Environmental Science Test 3 Terms

Mt. St. Helens

May 18th, 1980. Active stratovolcano in the Cascade Range of southwestern Washington that erupted.

Effects from Mt. St. Helen

Ash spread out everywhere, mudslides, widespread destruction of forests and homes.

2005 reactivation (Mt. St. Helens), know that there was some reactivation that occurred.

December 26, 2005. Activity in 2005 involved the continued growth of a new lava dome inside the crater left by 1980 eruption with some notable explosive events. 

Mt. Pinatubo, 1991

Philippines, second largest volcano eruption of the 20th century. Produced hot ash avalanches, mud flows, and a large ash cloud.

What violence of eruption depends on

Viscosity, Which depends on:

1. Composition (what the melt is made of)

2. Temperature

3. % of dissolved gases in the melt

Granitic Magmas

More viscous, 70%+ silica, short thick flows, too thick for violent explosions.

Basaltic Magmas

Less viscous, 50% silica, longer more fluid flows.

Andesitic Magma

In between granitic and basaltic magma.

Which component of magmas tends to be the most responsible for it explosiveness

Gases in lava flows.

What’s extruded in a volcanic eruption

Lava flows, Gases, Pyroclastics.

Pahoehoe

Higher temperature, more liquid, smooth surface.

Aa

Lower temperature, clumpy, thicker flow.

Gases

About 1 to 5% CO2, H2O, Sulfur, Other gases.

Pyroclastics

Fragments of pulverized rock erupted by a volcano.

Ash

Fine-grained material.

Lapilli

Rounded, pea-sized pieces, new.

Pumice

Rains down from volcanoes. Frothy, light rock.

Cinders

Similar to papilla, same size, more jagged, old.

Blocks

Rock sized pieces, comes out solid.

Bombs

Comes out liquid.

Shield Volcanoes

All liquid lava flow. EX: Mauna Loa (Hawaii).

Cinder Cones

All solid lava flows. EX: Sunset Crater (Arizona).

Composite Cones

Liquid and solid lava flow. EX: Mt. Rainier (Washington).

Pyroclastic Flows

Fast moving cloud of volcanic ash/rock, hot temperatures.

Nuee Ardantes

Type of pyroclastic flow with dense material.

Phreatic Explosions

Similar to geysers, heated explosion of water.

Fissure eruptions, and one place in the US they are found.

Crack in the Earth that has a flow of lava that comes out. Columbia River Basalts, Snake River Plain.

Calderas, and one place they are found.

Crater 1 km or more in size. Crater Lake, Oregon.

Volcanic necks, and two examples of these.

Old interior of a volcano, survived because it’s much stronger. Shipwreck, New Mexico and Devil’s Tower, Wyoming.

Uniformitarianism

Principle that present geological processes and rates have operated consistently over time, explaining Earth's features through slow, gradual changes.

Catastrophism

Suggests that Earth's history is defined by sudden, violent, and catastrophic events like floods and asteroid impacts.

James Hutton’s “present is the key to the past”.

Central idea of uniformitarianism, the principle that the same natural processes shaping Earth today have also shaped it throughout history. This concept implies that slow, gradual processes, such as erosion and sedimentation, are responsible for creating Earth's geologic features over long periods, suggesting the planet is much older than previously believed. 

Sir Charles Lyell’s “Principles of Geology”.

Foundational work in geology that introduced the theory of uniformitarianism, which states that geological processes occurring today have operated throughout Earth's history (he was more of a gradualist).

Bishop Ussher and catastrophism.

Calculated the Earth's creation in 4004 BC, laid the groundwork for catastrophism by suggesting a young Earth with a history of only a few thousand years.

Relative dates

Order of Events of geologic time.

Absolute dates

Exact Times of geologic time.

Key principles of relative dating from Niels Steno.

Superposition, original horizontality, lateral continuity, and cross-cutting relationships.

Principle of original horizontality

Sedimentary rocks are laid down originally horizontally.

Principle of superposition

Rock underneath one layer has to be older.

Principle of cross-cutting relationships

Any geological feature, such as a fault or an igneous intrusion, is younger than the rock layers it cuts across.

Principle of inclusions.

Rock that’s included in the other rock is older.

Principle of lateral continuity.

Sediments thin/pinch out at the ends.

Principle of faunal succession.

Different layers can be tied to different fossils.

Unconformities: Missing strata.

Normal to not have a complete time period.

3 Types of unconformities.

Angular, Disconformity, and Nonconformity.

Angular

When layers are at different angles from each other.

Disconformity

Missing time, between 2 types of sedimentary rocks.

Nonconformity

Younger sedimentary rock is deposited directly on top of much older, eroded igneous or metamorphic rock.

Be able to use Steno’s laws in a diagram problem (as done in class)

…

Fossils: what’s usually needed for their preservation.

Rapid burial, possession of hard parts.

Some ways fossils can be preserved:

Hard parts, carbon film, molds and casts, amber encasement, burrows and tracks, petrified wood (per mineralization).

Hard Parts

Hard parts like bones, teeth, and shells are more likely to be preserved as fossils because they resist decay and weathering better than soft tissues.

Carbon Film

Fossilization process where an organism's remains are compressed into a thin, two-dimensional film of carbon on a rock surface.

Molds and Casts

Two common fossilization processes where a fossil is formed through an impression left in sediment.

Molds

Empty space or impression left after an organism's remains decay.

Casts

Replica formed when that mold is later filled in with minerals or sediment.

Amber encasement

Occurs when an organism is trapped in tree resin, which hardens into amber over millions of years, creating a "time capsule".

Burrows and tracks

Preserved as trace fossils when the sediment they are made in is rapidly buried and hardened into rock, protecting them from destruction by erosion or other animals.

Petrified wood (permineralization)

Where minerals in groundwater replace the organic material of a tree, turning it into a stone replica.

Correlation: coordinating rock ages: matching of rocks to form a geologic time scale.

Process of matching and aligning rock layers from different locations to build a more complete geologic time scale. It involves matching similar rock units based on features like fossils, rock type, and chemical composition to determine their relative ages and place them in a chronological sequence.

Radiometric dating: what it is, and how it works. 3 types of radioactivity. Half-life and ratios parent to daughter material.

Technique used to determine the age of materials (such as rocks, fossils, or organic remains) by comparing the amount of a naturally occurring radioactive parent isotopeto the amount of its stable daughter product.

Alpha Emission: Loose 2P, 2N.

Beta Emission: Loose 1E.

Electron Capture: Gain 1E.

1 HL → 1:1

2 HL → 1:3

3 HL → 1:7

4 HL → 1:15

The geologic time scale: what it is.

System used to document Earth's 4.6-billion-year history, dividing it into a hierarchical system of eons, eras, periods, and epochs. It provides a timeline for major geologic and biological events, based on the rock strata and fossils that provide evidence of life and past conditions on Earth. 

Eons

The largest unit, spanning hundreds of millions to billions of years.

Eras

Subdivision of an eon, typically lasting hundreds of millions of years. 

Periods

Subdivision of an era, lasting from millions to tens of millions of years.

What Precambrian time is.

Represents over 80% of Earth's history and encompasses three eons: the Hadean, Archean, and Proterozoic. During this time, Earth's crust and atmosphere formed, and the first simple life forms appeared and evolved.

Phanerozoic

Eon covering the whole of time since the beginning of the Cambrian period, and comprising the Paleozoic, Mesozoic, and Cenozoic eras.

Paleozoic era

"ancient life", Rise of fish, amphibians, and the first plants and animals on land.

Mesozoic era

"middle life", "Age of Reptiles" for its dominance of dinosaurs.

Cenozoic era

"recent life", Current era, marked by the diversification and reign of mammals and birds after the extinction of the dinosaurs. 

Stromatolites: what they are, their age, and their significance.

Layered, fossilized structures formed by the trapping and binding of sediment by microbial mats, primarily cyanobacteria. They are some of the oldest evidence of life on Earth, with the oldest known fossils dating back over 3.5 billion years.

Significance of: Cambrian period (earliest complex life forms).

Rapid and diverse evolution of complex animal life, leading to the establishment of most major animal body plans that still exist today. This period saw the appearance of hard parts like shells and skeletons, the development of predator-prey relationships, and the colonization of diverse marine habitats

Devonian period (age of fishes).

Remarkable diversification and evolution of fish life. During this time, fish became dominant in aquatic environments.

Paleozoic-Mesozoic boundary (igneous dikes in the Appalachians during breakup of Pangaea and extinctions).

The igneous dikes in the Appalachians formed during the Late Triassic and Early Jurassic, which is in the Mesozoic Era, not at the Paleozoic-Mesozoic boundary. Their formation is associated with the Central Atlantic Magmatic Province (CAMP) and the breakup of the supercontinent Pangaea, and they are linked to the end, Triassic mass extinction. 

Mesozoic period (age of reptiles).

Defined by the dominance of reptiles, especially dinosaurs, on land and in the seas. During this period, the supercontinent Pangaea broke apart, and modern continents began to form.

Mesozoic-Cenozoic boundary (meteorite event as possible explanation for end of Mesozoic).

The transition from the Mesozoic to the Cenozoic Era, is widely accepted by the scientific community to have been caused by a massive meteorite (asteroid) impact. The event triggered a mass extinction that wiped out about 75% of all species, including all non-avian dinosaurs. 

Cenozoic fossils in Florida: mastodon, shells, corals, and know that it’s the present time period.

Florida's Cenozoic fossil record is exceptionally rich and diverse, featuring abundant mastodon remains, extensive beds of fossilized shells and marine invertebrates, and corals, including the state stone, agatized coral. The Cenozoic Era is indeed the present time period, starting approximately 66 million years ago and continuing today. 

Surface ocean currents, and what the driving force is behind them.

Rivers in the ocean, being driven by wind, which are fueled by the sun’s energy.

Gyres and their circulation patterns bending due to the Coriolis effect (right in the Northern Hemisphere producing clockwise flow, left in the Southern Hemisphere producing counter-clockwise flow).

The Coriolis effect causes ocean gyres to deflect and rotate, with clockwise flow in the Northern Hemisphere and counter-clockwise flow in the Southern Hemisphere. This is because the Earth's rotation causes objects in motion, like ocean currents, to be deflected to the right in the Northern Hemisphere and to the left in the Southern Hemisphere. This effect is responsible for the large, circular patterns of ocean circulation known as subtropical gyres. 

Upwelling, and the significance of upwelling off the cost of South America.

Upwelling is the process where cold, nutrient-rich water from the ocean's depths rises to the surface. Off the coast of South America, this process, particularly along the Humboldt Current (also called the Peruvian Current), is significant because it creates some of the world's most productive fishing grounds by supporting a massive population of phytoplankton.

Cold and warm currents.

Warm currents moving from the equator towards the poles, and cold currents moving from the poles toward the equator, which redistributes heat globally and influences climate. This circulation is driven by factors like wind, temperature, and salinity, creating both surface and deep-ocean currents that work together in a system often called the "global ocean conveyor belt".

The Sargasso Sea and its significance.

Unique, land-bordered region in the North Atlantic Ocean defined by its currents, which trap floating mats of Sargassum seaweed. Its significance lies in its vital role as a nursery, feeding, and migration corridor for numerous species, including eels, sea turtles, and whales.

Importance of ocean currents.

Navigation, moderates temperatures, can make places dryer (Atacama), can make places wetter (NW US), maintaining Earth’s heat balance (heat from tropics transferred to polar regions).

The Gulf Stream’s affect on the Southeast US, the UK, and Western Europe.

Creating milder winters and cooler summers along the Florida coast, while its continuation as the North Atlantic Current warms the United Kingdom and Western Europe, resulting in significantly milder winters and allowing for more temperate climates than other regions at similar latitudes

The California current’s influence on the western US.

By bringing cold, nutrient-rich water south, resulting in cooler coastal temperatures and a thriving marine ecosystem. This phenomenon creates productive fisheries, sustains marine life like whales and sea birds, and impacts the climate, leading to cooler summers compared to the east coast.

Characteristics of deep-ocean waters, and how they regulate world temperatures.

Dark, cold, and under high pressure. It helps regulate world temperatures by storing and transporting heat through deep-ocean currents through thermohaline circulation, and by absorbing and storing large amounts of carbon dioxide from the atmosphere

Tides: their causes.

The moon and the sun.

Why there are 2 tidal bulges at any one time.

Because the Moon's gravitational pull and inertia (the tendency of objects in motion to stay in motion) work in opposition on Earth's oceans. The Moon's gravity pulls the water on the side of Earth facing it, creating a bulge. Simultaneously, on the opposite side of Earth, inertia is stronger than the weaker gravitational pull, causing the water to bulge outwards and create a second bulge.

Lunar tides

The Moon's gravitational pull, which creates bulges of water on both the side of Earth closest to the Moon and the side farthest away. 

Solar tides

The Sun's gravitational pull, which also creates tidal bulges. 

Neap tides

The sun and moon's gravitational forces pull in different directions, partially canceling each other out. The lowest high tides and highest low tides, creating a small tidal range.

Spring tides

The gravitational forces of the sun and moon combine, pulling the ocean in the same direction. The highest high tides and lowest low tides, creating a large tidal range.

Tidal currents

Current that changes in high and low tide.

Tidal flats

Alternate from wet and dry.

The Fall Line and its importance in the SE US.

Where ocean currents come in and at everyday. A lot of cities are built on the Fall Line.

Tidal bores. Significance of the Bay of Fundy, Canada.

Place where tides are very extreme. Record-setting highest tides, which create unique ecosystems and a vast potential for tidal energy.

Influences on wave size.

Fetch (distance wind blows over water), time wind has been blowing, strength of wind.

Wave characteristics

Crest, trough, wave height, wavelength, period, wave base.

Crest

Top of the wave.

Trough

Bottom of the wave.