The stratigraphy and development of a floating peatland, Pinhook Bog, Indiana

Pinhook Bog is an acidic, weakly-minerotrophic peatland that occupies an ice-block depression in the Valparaiso Moraine in northwest Indiana. It has a floating mat similar to 22 ha in area but no central pond. Detailed stratigraphic descriptions of the peatland were made to analyze its developmental history and determine what factors may be responsible for mat formation. In addition to the obvious factors of climate and presence of mat-forming species, the development of extensive floating peatland mats is considered to be largely a function of deep, steep-sided basins that allow horizontal mat growth to exceed vertical peat accumulation. Other important contributing factors are clay-lined basins and the lack of inlets or outlets. These factors may result in water-level changes in the basin and weakly-minerotrophic waters conducive to Sphagnum growth.