SAJZ

Site Name: 
Stone site
State: 
Location: 
Alpena area
County: 
Alpena
Deposits: 
Elevation: 
190.00m
Date Ranges (Cal yr 2σ): 
End: 
5 500 BP
Start: 
6 000 BP
Site Notes: 
  • Mid Holocene lowland forest in southeastern Michigan
  • The Nipissing Lake transgression

John Zawiskie of the Cranbrook Institute of Science collected about twenty specimens of larch, pine and white-cedar wood at the operations of Spec Stone, Alpena Quarry, MI (Edw. C. Levy Co) during cold seasons of 2014 and 2015. The site is not far from the modern shoreline of Lake Huron. Six meters of Quaternary sediment containing organic beds with in-situ tree stumps were found exposed above Devonian limestone. Massive to stratified sand containing grass rootlets and scattered gravel overlies the bedrock in the center of the 400 m-long cut face. A buried Histosol containing upright to tilted in-situ tree stumps overlies the sand. A mollusk-bearing marl facies with numerous horizontal logs at its base overlies the buried forest bed and is succeeded by another thinner forest bed-marl couplet. The lower marl facies pinches out to the south and grades laterally into gravelly sand with channel-form scours. Radiocarbon dating of this section shown in the Figure documents two hundred years of peat accumulation from ca. 5600 to 5700 cal Yrs BP (Unit II and Unit III). The tree rings of collected specimens were crossdated into two chronologies spanning 110 and 150 years. The tree-ring records suggest two episodes of forested wetland drown by rising lake water level. The drowning of the forest is provisionally attributed to the spread of a lake or bay in a lagoon or fluvial-deltaic setting associated with rising base level during paleolake Nipissing transgression.

J. Zawiskie | Stratigraphy of the site.
J. Zawiskie. | Sampling larch stump at the site.