mineral of the Earth's crust; found in all three kinds of rocks. Use:radio and radar "crystals", ornamental, manufacture of glass and many other uses.

GARNET

Composition: Silicate with variable amounts of Fe, Mg, Mn, Ca, Al, and Cr X3Y2(SiO4) 3 (XàCa, Mg, Fe++,Mn++; YàAl,Fe+++,Cr+++) Cleavage: None Color: variable; dark red and reddish-brown are common Hardness: 7 to 7.5 Streak: white or pale shade of the body color Luster: vitreous Occurrence: common in metamorphic rocks and in some igneous rocks. Use: clear crystals are cut and polished as semi-precious gems (January Birthstone) Garnet is also used as an abrasive, for instance in sandpaper, because of its hardness and lack of cleavage.

KAOLINITE

Composition: hydrous aluminum silicate. Color: white Feel: greasy Smell: earthy Found in small masses. Note: does not react to acid, as does the rock chalk. Occurrence:results from the alteration of other aluminum silicates, particularly feldspar. Use:paper, china, brick.

Which is thicker, continental or oceanic crust?

Continental

Which of the following groups contains only nonsilicate minerals? a. olivine, biotite, muscovite b. muscovite, biotite, calcite c. augite, hornblende, olivine d. magnetite, calcite, galena

D

T/F To form an ion, an atom becomes electrically neutral.

False

Pyrite

FeS2 fools gold

what are Silicates rich in iron and magnesium called

Ferromagnesians.

Explain Covalent bonding

In covalent bonding adjacent atoms share electrons (diamond).

Metallic bonding

In metallic bonding the atoms are closely packed together and electrons move freely throughout the crystal (iron and gold).

Ionic bonding

Ions are fixed in place by their electrical attraction to one another

Ionic bonding

Ions are fixed in place by their electrical attraction to one another (halite).

What is the way that minerals reflect light called?

Luster

What is the core of the earth mostly made of?

Nickel and Iron

HORNBLENDE

One of a number of similar minerals collectively referred to as the amphibole group. Composition: complex hydrous calcium magnesium iron aluminum silicate. Color: dark green to black Hardness: 5 to 6 Cleavage: two at angles of 56° and 124° Crystals: frequently prismatic Occurrence: in igneous rocks and metamorphic rocks.

AUGITE

One of a number of similar minerals collectively referred to as the pyroxene group. Composition: complex calcium magnesium iron silicate. Hardness: 5 to 6 Cleavage: two at angles of 87° and 93°. Crystals: short, prismatic Occurrence: in igneous and metamorphic rocks.

The two most common silicate minerals in the crust are

Oxygen and Silicone (by weight) but quartz and feldspar

Proton, neutron and electron

Proton = positive Neutron = neutral Electron= negative

What are the most ommon minerals in the crust?

Silicates, specifically quartz

What are geologists who study the composition and origin of rocks called?

Structural Geologist

What is the Atomic mass?

The number of protons in each atom of that element.

Where are most deep ocean trenches located?

The pacific ocean

PLAGIOCLASE FELDSPAR

The term "plagioclase feldspar" refers to a continuous gradational series of minerals which range in chemical composition from pure sodic plagioclase, called albite, to pure calcic plagioclase, called anorthite. Composition: NaAlSi3O8 to CaAl2Si2O8 Color: white to gray Hardness: 6 Luster: vitreous Cleavage: two good at approximately 94°. Occurrence: found in igneous, metamorphic, and more rarely in sedimentary rocks. Use: in ceramics, semi-precious stones.

T/F A crater is a steep-walled funnel-shaped depression at the top of volcanoes formed by explosive eruptions.

True

T/F An electron is opposite in electrical charge to a proton.

True

T/F Ferromagnesian minerals are generally dark in color.

True

T/F Fluid lava (basaltic magma) allows dissolved gas to escape and produces mild eruptions of lava flows. This kind of eruption is associated with diverging plate boundaries.

True

T/F In the silicate minerals, the silica tetrahedra are combined with the non-silicate elements such as iron, magnesium, sodium, and aluminum.

True

T/F The viscosity of a lava determines how easily the gas can escape.

True

T/F The volcanoes of Hawaii are localized above a mantle hot spot (plume); they are not part of the East Pacific oceanic ridge.

True

The island of Hawaii is the youngest of the Hawaiian Islands.

True

True or False? At a convergent plate boundary, high mountains may be built during continent-continent collision.

True

True or False? Oceanic lithosphere records magnetic "stripes" of normally and reversely magnetized rocks.

True

True or False? Part of western California is attached to the Pacific Plate, while most of North America belongs to a separate plate.

True

True or False? Sea floor is created at spreading ridges and destroyed in subduction zones.

True

True or False? With increasing distance from an oceanic ridge, the rocks become older.

True

True or False? The asthenosphere is a weak, plastic layer over which lithospheric plates can move.

True, the athenosphere is a weak layer and the lithosphere moves over it.

What are typical rates of continental movement per year?

Typical rates of plate movement are 2 to 3 centimeters per year.

Which of the following groups of minerals is more likely abundant in the oceanic crust? a. quartz, orthoclase, plagioclase b. quartz, muscovite, halite c. augite, olivine, biotite d. hematite, gypsum, fluorite

a

Which of the following minerals belongs to the feldspar group? a. orthoclase b. olivine c. muscovite d. hornblende

a

batholith

a large bod of intrusive igneous rock exposed over an area of at least 100 km

stock

a small somewhat circular batholith

Crater

a steep walled funnel shaped depression at the top of volcanoes formed by explosive eruptions

Caldera

a very large crater which is sort of circular

smallest unit of an element is..

an atom

What is the name given to electrically charged atoms?

an ion

cation

an ion that has a positive charge

Any ion that has a negative electric charge is called

anion

Where does oceanic crust sink into the earth?

at deep ocean trenches and subduction zones

ferromagnesian minerals (silicate)

augite biotite chloirite hornblende olivine, usually darker

Silicate minerals a. are generally deficient in silicon and quartz b. contain relatively high amounts of calcium, magnesium, and iron oxides c. tend to be dark in color d. all of the above e. none of the above

b

A subduction zone is a feature of what kind of boundary?

converging plate boundaries.

What are the two tops of volcanoes?

crater and a caldera

sill

cuts straight across, parrellel to bedding

give examples of polymorphs

diamond and graphite

East african rift valley is what kind of boundary?

divergent

Carbonites (non silicates)

dolomite and calcite

isotopes

elements with same number ofatoms but different number of neutrons

framework silicates

feldspar plagoclase and orthoclase

Shield volcano

formed by low viscosity lava

Cinder cone volcano

fragments of volcanic rock that make up cinder cones, pyroclasts (ash, bombs blocks)

sulfates (non silicates)

gypsum

Chlorides(non silicate)

halite, diamond, graphite

aa lava

high visocity and thick

What is the fundamental force that drives convection currents?

hot mantle rises, it hits the plate, and it drags on the bottom of the plates and causes movement.

What does A polar-wander curve show?

how continents have moved, or drifted, relative to the magnetic poles.

What causes melting

increase in temperature, decrease in pressure

Andesitic Magma

intermediate, exists through melting of oceanic lithosphere and marine sediments along the subduction zones. creates andesite and diorite

What 2 super continents did pangea split into?

laurasua and gondwanaland

What is the name of the rigid outer layer of the Earth composed of the crust and outermost mantle?

lithosphere

pahoehoe lave

low viscosity, flow rapidly and smoothly

What is the mantle of the earth mostly made of?

magnesium, silicon and oxygen

Oxides (non silicate)

megnetite hematite limonite

What kind of magma (lava) is associated with converging plate boundary?

metamorphic

sheet silicates

mica and clay groups

compostie or strato volcano

mostly andesite and mostly found behind subductions zones

Where are the oldest rocks found?

on continents

Sulfides (non silicate)

pyrite, galena, chalcopyrite

What mineral is used to help make glass?

quartz