Marine Geology: Research Beneath the Sea

Imagine the ocean basins drained of all their water. What would the bottom topography look like? Were mountain ranges and carved canyons hidden beneath the dark waters? How old are the rocks and sediments on the ocean floors? Geologists in the early nineteenth century speculated that the ocean floors were dull expanses of mud-- featureless and flat. For centuries, naturalists also thought that the oldest rocks on Earth were on the ocean floors. They believed that the present-day ocean basins formed at the very beginning of the Earth's history and throughout time they had slowly been filling by a constant rain of sediment from the lands. Data gathered since the 1930's have enabled scientists to view the seafloor as relatively youthful and geologically dynamic, with mountains, canyons, and other topographic forms similar to those found on land. The seafloor is no more than 200 million years old--a "young" part of the globe's crust compared to the continents which may contain rocks nearly 20 times that age.

Scope of Marine Geology

The Marine Geology program of the U.S. Geological Survey (USGS) strives to increase our understanding of the geology of the lands covered by water, just as the Survey's program on land has, since 1879, worked to understand the geology of U.S. lands ashore. Marine geologists compile data about the topography or shape of the ocean floors, the distribution and type of bottom sediments, the composition and structure of the underlying rocks, and the geologic processes that have been at work throughout the seafloor's history. Using this information, marine geologists assess the mineral resources of the seafloor, predict the location of certain hazards, investigate marine geologic processes, and, in a more aesthetic sense, add to our overall scientific understanding of the Earth.

1. Methods and Equipment
2. Plate Tectonics
3. Resources in the Marine Realm
4. Predicting Effects of Marine Processes
5. New Frontiers
6. Interesting Images of Marine Geology