The Lithosphere Flashcards
What is the lithosphere?
The solid outer layer of Earth, including the crust and upper mantle.
Why is the lithosphere important?
It provides materials for life, influences soil composition, and interacts with the atmosphere and hydrosphere.
What are the two main components of the lithosphere?
The solid crust (Earth’s rigid outer shell) and the asthenosphere (semi-fluid layer beneath the crust).
What are the two types of crust?
Oceanic crust (Basalt), Continental crust (Granite)
Thin, dense, rich in Mg & Fe.
Oceanic crust (Basalt)
Thick, less dense, rich in Si & Al.
Continental crust (Granite)
What are the three main types of rocks?
Igneous Rocks, Sedimentary Rocks, Metamorphic Rocks
Formed from cooling magma/lava.
Igneous Rocks
Formed from compressed sediments.
Sedimentary Rocks
Formed by heat and pressure altering existing rock.
Metamorphic Rocks
How does the rock cycle work?
Rocks change form through weathering, melting, pressure, and cooling over time.
When denser oceanic crust sinks beneath continental crust, recycling rock material.
subduction
Where does new crust form?
At spreading zones (mid-ocean ridges & rift valleys), where magma rises and solidifies.
The breakdown of rocks by physical, chemical, or biological processes.
weathering
What are the two main types of weathering?
Mechanical Weathering and Chemical Weathering
Physical breakdown (wind, ice, water, plant roots).
Mechanical Weathering
Chemical alteration (acidity, oxidation, water dissolution).
Chemical Weathering
What are the main components of soil?
Minerals, organic matter, water, and air.
Layers of soil that develop over time
soil horizons
Organic material.
O Horizon
Topsoil, rich in nutrients.
A Horizon
Leached layer
E Horizon
Subsoil with minerals from above.
B Horizon
Parent material (weathered rock
C Horizon
The ability of soil to hold and exchange nutrients (Ca²⁺, K⁺, Mg²⁺)
Cation Exchange Capacity (CEC)
How does soil pH affect phosphorus availability?
Neutral pH, Acidic soil, Basic soil:
P is available.
Neutral pH
P binds with Fe & Al.
Acidic soil
P binds with carbonates, making it unavailable.
Basic soil:
How do plants contribute to weathering?
Roots release CO₂, forming acids that break down rock.
Organic acids & chelators dissolve minerals.
Minerals created by organisms, such as corals, shellfish, and plankton forming CaCO₃ (limestone)
biogenic minerals
High chemical weathering, deep soils, nutrient loss.
Warm, wet climates
More mechanical weathering, acidic soils.
Cold, wet climates
Carbonates & salts accumulate, nutrient-poor.
Arid climates
How do glaciers affect soil formation?
Remove old soils through erosion.
Deposit mixed materials (till), creating young, undeveloped soils.
