In Svalbard we find rocks from practically every geological period. Geology tell its visible tale in Svalbard where vegetation is so sparse.
Nowadays, Svalbard looks as though it was just emerging from an Ice Age: exposed and barren, more than half of it covered by glaciers driving large amounts of deposits ahead of them. Rivers wash away stones, gravel and silt, all of which finally settles on valley floors, forming plains or deltas. The scarce vegetation fails to cover geological features, which is why Svalbard has fascinated geologists ever since the first Norwegian geological expedition led by Baltazar Mathias Keilhau in 1827. Now Svalbard is a favourite amongst geologists from all over the world.
The Oldest Rocks
The oldest rocks, which are from the Precambrian period (>1,000-440 million years old), make up the bedrock. They consist of metamorphosed sedimentary and igneous rock such as mica shale, gneiss and partially melted and re-crystallised rock such as granite. At Raufoss, on North Spitsbergen, they have found grains of the mineral zircon which are believed to be 3.2 billion years old. There are hardly any fossil remains from the Precambrian Period except for colonies of algae (stromatolites). The scarcity of fossils is due to the extreme rock metamorphosis going on at the time and also to the fact that life was still rudimentary.
More than 400 million years ago the earth's crust in the region of Svalbard was on the move, and chains of mountains were formed through folding (the Caledonian Orogeny). Into these mountains, granite intruded. Granite is what makes up some of the highest remaining peaks in Svalbard, where erosion has broken down most of what once was the Caledonian mountains. The debris now accounts for the bulk of subsequent sedimentation.
The Devonian Period
The formation of mountains through folding was followed by the Devonian Period (approx. 375 million years ago) when central parts of Spitsbergen started sinking. Vast amounts of sediments settled, forming layers that were thousands of metres thick. This went on in a dry period, partly on land, partly in fresh and brackish water. The oldest fossils of extinct armoured fishes are found here, together with fossils of primitive plants.
The Carboniferous Period
The dry Devonian climate was followed by relative humidity in the Carboniferous Period which left us sediments in shallow marine waters and on low-land plains. Sand, clay, and vegetal remains have turned into sandstone, shale and coal seams. The coal strata that form the basis of the Pyramid stem from this period. Then, some 300 million years ago, the land was once more flooded from the sea, and lime was subsequently deposited together with dolomite, anhydrite, and gypsum. We also find layers with plenty of sea fossils from the end of the Permian Period (250 million years ago).
The Triassic, Jurassic and Cretaceous Periods
Svalbard was much closer to the equator than it is now. During the Triassic, Jurassic and Cretaceous Periods (25065 million years ago) it moved from latitudes 50° to 70° North. The climate at the time was temperate and humid. We find, from that period, alternating terrestrial and marine deposits which contain an abundance of sea fossils such as bivalves and squid shells. Volcanic activity entailed intrusions of melted rock (dolerite) between the strata in several places. On King Charles' Land, the lava flowed out onto the surface, covering wooded areas which can be recognised today from petrified tree trunks below the lava flow.
In strata that are one hundred million years old we find footprints from dinosaurs that enjoyed a warm climate and lush vegetation. Footprints have been left near Festningen by plant-eating, and at Kvalvågen by carnivorous dinosaurs. It should be noted that plants and animals requiring a warm climate originated when Svalbard was located further to the south. Continental drift is still going on, and Svalbard is now on its way towards the north-east at a velocity of 1.5 cm a year.
The Tertiary Period
In the Tertiary Period (65-2 million years ago) there was intense pressure in the earth's crust, both from the east and the west, the result of which was new folding and formation of mountain chains. When Willem Barents discovered Svalbard in 1596, he called the place Spitsbergen [meaning: pointed mountains] because of the ragged and pointed mountains on the north-west coast. The Tertiary Period also saw the development of large swamps in central parts of Svalbard. Here we find the important coal strata which have been subject to comercial exploitation in Longyearbyen, Sveagruva and Barentsburg.
During the last two millions of years, Svalbard's geology has been dominated by volcanic activity and glaciations. In volcanic eruptions 70,000 years ago, lava flowed over large areas, and hot springs bear witness of that activity to this day. Thousands of kilometres of rock have crumbled under the last glaciations while the landscape, such as we know it, was gradually being sculpted out of rock.
• Geological maps over Svalbard (The Norwegian Polar Institute)