Understanding the history of Holocene landscape evolution is critical because the range of climate change during this time interval is generally considered to be within the realm of foreseeable environmental fluctuations. Reconstructing post-glacial geomorphic events therefore demonstrates the potential range of landscape change that may occur in the future. This doctoral dissertation research project will reconstruct the post-glacial geomorphic history of the upper Muskegon River system in Michigan in order to test the links between fluvial systems and climate fluctuations that apparently occurred during the Holocene. The size and number of preserved paleochannels and terraces in the upper Muskegon indicate that substantial changes occurred in channel geometry through post-glacial time. Paleochannels will be measured to determine the cross-sectional form and bankfull dimensions. Several cores of sediment from paleochannels and adjacent alluvial deposits will be extracted to determine types and amounts of sediment moving through these streams as well as to identify discontinuities in the stratigraphic sequence. A chronology based on radiocarbon dating of organic material from alluvial deposits and paleochannel peats will determine the sequence of geomorphic events. Results of these analyses are expected to show that significant geomorphic events correlate with known climatic fluctuations or are linked to autogenic controls. The research also will attempt to determine the impact of 19th century logging on the system. The General Land Office pre-settlement survey records of Michigan will be examined for data on the position, size, and streambed sediment of the Muskegon River prior to logging. This will be compared to current conditions to determine historic changes in the Muskegon River.<br/><br/>This research is part of an ongoing research program that is focusing on post-glacial landscape development in Michigan, which lies in the core of the Great Lakes basin. In contrast to the glacial history of the region, very little is known about Holocene landscape evolution and associated forcing variables. The results from this study will contribute to understanding landscape sensitivity to climate change and human impact in the Great Lakes region during the Holocene. This study will improve understanding of the response of streams to climate change and logging as well as to other kinds of adjustments. In addition, it will provide important data that can be used to test prehistoric climate models. Rivers are especially important because they are a critical part of the ecosystem and heavily utilized. This study is of particular interest to society considering the economic costs of flooding, stream erosion, and increased sediment load, all of which are affected by climate change and/or logging. Proper management should consider future responses to climate change and human impact, which can be predicted more accurately when the past record is known. In most cases, management decisions are based on very short records (less than 100 years) without considering the longer geomorphic history of the stream system. This is especially true in the Great Lakes basin, because very little is known about prehistoric stream response. As a Doctoral Dissertation Research Improvement award, this award also will provide support to enable a promising student to establish a strong independent research career.
Doctoral Dissertation Research: Landscape Response to Holocene Environmental Change: The Evolution of the Muskegon River, Michigan