1.5 Dutch landscape above sea level

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Today

Instruction 1.5 The Dutch landscape

The Dutch landscape

The Dutch landscape consists of:

• The Netherlands above sea level
• The Netherlands below sea level

Catchment areas

The Rhine, the Meuse and the tributaries of these rivers have had many catchment areas.

These rivers have deposited a thick layer of sand and river gravel over the whole of the Netherlands.

Terms:

tributaries = zijrivieren

catchment = stroomgebied

Sand and river gravel in the Netherlands

Why is it that thick layers of sand and river gravel were deposited all over the Netherlands by these rivers?

The Netherlands lies in the lower course of the catchment area of the Rhine and the Meuse. Here the water flows slowly and the material carried by the rivers is deposited.

Ice ages

In the diagram we see the average summer temperature.

The landscape of the Netherlands above sea level was largely formed in the cold periods between 200,000 years and 10,000 years ago.

Ice ages

During the second-last ice age ice slided from Scandinavia into the Netherlands.

NL: ~21.000 years ago

Het is winter in Nederland. Er steekt een felle, koude oostenwind die koude lucht meevoert van de ijskap in het noordoosten. 's Nachts daalt de temperatuur tot min 30. Door de felle koude ontstaan er krimpscheuren in de grond, die soms met een luide knal openspringen. Over de kale vlakte stuift zand en sneeuw; het oppervlak bestaat uit een laagje stenen die door het stuivende zand gepolijst worden, op ander plekken liggen lage duinen. Daartussen een netwerk van krimpscheuren. Op wat mossen, gras en een enkele poolwilg na is er geen begroeiing. Zelfs de mammoetjagers komen hier niet....

Zo zag Nederland er zo'n 21000 jaar geleden uit tijdens het koudste deel van de laatste ijstijd.  Een grimmig beeld. Maar dit gold alleen voor de meest extreme kou. Er waren ook warmere perioden met een uitbundig bloeiende steppe-tundra en kuddes mammoeten, en zelfs bossen.

NL: ~150.000 years ago

Push morenes

The different ice tongues pushed up the ground at the front and the sides to make push moraines.

From which material are the push moraines made?

Push morenes

The different ice tongues pushed up the ground at the front and the sides to make push moraines.

From which material are the push moraines made?

The push moraines consist of sand and river gravel. This sand and river gravel was deposited by (precursors of) the Rhine and the Meuse all over the Netherlands.

Push morenes

At the end of the cold period the ice retreated.

You can still see push moraines in the landscape of the Netherlands above sea level.

For example:
The Veluwe
The Utrechtse Heuvelrug

Meltwater

Why are there now gaps in the push moraines?

Meltwater

Why are there now gaps in the push moraines?
The large volume of meltwater from the ice tongue washed away parts of the moraine, thus creating meltwater valleys.

Remains from the ice age

To the north of the big rivers you can find erratic boulders, some with a
diameter of over a metre. These boulders were brought along with the ice and deposited in the Netherlands when the ice melted.

Why do you only find these erratic boulders to the north of the big rivers?

Remains from the ice age

To the north of the big rivers you can find erratic boulders, some with a
diameter of over a metre. These boulders were brought along with the ice and deposited in the Netherlands when the ice melted.

Why do you only find these erratic boulders to the north of the big rivers?

Because the ice only reached halfway across the Netherlands.

Next week

1.6 Dutch landscape below sea level