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:''This article is about the range in Oregon. For the larger grouping also known as the Coast Ranges, see Pacific Coast Ranges.'' The Oregon Coast Range, often called simply the Coast Range and sometimes the Pacific Coast Range, is a mountain range, in the Pacific Coast Ranges physiographic region, in the U.S. state of Oregon along the Pacific Ocean. This north-south running range extends over from the Columbia River in the north on the border of Oregon and Washington, south to the middle fork of the Coquille River. It is wide and averages around in elevation above sea level. The coast range has three main sections, a Northern, Central, and Southern. The oldest portions of the range are over 60 million years old, with volcanics and a forearc basin as the primary mountain building processes responsible for the range. It is part of the larger grouping known as the Pacific Coast Ranges that extends over much of the western edge of North America from California to Alaska. The range creates a rain shadow effect for the Willamette Valley that lies to the east of the mountains, creating a more stable climate and significantly less rain than the coastal region of the state. To the west where the range over-shadows the Oregon Coast, the range causes more precipitation to fall on that side of the mountains, contributing to the numerous rivers that flow to the Pacific Ocean. Marys Peak in the Central Coast Range is the highest peak at 4,097 feet (1,248 m). Logging is a major industry in the range in both private and government owned forests. Both the state and federal government manage forests in the Oregon Coast Range. The mountains are home to a variety of wildlife including black bear, elk, deer, beaver, many species of birds, and bats among others. Fish, including salmon and trout, and other aquatic life inhabit the streams and rivers flowing through the range. ==Geology== Volcanic activity approximately 66 million years ago in the Cretaceous Period created offshore islands beginning in the southern portion of the current range.〔Orr, Elizabeth and William Orr, and Ewart Baldwin. Geology of Oregon. Kendall/Hunt Publishing, 1992, 4th edition.〕 These Roseburg volcanics were followed by the Siletz River Volcanics in the northern portions of the range, and lastly a series of basalt flows from the Columbia River basalts also added to these formations with some smaller flows in-between.〔 Much of the formations are the result of pillow basalt formations created when a hot basalt flow rapidly cooled upon meeting the salt water of the ocean.〔 These deposits offshore were then pushed into the continental plate as a forearc basin rotating slowly over millions of years.〔 This tectonic collision forced the basalt formations (and newer sedimentary rock formations that include marine terrace deposits) upward and created the coastal range.〔 Additional basalt flows originated from Eastern Oregon and added to the layers that were uplifted, as the newer Cascade Mountains had not yet been formed.〔 By the Early Oligocene period c. 30 million years ago the current coastline was in place and erosion has continued to shape the range.〔 primarily through rivers cutting deep valleys through the igneous and sedimentary rocks.〔 The geologic boundaries of the coast range formation extend from southwest Washington state in the north to around the Coquille River in the south where the older and taller Klamath Mountains begin.〔 In the east the mountains begin as foothills forming the western edge of the Willamette Valley and continue west to the coastline and beyond where the basalt formation tapers off into the continental shelf and ends at the continental slope with several banks and basins off shore.〔 Physiographically, they are a section of the larger Pacific Border province, which in turn are part of the larger Pacific Mountain System physiographic division. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Oregon Coast Range」の詳細全文を読む スポンサード リンク
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