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A new, full-color poster featuring the bedrock stratigraphic units of Wisconsin is now available from the Wisconsin Geological and Natural History Survey, a part of the University of Wisconsin–Extension.
Underneath soil and glacial deposits, or in some places at the Earth’s surface, rocks are found in stratified layers. It’s common knowledge that these rocks have names such as limestone, sandstone, and so forth. But geologists also classify rocks that have similar characteristics into named stratigraphic units; the major categories are groups, which can be further broken down into formations, which can be subcategorized into members. Not all rock units, however, can be conveniently categorized this way; for example, not every formation belongs to an overarching group, and all formations do not have member subdivisions.
The poster includes a statigraphic profile showing these named categories of Wisconsin bedrock as well as age-related information and rock type. Based on a 1968 publication by former Survey director M.E. Ostrom, the new version reflects the results of the ongoing research and current thinking about the Precambrian and Paleozoic rock in Wisconsin—the rocks that date from 2,800 million to 354 million years ago.
Plots of the poster (Open-File Report 2006-06) are available in two sizes: 16 x 21 inches ($10) and 34 x 44 inches ($20). It is also available in Adobe® Acrobat® format on 1 CD-ROM for $5. Purchases may be made from the Wisconsin Geological and Natural History Survey, 3817 Mineral Point Road, Madison, Wisconsin 53705-5100; telephone 608/263.7389. Shipping and handling charges are extra; refer to our order form, which is in Adobe Acrobat format. MasterCard and Visa customers may telephone their orders between the hours of 8 am and 4:30 pm, Monday through Friday. Plots will be delivered rolled. |
