Back to Preface of Vaksdal Bygdebok The bedrock in Modalen is very old. It is built up gradually in several stages, and it has a long development history. The geological map and profile provides an overview of the bedrock in Modalen and surrounding area. The map is based on "Bedrock map of Norway", published by the Geological survey participation, but is modified somewhat. Several geologists have contributed to the knowledge of the area. The first was J.Rekstad from the Geological Survey in summer 1906, 07 and 08 worked in the northeast. Later, geologists from the University of Bergen, the work here; Anders Kvalein the eastern part, Helge Askvik in northern and western half and Ellen Sigmond with assistants in several parts of the map. Jean W. Gray, University of Oxford, took his examination of a work over the southeastern part, about Eksingedalen. Otherwise, the Geological Survey examined talc deposits south of the Fram Fjord. The bedrock in the area is made up of three main parts. The oldest and lower part,which we call the basement, forming the bedrock for most of the map, west of a line of Lavik in Eksingedalen to Arnafjord. The next and the middle unit, Fyllittgruppen, consists of metamorphic sediments,deposited on thebasement surface, probably in the geological time periods Cambrianand Ordovician (600-450 million years ago). In Fyllittgruppen is where bodies of a very special rock, an altered olivine rock. In Ordovician and Silurian the following periods and Devon (505-370 million years ago) was the Caledonian mountain range formed by the collision of the North American and European continents. The Caledonian mountain range characterizes the bedrock throughout the area of folded and transformation of the rocks. It also led to large flakes of the crust was pushed up and over other rocks sliding covers. Sliding tires form the third and practice most large unit in the area (see profile).
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