The changing landforms of Finland

Abstract

This paper examines briefly the general outlines of the relief in Finland, bedrock and surficial landforms, their origins, and the factors that have affected their development. The basic framework for the relief in Finland is formed by the highly eroded Precambrian bedrock, between 3,000 and 1,500 million
years of age. It is covered in most places by a 3–4-metre layer of much younger and clearly distinct surficial deposits. The ancient fold mountains that occupied the area of Finland have been worn down by weathering and erosion processes to form a fairly even peneplain with a mean height above sea level of 154 metres and a maximum height of 1,328 metres (Halti). About 80 percent of the country’s surface area consists of low-lying land below 200 metres above sea level.

The fractured nature of the bedrock is reflected in the existence of elongated fissure valleys and fault cliffs, and rift valleys and erosion-smoothed horsts in places. Quartzite deposits, in particular, frequently stand out from their environment to form monadnocks. The remains of nine ancient meteorite craters have also been found in the bedrock. The most common type of surficial deposit is till, characteristically in the form of glaciogenic hummocky moraines, drumlins and end moraines, while glaciofluvial landforms, such as eskers, deltas, kame fields, and large ice-marginal complexes such as the Salpausselkä moraines, are also among the basic elements of the topography. The most notable among the landforms dating from after the deglaciation (12,000–9000 years ago) are clay plains, river valleys, beach and dune formations and mires. Particularly the glaciofluvial landforms have been badly spoiled by human activity in places, in the form of the large-scale extraction of sand and gravel.