Oceanography- Chapter 1, 2, and 3

Partial melting of proto-Earth

Stratification

Proto-Earth

A larger than Earth lifeless sphere without oceans. The process of density stratification caused this, and it was homegenous.

Earth is

the only celestial body with vast oceans of liquid on its surface

Earth is a

Misomer, with 70.8% of its surface covered by oceans

Oceans contribute to how much of the oxygen that we breathe.

70%

The ocean remains…

one of the least explored frontiers

Outgassing

Occurred during density stratification and was responsible for forming Earth's second atmosphere.

What is the relationship between the crust and the lithosphere?

The crust is part of the lithosphere.

Divergence is to moving away as convergence is to

Moving foward

Plates move apart at () boundaries, move together at () boundaries, and move side to side at () boundaries.

Divergent, convergent, transform

Which geological features are associated with divergent boundaries?

Mid-ocean ridges and rift valleys

How are Earth’s geographical and magnetic axes oriented relative to each other?

Earth’s geographical and magnetic axes are oriented at a slight angle from each other.

What sets Earth apart from other planets?

The liquid state which covers a significant portion of the planet's surface.

Oceans are

The largest ecosystem, influencing climate, weather, and our air

What are Earth’s four principal oceans?

The Pacific, the Atlantic, the Indian, and the Arctic

What ocean is recognized as an additional ocean?

The Southern Ocean

Which ocean is the largest and deepest, covering more than half of Earth?

The Pacific

What size is the Atlantic Ocean?

Half the size of the Pacific

What size is the Indian Ocean?

Slightly smaller than the Atlantic

What is the size of the Artic Ocean?

Smallest and shallowest

Where is the Southern Ocean?

Encircles Antarctica

What is a sea?

A sea is often small and shallow and enclosed by land and directly connected to the world ocean

What key characteristics separate a sea from an ocean?

A sea is generally smaller and shallower.

Crust

Low density and silicate materials

What is a seamount?

An active volcano that occurs along the crest of the mid-ocean

Where do magnetic field lines exit the Earth today?

At the South Pole

Mantle

Mainly Fe and Mg silicate materials

Core

High denisty, mainly Fe and Ni

Lithosphere

Cool rigid shell,

Atmosphere

Relatively hot, plastic, high viscosity

Isostatic rebound

Rising of crust formerly pulled down by glacier ice

Low oxygen

Extinction events

High oxygen

Biodiversity increase

Great oxidation event

Occurred 2.45 billion years ago and increased oxygen and ozone

What concept did Alfred Wegener create in terms of plate tectonics?

Continental drift

What two things were Wegener’s evidence for plate tectonics?

Pangea and Panthalassa

What was the evidence for continental drifting?

Puzzle-like fit was explored in the 1960s.

Evidence for plate tectonics

New technology explored from World War 2,

Evidence for plate tectonics

Earth has magnetic polarity recorded in igneous rocks.

What is paleomagnetism?

The study of Earth’s ancient magnetic fields

Earth’s polarity reverses periodically. How many reversals have occurred in the past 76 million years?

176 million reversals

What are magnetic anomalies?

Regular pattern of north-south magnetism stripes

What else is evidence for plate tectonics?

Apparent polar wandering and locations of the North Pole have changed over time.

Coral reef development

Fringing reefs, barrier reefs, atolls

How old is the oldest ocean floor?

180 million years