9 - Earth’s Materials and Surface Processes

Question 1

Define:

mineral

Answer 1

A natural, inorganic solid with a defined composition and structure.

Minerals have a definite chemical composition and an orderly internal structure, making them the basic components of rocks.

Question 2

Explain:

How do minerals form in nature?

Answer 2

Through magma cooling, water evaporation, or chemical precipitation.

Example: minerals like quartz and feldspar crystallize as magma cools, forming unique structures.

Question 3

Identify:

What type of mineral is formed from the evaporation of seawater?

Answer 3

Halite

(rock salt)

Halite forms when seawater evaporates, leaving behind salt crystals.

Question 4

Explain:

What are the five basic properties used to identify minerals?

Answer 4

1. Color
2. Streak
3. Hardness
4. Cleavage
5. Density

Color: Shows the mineral’s outward appearance, but may vary.

Streak: Reveals the mineral’s powder color, often more reliable.

Hardness: Measures resistance to scratching using the Mohs scale.

Cleavage: Describes how a mineral breaks along flat planes.

Density: Compares the mineral’s mass to its volume.

Question 5

True or False:

Minerals can be synthetically formed in a laboratory.

Answer 5

True

Some minerals, like synthetic diamonds, can be created under controlled conditions, although they have different formation histories.

Question 6

Explain:

List the common characteristics of most minerals.

Answer 6

• Naturally Occurring
• Inorganic
• Solid State
• Definite Chemical Composition
• Crystalline Structure

Naturally Occurring: Formed by natural geological processes.

Inorganic: Not made by living organisms.

Solid State: Exists as a solid under normal conditions.

Definite Chemical Composition: Has a specific chemical formula.

Crystalline Structure: Atoms are arranged in an orderly, repeating pattern.

Question 7

Define:

crystal structure

Answer 7

The orderly arrangement of atoms in a mineral.

The crystal structure is key to determining a mineral’s physical properties, such as cleavage and hardness.

Question 8

Explain:

How does the crystal structure affect a mineral’s properties?

Answer 8

It determines the mineral’s hardness, cleavage, and appearance.

Minerals with different arrangements of atoms can have vastly different physical and optical properties.

Question 9

Identify:

What is the process of forming a mineral’s crystalline structure?

Answer 9

crystallization

Crystallization occurs as minerals form from molten rock or evaporating solutions, where atoms arrange into a specific pattern.

Question 10

Explain:

What are the types of cleavage in minerals?

Answer 10

• Perfect Cleavage
• Good Cleavage
• Poor Cleavage

Perfect Cleavage: Breaks cleanly along flat planes (e.g., mica).

Good Cleavage: Breaks along planes but not as smoothly (e.g., feldspar).

Poor Cleavage: Breaks irregularly or with difficulty (e.g., quartz).

Question 11

Define:

What is the hardness of a mineral?

Answer 11

The ability of a mineral to resist scratching.

Hardness is measured on the Mohs scale, ranging from 1 (softest) to 10 (hardest).

Question 12

True or False:

A mineral’s hardness can change based on how it forms.

Answer 12

False

Hardness is intrinsic to a mineral’s structure and remains constant regardless of formation conditions.

Question 13

Define:

What is luster in a mineral?

Answer 13

The way a mineral reflects light.

Luster can be metallic (shiny) or non-metallic (glassy, pearly, or dull), and it helps with mineral identification.

Question 14

True or False:

Density is affected by the mineral’s crystal structure.

Answer 14

True

The density of a mineral depends on how tightly its atoms are packed within the crystal structure, with denser packing leading to higher density.

Question 15

Explain:

How is density useful in identifying minerals?

Answer 15

It helps distinguish minerals of similar appearance.

Denser minerals feel heavier compared to less dense ones of the same size.

Question 16

Identify:

What is the color of a mineral’s powdered form known as?

This may not be visible for some minerals.

Answer 16

streak

Streak is often more reliable for identifying minerals than surface color, which can vary due to impurities.

Question 17

Explain:

Why is streak more reliable than color for identification?

Answer 17

Streak shows the mineral’s true, consistent color in powdered form.

Surface color can vary due to impurities, while the streak remains constant.

Question 18

Define:

rock cycle

Answer 18

The continuous process of forming, altering, and transforming rocks.

The cycle involves processes like cooling, weathering, compaction, and metamorphism.

Question 19

Define:

rock

Answer 19

A naturally occurring solid composed of one or more minerals.

Rocks form through geological processes and can be classified into three main types: igneous, sedimentary, and metamorphic.

Question 20

Explain:

What are the 3 main types of rocks?

Answer 20

1. Igneous Rocks
2. Sedimentary Rocks
3. Metamorphic Rocks

Igneous Rocks: Formed from the cooling and solidification of molten rock (magma or lava).

Sedimentary Rocks: Created by the compaction and cementation of sediments over time.

Metamorphic Rocks: Produced when existing rocks are transformed by heat, pressure, or chemical processes.

Each type forms through distinct processes, such as cooling, compaction, or heat and pressure.

Question 21

Identify:

What igneous rock forms when magma cools slowly underground?

Answer 21

intrusive

Intrusive igneous rocks cool slowly, resulting in coarse-grained textures, such as granite.

Question 22

Explain:

How does an extrusive igneous rock form?

Answer 22

When lava cools quickly on the surface.

These rocks, such as basalt, usually have a fine-grained or glassy texture because the rapid cooling prevents the growth of large crystals.

Question 23

Identify:

What is the primary factor that classifies an igneous rock?

Answer 23

Cooling rate

The rate at which magma or lava cools determines the size of the crystals formed, distinguishing intrusive and extrusive rocks.

Question 24

Identify:

What type of rock is pumice?

Answer 24

Extrusive igneous rock

Pumice forms when lava cools quickly and traps gas bubbles, creating a porous, lightweight texture. It is often used as an abrasive material.

Question 25

# Explain: How does **sedimentary rock** form?

Answer 25

From the **accumulation**, **compaction**, and **cementation** of sediments. ## Footnote These rocks often have layers and can be classified as clastic, chemical, or biological based on their composition.

Question 26

# Explain: What are the three **main types** of **sedimentary rocks**?

Answer 26

1. Clastic 2. Chemical 3. Biological ## Footnote **Clastic**: Formed from the accumulation and cementation of rock fragments. **Chemical**: Created from minerals precipitated out of solution, often after water evaporates. **Biological**: Produced from the remains of plants and animals, such as shells or organic material.

Question 27

# Identify: What rock **forms** from **accumulated** and **cemented** fragments?

Answer 27

Clastic sedimentary rock ## Footnote *Clastic sedimentary rocks*, like sandstone and shale, are made from particles of pre-existing rocks.

Question 28

# Explain: How are **chemical sedimentary rocks** formed?

Answer 28

From the **evaporation of water** and the **precipitation of dissolved minerals**, such as limestone and rock salt.

Question 29

# Explain: How do **metamorphic rocks** form?

Answer 29

When rocks undergo **high heat** and **pressure**, causing changes. ## Footnote These rocks can be either *foliated* or *non-foliated*, depending on how the minerals are aligned during metamorphism.

Question 30

# Identify: What is the **most common rock** formed by **contact metamorphism**?

Answer 30

Marble ## Footnote **Marble** forms when *limestone* is subjected to heat and pressure, commonly near igneous intrusions.

Question 31

# Define: contact metamorphism

Answer 31

Type of metamorphism where rocks are altered primarily due to the heat from a nearby body of magma. ## Footnote *Contact metamorphism* typically results in changes to the texture of the rocks, often producing non-foliated textures.

Question 32

# Identify: What **metamorphism** results from **large-scale pressure** and **heat**?

Answer 32

Regional ## Footnote *Regional metamorphism* occurs over large areas and often produces foliated rocks like schist and gneiss.

Question 33

# Identify: What is the **rock formed** by the **metamorphism of shale**?

Answer 33

Schist ## Footnote **Schist** forms under high pressure and temperature, resulting in a foliated texture with visible mineral grains.

Question 34

# Define: biochemical cycle

Answer 34

The **recycling** of **elements** and **compounds** through Earth's ecosystems. ## Footnote These cycles are essential for **sustaining** life by ensuring that key elements, such as carbon, nitrogen, and oxygen, are reused.

Question 35

# Identify: List the major **biochemical cycles** on Earth.

Answer 35

* Carbon Cycle * Nitrogen Cycle * Oxygen Cycle * Phosphorus Cycle * Water Cycle ## Footnote **Carbon Cycle**: The movement of carbon through the atmosphere, organisms, and Earth systems. **Nitrogen Cycle**: The transfer of nitrogen between the atmosphere, soil, and living organisms. **Oxygen Cycle**: The circulation of oxygen through photosynthesis, respiration, and the atmosphere. **Phosphorus Cycle**: The movement of phosphorus through rocks, soil, water, and organisms. **Water Cycle**: The cycling of water through evaporation, condensation, and precipitation.

Question 36

# Identify: What is the **primary source** of energy for the **water cycle**?

Answer 36

The Sun ## Footnote *Solar energy* drives the evaporation of water, which is a key process in the water cycle.

Question 37

# Explain: What are the **ways** carbon moves through the **carbon cycle**?

Answer 37

* Photosynthesis * Respiration * Combustion * Decomposition * Carbon Storage * Ocean Exchange ## Footnote **Photosynthesis**: Plants take in CO₂ and convert it into organic compounds. **Respiration**: Animals and plants release CO₂ by breaking down glucose. **Combustion**: Burning fuels and organic matter releases CO₂ into the atmosphere. **Decomposition**: Decomposers break down dead organisms, releasing CO₂ and carbon into the soil. **Carbon Storage**: Carbon is stored in fossil fuels, soil, and sediments. **Ocean Exchange**: Oceans absorb and release CO₂, cycling it between surface and deep waters.

Question 38

# True or False: The carbon cycle **moves carbon** through the **atmosphere**, **oceans**, and **land**.

Answer 38

True ## Footnote Carbon *cycles* through these systems via processes like photosynthesis, respiration, and ocean absorption.

Question 39

# Define: nitrogen fixation

Answer 39

The **conversion of nitrogen** into plant-usable forms like **ammonia**. ## Footnote This process is primarily carried out by bacteria in the soil or in the roots of legumes.

Question 40

# Identify: Which **form of nitrogen** can plants directly use for **growth**?

Answer 40

Nitrate ## Footnote **Nitrate** is the form of nitrogen that plants absorb through their roots to build proteins and other important compounds.

Question 41

# Explain: What is the role of decomposers in the carbon and nitrogen cycles?

Answer 41

Decomposers **recycle** carbon and nitrogen from **dead organisms**. ## Footnote **Decomposers** break down organic matter, returning carbon and nitrogen to the soil and atmosphere, where they can be reused by plants and animals, sustaining ecosystems.

Question 42

# Define: weathering

Answer 42

The **breakdown** of **rocks** and **minerals** into smaller particles. ## Footnote Weathering is a key process in *soil formation* and influences landscapes by gradually breaking down rock material through environmental interactions.

Question 43

# Explain: What are the **two main types** of weathering?

Answer 43

1. Physical 2. Chemical ## Footnote **Physical**: Breaks rocks into smaller pieces without changing their composition (e.g., freeze-thaw). **Chemical**: Alters the chemical composition of rocks through reactions like oxidation or dissolution.

Question 44

# Explain: How does erosion **differ** from weathering?

Answer 44

* **Erosion** moves weathered materials * **Weathering** breaks down rocks. ## Footnote Weathering occurs in place, breaking down rocks into smaller particles, while erosion transports these materials via wind, water, or ice.

Question 45

# Describe: How does **wind** cause **erosion**?

Answer 45

By **carrying** away **loose particles**. ## Footnote *Wind erosion* is most common in dry, arid environments and can create sand dunes, reshape landscapes, and remove soil particles.

Question 46

# Define: What is **soil formation**?

Answer 46

The breakdown of **rocks** and **organic material** to form soil. ## Footnote It involves *weathering*, *erosion*, and the accumulation of organic matter over time.

Question 47

# Explain: What **factors** influence the rate of **soil formation**?

Answer 47

* Climate * Parent Material * Organisms * Topography * Time ## Footnote **Climate**: Temperature and rainfall affect weathering rates and organic matter decomposition. **Parent Material**: The type of rock influences soil texture, fertility, and mineral composition. **Organisms**: Plants, animals, and microorganisms contribute to organic matter and nutrient cycling. **Topography**: Slope and elevation impact water drainage and erosion, affecting soil development. **Time**: Soil formation is a slow process, taking centuries to millennia depending on conditions.

Question 48

# Explain: What are the **three main types** of soil?

Answer 48

1. Sand 2. Silt 3. Clay ## Footnote **Sand**: Coarse particles, drains quickly, and holds little water. **Silt**: Medium-sized particles, smooth texture, and retains moderate water. **Clay**: Fine particles, retains water well but drains poorly.

Question 49

# Define: feedback | Earth systems

Answer 49

It refers to **processes** affecting systems through **component interactions**. ## Footnote Feedback in Earth's systems involves interactions that either **amplify** (positive feedback) or **stabilize** (negative feedback) changes, such as melting ice amplifying warming or vegetation reducing soil erosion.

Question 50

# Explain: What are **3 Earth systems** involved in feedback interactions?

Answer 50

1. Geosphere 2. Hydrosphere 3. Biosphere ## Footnote **Geosphere**: Includes Earth's rocks, minerals, and landforms, interacting with other systems. **Hydrosphere**: Includes all Earth's water, such as oceans, rivers, and glaciers, driving energy exchange. **Biosphere**: Includes all living organisms that interact with Earth's physical and chemical systems.

Question 51

# Explain: How do changes in the **biosphere** impact the **geosphere**?

Answer 51

**Organisms** in the biosphere contribute to **soil formation** and **weathering**. ## Footnote Plant roots break down rocks, promote soil formation, and enhance erosion and mineral cycling, impacting the geosphere.

Question 52

# Explain: How does the **biosphere** affect the **hydrosphere**?

Answer 52

By **releasing water** from plants, affecting **rainfall** and **humidity**. ## Footnote This process is vital in regulating the water cycle and maintaining regional climates.

Question 53

# Identify: What is an **example** of a **positive feedback loop** in Earth's systems?

Answer 53

The melting of polar ice. ## Footnote As ice melts, it exposes darker ocean water, which absorbs more heat and **accelerates** the melting process.

Question 54

# Define: What is a **negative feedback loop** in Earth's systems?

Answer 54

A process that **stabilizes** Earth's systems by counteracting changes. ## Footnote An example is the increase in plant growth due to higher carbon dioxide levels, which removes excess CO2 from the atmosphere.