Geologic Field Trips along the Boundary between the Central Lowlands and Great Plains: 2014 Meeting of the GSA North – Central Section
Geological and human forces have created some spectacular treasures at the boundary between the Central Lowlands and the Great Plains, and three of them are explored in this guide. In northern Nebraska, the Ashfall Fossil Beds site, a world-class Lagerstätte of articulated mammal, reptile, and bird skeletons, reveals the mass death of a Miocene biotic community. Chapter 1 provides a detailed overview of the geology, paleontology, and reconstructed paleocommunity at Ashfall. The bluffs of the Missouri River in eastern Iowa contain some classic type sections of Pleistocene stratigraphic units. Chapter 2 explores the historical development of Pleistocene stratigraphy in this area and presents new data to refine understanding of the area’s complex geological history. Finally, Chapter 3 presents a unique tour of the Nebraska State Capitol in Lincoln, which is clad with Indiana limestone and adorned with igneous, metamorphic, and sedimentary rocks from European and U.S. quarries. The field guide describes the historical, architectural, and geological aspects of these stones.
Pleistocene geology and classic type sections along the Missouri River valley in western Iowa
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Published:January 01, 2014
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CiteCitation
Charles W. Rovey, II, E. A. Bettis, III, 2014. "Pleistocene geology and classic type sections along the Missouri River valley in western Iowa", Geologic Field Trips along the Boundary between the Central Lowlands and Great Plains: 2014 Meeting of the GSA North – Central Section, Jesse T. Korus
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Abstract
This field guide describes four exposures of glacigenic sediment along the Missouri River bluffs east of Omaha, Nebraska. Field trip stops include Loveland, Iowa, which is the type section of the Loveland Silt and Pisgah Formation (Illinoian and Early Wisconsinan loess) and Crescent Quarry, which exposes the type Nebraskan till. Additionally we will examine core samples of the Kennard Formation, a new stratigraphic unit consisting of multiple pre-Illinoian loesses. We also present recent results on the pre-Illinoian till stratigraphy in the Missouri River valley region. A variety of evidence indicates that the present location of the Missouri River valley originated sometime between deposition of the youngest (pre-Illinoian) till and the (Illinoian) Loveland Silt. The spatial distribution of the youngest pre-Illinoian till further suggests that this reach of the Missouri River (along the Iowa-Nebraska border) was established as an ice-marginal stream along the western terminus of the last pre-Illinoian glaciation.
- Cenozoic
- chronostratigraphy
- clastic sediments
- clay
- clay mineralogy
- Douglas County Nebraska
- field trips
- fluvial environment
- glacial environment
- glaciation
- glaciofluvial environment
- guidebook
- Iowa
- loess
- Loveland Loess
- Missouri River
- Nebraska
- paleomagnetism
- Pleistocene
- Pottawattamie County Iowa
- properties
- Quaternary
- reversals
- sand
- sediments
- silt
- spatial distribution
- textures
- till
- type sections
- United States
- western Iowa
- Loveland Iowa
- Pisgah Formation
- Folsom Quarry
- Glenwood Quarry
- Kennard Formation
- Crescent Quarry