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Kettle Lakes on Pitted Outwash Plain. Fjord Lake – glacial rock-basin lakes. A limnologically important feature of many marine & estuarine fjords is the presence of a partial dam of rock or moraine near the mouth, which prevents full circulation w/ the ocean. Saltstraumen, Norway.
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Fjord Lake – glacial rock-basin lakes • A limnologically important feature of many marine & estuarine fjords is the presence of a partial dam of rock or moraine near the mouth, which prevents full circulation w/ the ocean. • Saltstraumen, Norway
Thaw (Cryogenic) Lakes – perennially frozen ground=permafrost
Continental Glaciation:Finger LakesModified by glaciers. The present lakes were preglacial streamvalleys or earlier lakes.
Lakes of Tectonic Origin • Old, deep lakes & many of the World’s largest lakes • Many formed during or before Pliocene era (1-10 million yrs. Ago) • New Disaster: Reserviours, Lakes in danger after quake China
Volcanic Lakes: Crater LakeCrater Lake, Oregon (10km across, 600m deep)
Extraterrestrial Forces:Astroblemes Manicougan
Chubb Lake - formed when meteors hit the Earth and formed large depressions which filled with water
Sinkhole Lake Formation • Dissolution of soluble rock by dilute acids in water percolating through it. • Results in small caves that are usually small and steep-sided. • Limestone
Oxbow Lakehttp://www.school-portal.co.uk/GroupDownloadFile.asp?file=21606 • Loop of a meandering river is cut off by silt deposition.
Biological Formations -Animals Beaver Dam Lakes -Reservoirs
Anthropogenic Lakes • Based on the reading in Ch.11, how do you think Lake Manahawkin was created?
Dam Disasters • Raw Video: Heavy Rains Cause Iowa Dam Break • Raw Video: House Crashes Into Bridge
Origins of Wetlands • Similar to lakes (glaciation, tectonic effects, volcanism), except wetlands are shallow. • <1m of water. • Some marshes swamps and bogs formed from filled in lakes. • Riparian vegetation becomes established when river becomes stable and forms a delta. • How can climate affect these areas?
Origins of Estuaries • Geologic events that turn rivers into lakes will create estuaries near the ocean. • Most originate from glacial melt & some from tectonic processes. • Can also be produced from large tidal delta regions by sedimentation where large rivers meet the sea.
Coastal Plain Estuaries • Coastal plain estuaries formed during the end of the last ice age. At this time, sea level rose because of melting ice and warming ocean waters. The rising water flooded coastal river valleys, forming estuaries. The Cape Fear River estuary is a coastal plain estuary.
Bar-Built Estuaries • Bar-built estuaries are found where sand bars form on a coastline. The water behind the sand bars are partly cut off from the sea. The Albemarle-Pamlico Sound behind the Outer Banks is a bar-built estuary.
San Francisco Bay, California - A tectonic estuary Photo courtesy of the U.S. Geological Survey
Glacier Fjord • Fjords are deeply cut valleys that are formed by the movement of glaciers. When glaciers moved north at the end of the last ice age, the sea filled in the valleys and formed estuaries. • Photo courtesy of the National Aeronautics and Space Administration (NASA)
