Fluvial Landform (12.Exhumed river Channel )

                                                                                                                                                      Back to Fluvial Landform

• An exhumed river channel is a ridge of sandstone.

• The softer flood plain mudstone is eroded away.

• The process :

                     1. The deposition of sand within a river channel & mud on the adjacent floodplain.
                     2. Eventually the channel is abandoned.
                     3. Over time becomes buried by flood deposits from other channels.
                    4. Because the sand is porous 
                    5. Groundwater flows more easily through the sand than through the mud of the floodplain deposits.

• Minerals can cement the grains together converting the loose sand into sandstone. 

• Millions of years later, erosion can remove the softer, less cemented mud stone.

• An exhumed river channel is a form of inverted relief.

• Exhumed channels are important indicators for ancient stream flow direction.

Fluvial Landform (11.Endorheic Basin )

                                                                                                                                                      Back to Fluvial Landform

Caspian Sea

• An endorheic basin is a closed drainage basin.

• That retains water.

• Allows no outflow to other external bodies of water, such as ;

                                   rivers

                                   oceans

• Water accrued in a drainage basin eventually flows out through rivers or streams.

• An endorheic basin, rain that falls within it does not flow out.

•  The bottom of such a basin is typically occupied by a salt lake or salt pan.

Great Salt Lake

• Endorheic water bodies include some of the largest lakes in the world, such as;

                      Aral Sea
                     Caspian Sea

• Endorheic lakes are bodies of water do not flow into the sea.

• Endorheic lakes are usually in the interior of a body mass, far from an ocean.

• Watersheds are often confined by natural geologic land formations .

• The inland water flows into dry watersheds .

• endorheic lakes are usually more sensitive to environmental pollutants inputs than water bodies that have access to oceans.

Uureg Nuur

examples:

• Lake Tanganyika in Africa.
• Lake Lahontan in North America.
• Salar de Atacama, in the Atacama Desert, Chile.
• Lake Trasimeno, in Italy.
• Lake Velence, in Hungary.
• Bolsón de Mapimí, in northern Mexico.
• Willcox Playa of southern Arizona
• Qattara Depression, in Egypt.
• Chott Melrhir, in Algeria.

Wfm tarim basin