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

Thaw (Cryogenic) Lakes – perennially frozen ground=permafrost

Continental Glaciation:Finger Lakes

Modified by glaciers. The present lakes were preglacial stream

valleys 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

Graben Lake: Tahoegrabens=single or multiple faults

Rift Graben Lake: Baikal

More Rift Lakes

Volcanic Lakes: Crater LakeCrater Lake, Oregon (10km across,

600m deep)

Lakes w/ Other Origins

Extraterrestrial Forces:Astroblemes

Manicougan

Chubb Lake - formed when meteors hit the Earth and formed large depressions which filled with water

Sinkhole Lake

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.

Oxbow cutoff to form separate lake

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.

Chesapeake Bay

Barnegat Bay

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)

Mississippi River – Estuaries produced from deltas