Two Creeks Buried Forest State Natural Area
Encyclopedia
Two Creeks Buried Forest State Natural Area is a site in the Wisconsin State Natural Areas Program
and a unit of the Ice Age National Scientific Reserve
. The site lies in the northeast corner of Manitowoc County
on the shore of Lake Michigan
north of Two Creeks, Wisconsin
, USA. Exposed on the steep lakeshore is a stratum
of floral remains embedded in sediment
, which is sandwiched between layers of glacial till
. The logs, branches, pine needles, pinecones, moss, and other forest litter have been radiocarbon dated
to 11,850 years B.P.
This is an important site in geochronology
because it firmly establishes the timeframe of advances and retreats during the last glacial period.
The lower layer of glacial till was deposited by the Cary substage of the Wisconsin glaciation. The remains in the park prove that a warmer interval followed in which the glacier
retreated and a forest of spruce, pine, and hemlock grew. A count of growth rings in the logs produced an average age of 60 years in these trees. Then the climate cooled again and the Valders substage began. A glacial tongue blocked Lake Michigan's drainage, causing the water level to rise and flood the forest, carrying in sediments which buried the forest floor. The glacier proceeded to flow over the forest, flattening it and ultimately depositing another layer of glacial till over it.
Two Creeks Buried Forest State Natural Area is open to visitation. The site has no trails or displays, but visitors can park in the northwest corner of the site and wander freely across the grounds. Collection of any material is prohibited.
Wisconsin State Natural Areas Program
The Wisconsin State Natural Areas Program is a conservation program created to highlight and protect areas with outstanding natural or archaeological resources in the U.S. state of Wisconsin. There are currently 609 State Natural Areas encompassing a total of more than...
and a unit of the Ice Age National Scientific Reserve
Ice Age National Scientific Reserve
The Ice Age National Scientific Reserve is a collection of nine sites in Wisconsin that preserve geological evidence of glaciation. The reserve was created in 1971 to protect the scientific and scenic value of the landforms...
. The site lies in the northeast corner of Manitowoc County
Manitowoc County, Wisconsin
Manitowoc County is a county in the U.S. state of Wisconsin. As of 2000, the population was 82,887. Its county seat is Manitowoc. The United States Census Bureau's Manitowoc Micropolitan Statistical Area includes all of Manitowoc County.-Government:...
on the shore of Lake Michigan
Lake Michigan
Lake Michigan is one of the five Great Lakes of North America and the only one located entirely within the United States. It is the second largest of the Great Lakes by volume and the third largest by surface area, after Lake Superior and Lake Huron...
north of Two Creeks, Wisconsin
Two Creeks, Wisconsin
Two Creeks is a town in Manitowoc County, Wisconsin, United States. The population was 551 at the 2000 census. The unincorporated community of Two Creeks is located in the town.-Geography:...
, USA. Exposed on the steep lakeshore is a stratum
Stratum
In geology and related fields, a stratum is a layer of sedimentary rock or soil with internally consistent characteristics that distinguish it from other layers...
of floral remains embedded in sediment
Sediment
Sediment is naturally occurring material that is broken down by processes of weathering and erosion, and is subsequently transported by the action of fluids such as wind, water, or ice, and/or by the force of gravity acting on the particle itself....
, which is sandwiched between layers of glacial till
Till
thumb|right|Closeup of glacial till. Note that the larger grains in the till are completely surrounded by the matrix of finer material , and this characteristic, known as matrix support, is diagnostic of till....
. The logs, branches, pine needles, pinecones, moss, and other forest litter have been radiocarbon dated
Radiocarbon dating
Radiocarbon dating is a radiometric dating method that uses the naturally occurring radioisotope carbon-14 to estimate the age of carbon-bearing materials up to about 58,000 to 62,000 years. Raw, i.e. uncalibrated, radiocarbon ages are usually reported in radiocarbon years "Before Present" ,...
to 11,850 years B.P.
Before Present
Before Present years is a time scale used in archaeology, geology, and other scientific disciplines to specify when events in the past occurred. Because the "present" time changes, standard practice is to use AD 1950 as the origin of the age scale, reflecting the fact that radiocarbon...
This is an important site in geochronology
Geochronology
Geochronology is the science of determining the age of rocks, fossils, and sediments, within a certain degree of uncertainty inherent to the method used. A variety of dating methods are used by geologists to achieve this, and schemes of classification and terminology have been proposed...
because it firmly establishes the timeframe of advances and retreats during the last glacial period.
The lower layer of glacial till was deposited by the Cary substage of the Wisconsin glaciation. The remains in the park prove that a warmer interval followed in which the glacier
Glacier
A glacier is a large persistent body of ice that forms where the accumulation of snow exceeds its ablation over many years, often centuries. At least 0.1 km² in area and 50 m thick, but often much larger, a glacier slowly deforms and flows due to stresses induced by its weight...
retreated and a forest of spruce, pine, and hemlock grew. A count of growth rings in the logs produced an average age of 60 years in these trees. Then the climate cooled again and the Valders substage began. A glacial tongue blocked Lake Michigan's drainage, causing the water level to rise and flood the forest, carrying in sediments which buried the forest floor. The glacier proceeded to flow over the forest, flattening it and ultimately depositing another layer of glacial till over it.
Two Creeks Buried Forest State Natural Area is open to visitation. The site has no trails or displays, but visitors can park in the northwest corner of the site and wander freely across the grounds. Collection of any material is prohibited.
External links
- Two Creeks Buried Forest State Natural Area
- Two Creeks Buried Forest geology from the National Park Service