Weathering Processes and Types

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Questions and Answers

What process results in the oxidation and weathering of iron-rich rocks?

Erosion by wind

Chemical weathering

Oxidation (correct)

Hydrolysis

Which of the following contributes to biological weathering?

Frost wedging

Mineral solubility

Thermal expansion

Plant roots (correct)

What is the primary result of burrowing animals on the landscape?

Acidic leaching

Physical weathering (correct)

Hydration processes

Chemical weathering

During which melting process does the pressure on a rock decrease while the temperature remains constant?

Decompression Signup and view all the answers

Which term describes the process of rocks being broken down by chemical reactions with biological acids?

Chemical weathering Signup and view all the answers

What characteristic allows hot rocks to rise in the Earth's mantle during convection currents?

Low density Signup and view all the answers

What initiates flux melting in rocks?

Addition of water or carbon dioxide Signup and view all the answers

Which layer of the Earth is known to be the hottest, reaching temperatures above 9000 Fahrenheit?

Inner core Signup and view all the answers

What is the main process by which rocks change in form, composition, and structure due to heat and pressure?

Metamorphism Signup and view all the answers

Which factor primarily affects the mineral composition and crystalline textures of metamorphic rocks?

Pressure and temperature Signup and view all the answers

During which geological setting would you expect to find low temperature metamorphism?

Subduction zone Signup and view all the answers

What is the term used to describe the rate at which temperature increases with depth in the Earth's crust?

Geothermal gradient Signup and view all the answers

Which of the following describes the changes that occur during burial metamorphism?

Recrystallization of minerals Signup and view all the answers

What happens to rocks during the metamorphic process at high pressures?

Their mineral composition changes Signup and view all the answers

What role do chemically active fluids play in metamorphism?

They introduce new minerals into the rock Signup and view all the answers

What is described as the rock placed on top of the fault?

Footwall Signup and view all the answers

What is a characteristic of metamorphism occurring at subduction zones?

Low temperature and high pressure Signup and view all the answers

Who explained the process of seafloor spreading?

Harry Hess Signup and view all the answers

What forms as a result of magma rising and cooling during seafloor spreading?

Mid-ocean ridge Signup and view all the answers

What happens to the older oceanic crust as new crust forms?

It melts back into the mantle Signup and view all the answers

Which of the following best describes a continental shelf?

A shallow underwater extension of the continent Signup and view all the answers

What is true about abyssal plains?

They cover 50% of the Earth’s surface Signup and view all the answers

What is a seamount?

An underwater volcano that has formed a flat peak Signup and view all the answers

What defines a trench in the ocean?

The deepest part of the ocean Signup and view all the answers

What is the primary method used in radiometric dating to determine the age of an object?

Assessment of radioactive isotope decay Signup and view all the answers

Which technique uses the number of annual growth rings to determine the age of a tree?

Dendrochronology Signup and view all the answers

Which of the following is NOT a method of absolute dating?

Index fossil correlation Signup and view all the answers

How does thermoluminescence dating primarily function?

By measuring light emissions released from heated objects Signup and view all the answers

What concept does stratigraphy rely on for dating sedimentary layers?

Lowest layers being the oldest Signup and view all the answers

Which eon of geological time is characterized by the first appearance of life forms on Earth?

Archaean Eon Signup and view all the answers

What is the main purpose of the Geologic Time Scale?

To relate geological strata to time and historical events Signup and view all the answers

In amino acid dating, what aspect of biological samples is analyzed to determine age?

Change in protein content over time Signup and view all the answers

What significant event contributed to the demise of coral reefs, jawless fishes, and trilobites?

The Kellwasser Event Signup and view all the answers

Which feature of amphibians necessitates their return to water?

The requirement to lay eggs in water Signup and view all the answers

During which period did the evolution of the first reptiles occur?

Carboniferous Period Signup and view all the answers

What was a major characteristic of the Mesozoic Era?

Age of reptiles Signup and view all the answers

Which group of reptiles gave rise to the mammals during the Permian Period?

Synapsids Signup and view all the answers

What event marked the end of the Mesozoic Era?

Extinction of dinosaurs Signup and view all the answers

Which of the following is true about the Cenozoic Era?

It is known as the 'Age of Mammals' Signup and view all the answers

What climate conditions characterized the Carboniferous Period?

Warm and moist with dense swampy forests Signup and view all the answers

What is the Proterozoic Eon primarily characterized by?

Extensive shallow epicontinental seas Signup and view all the answers

During which period did almost all marine organisms come into existence?

Cambrian Period Signup and view all the answers

Which era is known as the time of visible life?

Phanerozoic Era Signup and view all the answers

What significant development occurred in the Silurian Period?

First vascular plants Signup and view all the answers

Which statement about the Ordovician Period is true?

It marks the earliest appearance of vertebrates. Signup and view all the answers

What marked the Cambrian Period's significance in geological history?

The evolution of organisms capable of making shells. Signup and view all the answers

What was a prominent feature of the Devonian Period?

Widespread forests of seed ferns existed. Signup and view all the answers

Which factor contributed to the division of geological time into eras?

Extinction events and evolution of life forms Signup and view all the answers

Study Notes

Weathering

Weathering is the process of breaking down rocks into smaller pieces.
Agents of weathering include water, salt, temperature, plants, and animals.
Water seeps into cracks, freezes, expands, and breaks the rock apart.
Saltwater can crystallize in cracks, putting pressure on the rock and causing it to break.
Thermal stress occurs when rocks expand and contract due to temperature changes, weakening and crumbling them.
Plant roots growing into cracks can force the rock apart.
Animals burrowing or digging can break and move rocks and soil.

Types of Weathering

Physical weathering breaks rocks into smaller pieces without changing their chemical composition.
- Abrasion: rocks rubbing against each other.
- Freeze-thaw: water freezing and expanding in cracks.
- Exfoliation: pressure release from uplift and erosion.
Chemical weathering involves a chemical reaction between rocks and water, forming new minerals or soluble salts.
- Carbonation: carbon dioxide dissolves in water, creating carbonic acid.
- Hydrolysis: acidic water reacts with minerals, forming clay and soluble salts.
- Oxidation: rocks react with oxygen and water, often resulting in a rusty color.
Biological weathering involves organisms weakening rocks.
- Plant roots growing into cracks.
- Burrowing animals.
- Acidic substances produced by plants or animals.

Earth's Internal Heat Source

Inner core is the hottest layer.
Convection currents occur in the air, ocean, and mantle due to temperature differences.
Hotter, less dense rock rises; cooler, more dense rock sinks.

Types of Melting

Partial melting: some minerals melt while others remain solid.
Flux melting: water or carbon dioxide lowers the melting temperature.
Decompression melting: reduced pressure allows rocks to melt at lower temperatures.

Metamorphism

Metamorphism is the process where rocks change in form, composition, and structure due to heat, pressure, and/or chemically active fluids.
Factors affecting metamorphism include temperature and pressure.
- Higher temperatures cause recrystallization, forming larger crystals.
- Increased pressure changes mineral composition and texture.
Types of metamorphism include regional, contact, shock, and burial metamorphism.

Two Types of Pressures on Rocks

Vertical/Confining pressure: stress from overlying material.
Directed/Differential pressure: stress from forces in a particular direction.
Foliation: flat or wavy parallel cleavage planes due to directed pressure.
Hydrothermal fluids: dissolved minerals react with rocks, altering composition.
Metamorphism:
- Metasomatism - alteration by fluids.
- Regional: large areas, high temperature and pressure.
- Contact: heat from magma intrusions.
- Shock: heat and shock waves from impacts.
- Burial: lower temperatures and pressures.
- High-pressure: in subduction zones

Types of Folds and Faults

Folds: bends in layers of rock.
Anticline: upward arching fold.
Syncline: downward folding fold.
Monocline: step-like fold.
Faults: fractures in rocks where movement has occurred.
Normal Fault: hanging wall moves down relative to footwall.
Reverse Fault: hanging wall moves up relative to footwall.
Strike-Slip Fault: blocks move horizontally.

Seafloor Spreading

Mid-ocean ridges occur where seafloor spreading creates new crust.
Seafloor spreading is a process where tectonic plates move apart.
Magma rises to the surface at mid-ocean ridges to form new oceanic crust.

Stratigraphy and Dating Techniques

Stratigraphy: study of rock layers or strata.
- Law of Original Horizontality: beds of sedimentary rock are deposited horizontally.
- Law of Superposition: oldest layers are on the bottom, youngest on top.
- Law of Lateral Continuity: layers extend laterally until interrupted.
Relative Dating: ages are determined by their position relative to other layers.
Absolute(Numerical) Dating: exact age is determined.
- Radiometric Dating: radioactive decay of isotopes.
- Amino acid dating: protein content changes
- Dendrochronology: tree rings
- Thermoluminescence: heat-induced emissions.

Geologic Time Scale

Eons: largest subdivisions of time.
Eras: further divisions of eons.
Periods: further divisions of eras.
Epochs: further divisions of periods.
The geologic time scale organizes Earth's history.

Periods and Epochs

Cambrian, Ordovician, Silurian, Devonian, Carboniferous, Permian, Triassic, Jurassic, Cretaceous, Paleocene, Eocene, Oligocene, Miocene, Pliocene, Pleistocene, Holocene.

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Description

This quiz covers the fundamental concepts of weathering, including its definition and the various agents and types involved. Learn about how physical and chemical weathering contribute to the breakdown of rocks, and explore specific processes like abrasion and freeze-thaw. Challenge your knowledge on how natural elements shape our geological landscape!