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Introduction to the Ocean Floor

<p><strong>Fig. 7.1.</strong> A US Navy oceanographic survey ship using a multi-beam wide-angle sonar system to map the ocean floor</p><br />

The ocean floor covers more than 70 percent of the planet’s surface. Like dry land, the ocean floor has various features including flat plains, sharp mountains, and rugged canyons (Fig. 7.1). However, the lowest point in the world ocean is much deeper than the highest point on land. The ocean floor is continually being formed and destroyed. To understand the ocean floor and its diverse features, it is important to learn about the formation of the earth and its geological history.

 

Ocean Literacy Principles

Principle 1: The earth has one big ocean with many features.

Ocean Literacy Fundamental Concept: An ocean basin’s size, shape and features (such as islands, trenches, mid-ocean ridges, rift valleys) vary due to the movement of Earth’s lithospheric plates. Earth’s highest peaks, deepest valleys and flattest vast plains are all in the ocean. (OLP 1b)

 

To build an understanding of the shapes and features of the ocean, it is important to understand plate tectonics and the subduction and renewal of the oceanic crusts.

 

These concepts will be explored in this unit through the following activities and investigations:

Activity

Activity: Modeling Earth’s Dimensions

Diagram the layers of the earth and the study their physical characteristics.

Activity

Activity: Timeline of Earth

Develop a model to illustrate the timeline of Earth’s geological and evolutionary history.

Activity

Activity: Modeling Plate Spreading

Simulate tectonic plate spreading by modeling convection currents that occur in the mantle.

Activity

Activity: Earth’s Plates

Examine a map of the earth’s tectonic plates. Based on evidence that has been found at plate boundaries, make some hypotheses about the movement of those plates.

Activity

Activity: Continental Movement over Long Time Scales

Evaluate and interpret several lines of evidence for continental drift over geological time scales.

Activity

Activity: Crayon Rock Cycle

Simulate the rock cycle using crayons to build an understanding of the processes that occur to create sedimentary, metamorphic, and igneous rock.

Activity

Activity: Sediment Cores

Simulate taking sediment cores in the ocean to build an understanding of sediment layering and sediment core sampling.

 

Principle 7: The ocean is largely unexplored.

Ocean Literacy Fundamental Concept: New technologies, sensors and tools are expanding our ability to explore the ocean. Ocean scientists are relying more and more on satellites, drifters, buoys, subsea observatories and unmanned submersibles. (OLP 7d)

 

In order to build an understanding that the seafloor and oceanic crust are one of largest and least explored features of the ocean and the earth, it is important to understand the history and challenges that have been faced by deep sea exploration.

 

These concepts will be explored in this unit through the following activities and investigations:

Activity

Activity: Interpreting Contour Maps

Use two-dimensional maps to learn about the major landform and seafloor features of the earth.

Activity

Activity: Contour and Raised Relief Maps

Construct contour and raised relief maps of common underwater features.

Activity

Activity: Contour Lines and Nautical Charts

Use bathymetric sounding data from nautical charts to map seafloor features.

Activity

Activity: Simulating Sonar Mapping of The Ocean Floor

Simulate the collection and use of sonar data to make hypotheses about the ocean floor.

 

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Representative Image: 
Exploring Our Fluid Earth, a product of the Curriculum Research & Development Group (CRDG), College of Education. University of Hawaii, 2011. This document may be freely reproduced and distributed for non-profit educational purposes.