Mapping and Interpreting the Glacial Geology of Pictured Rocks National Lakeshore, Michigan

Mapping and Interpreting the Glacial Geology of Pictured Rocks National Lakeshore, Michigan
Author: Sarah M. VanderMeer
Publisher:
Total Pages: 237
Release: 2018
Genre: Drift
ISBN:

Pictured Rocks National Lakeshore is among the most popular parks in Michigan, yet prior to this study, it was the only National Park that lacked a detailed surficial geology map characterizing the distribution of sediments and landforms. Additionally, much of the landscape remained unexplored. These factors prevented thorough interpretations of landscape development and evolution. This research aims to map and further explore the relationship of glacial sediments and landforms throughout Pictured Rocks to refine and expand the current understanding of glacial events that shaped this landscape. A new, detailed (1:24,000-scale) surficial geology map of the ten 7.5-minute quadrangles that contain Pictured Rocks was developed as part of this study. Sediments were classified below the surface soil horizons throughout the mapped area. Additionally, the horizontal-to-vertical spectral ratio (HVSR) passive seismic method was employed throughout the greater Pictured Rocks region to estimate glacial sediment thickness and subsurface bedrock topography. Optically Stimulated Luminescence (OSL) dating was performed on two samples chosen from specific landforms of interest to help develop a chronological framework for this region. However, insufficient sediment bleaching yielded ambiguous OSL results. Field investigations were combined with several additional, preexisting datasets to produce the final surficial geology map of the Pictured Rocks area. Mapping reveals notable regional differences in sediment and landform distribution. The western portion of Pictured Rocks consists of subtle subglacial and ice-marginal landforms that appear to have been segmented by subsequent proglacial outwash deposition. These features are largely underlain by undifferentiated thin sediment accumulations above shallow bedrock. The east displays thicker accumulations of glaciofluvial sediments consisting of various outwash units. Collectively, the surficial geology in the west and east areas of Pictured Rocks create a landform suite that is characteristic of actively receding glaciers in temperate climate conditions. Several buried bedrock valleys were also discovered and/or confirmed throughout the study area, which are interpreted as southern extensions of the glacial tunnel valley network carved into the floor of the Lake Superior basin north of Pictured Rocks. Sediments deposited during the final stages of deglaciation buried the southernmost segments of many of these valleys. The surficial geology map and subsurface findings serve as primary resources to guide landform interpretations throughout the study area. These interpretations are integrated into a newly-proposed reconstruction of glacial events that occurred from the late Pleistocene through final deglaciation of the Pictured Rocks region during the early Holocene. This research has revealed greater detail of sediment-landform assemblages and the subsurface bedrock topography, which has led to a more comprehensive analysis of the glacial processes that shaped the Pictured Rocks landscape.

Quaternary Glaciation of the Great Lakes Region

Quaternary Glaciation of the Great Lakes Region
Author: Alan Kehew
Publisher: Geological Society of America
Total Pages: 252
Release: 2018
Genre: History
ISBN: 0813725305

Taking advantage of new technological advances in Quaternary geology and geomorphology, this volume showcases new developments in glacial geology. Honoring the legacy of Frank Leverett and F.B. Taylor's 1915 USGS monograph of the region, this book includes 12 chapters that cover diverse topics ranging from hydrogeology, near-surface geophysics, geotectonics, and vertebrate paleontology to glacial geomorphology and glacial history. Several papers make use of detailed but nuanced shaded relief maps of digital elevation models of LiDAR data; these advances are brought into historical perspective by visiting the history of geologic mapping of Michigan. Looking forward, interpretations of the shaded relief maps evoke novel processes, such as regional evolution of subglacial and supraglacial drainage systems of receding glacial margins. The volume also includes assessment of chronological issues in light of greater accuracy and precision of radiocarbon dating of plant fossils using accelerator mass spectrometry versus older techniques.

Geology of Michigan

Geology of Michigan
Author: John Adam Dorr
Publisher: University of Michigan Regional
Total Pages: 500
Release: 1970
Genre: Nature
ISBN:

Studies the land and waters of Michigan

Under Michigan

Under Michigan
Author: Charles Ferguson Barker
Publisher: Wayne State University Press
Total Pages: 53
Release: 2005-10-21
Genre: Juvenile Nonfiction
ISBN: 0814336493

An exciting trip below the surface of Michigan’s rocks and fossils. Most people recognize Michigan by its mitten-shaped Lower Peninsula and the Great Lakes embracing the state. Underneath the earth’s surface, however, is equally distinctive evidence of an exciting history. Michigan rests on sedimentary rocks that reach down into the earth’s crust more than fourteen thousand feet—a depth three-and-a-half times deeper than the Grand Canyon. Within these layers of rock rest all sorts of ancient fossils and minerals that date back to the eras when tropical seas spread across Michigan and hot volcanoes flung molten rock into its skies—long before mile-thick glaciers bulldozed over Michigan and plowed through ancient river valleys to form the Great Lakes. Under Michigan is the first book for young readers about the geologic history of the state and the structure scientists call the Michigan Basin. A fun and educational journey, Under Michigan explores Earth’s geological past, taking readers far below the familiar sights of Michigan and nearby places to explain the creation of minerals and fossils and show where they can be found in the varying layers of rock. Readers will learn about the hard rock formations surrounding Michigan and also discover the tall mountain ridges hidden at the bottom of the Great Lakes. With beautiful illustrations by author Charles Ferguson Barker, a glossary of scientific terms, and charming page to keep field notes, Under Michigan is a wonderful resource for young explorers to use at home, in school, or on a trip across Michigan.