Book contents
- Frontmatter
- Contents
- Contributors
- Preface
- PART I The Chronostratigraphy of the Uintan through Arikareean
- 1 Magnetic stratigraphy and biostratigraphy of the middle Eocene Uinta Formation, Uinta Basin, Utah
- 2 Biostratigraphy and magnetostratigraphy of the Bridgerian-Uintan Washakie Formation, Washakie Basin, Wyoming
- 3 Magnetic stratigraphy, sedimentology, and mammalian faunas of the early Uintan Washakie Formation, Sand Wash Basin, northwestern Colorado
- 4 Theoretical biochronology, the Bridgerian-Uintan boundary and the “Shoshonian Subage” of the Uintan
- 5 Middle Eocene mammalian faunas of San Diego County, California
- 6 Stratigraphy and paleomagnetism of the middle Eocene Friars Formation and Poway Group, southwestern San Diego County, California
- 7 Magnetostratigraphy of the upper middle Eocene Coldwater Sandstone, central Ventura County, California
- 8 Stratigraphy and paleomagnetism of the upper middle Eocene to lower Miocene (Uintan to Arikareean) Sespe Formation, Ventura County, California
- 9 Magnetostratigraphy of the Eocene-Oligocene transition in Trans-Pecos Texas
- 10 Magnetic stratigraphy of the Duchesnean part of the Galisteo Formation, New Mexico
- 11 Stratigraphy and vertebrate faunas of the Bridgerian-Duchesnean Clarno Formation, north-central Oregon
- 12 Eocene-Oligocene faunas of the Cypress Hills Formation, Saskatchewan
- 13 Magnetic stratigraphy of the White River Group in the High Plains
- 14 Magnetostratigraphy and biostratigraphy of the Eocene-Oligocene transition, southwestern Montana
- 15 The Whitneyan-Arikareean transition in the High Plains
- PART II Common Vertebrates of the White River Chronofauna
- Summary
- Index
13 - Magnetic stratigraphy of the White River Group in the High Plains
Published online by Cambridge University Press: 06 July 2010
- Frontmatter
- Contents
- Contributors
- Preface
- PART I The Chronostratigraphy of the Uintan through Arikareean
- 1 Magnetic stratigraphy and biostratigraphy of the middle Eocene Uinta Formation, Uinta Basin, Utah
- 2 Biostratigraphy and magnetostratigraphy of the Bridgerian-Uintan Washakie Formation, Washakie Basin, Wyoming
- 3 Magnetic stratigraphy, sedimentology, and mammalian faunas of the early Uintan Washakie Formation, Sand Wash Basin, northwestern Colorado
- 4 Theoretical biochronology, the Bridgerian-Uintan boundary and the “Shoshonian Subage” of the Uintan
- 5 Middle Eocene mammalian faunas of San Diego County, California
- 6 Stratigraphy and paleomagnetism of the middle Eocene Friars Formation and Poway Group, southwestern San Diego County, California
- 7 Magnetostratigraphy of the upper middle Eocene Coldwater Sandstone, central Ventura County, California
- 8 Stratigraphy and paleomagnetism of the upper middle Eocene to lower Miocene (Uintan to Arikareean) Sespe Formation, Ventura County, California
- 9 Magnetostratigraphy of the Eocene-Oligocene transition in Trans-Pecos Texas
- 10 Magnetic stratigraphy of the Duchesnean part of the Galisteo Formation, New Mexico
- 11 Stratigraphy and vertebrate faunas of the Bridgerian-Duchesnean Clarno Formation, north-central Oregon
- 12 Eocene-Oligocene faunas of the Cypress Hills Formation, Saskatchewan
- 13 Magnetic stratigraphy of the White River Group in the High Plains
- 14 Magnetostratigraphy and biostratigraphy of the Eocene-Oligocene transition, southwestern Montana
- 15 The Whitneyan-Arikareean transition in the High Plains
- PART II Common Vertebrates of the White River Chronofauna
- Summary
- Index
Summary
ABSTRACT
Magnetostratigraphic sampling was conducted on key fossiliferous exposures of the upper Eocene-lower Oligocene (Chadronian-Whitneyan) White River Group in North Dakota, the Pine Ridge area of Nebraska, the North Platte River-Wildcat Ridge area of Nebraska and Wyoming, and the Cedar Creek area of northeastern Colorado. Together with results from other White River outcrops reported elsewhere, a general magnetostratigraphic pattern can be seen. Most sections are of predominantly reversed polarity, but there are two short zones of normal polarity in the middle and late Chadronian, another in the early Orellan, and another in the late Whitneyan. Based on 40Ar/39Ar dates and correlation to the Berggren et al. (1995) time scale, the middle Chadronian normal magnetozone correlates with Chron C16n (35.4-35.6 Ma), the late Chadronian normal magnetozone with Chron C15n (35.7-35.9 Ma), the early Orellan normal magnetozone with Chron C13n (33.0-33.5 Ma), and the late Whitneyan with Chron C12n (30.5-30.9 Ma). The Chadronian spans the interval from about 37 Ma to about 33.8 Ma; the Orellan from 33.8-32 Ma; the Whitneyan from 32 to about 30 Ma.
INTRODUCTION
The richly fossiliferous and spectacularly scenic badlands of the White River Group in the High Plains (Fig. 1) have been a magnet to fossil collectors and paleontologists ever since the first fossils were collected and described in 1846. In the century and a half since then, tens of thousands of fossils of extraordinary quality have been recovered from White River rocks, making them the most productive mammal-bearing sequence in North America.
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- The Terrestrial Eocene-Oligocene Transition in North America , pp. 262 - 277Publisher: Cambridge University PressPrint publication year: 1996
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