|
The Teays River was a major preglacial river that drained much of the present Ohio River watershed, but took a more northerly downstream course. Traces of the Teays across northern Ohio and Indiana are represented by a network of river valleys. The largest still existing contributor to the former Teays River is the Kanawha River in West Virginia, which is itself an extension of the New River. The name Teays from the Teays Valley is associated with this buried valley since 1910.〔The Glacial Boundary in Western Pennsylvania, Ohio, Kentucky, Indiana, and Illinois; George Frederick Weight; Bulletin of the United States Geological Survey No. 58; Washington, Government Printing Office; 1890; pg 86-88〕 The more appropriate name would be ancestral Kanawha Valley.〔Glacial Geology of Wabash County, Indiana: William J. Wayne and William D. Thornbury; Indiana Department of Conservation, Geological Survey; Bulletin No. 5; Bloomington, Indiana; 1951〕 The term Teays is used when discussing the buried portion of the ancestral Kanawha River.〔 The Teays was comparable in size to the Ohio River. The River's headwaters were located near Blowing Rock, North Carolina and subsequently flowed through Virginia, West Virginia, Ohio, Indiana and Illinois. (Hansen, 1995). 〔Teays River; ES 767 Quaternary Geology, Fall 2011; Wesley C. Smith; Emporia State University, Earth Science Department: Webpage submitted on November 28, 2011〕 The largest tributary to the Teays River was the Old Kentucky River (Teller 1991), which extended from southern Kentucky through Frankfort and subsequently flowed northeast, meeting other tributaries and eventually joining the Teays.〔 ==Creation== Scattered erratics in northeastern Kentucky and southern Ohio 〔Leverett; 1929, pp. 33-47〕 are pre-Kansan in age. Only the Nebraskan, is recognized as earlier than Kansan, these have been designated as remnants of deposits left by the Nebraskan glacier.〔Thwaites, 1946, pl. 3〕 The ice sheet overrode the preglacial Teays creating ponds or glacial lakes. The back up of water diverted the upper basin over the surrounding divides into the preglacial Ohio River. Thus the ‘deep stage’ more likely is post-Nebraskan and pre-Kansan in age rather than preglacial. With the withdrawal of the Nebraskan glacier, which caused integration of the upper Kanawha (Teays) with the preglacial Ohio, a vastly shortened, unnamed descendant of the Teays apparently headed somewhere in west-central Ohio and cut the ‘deep stage’ across Ohio, Indiana, and Illinois during the long Aftonian interglacial stage, which followed.〔 If the sequence of bedrock formations of northern Indiana were exposed, the extensive cliffs along the ‘deep stage’ of the Teays and its tributaries would provide a clearer understanding of the stratigraphy of northern Indiana. The entire Silurian section below the Liston Creek limestone 〔Indiana Division of Geology, 1949, pl. 2〕 and a few feet of the upper Ordovician probably would be visible in the vicinity of La Fontaine.〔 In Wabash County the part of the Teays Valley above the ‘deep stage’ consists of broad terraces at an altitude of about . From this terrace level the bedrock rises gradually to the on the Lexington pene-plain surface. These terraces probably correspond in age to an erosional surface in the unglaciated areas known as the Parker strath, which was the result an erosion cycle that ended prior to Kansan phase of the pre-Illinoian glaciation.〔Fenneman, 1938, p. 443〕 More recent correlation 〔Thornbury, 1948, p. 1359〕 places its age as pre-Nebraskan. The Parker strath probably represents an erosional level existent at the beginning of the Pleistocene before the rejuvenation associated with, and following, the Nebraskan glaciation. The general appearance and width of the strath terrace along the Teays Valley in Indiana indicates that it represents only a slight rejuvenation following the Lexington cycle.〔 In Virginia and West Virginia, the Teays River flowed in the valleys of the modern New River and Kanawha River (Hansen, 1995). The river then flowed west to Scioto County, Ohio and to Ross County, Ohio near Chillicothe. The valley then disappears under glacial sediments but can be tracked using water well yields and other means (Hansen, 1995). A total of seven tills have been identified within the Teays River Valley (Andrews, 2004). In portions of Ohio, the buried valley is up to wide and lies beneath of glacial sediments (Hansen, 1995).〔 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「Teays River」の詳細全文を読む スポンサード リンク
|