Phys 203 - Second Examination Lecture Notes

What is a biogenic sedimentary rock?

A biogenic sedimentary rock lithifies through the action of lifeforms. Chalk, coquina, and bituminous coal are three common examples of biogenic sedimentary rocks.

What is a chemical sedimentary rock?

A chemical sedimentary rock lithifies through the process of chemical reactions. Common examples of chemical sedimentary rocks include limestone which is the lithification of the mineral calcite, dolostone which is the lithification of the mineral dolomite, and chert which is the lithification of the mineral quartz.

What is a clastic sedimentary rock?

A clastic sedimentary rock lithifies through the action of physical forces.

What does quenching mean?

instantaneous crystallization of a rock

What is the least reliable way to identify a mineral?

its color

What is a dull luster?

no luster, the mineral does not reflect light well at all

What is the rock cycle?

A cycle that shows how rocks are continuously changing from one type to another; any rock can become any other type of rock.

What are triple nesosilicates?

A nesosilicate bonded to a sorosilicate, resulting in three silicon atoms covalently bonded to one another

What is a rock defined as?

A rock is defined as a naturally occurring solid inorganic object that is an aggregate (a mixture) of minerals.

What is a propane?

A triple methane

Why is there always an oxygen atom between any two silicon atoms in a silicate mineral?

Although the carbon-carbon covalent bond is strong enough to build organic molecules, the silicon-silicon covalent bond is not strong enough to build silicate minerals. However, the silicon-oxygen covalent bond is strong enough to build silicate minerals.

What is a pegmatitic rock?

An igneous rock that takes an extremely long time to cool and crystalize which gives it an extremely coarse-grained texture.

What is a glassy rock?

An igneous rock that takes an extremely short time to cool and crystalize which gives it an extremely fine-grain texture.

What is a metamorphic rock?

Any rock that forms from the change of a pre-existing rock is called a metamorphic rock, one of the three main types of rock. The original rock is called the parent rock, while the new metamorphic rock that formed from the parent rock is called the daughter rock.

What is igneous rock defined as?

Any rock that forms from the crystallization of molten rock is called igneous rock

What is a sedimentary rock?

Any rock that forms from the lithification of sediment is called sedimentary rock.

Why doe a rock not have the definite chemical structure?

Because a rock is an aggregate (a mixture) of many different minerals.

What two elements form covalent bonds in a tetrahedral geometry?

Carbon and Silicon

What are examples of cleavage types?

Cubic Cleavage(breaks into right angles), Diagonal Cleavage(breaks into slanted angles), and Lateral Cleavage(breaks into thin sheets)

What is the hardest mineral on the Mohs Scale?

Diamond

What are some examples of habit types?

Equant Habit(forms with equal angles), bladed habit(forms into rods, and Fibrous Habit(forms into long threads)

What texture do extrusive igneous rocks have?

Extrusive/volcanic igneous rocks typically take a short time to cool and crystallize. This faster, more rapid cooling is only able to build small crystals throughout the rock. The result is a rock with a fine-grained texture.

What kind of rock makes up the continents?

Felsic igneous rock and over it a layer of sedimentary rock

What do higher numbers of the Mohs Scale indicate?

Harder minerals

What is a mafic igneous rock?

Igneous rocks composed predominantly of dark silicates.

What is a felsic igneous rock?

Igneous rocks composed predominantly of light silicates.

What texture do intrusive igneous rocks have?

Intrusive/plutonic igneous rocks typically take a long time to cool and crystallize. This slower, more gradual cooling builds large crystals throughout the rock. The result is a rock with a coarse-grained texture.

What is theoretically possible given silicon's tetrahedral covalent bonding?

It is theoretically possible that life could evolve on another planet based on silicate minerals, which themselves compose rocks, as we will discuss shortly. Imagine a planet with rock people, rock dogs, rock cats, and rock trees. This would be a planet where all life evolved based on silicate minerals instead of organic molecules.

What do lower numbers of the Mohs Scale indicate?

Less hard minerals

What are inosilicates?

Long chains of silicon atoms covalently bonded to one another (with oxygen atoms between them of course) as well as to other atoms. These are one-dimensional, single-chain inosilicates, such as the pyroxenes.

What kind of rock makes up the bottom of the oceans?

Mafic igneous rock and over it a layer of sedimentary rock

What is intrusive igneous rock? What is extrusive igneous rock?

Magma that crystallizes into solid rock is called intrusive igneous rock, since it forms deep within the Earth. Lava that crystallizes into solid rock is called extrusive igneous rock, since it formed from lava that extruded out of the Earth. Another term for intrusive igneous rock is plutonic igneous rock, and another term for extrusive igneous rock is volcanic igneous rock.

What is a foliated metamorphic rock?

Metamorphic rocks that have a folded shape resulting from asymmetrical pressures are called foliated metamorphic rocks.

What are organic molecules?

Molecules based on the carbon atom are called organic molecules, an enormous category of molecules that is the basis of all life on planet Earth

What is the difference between magma and lava?

Molten rock deep within the Earth is called magma, while molten rock that has extruded out of the Earth is called lava.

What are the simplest silicate minerals?

Nesosilicates such as the olivines and the garnets

What is petrogenesis?

Petrogenesis is the study of how rocks form.

What is petrography?

Petrography is the classification of rocks, the study of different types of rocks.

What is petrology?

Petrology is the study of rocks, and a petrologist is someone who studies rocks. These words are derived from the Greek root petro- for rock.

What are sediments?

Rocks on the surface of the Earth are subjected to wind, rain, and other natural forces that degrade (weaken and destroy) the rocks, ultimately breaking them into small pieces called sediments

What are the three subcategories of sedimentary rocks?

Sedimentary rocks are classified into three subcategories: clastic sedimentary rocks, chemical sedimentary rocks, and biogenic sedimentary rocks.

How does the Wentworth scale classify sediments?

Sediments are classified as gravels, sands, silts, and clay/mud based on their size. The largest sediments are gravels, which lithify into an extremely course-grained clastic sedimentary rock called conglomerate. Sands are somewhat smaller sediments, which lithify into a moderately course-grained clastic sedimentary rock called sandstone. Silts are even smaller sediments, which lithify into a moderately fine-grained clastic sedimentary rock called siltstone. Finally, the smallest sediments are clay/mud, which lithify into an extremely fine-grained clastic sedimentary rock called shale.

What is the least hardest mineral on the Mohs Scale?

Talc

What are some other minor properties of minerals?

Taste, smell, magnetism, and chemical reactivity

What is a scale used for sediment size scale?

The Wentworth scale

What happens if we add thermal energy to a tectosilicate?

The addition of thermal energy breaks chemical bonds and thus it would break down into multiple phyllosilicates. We can continue to add more heat and break more chemical bonds which take us from phyllosilicates to inosilicates to sorosilicates to nesosilicates.

What are the carbonates?

The carbonates are a mineral group based on the carbon-oxygen trigonal planar group. (examples of carbonate minerals include calcite, magnesite, dolomite, and smithsonite)

what is the cleavage of a mineral?

The cleavage of a mineral is its crystal geometry when broken

What are the layers of the geosphere in order, beginning from the center of the Earth?

The core, mantle, and the crust.

Which silicates have the highest density? The lowest?

The dark silicates have the highest density due to amount of metals in them, the light silicates have the least density. And the intermediate silicates have intermediate densities.

Which silicates have the highest melting temperatures? The lowest melting temperatures?

The dark silicates have the highest melting temperatures and the white silicates have the lowest melting temperatures. The intermediate silicates have intermediate melting temperatures.

Which silicates have the least complex chemical structure? The most complex chemical structures?

The dark silicates have the least complex chemical structure and the white silicates have the most complex chemical structures. The intermediate silicates have intermediately complex chemical structures.

What is the specific gravity of a mineral?

The density of a mineral as compared with the density of liquid water is called the specific gravity of the mineral (For example, if a mineral has a specific gravity of two, this means that its density is twice the density of liquid water)

What is the density of a mineral?

The density of a mineral is the ratio of its mass to its volume

What is the habit of a mineral?

The habit of a mineral is its crystal geometry if it happens to form without confinement

What are the halides?

The halides are the mineral group where halogens such as fluorine, chlorine, and bromine bond with metals. (examples of halide minerals include halite, villiaumite, fluorite, and sylvite)

What is the hardness of a mineral?

The hardness of a mineral is its resistance to scratching or rubbing

What is the Mohs Scale?

The hardness of minerals is quantified with the Mohs scale

What must not happen if heat changes a parent rock into a metamorphic daughter rock?

The heat must not melt the rock, otherwise it would become a igneous rock.

What are the layers of the core of the Earth?

The inner core is the most dense and the hottest but keeps from melting due to extremely high pressure. After this comes the molten outer core, which as the name suggests is molten as the pressure is low enough while the temperature is high enough.

What are the intermediate silicates?

The inosilicates and the phyllosilicates

What is an angular?

The irregular and jagged shapes in sedimentary rocks caused by natural forces that weaken and destroy rocks.

What is the luster of a mineral?

The luster of a mineral is how the mineral reflects light

What are the native elements?

The native elements are minerals composed of a single type of atom, usually metals such as pure aluminum, pure iron, pure nickel, pure copper, pure zinc, pure silver, pure platinum, pure gold, or pure lead.

Which silicates have the highest oxygen-to-silicon rations as well as the most amount of metals?

The nesosilicates and the more complex the molecules get the less the ratio between oxygen and silicon gets and fewer metals are seen.

What are the dark silicates?

The nesosilicates and the sorosilicates

What are the oxides?

The oxides are the mineral group where metals bond with oxygen. (examples of oxide minerals include iron oxides such as hematite, magnetite, and wüstite, aluminum oxides such as corundum, and copper oxides such as cuprite and tenorite)

What is a methane?

The simplest organic molecule would be a single carbon atom covalently bonded to other atoms

What is a streak of a mineral?

The streak of a mineral is its color in its powdered form

What are the sulfates?

The sulfates are a mineral group based on the sulfur-oxygen tetrahedral group. (examples of sulfate minerals include gypsum, anglesite, epsomite, and thenardite)

What is the technical term for a smoothed shaped caused by natural erosion?

The technical term for this smoothed shape is rounded.

What are the light silicates?

The tectosilicates

What is the tenacity of a mineral?

The tenacity of a mineral is its resistance to breaking or deforming

What is a phaneritic rock?

The term for the coarse-grained texture of igneous rocks is phaneritic.

What is a aphanitic rock?

The term for the fine-grained texture of igneous rocks is aphanitic.

What are the two most important felsic igneous rocks?

The two most important felsic igneous rocks are rhyolite(fine-grain and extrusive) and granite(coarse-grain and intrusive). (see rock chart in notes)

What are the two most important intermediate igneous rocks?

The two most important intermediate igneous rocks are andesite(fine-grain and extrusive) and diorite(coarse-grain and intrusive). (see rock chart in notes)

What are the two most important mafic igneous rocks?

The two most important mafic igneous rocks are basalt(fine-grain and extrusive) and gabbro(coarse-grain and intrusive). (see rock chart in notes)

What are cycloalkane organic molecules?

They are rings composed of carbon-carbon covalent bonds.

What are cyclosilicates?

They are rings composed of silicon-oxygen covalent bonds. (examples include benitoites, axinites, beryls, and tourmalines)

What is it called when metamorphic rocks form primarily from heat, with pressure and chemical reactions being less important processes?

This is called contact metamorphism.

What is it called when metamorphic rocks form primarily from chemical reactions, with pressure and heat being less important processes?

This is called hydrothermal metamorphism.

What is it called when metamorphic rocks form primarily from pressure, with chemical reactions and heat being less important processes?

This is called regional metamorphism.

Is it true that all rocks can be classified into one of the three major rock categories (igneous, metamorphic, sedimentary).

This is false. By example, the rock migmatite forms from heat that melts some parts of the rock which then recrystallizes into solid rock, but the heat also changes other parts of the rock without melting those parts of the rock. As such migmatite does not fit into any one rock category.

What are tectosilicates?

Three-dimensional sheets of silicate material (examples include zeolites, the feldspars, and quartz)

What is a ethane?

Two methanes covalently bonded to each other

What are phyllosilicates?

Two-dimensional sheets of silicate material (examples include serpentines and the micas)

What is a way we can easily measure density?

We can measure the density of a mineral by immersing it in a liquid(usually water). If the mineral is more dense than the liquid, then the mineral will sink until it lands at the bottom of the container. If the mineral is less dense than the liquid, then the mineral will rise until it floats on the surface of the liquid.

How can we test hardness?

We can test the hardness of two minerals by rubbing or scratching them against each other

It is possible for an igneous rock to have both large and small crystals?

Yes. Some igneous rocks have both large crystals and small crystals in the same rock. This occurs when there is an interruption in the cooling history of the rock. This unusual texture is called porphyritic. The large crystals in a porphyritic igneous rock are called the phenocrysts, while the small crystals in a porphyritic igneous rock are called the groundmass.

What is a mineral?

a naturally occurring, inorganic solid that has a crystal structure and a definite chemical composition

What is the difference between rocks and minerals?

a rock does not have a definite chemical structure

What are the three broad categories of rocks?

igneous rocks, sedimentary rocks, and metamorphic rocks

What two names does a mineral have?

mineral name and a chemical name

What does it mean to lithify?

sediments that have become lithified, means that they have become a rock

who is a mineralogist?

someone who studies minerals

What is the most abundant group of minerals?

the most abundant group of minerals are the silicate minerals, which are based on the silicon-oxygen tetrahedral group

What are the sorosilicates?

the sorosilicates, such as the epidotes, which are essentially double nesosilicates

What is Mineralogy?

the study of minerals