When you arrive at GZ, you will not need to leave the public roadway to observe this formation. It can in fact be see for miles. However, if you look directly north you will have a great view of Old Baldy.
Old Baldy is located about 7 miles (11 km) north of Lynch, Nebraska, and about half a mile (about a kilometer) south of the Missouri River. It is part of a line of bluffs at the southern edge of the Missouri valley; it rises an additional 70 feet (21 m) above the surrounding highlands, reaching an elevation of 1,585 feet (483 m) above sea level.
The formation making up the hill is part of the Pierre Shale, deposited in the deep marine waters of the Western Interior Seaway during the Campanian and Maastrichtian ages of the late Cretaceous period, 70–80 million years ago. The Pierre consists chiefly of dark shale, but also contains chalky strata, one of which is exposed at the top of the hill. The chalk does not readily support plant growth, giving the hill its conspicuous bald appearance.
Addiitonal Information
The Pierre Shale is a geologic formation or series in the Upper Cretaceous which occurs east of the Rocky Mountains in the Great Plains, from Pembina Valley in Canada to New Mexico.
The Pierre Shale was described by Meek and Hayden in 1862 in the Proceedings of the Academy of Sciences (Philadelphia). They described it as a dark-gray shale, fossiliferous, with veins and seams of gypsum, and concretions of iron oxide. The Pierre Shale is about 700 feet (210m) thick at the type locality. It overlies the Niobrara division and underlies the Fox Hills beds. It was named for an occurrence near Fort Pierre on the Missouri River in South Dakota.
The Pierre Shale is of marine origin and was deposited in the Western Interior Seaway. It is correlative with other marine shales that occur farther west, such as the Bearpaw Shale, Mancos Shale and the Lewis Shale. It correlates with the Lea Park Formation in central Alberta. The Pierre is overlain by marginal marine deposits of the Fox Hills Formation.
To claim this EarthCache please answer the following questions:
- Based on what you observe at the site plus the information in this text, why do you think contributes to this formation earning the nickname "Old Baldy"?
- You should be able to observe distict separations in the formation. What do you think causes these and how many do you see?
- Name at least one very noticeable difference between Old Blady and the surrounding formations.
- (Optional) Please post a photo at GZ of those in your party.
References:
- "Faces of the Land: Nebraska Environmental Trust 2005 Annual Report to Nebraska Citizens".
- "Conservation and Outdoor Recreation: May 2006". National Park Service.Retrieved 2011-04-08.
- "Feature Detail Report for: Old Baldy". USGS Geographic Names Information System. Retrieved 2011-04-08.