Historical Geology Test 1 Study Guide

The universe was all in one place, with all its matter and energy squished into an __________ before the explosion.

infinitely small point, a singularity

The Big Bang occurred approximately __________ billion years ago.

14.4

The explosion happened __________ minutes after the Big Bang.

3-20

The __________ effect describes the change in pitch of sound when an object moves closer.

Doppler

When a galaxy is shifting closer, light will shift __________ on the spectrum.

blue

Hubble’s Law, established by __________ in 1929, provided evidence to support Lamitre’s theory.

Edwin Hubble

A nebula is defined as a cloud of __________ and __________ within the universe.

gas and dust

The Earth's early atmosphere likely contained hydrogen cyanide, carbon dioxide, and other __________ gases.

toxic

The first oceans formed approximately __________ billion years ago.

3.8

The earliest cells called __________ microspheres were created when organic molecules became trapped in bubbles.

proteinoid

The Endosymbiotic theory states that eukaryotes formed from __________ of prokaryotes.

communities

Igneous rocks are formed from __________ molten material, indicating volcanic activity.

cooled

Sedimentary rocks that contain fossils indicate __________ life forms and ecosystems.

past

The detrital sedimentary cycle begins with __________, followed by erosion, transport, deposition, and lithification.

uplift

Walther's law states that as depositional environments migrate laterally, sediments of one environment come to lie on top of sediments of the __________ environment.

adjacent

Deltas are modified by waves, tides, and __________ forces, leading to different sedimentary environments.

stream

Transgression refers to rising sea levels, while __________ refers to falling sea levels.

regression

Absolute dating provides the actual age of rocks through __________ dating.

radioactive

Igneous rocks are best for radiometric dating because they contain only a __________ isotope when they form.

parent

The Principle of Superposition states that the __________ layer is on the bottom, and the youngest is on the top.

oldest

Index fossils are widespread geographically and occur in __________ numbers to help date geological times.

large

An __________ represents geological time not represented in the rock record.

unconformity

A __________ unconformity is an erosional surface on tilted strata followed by younger layers.

angular

Big Bang Theory

A scientific explanation of how the universe began approximately 14.4 billion years ago from an infinitely small point (singularity) that exploded.

Solar Nebular Theory

The theory that the solar system formed from a rotating cloud of gas and dust, leading to the formation of the Sun and planets.

Nebula

A cloud of gas and dust in space, which is the birthplace of stars and planetary systems.

Nuclear Fusion

The process in which hydrogen atoms combine to form helium, releasing energy; this occurs in the core of stars.

Endosymbiotic Theory

The theory that eukaryotic cells originated from communities of prokaryotic cells, leading to a symbiotic relationship.

Igneous Rocks

Rocks formed from cooled molten material, indicating past volcanic activity.

Sedimentary Rocks

Rocks formed from sediment deposition, preserving fossils and geological history.

Metamorphic Rocks

Rocks that are altered by heat and pressure, showing evidence of tectonic processes.

Walther's Law

The principle stating that as depositional environments shift laterally, sediments from one environment will lie above those from adjacent environments.

Transgression

A geological process where rising sea levels flood land, depositing deeper marine sediments over shallower ones.

Relative Dating

Determining the age of rock layers or fossils based on their position in the geological strata.

Absolute Dating

Determining the actual age of a rock through techniques like radioactive dating.

Unconformity

A surface in the geological time record representing missing time, often caused by erosion or non-deposition.

Index Fossils

Fossils that are widespread, exist for a short geological time, and are easily identified, used to date rock layers.

Hubble's Law

A principle stating that the farther away a galaxy is, the faster it is moving away from us, supporting the Big Bang theory.

Bright Line Spectra

The spectrum of light emitted by elements, showing blue shift for approaching galaxies and red shift for receding galaxies.

Age of Earth

Approximately 4.56 billion years old, determined through radiometric dating of the oldest rocks and minerals.

Formation of Oceans

The first oceans formed about 3.8 billion years ago when the Earth cooled enough to allow liquid water.

Proteinoid Microspheres

Early cell-like structures formed from organic molecules that were trapped in bubbles and displayed some characteristics of life.

Metamorphism

The process of transforming existing rocks through heat and pressure, forming metamorphic rocks.

Transgression vs Regression

Transgression: Rising sea levels; Regression: Falling sea levels, each affecting sediment deposition patterns.

Relative Dating

Determining the age of rock layers based on their position rather than through absolute dating methods.

Angular Unconformity

An erosional surface on tilted or folded rock strata, where younger sediments are deposited on top.

Disconformity

A gap in the geological record between parallel rock layers, indicating erosion or nondeposition.

Big Bang Theory

The theory that the universe began approximately 14.4 billion years ago from a singularity that exploded.

Singularity

An infinitely small point in which all matter and energy of the universe was concentrated before the Big Bang.

Doppler Effect

The change in pitch of sound waves when an object moves closer or further away, which supports the Big Bang theory.

Bright Line Spectra

The phenomenon where light shifting to blue indicates a galaxy is moving closer, and shifting to red indicates it is moving away.

Hubble’s Law

Edwin Hubble's 1929 discovery that supports the Big Bang theory, indicating that galaxies are moving away from us.

Nebula

A cloud of gas and dust in space, considered the birthplace of our Solar System.

Solar Nebular Theory

The theory explaining the formation of the Solar System through the collapse of a gas and dust cloud.

Protoplanets

Small celestial bodies that coalesced to form planets during the early stages of the Solar System.

Nuclear Fusion

The process by which hydrogen atoms combine under immense pressure and heat to form helium, releasing light energy.

Age of Earth

Approximately 4.56 billion years.

Formation of the Moon

The Moon formed around 4.5 billion years ago, shortly after Earth.

Oldest Rock

The oldest known rock is approximately 4.47 billion years old.

Early Atmosphere Composition

Earth's early atmosphere likely contained hydrogen cyanide, carbon dioxide, carbon monoxide, nitrogen, hydrogen sulfide, and water.

First Oceans Formation

First oceans formed around 3.8 billion years ago when Earth cooled enough to have liquid water.

Proteinoid Microspheres

Early cell-like structures formed from organic molecules trapped in bubbles, exhibiting some characteristics of living cells.

Endosymbiotic Theory

The theory that eukaryotes originated from communities of prokaryotes that developed a symbiotic relationship.

Igneous Rocks

Rocks formed from cooled molten material, indicating volcanic activity.

Sedimentary Rocks

Rocks that record the history of deposition and may contain fossils.

Metamorphic Rocks

Rocks formed from the alteration of existing rocks under heat and pressure.

Detrital Sedimentary Rocks

Sedimentary rocks made from grains weathered from previously existing rock and cemented together.

Detrital Sedimentary Cycle

The cycle including uplift, erosion, sediment transportation, deposition, and lithification.

Facies

Sets of characteristics representing a particular depositional environment.

Walther's Law

States that as depositional environments migrate, the sediments of one environment lie on top of those of adjacent environments.

Braided Streams

Stream systems with horizontal beds of conglomerates and sands, characterized by limited mud.

Meandering Streams

Stream channels that migrate downstream, producing distinctive sediment patterns.

Deltas

Landforms created by sediment deposition at the mouth of rivers, modified by waves and tides.

Transgression

A rise in sea level that leads to the flooding of land and deposition of deeper marine sediments.

Regression

A fall in sea level that exposes land and leads to shallower deposits.

Absolute Dating

Determining the actual age of rock through methods like radioactive dating.

Relative Dating

Determining the age of rock layers based on their position relative to one another.

Half-life

The time required for half of the radioactive isotopes in a sample to decay.

Principle of Superposition

In undisturbed rock layers, the oldest layer is at the bottom and the youngest at the top.

Principle of Original Horizontality

Layers of sediments are originally deposited horizontally.

Principle of Lateral Continuity

Sediments are deposited over large areas and continue laterally until they thin out.

Principle of Cross-Cutting Relationships

Any geological feature that cuts across another is younger than the feature it cuts.

Principle of Inclusions

Rock fragments included in a layer are older than the layer itself.

Index Fossils

Fossils that are widespread, existed for a short time, easy to identify, and abundant.

Unconformities

Surfaces representing a gap in the geological record, indicating missing time.

Disconformity

An unconformity between parallel rock layers, indicating erosion or nondeposition.

Angular Unconformity

Unconformity where younger layers are deposited over tilted or folded strata.

Nonconformity

An unconformity where sedimentary rocks are deposited over eroded igneous or metamorphic rocks.