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Glacier Bay National Park & Preserve Seafloor Maps

Seafloor maps of Muir Inlet, Glacier Bay National Park & Preserve were developed by USGS and the University of Illinois. The seafloor was mapped at depths ranging from just below the surface to greater than 300 m in the deepest fjord basins. Substrates were characterized by high-resolution, multibeam bathymetry and backscatter imagery, numerous ground-truth sources, and knowledge of the local fjord environment.

Muir Inlet is a glacial fjord with a shallow sill topped with a glacial-morainal-bank complex at the mouth, steeply sloping walls, and multiple deep basins separated by transverse sills and morainal banks. Several glaciers formed a confluent tidewater-glacier complex that terminated at the mouth of Muir Inlet between 1860 and 1899. Today the glaciers have retreated as much as 50 km, no longer terminate at tidewater, and are separated from the fjord by ice-contact deltas. Upper Glacier Bay is undergoing glacial isostatic uplift at a rate of 25 mm/yr due to ice loss.

Muir Inlet is a highly dynamic estuarine environment due to deglaciation, sedimentation, and vigorous tidal currents. The seafloor is dominated by unconsolidated sediments; 89% of Muir Inlet is covered by mud derived from the high fluxes of glacial debris. Bedrock covered about 6% of mapped area; mixed sediments (sand- and gravel-sized particles) covered about 3%; and boulder/rubble covered about 1%.

Reports, maps, data and metadata created by this project can be downloaded from the NPS Integrated Resource Management Applications Portal. Please see below for direct download links to each product.


Marine Benthic Habitat Mapping of Muir Inlet, Glacier Bay National Park & Preserve (PDF 9.9MB)


Maps - Muir Inlet, Glacier Bay, Alaska (ZIP 318MB)

The maps include:
Sheet 1 - Muir Inlet Bathymetry
Sheet 2 - Lower Muir Inlet Habitat Map
Sheet 3 - Upper Muir Inlet Habitat Map
Sheet 4 - Muir Inlet Geoforms

Data and Metadata

Marine Benthic Habitat Mapping Data for Muir Inlet, Glacier Bay National Park and Preserve, Alaska (ZIP 67.5MB)

Last Updated: May 07, 2012