Accretionary Wedge - Examples

Examples

• Chilean Coast Range between 38°S and 43°S (Bahía Mansa Metamorphic Complex).
• Calabrian Accretionary Wedge in the Central Mediterranean - The Neogene tectonics of the central Mediterranean are related to the subduction and trench rollback of the Ionian basin under Eurasia, causing the opening of the Liguro‐Provençal and Tyrrhenian back‐arc basins and the formation of the Calabrian accretionary wedge. The Calabrian accretionary wedge is a partially submerged accretionary complex located in the Ionian offshore and laterally bounded by the Apulia and Malta escarpments.
• The Olympic Mountains located in Washington State. The mountains began to form about 35 million years ago when the Juan de Fuca Plate collided with and was forced under (subducted) the North American Plate.
• Kodiak Shelf in the Gulf of Alaska - The geology of the Chugach National Forest is dominated by two major lithologic units, the Valdez Group (Late Cretaceous) and the Orca Group (Paleocene and Eocene). The Valdez Group is part of a 2,200-km-long by 100-km-wide belt of Mesozoic accretionary complex rocks called the Chugach terrane. This terrane extends along the Alaska coastal margin from Baranof Island in southeastern Alaska to Sanak Island in southwestern Alaska. The Orca Group is part of an accretionary complex of Paleogene age called the Prince William terrane that extends across Prince William Sound westward through the Kodiak Island area, underlying much of the continental shelf to the west
• Neogene accretionary wedge off Kenai Peninsula, Alaska - Subduction accretion and repeated terrane collision shaped the Alaskan convergent margin. The Yakutat Terrane is currently colliding with the continental margin below the central Gulf of Alaska. During the Neogene the terrane's western part was subducted after which a sediment wedge accreted along the northeast Aleutian Trench. This wedge incorporates sediment eroded from the continental margin and marine sediments carried into the subduction zone on the Pacific plate.
• The Franciscan Formation of California - Franciscan rocks in the Bay Area range in age from about 200 million to 80 million years old. The Franciscan Complex is composed of a complex amalgamation of semi-coherent blocks,called tectonostratigraphic terranes, that were episodically scraped from the subducting oceanic plate, thrust eastward, and shingled against the western margin of North America. This process formed a stacking sequence in which the structurally highest rocks (on the east) are the oldest,and in which each major thrust wedge to the west becomes younger. Within each of the terrane blocks, however, the rocks become younger upsection, but the sequence may be repeated multiple times by thrust faults.
• The Apennines in Italy are largely an accretionary wedge formed as a consequence of subduction. This region is tectonically and geologically complex, involving both subduction of the Adria micro-plate beneath the Apennines from east to west, continental collision between the Eurasia and Africa plates building the Alpine mountain belt further to the north and the opening of the Tyrrhenian basin to the west.