The Ritland crater is an impact crater at Ritland farm in Hjelmeland municipality in eastern

Rogaland Rogaland () is a Counties of Norway, county in Western Norway, bordering the North Sea to the west and the counties of Vestland to the north, Vestfold og Telemark to the east and Agder to the east and southeast. In 2020, it had a population of 47 ...

county, Norway. The crater is about east of the village of

Hjelmelandsvågen Hjelmelandsvågen is the administrative centre of Hjelmeland municipality, Norway. The village is located on the south side of the mouth of the Jøsenfjorden. The village has a population (2019) of 592 and a population density of . The Norwegia ...

and about south of the

Jøsenfjorden Jøsenfjorden is a fjord in the municipality of Hjelmeland in Rogaland county, Norway. The fjord is a branch off of the main Boknafjorden. The fjord has a length of and a width between . The Norwegian National Road 13 runs along the northern ...

. The crater is about in diameter, and was created when a meteorite with an estimated diameter of struck here about 500–600 million years ago. The crater was later buried by sediments, of which it has been partly recovered. The structure was first discovered as a possible (suspected) impact crater in 2000 by geologist Fridtjof Riis. The Research Council of Norway has funded scientific research of the crater. In 2009, scientists from the University of Oslo considered it proven that the crater was formed by meteorite impact, according to Professor Henning Dypvik from the Institute for Geological Sciences at the University of Oslo.

Details

The sediments and fossils at Ritland have been studied by geologists since the 1950s. The depth of the circular structure is about , with a diameter of about . Research has focused on trying to find evidence that the crater resulted from a meteoric impact. In 2008 it was announced that microscopic evidence was found, and that the structure is an impact crater. The crater dates from before mid

Cambrian The Cambrian Period ( ; sometimes symbolized C with bar, Ꞓ) was the first geological period of the Paleozoic Era, and of the Phanerozoic Eon. The Cambrian lasted 53.4 million years from the end of the preceding Ediacaran Period 538.8 million ...

, as fossils from mid Cambrian are found in sediments that have accumulated in the crater. The evidence for the structure being an impact crater stems from identification of shocked quartz particles, which only form under the very high pressures (5-10 GPa) present during a meteoric impact. The sediments in the crater are described as landslides in the bottom of the crater, followed by shale sediments deposited during a period when the sea had invaded the area. On top of the clay sediments are coarser sediments. During the Caledonian orogeny the crater was buried under a several kilometre thick

mountain chain A mountain chain is a row of high mountain summits, a linear sequence of interconnected or related mountains,Whittow, John (1984). ''Dictionary of Physical Geography''. London: Penguin, p 87. . or a contiguous ridge of mountains within a larger m ...

. The overlaying mountains were later eroded, and the crater was again exposed.

References

External links

Map overview of the Ritland crater

{{Impact cratering on Earth Earth Impact Database Impact craters of Norway Cambrian impact craters Landforms of Rogaland Hjelmeland