East Pacific Rise

File:East Pacific Rise.jpg

The East Pacific Rise, running South from the Gulf of California

In terms of area of recently-formed ocean crust (red-orange areas), the East Pacific Rise is the largest.

The East Pacific Rise is a mid-oceanic ridge, a seafloor spreading zone located along the floor of the Pacific Ocean, similar to the mid-Atlantic ridge. It runs from an undefined point near Antarctica in the south northward to its termination at the northern end of the Gulf of California in the Salton Sea basin in southern California. The southern stretch of the East Pacific Rise is one of the fastest-spreading sections of the Earth's mid-ocean ridge system.

Overview

According to the interpretations of geodetic data, the Pacific oceanic crust is moving away from the East Pacific Rise to either side at an average rate of about 7.5 cm/year. Due east of the Baja California Peninsula, the Rise is sometimes referred to as the Gulf of California Rift Zone. In this area, newly formed oceanic crust is intermingled with rifted continental crust originating from North America. The southern extension of the East Pacific Rise (called the Pacific-Antarctic Ridge) merges with the Southeast Indian Ridge at the Macquarie Triple Junction south of New Zealand.

Plate tectonics interpretation

The East Pacific Rise separates the Pacific Plate to the west from (north to south) the North American Plate, the Rivera Plate, the Cocos Plate, the Nazca Plate, and the Antarctic Plate.

On the eastern side of the seafloor spreading ridge the eastward moving Cocos and Nazca plates meet the westward moving South American Plate and the North American Plate and are being subducted under them. The belt of volcanoes along the Andes and the arc of volcanoes through Central America and Mexico are the direct results of this collision.

Near Easter Island, the East Pacific Rise meets the Chile Rise at the Easter Island and Juan Fernandez microplates, trending off to the east where it subducts under the South American Plate at the Peru–Chile Trench along the coast of southern Chile.

On the eastern side of the rise the eastward moving Cocos and Nazca plates meet the westward moving South American Plate and the North American Plate and are being subducted under them. The belt of volcanoes along the Andes and the arc of volcanoes through Central America and Mexico are the direct results of this collision.

Features

File:BlackSmoker.jpg

East Pacific Rise, 21 degrees north. Base of "black smoker" chimney

Along the East Pacific Rise the hydrothermal vents called black smokers were first discovered and have been extensively studied. These vents are forming volcanogenic massive sulfide ore deposits on the ocean floor. Many strange deep-water creatures have been found here.

External links

• East Pacific Rise 2004 – Scripps Institution of Oceanography
• Columbia University Researchers Find Key to the Formation of New Seafloor Spreading Centers – Columbia University