Varved Shale

Varved shale is shale deposited from melted ice in a lake in which the depositional layers appear in pairs. In simpler words, varved shale is layers of shale.

• Varve coming from the Swedish term ‘in layers’ or ‘revolution’ and are thin, laminar structures and when seen edge on, looks like tree rings.
• Shale is a fine grained sedimentary rock made of mud and clay.

Varved shale is made when shale is formed by melted ice in a lake where the layers appear in pairs. Each pairs represents a seasonal worth of shale deposited. This can help tell when approximately when each layer of varved shale was made.

Fiords

A fiord, also spelt fjord is a narrow body of water the sea between steep cliffs, formed by glacial erosion.

It is formed when a glacier cuts a U-shaped valley by abrasion of the surrounding bedrock. Fiords usually have a sill or a rise at their mouth caused by the previous glacier’s terminal moraine (a glacier’s mark of the maximum advance of the glaciers) which causes extreme currents and large saltwater rapids.

Some coral reefs are found in the bottom of a fiord. The marine life of the coals is believed why fiord areas are generous with fish. The reefs are hosts to many marine animals such as plankton, coral, anemones, fish, several species of shark and many more. Most marine creatures in fiords are adapted to the greater pressure of the water column above it and the darkness of the sea.

Skerries are also found in fiords. In some places near seaweed margins of areas with fjords, there are many ice-scoured channels and in many directions that the rocky coast is divided into thousands of island blocks, some large and mountainous and others merely rocky points or rock reefs. These are skerries. Skerries are usually formed at the outlet of fiords where submerged glacially valleys occur perpendicular to the coast join.