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BASIN OCEAN FLOOR. Objectives At the end of the lesson the students are expected to: i dentify the major features of the Ocean Basin Floor and the Oceanic Ridge l abel the features of the Ocean Floor List and describe the three types of Seafloor Sediment .
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Objectives At the end of the lesson the students are expected to: • identify the major features of the Ocean Basin Floor and the Oceanic Ridge • label the features of the Ocean Floor • List and describe the three types of Seafloor Sediment
The OCEAN BASIN FLOOR lies between the continental margin and the oceanic ridge.
Ocean Basin Floor • Deep-ocean trenches • Abyssal plains • Seamounts
DEEP-OCEAN TRENCHES are long, relatively narrow creases in the seafloor that form the deepest parts of the ocean • volcanic island arc- arc shaped row of active volcanoes
Challenger Deep(Mariana Trench) - the deepest known part of the world ocean
ABYSSAL PLAINS are deep, incredibly flat features. These regions are likely the most level places on Earth.
SEAMOUNTS are isolated volcanic peaks which may rise hundreds of meters above the surrounding topography.
Some are formed as a result of hot spots while others may form near oceanic ridges • Volcanic islands in the Atlantic • Azores • Ascension • Tristan da Cunha • St. Helena
Oceanic ridge or Mid-Ocean ridge Is topographically elevated feature that is found near the center of the most ocean basins. It is characterized by extensive faulting and numerous volcanic structures that have developed on the newly formed crust. MID-OCEAN RIDGE
TERRIGENOUS SEDIMENTS • BIOGENOUS SEDIMENTS • HYDROGENOUS SEDIMENTS SEAFLOOR SEDIMENTS
consist primarily of mineral grains that were weathered from continental rocks • accumulates slowly (5000-50,000yrs to deposit 1cm abyssal clay layer • color may be red or brown TERRIGENOUS SEDIMENTS
Biological origin- primarily shells and skeletons of marine animals and algae. BIOGENOUS SEDIMENTS
Calcareous oozes -remains of foraminifera and coccolithophores -may form chalk • Siliceous oozes -remains of radiolarians and diatoms • Phosphate-rich materials -from bones, teeth and scales of fish Types of Biogenous sediments
Consist of minerals that crystallize directly from seawater through various chemical reactions • maa HYDROGENOUS SEDIMENTS