Earth and Space Final Exam

Geological Timeline

A chronological framework that organizes Earth's history into various units based on geological and paleontological evidence.

Eons

The largest divisions of geological time, spanning hundreds of millions to billions of years. Examples include the Hadean, Archean, Proterozoic, and Phanerozoic.

Eras

Subdivisions of eons, lasting tens to hundreds of millions of years. Examples include the Paleozoic, Mesozoic, and Cenozoic eras that represent significant periods in Earth's history characterized by distinct geological and biological events.

Periods

Subdivisions of eras, lasting tens of millions of years. Examples include the Cambrian, Jurassic, and Quaternary periods.

Epochs

Subdivisions of periods, lasting several million years. Examples include the Paleocene, Eocene, and Holocene epochs that mark significant evolutionary and climatic changes.

Index Fossils

Fossils of organisms that lived during a relatively short, specific time period and are used to identify and correlate the ages of rock layers

Relative Dating

A method of determining the age of a rock or fossil by comparing its placement with that of other rocks or fossils in a sequence

Principle of Superposition:

In an undisturbed sequence of rock layers, the oldest layers are at the bottom and the youngest layers are at the top.

Principle of Original Horizontality

The principle that sedimentary rock layers are originally deposited in horizontal layers.

Principle of Cross-Cutting Relationships

The principle that a geological feature, such as a fault or intrusion, is younger than the rocks it cuts through

Principle of Unconformities

Gaps in the geological record that represent periods of erosion or non-deposition

Principle of Inclusions

Fragments of one rock type enclosed within another rock type, indicating that the inclusion is older than the surrounding rock

Fossils

Preserved remains or traces of ancient organisms

Mineral Replacement

A fossilization process where the original material of an organism is replaced with minerals

Recrystallization

A process where the original minerals in a fossil are dissolved and reformed into new minerals

Mold and Cast

A type of fossilization where an organism leaves an impression (mold) that is later filled with minerals (cast)

Carbon Film

A thin layer of carbon residue left by an organism, often preserving fine details

Trace Fossil

Indirect evidence of an organism's presence, such as footprints, burrows, or feces

Body Fossil

Fossils that consist of the actual remains of an organism, such as bones or shells

Original Preservation

Fossils that retain their original structure and composition

Altered Hard Parts

Fossils where the hard parts of an organism, like bones or shells, have undergone chemical changes

Continental Drift Theory vs Theory of Plate Tectonics

Continental Drift Theory, proposed by Alfred Wegener, suggested continents were once joined and have since drifted apart based on fossil and geological evidence. Plate Tectonics, developed later, expanded on this by explaining the movement of Earth's lithospheric plates driven by mantle convection, providing a more comprehensive understanding of geological phenomena.

Milankovitch Theory

This theory describes how variations in Earth's orbit and axial tilt (eccentricity, obliquity, and precession) affect climate patterns over thousands of years, contributing to cycles of ice ages and warmer periods. Greater tilt angles result in more extreme seasonal variations, while smaller angles lead to milder seasons, during periods of high eccentricity, summers can be warmer and winters colder in one hemisphere, depending on the timing of perihelion and aphelion

Absolute vs Relative Dating

Absolute dating provides a specific age or date range for an object using methods like radiocarbon dating, while relative dating determines the age of an object in relation to other objects or layers, without providing a specific date

How did life start on the Earth?

• Hydrothermal Vents: Life may have originated at hydrothermal vents on the ocean floor, where mineral-rich water provides the necessary chemicals and energy for the formation of organic molecules

• Primordial Soup: This theory suggests that life began in a "primordial soup" of organic molecules, possibly sparked by lightning or ultraviolet radiation. The famous Miller-Urey experiment demonstrated that amino acids, the building blocks of life, could form under conditions thought to resemble early Earth's atmosphere

• Panspermia: This hypothesis proposes that life, or at least the building blocks of life, came to Earth from space via comets, meteorites, or cosmic dust

Cause of Extinction Events

Extinction events can be caused by various factors, including volcanic eruptions, asteroid impacts, climate change, and human activities. The "Big Five" mass extinctions were driven by such catastrophic events

Principle of Uniformitarianism vs. Catastrophe

Uniformitarianism, proposed by James Hutton, suggests that geological processes occurring today have been constant over time, shaping Earth's surface gradually. Catastrophism, on the other hand, posits that Earth's features were formed by sudden, short-lived, and violent events

Mineral

A naturally occurring, inorganic solid with a definite chemical composition and a crystalline structure

Rock

A solid aggregate of one or more minerals or mineraloids

Metallic Mineral

Minerals that contain metal elements in their chemical composition and can be economically extracted

Tailings

Residue or waste material left after the extraction of valuable minerals from ore

Industrial Mineral

Non-metallic minerals used in various industries for their physical and chemical properties

Gem

A precious or semi-precious mineral that is cut and polished for use in jewelry

Synthetic Mineral

Man-made minerals created to mimic natural minerals

Mineral Deposit

A concentration of minerals in the Earth's crust that is economically viable to extract

Ore

A naturally occurring rock or mineral that contains a valuable substance that can be extracted for profit

Hydrothermal Fluids

Hot, mineral-rich water that circulates through rocks, often leading to the formation of mineral deposits

Placer Ores

Mineral deposits formed by the concentration of valuable minerals in river or beach sediments

Bedrock

The solid rock underlying loose deposits such as soil or alluvium

Aggregates

Materials composed of sand, gravel, crushed stone, or slag used in construction

Streak

The color of a mineral in powdered form, usually obtained by rubbing the mineral on a streak plate

Hardness (Moh’s Hardness Scale)

A measure of a mineral's resistance to scratching, ranked on the Mohs scale from 1 (talc) to 10 (diamond)

Lustre

The way a mineral reflects light from its surface

Adamantine

A type of lustre that is exceptionally brilliant, like that of a diamond

Earthy

A dull, non-reflective lustre resembling soil

Pearly

A lustre that resembles the iridescence of a pearl

Resinous

A lustre that looks like resin or amber

Silky

A lustre that appears fibrous, like silk

Vitreous

A glassy lustre

Metallic

A lustre that resembles metal

Effervescence

The reaction of a mineral with acid, producing bubbles of gas

Crystal Habit

The characteristic shape or form of a mineral's crystals

Specific Gravity

The ratio of a mineral's density compared to the density of water

Lava

Molten rock that has erupted onto Earth's surface

Magma

Molten rock beneath Earth's surface

Bowen’s Reaction Series

A sequence that describes the order in which minerals crystallize from cooling magma

Extrusive

Igneous rocks formed from lava that cools quickly on Earth's surface (can’t see the different grains)

Intrusive

Igneous rocks formed from magma that cools slowly beneath Earth's surface (can see the different grains)

Felsic

Igneous rocks rich in feldspar and silicon, typically light-colored

Mafic

Igneous rocks rich in magnesium and iron, typically dark-colore

Lithification

he process of turning sediment into rock through compaction and cementation

Clastic Rocks

Sedimentary rocks composed of fragments of pre-existing rocks

Bioclastic

Sedimentary rocks formed from the remains of living organisms

Chemical Sedimentary

Rocks formed from the precipitation of minerals from water

Organic

Sedimentary rocks formed from the accumulation of plant or animal debris

Contact Metamorphism

Metamorphism caused by heat from nearby magma

Regional Metamorphism

Metamorphism affecting large areas of the crust, typically associated with mountain building

Hydrothermal Metamorphism

Metamorphism caused by hot, mineral-rich fluids

Foliated

Metamorphic rocks with a layered or banded appearance

Non-Foliated

Metamorphic rocks without a layered or banded appearance

Igneous Rock Cycle

Formed from the cooling and solidification of magma or lava.

Sedimentary Rock Cycle

Formed from the compaction and cementation of sediments

Metamorphic Rock Cycle

Formed from the alteration of existing rocks due to heat and pressure

Mineral Characteristics

• Naturally Occurring: Formed by natural processes.

• Inorganic: Not made by biological processes.

• Solid: Maintains a definite shape and volume.

• Definite Chemical Composition: Has a specific chemical formula.

• Crystalline Structure: Atoms are arranged in an orderly pattern

Quartzite’s Parent Rock

Sandstone

Gneiss Parent Rock

Granite or Schist (picture is granite)

Slate Parent Rock

Shale

Comparing Limestone, Marble, Granite for Building Materials or Statues

• Limestone: Sedimentary rock, easily carved, used in buildings and statues but less durable.

• Marble: Metamorphic rock, formed from limestone, more durable and aesthetically pleasing, used in sculptures and buildings.

• Granite: Igneous rock, very hard and durable, used in construction and monuments

Relationship Between Cooling Rates and Mineral Size

• Slow Cooling: Forms large crystals (e.g., granite).

• Fast Cooling: Forms small or no crystals (e.g., basalt)

Example of How a Mineral or Earth Material is Used and Why

Quartz: Used in glassmaking due to its high silica content and durability
Halite (Salt): Used in food seasoning and preservation due to its ability to enhance flavor and inhibit bacterial growth. It's also used in de-icing roads in winter

Talc: Commonly used in baby powder and cosmetics for its softness and ability to absorb moisture. It's also used as a lubricant and in the production of ceramics

Gypsum: Used in the production of drywall and plaster because it can be easily shaped and hardens quickly. It's also used in cement and as a soil conditioner

Graphite: Used in pencils due to its ability to leave marks on paper. It's also used as a lubricant and in batteries for its excellent conductivity

Copper: Widely used in electrical wiring and plumbing due to its excellent conductivity and malleability. It's also used in coins and various alloys

Granite

Coarse-grained, intrusive igneous rock

Obsidian

Glassy, extrusive igneous rock.

Rhyolite

Fine-grained, extrusive igneous rock.

Basalt

Fine-grained, extrusive igneous rock.

Conglomerate

Clastic sedimentary rock with rounded fragments.

Gneiss

Foliated metamorphic rock

Marble

Non-foliated metamorphic rock

Pyrite

Metallic luster, known as "fool's gold."

Calcite

Effervesces with acid

Magnetite

Magnetic properties

Talc

Softest mineral on Mohs scale.

Diamond

Hardest Mineral on Earth

Bituminous Coal

Organic sedimentary rock.

Coquina

Bioclastic sedimentary rock

Quartz

Vitreous luster

Mineral Properties

• Effervescence: Reaction with acid (e.g., calcite).

• Magnetism: Attraction to magnets (e.g., magnetite).

• Metallic Lustre: Reflects light like metal (e.g., pyrite).

• Moh’s Scale: Talc (1) is the softest, diamond (10) is the hardest.

• Adamantine: Brilliant luster (e.g., diamond)

Example of Felsic Rocks

Granite, rhyolite

Example of Mafic Rocks

Basalt, gabbro

Examples of Intrusive rocks

Granite, gabbro

Example of Extrusive Rocks

Basalt, obsidian