earth and space science units 1-3 review

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What does the theory of plate tectonics explain?

It explains that Earth's lithosphere is divided into plates that float on the asthenosphere, which moves due to convection currents in the mantle.

How do oceanic crust and continental crust differ in density and thickness?

Oceanic crust is denser and thinner than continental crust, which is thicker but less dense.

What geological features are associated with convergent boundaries?

Convergent boundaries can form deep ocean trenches, volcanic mountain ranges, and are associated with significant earthquake activity.

What occurs at divergent boundaries?

At divergent boundaries, tectonic plates move apart, allowing magma to rise and create new oceanic crust, forming mid-ocean ridges and rift valleys.

What is a transform boundary and its geological significance?

A transform boundary occurs when two tectonic plates slide horizontally past each other, causing significant earthquakes.

What happens during subduction?

A denser oceanic plate sinks beneath a lighter continental plate, leading to melting and the rise of magma, which can form volcanoes.

How do convection currents affect tectonic plate movement?

Convection currents in the mantle, caused by heat from the core, push and pull the tectonic plates on Earth's surface.

What are the main layers of the Earth?

The Earth has four main layers: crust, mantle, outer core, and inner core, with increasing temperature, pressure, and density as depth increases.

How does the lithosphere differ from the asthenosphere?

The lithosphere is the rigid outer layer of Earth, while the asthenosphere is a semi-fluid layer beneath it that allows for plate movement.

What geological features form at a convergent boundary between two continental plates?

Mountains form when two continental plates collide, such as the Himalayas.

What is a well-known example of a transform boundary?

The San Andreas Fault is a well-known example of a transform boundary.

Why are earthquakes common along plate boundaries?

The movement of plates at boundaries creates stress in the Earth's crust, which is released as earthquakes.

How does volcanic activity relate to plate tectonics?

Volcanoes form at convergent boundaries where subduction occurs, at divergent boundaries like the Mid-Atlantic Ridge, or over hot spots.

What is a hotspot in geology?

A hotspot is a stationary area in the Earth's mantle where hot magma rises, creating volcanic activity as tectonic plates move over it.

How do mid-ocean ridges form?

Mid-ocean ridges form at divergent boundaries where two oceanic plates move apart, allowing magma to rise and create new crust.

What are the differences between the inner core and outer core?

The inner core is solid and made of iron and nickel due to high pressure, while the outer core is liquid and also composed of iron and nickel.

How do scientists identify plate boundaries using earthquake patterns?

Earthquake activity is concentrated along plate boundaries, with depth, location, and intensity helping to identify the type of boundary.

What role does pressure play in the Earth's mantle?

Increased pressure causes rock in the asthenosphere to behave plastically, allowing it to flow and support tectonic plate movement.

What is the significance of convection currents in the mantle?

Convection currents drive tectonic plate movement, leading to the creation of new crust at divergent boundaries and destruction at subduction zones.

How are mountains, volcanoes, and earthquakes connected to plate tectonics?

Mountains form at convergent boundaries, volcanoes at both convergent and divergent boundaries, and earthquakes occur at all types of boundaries.

What is the rock cycle?

The rock cycle is a continuous process involving the formation, alteration, and recycling of rocks on Earth.

What are the main processes of the rock cycle?

The main processes include the formation of igneous rocks through cooling and solidification, transformation into metamorphic rocks through heat and pressure, and breakdown into sediments that form sedimentary rocks.

What role does magma play in the rock cycle?

Magma is molten rock that cools and solidifies to form igneous rocks, which can later undergo weathering and erosion to form sedimentary rocks.

How does metamorphism contribute to the rock cycle?

Metamorphism changes existing rocks under heat and pressure, leading to the formation of metamorphic rocks, which can then become sediments.

What is the significance of weathering and erosion in the rock cycle?

Weathering breaks down rocks into sediments, while erosion transports these sediments, which can be compacted and cemented to form new sedimentary rocks.

Provide an example of a rock transitioning through all three stages of the rock cycle.

An igneous rock like granite can weather into sediments, which form sedimentary rock like sandstone, and then transform into metamorphic rock like quartzite.

What defines igneous rocks?

Igneous rocks are formed from the cooling and solidification of molten magma or lava.

What is the difference between intrusive and extrusive igneous rocks?

Intrusive igneous rocks form beneath the Earth's surface from slowly cooling magma, while extrusive igneous rocks form on the surface from rapidly cooling lava.

How does the cooling rate of magma affect the texture of igneous rocks?

A slower cooling rate results in larger mineral crystals and a coarse-grained texture, while a faster cooling rate leads to smaller crystals and a fine-grained texture.

What characterizes felsic igneous rocks?

Felsic igneous rocks are rich in light-colored minerals such as quartz and feldspar.

How does silica content influence the classification of igneous rocks?

High silica content leads to lighter-colored, felsic rocks, while low silica content results in darker, mafic rocks.

What is an example of an extrusive igneous rock?

Basalt, which forms from the rapid cooling of lava on the Earth's surface.

Define sedimentary rocks and their primary mode of formation.

Sedimentary rocks are formed through the accumulation, compaction, and cementation of sediments.

Differentiate between clastic, chemical, and organic sedimentary rocks.

Clastic rocks are made of fragments of other rocks, chemical rocks form from mineral precipitation, and organic rocks originate from the remains of living organisms.

What is the role of cementation in sedimentary rock formation?

Cementation binds sediments together through the deposition of minerals, forming solid rock.

Explain lithification in the context of sedimentary rocks.

Lithification transforms loose sediments into solid rock through compaction and cementation.

What defines metamorphic rocks?

Metamorphic rocks are formed through the alteration of existing rocks due to heat, pressure, and chemically reactive fluids.

What is the difference between foliated and non-foliated metamorphic rocks?

Foliated rocks have a layered appearance due to aligned mineral grains, while non-foliated rocks lack this structure.

How do heat and pressure contribute to metamorphic rock formation?

Heat and pressure cause changes in mineral composition and texture, leading to the formation of metamorphic rocks.

What is the significance of mineral alignment in foliated metamorphic rocks?

Mineral alignment reflects the directional forces during metamorphism, resulting in a layered appearance.

What is regional metamorphism?

Regional metamorphism occurs over large areas due to high pressures and temperatures, often during mountain-building events.

How does contact metamorphism differ from regional metamorphism?

Contact metamorphism occurs when rocks are heated by nearby molten magma, affecting a smaller area compared to the widespread effects of regional metamorphism.

What is contact metamorphism?

Contact metamorphism occurs locally due to the heat from nearby magma.

What is recrystallization in metamorphic rocks?

Recrystallization involves the growth of new mineral crystals in response to changing conditions during metamorphism.

Define physical weathering.

Physical weathering, or mechanical weathering, involves the breakdown of rocks into smaller fragments without changing their chemical composition.

Give an example of physical weathering.

Frost action, where water freezes in rock crevices, causing the rock to fracture.

How does abrasion contribute to physical weathering?

Abrasion occurs when rocks are physically worn down by the impact of other rocks, particles, or moving fluids.

How do temperature changes contribute to physical weathering?

Temperature changes cause rocks to expand when heated and contract when cooled, leading to cracks and fractures.

Describe freeze-thaw cycles in rock weathering.

Freeze-thaw weathering occurs when water fills cracks in rocks, freezes, expands, and pushes the crack apart.

What are the weathering products of quartz, feldspar, and calcite?

Quartz weathers to sand particles, feldspar weathers to clay particles, and calcite weathers to calcium and carbonate in solution.

Define chemical weathering.

Chemical weathering involves the alteration of rocks through chemical reactions, leading to changes in mineral composition.

Provide an example of chemical weathering.

The dissolution of limestone by acidic rainwater.

What role does oxygen play in chemical weathering?

Oxygen reacts with iron-rich minerals, forming iron oxides (rust) and contributing to rock breakdown.

How does acid rain impact chemical weathering?

Acid rain accelerates chemical weathering by reacting with minerals in rocks, leading to the formation of soluble substances.

What is erosion?

Erosion is the process of moving and transporting weathered material from one location to another.

Differentiate between weathering and erosion.

Weathering is the breakdown of rocks into smaller particles, while erosion involves the transportation and removal of those particles.

How does gravity contribute to erosion?

Gravity pulls rocks and sediments downhill, causing them to move and contribute to erosion.

What role does running water play in erosional landforms?

Running water carves valleys, creates river channels, and forms features like waterfalls and meanders through erosion.

How do meanders form in rivers?

Meanders form through the erosion of the outer bank and deposition on the inner bank of a river bend.

What is sediment sorting in rivers?

Sediment sorting refers to the separation of particles based on size and weight during transportation.

Identify a landform created by sediment deposition at a river mouth.

A delta is formed by the deposition of sediments at the mouth of a river.

How does a river's velocity influence its sediment-carrying capacity?

Higher river velocities increase the sediment-carrying capacity, allowing transport of larger particles.

What are sediments and their origin in rivers?

Sediments are solid particles transported and deposited by agents like rivers, originating from the weathering and erosion of rocks.

Explain the trend of stream velocity in relation to sediment transport.

Smaller particles require lower velocities to be transported, while larger particles need higher velocities.

Under what conditions does sediment deposition occur?

Sediment deposition occurs when stream velocity is too low to transport particles, leading to the deposition of larger particles first.

How do glaciers contribute to erosion and deposition?

Glaciers erode landscapes by scraping and plucking rocks, then deposit debris in new locations as they melt.

Four main components of soil

Mineral particles, organic matter, water, and air.

Sand, silt, and clay particle size and texture

Sand particles are largest and gritty, silt particles are medium-sized and smooth, clay particles are smallest and sticky.

Effect of particle size on porosity and permeability

Smaller particles (clay) increase porosity but decrease permeability; larger particles (sand) have lower porosity but higher permeability.

Importance of soil air for plant roots

Soil air provides oxygen necessary for root respiration and healthy plant growth.

Influence of soil moisture on plant growth and chemical weathering

Soil moisture is essential for plant uptake and influences chemical weathering by facilitating reactions.

Porosity

The percentage of soil volume that is pore space.

Permeability

The ability of soil to transmit water.

Relationship between porosity and permeability

They are related because pore space affects water movement.

Soil type with highest porosity

Clay has the highest porosity.

Soil type with highest permeability

Sand has the highest permeability.

N-P-K nutrients

N-P-K stands for Nitrogen (N), Phosphorus (P), and Potassium (K).

Role of Nitrogen in plants

Nitrogen promotes leaf growth.

Role of Phosphorus in plants

Phosphorus supports root and flower development.

Role of Potassium in plants

Potassium aids overall plant health and disease resistance.

Improvement of soil fertility by organic matter

Organic matter improves fertility by providing nutrients and enhances structure by increasing aggregation and water retention.

CLORPT

CLORPT stands for Climate, Organisms, Relief (topography), Parent material, Time—all influence soil formation processes.

Interaction of parent material and climate

Parent material provides the mineral base; climate affects weathering rates and organic activity, together shaping soil characteristics.

Soil texture triangle

The soil texture triangle is a tool that classifies soil based on the percentages of sand, silt, and clay.

Soil texture classification for 40% sand, 40% silt, and 20% clay

Soil with 40% sand, 40% silt, and 20% clay is classified as loam.

Main soil horizons

O, A, B, C, R.

Soil horizons

O: Organic layer (decayed material), A: Topsoil (mixed organic and mineral), B: Subsoil (accumulated minerals), C: Weathered parent material, R: Bedrock

Water-holding capacity

The soil's ability to retain water for plant use.

Clay soil

Holds the most water.

Sandy soil

Drains the fastest.

Soil degradation

Caused by human activities including deforestation, overgrazing, excessive tillage, and pollution.

Soil conservation methods

Techniques like contour plowing, crop rotation, and terracing that reduce erosion and nutrient loss.

Groundwater

Water stored underground in soil or rock, unlike surface water which is found in rivers, lakes, etc.

Zone of saturation

Where all pores are filled with water.

Zone of aeration

Above the zone of saturation, where pores are filled with air.

Water table

The boundary between the zone of saturation and the zone of aeration; it rises with rainfall and falls during drought.

Aquifer

An underground layer of water-bearing permeable rock or sediment.

Confined aquifers

Trapped between impermeable layers.

Unconfined aquifers

Have a permeable layer above.

Difference between porosity and permeability

Porosity is the volume of pore spaces; permeability is the ability to transmit water through those spaces.