文章基本信息

标题：High-level strata containing early Miocene mammals on the Bighorn Mountains, Wyoming. American Museum novitates ; no. 2490
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作者：McKenna, Malcolm C. ; Love, J. D. ; Darton, Nelson Horatio, - . 等
期刊名称：American Museum Novitates
印刷版ISSN：0003-0082
电子版ISSN：1937-352X
出版年度：1972
卷号：1972
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出版社：American Museum of Natural History
摘要："Fossil mammals of early Miocene age have been found in strata composing Darton's Bluff on the crest of the Bighorn Mountains in the Hazelton Peak Quadrangle, Johnson County, Wyoming. Dating the host strata provides a reference datum for the reconstruction of regional sedimentation during early Miocene time and for determination of the maximum age of epeirogenic uplift. As a result of regional aggradation, the Bighorn Basin was filled with sediments. These buried the rugged peaks and canyons of the Bighorn Mountains up to a level corresponding to the present 9000-foot altitude during early Miocene time. The lower Miocene and older rocks are beveled by the subsummit surface, a remarkably flat and even surface of Miocene or Pliocene age. Excavation of the Bighorn and Powder River basins and exhumation of the Bighorn Mountains must have been accomplished during the relatively short interval of late Cenozoic time after the subsummit surface was cut"--P. [1].