Marine Geology

Jack Morelock

The Earth is truly a water planet with about 71 percent of the surface covered with water. This water cover prevented study of the deep submerged ocean floors until technological developments allowed improved surveys of ocean areas. Part of the reason that a revolution in geological thinking about tectonics came late is that collection of data from oceanic areas is a capability resulting from research techniques developed after 1950.

Scientists follow the journalist's basic axim "who, what, when, where," but add a more basic element, how. For many years, how was incomplete in Geology, we settled for "we observe it, so something happened." We are not far out of the observational phase, but with new technology and building on the shoulders of past geologists we now have more of the how.

Plate tectonics has been called the revolution in geology -- comparable to the genetic code for biologists. But this is just one of many small "revolutions" or advances in our knowledge. Sea level changes have been understood in the light of new concepts; processes of sedimentation and changes in coastlines are looked at with new understanding. With a new millenium and within the span of a lifetime, we are able to comprehend the earth with unified theories.

Remote sensing and Graphic Information Systems technonolgy are now a routine part of a geologists toolkit. Our maps and presentations are done with the computer and we take a direct part in developing the material that we present. Slow in coming, but rapidly increasing, electronic publication of papers and internet posting of conference abstracts has made data available to us. GIS base maps are available for most of the world.

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We will look at marine geology in two ways -

• the processes that shape ocean features and affect marine sediments, and
• the marine geological environments

We first look at the processes that shape and modify the earth. Erosion, sedimentation, weathering, faulting, folding, vulcanism are but a few of the processes studied by geologists. Many of the processes affecting the marine environment have been placed into the first four chapters.

Each of the boxes below will take you to a chapter

	Seafloor Features Tectonics the basic shape and pattern of the earth is developed by tectonic activity
	Physical Processes These are the tides, waves and currents of the water cover that affect the bottom features
	Sealevel Changes Changes in sea level have a profound effect on the areal extent of the continental shelf and on the depth of water over the continental margin. The most affected part are the coastal system features which move with the shoreline.
	Marine Sedimentation The character of the sediments are important in developing the sedimentary environment character

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The processes act within the set of environments that we include under marine environments - coastal, margin and deep sea and a special environment, coral reefs - and weave into our study the place of the processes in each environment along with a description and discussion of the environments.

Each of the boxes below will take you to a chapter in the notes

	Coastal Systems These are the environments associated with the shoreline that adjust to moving sea level. They are rapidly (in terms of geological time) changing environments of deposition and erosion.
	Continental Margins This is the realm of continental shelf and slope that lie between the coastal features and the deep sea.
	Coral Reefs Modern coral reefs lie in a belt between 30o north and south latitude. The present reefs developed during the past 10,000 years on the continental shelves
	Deepsea and Paleoceanography This is the ocean floor below several thousand meters of water. A realm of different crustal rocks and surface features.

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finally, we will look at the potential resources of the ocean and the environmental problems encountered in recovering these resources.

Marine Resources and Environmental Concerns In this chapter we examine the bulk to precious hard minerals and petroleum resources available in the ocean and look at the environmental consequences of marine mineral extraction.

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