9 - Earth’s Materials and Surface Processes Flashcards
This deck covers mineral and rock identification, the rock cycle, and Earth's biogeochemical cycles. It also explores surface processes like weathering, erosion, and soil formation, as well as interactions between Earth's systems. (54 cards)
Define:
mineral
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.
Explain:
How do minerals form in nature?
Through magma cooling, water evaporation, or chemical precipitation.
Example: minerals like quartz and feldspar crystallize as magma cools, forming unique structures.
Identify:
What type of mineral is formed from the evaporation of seawater?
Halite
(rock salt)
Halite forms when seawater evaporates, leaving behind salt crystals.
Explain:
What are the five basic properties used to identify minerals?
- Color
- Streak
- Hardness
- Cleavage
- 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.
True or False:
Minerals can be synthetically formed in a laboratory.
True
Some minerals, like synthetic diamonds, can be created under controlled conditions, although they have different formation histories.
Explain:
List the common characteristics of most minerals.
- 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.
Define:
crystal structure
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.
Explain:
How does the crystal structure affect a mineral’s properties?
It determines the mineral’s hardness, cleavage, and appearance.
Minerals with different arrangements of atoms can have vastly different physical and optical properties.
Identify:
What is the process of forming a mineral’s crystalline structure?
crystallization
Crystallization occurs as minerals form from molten rock or evaporating solutions, where atoms arrange into a specific pattern.
Explain:
What are the types of cleavage in minerals?
- 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).
Define:
What is the hardness of a mineral?
The ability of a mineral to resist scratching.
Hardness is measured on the Mohs scale, ranging from 1 (softest) to 10 (hardest).
True or False:
A mineral’s hardness can change based on how it forms.
False
Hardness is intrinsic to a mineral’s structure and remains constant regardless of formation conditions.
Define:
What is luster in a mineral?
The way a mineral reflects light.
Luster can be metallic (shiny) or non-metallic (glassy, pearly, or dull), and it helps with mineral identification.
True or False:
Density is affected by the mineral’s crystal structure.
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.
Explain:
How is density useful in identifying minerals?
It helps distinguish minerals of similar appearance.
Denser minerals feel heavier compared to less dense ones of the same size.
Identify:
What is the color of a mineral’s powdered form known as?
This may not be visible for some minerals.
streak
Streak is often more reliable for identifying minerals than surface color, which can vary due to impurities.
Explain:
Why is streak more reliable than color for identification?
Streak shows the mineral’s true, consistent color in powdered form.
Surface color can vary due to impurities, while the streak remains constant.
Define:
rock cycle
The continuous process of forming, altering, and transforming rocks.
The cycle involves processes like cooling, weathering, compaction, and metamorphism.
Define:
rock
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.
Explain:
What are the 3 main types of rocks?
- Igneous Rocks
- Sedimentary Rocks
- 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.
Identify:
What igneous rock forms when magma cools slowly underground?
intrusive
Intrusive igneous rocks cool slowly, resulting in coarse-grained textures, such as granite.
Explain:
How does an extrusive igneous rock form?
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.
Identify:
What is the primary factor that classifies an igneous rock?
Cooling rate
The rate at which magma or lava cools determines the size of the crystals formed, distinguishing intrusive and extrusive rocks.
Identify:
What type of rock is pumice?
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.