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〕 }} Summer Lake is a large, shallow, alkali lake in Lake County, Oregon, United States located south of the small, unincorporated community of Summer Lake, Oregon. At high water it is about long and wide, and supports a wide variety of birds and other wildlife in its marshes. The lake was named by explorer John C. Fremont on his expedition into Central Oregon in 1843. == Ancient Lake Chewaucan == The arid lands around Summer Lake were once lush. During the Pleistocene Epoch, vast areas of this region of south central Oregon were covered by lakes and wetlands. As the last ice age was ending, rain and runoff from melting snow filled the lowlands throughout this region of the Great Basin, creating an immense, freshwater lake called Lake Chewaucan. The lake covered at depths of up to .〔"Ancient Lakes", Oregon Historical Marker, Summer Lake, Oregon.〕 Lake Chewaucan covered the Summer Lake basin and drainage system much of the late Pleistocene. The last high water period is thought to have occurred about 13,000 years ago. There is no archaeological evidence of human use of Lake Chewaucan during this time. The earliest evidence for possible human occupation of the basin comes from the Paisley Caves excavated by Luther Cressman in the late 1930s. Cressman found some inconclusive evidence that humans could have begun occupation of the Summer Lake area around 11,000 years ago.〔Jerrems, Jerry, ("An Archaeological View of Summer Lake Valley, Oregon" ), Sundance Archeological Research Fund, University of Nevada, Reno, Reno Nevada, 27 April 2007.〕 Lake Chewaucan began to dry up at the close of the Pleistocene. As it shrank, salts and alkali were concentrated in its remaining waters. The exposed lake bottom sediments were blown by the prevailing westerly winds to form the sand dunes that still lie on the east side of Summer Lake.〔"Broken Bedrock", Oregon Historical Marker, Summer Lake, Oregon.〕 Today, Summer Lake and Abert Lake are separated by and are the only remnants of Lake Chewaucan.〔 At high water, Summer Lake is about long and wide; however, water levels fluctuate dramatically, and sometimes the lake is almost dry in summer.〔 The main source of fresh water is the small spring-fed Ana River, which is used for irrigation.〔〔Witty, Jim, ("Ana River" ), ''The Bulletin'', Bend Oregon, 5 January 2007.〕 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「Summer Lake (Oregon)」の詳細全文を読む スポンサード リンク
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