The smooth sea-side rockface at Rognstranda began its life as volcanic rocks and sediments 1500 million years ago.
The rocks became deformed and metamorphosed during the Sveconorwegian orogen (mountain-building event), about 1000 million years ago. The rocks were transformed into different gneisses, at certain depths deep inside the mountain chain. The mountains were later eroded and the gneisses uplifted, and after several millions of years, they were flooded by the Cambro-Silurian seawater.
During this period, lasting from 540-415 million years ago, the gneisses were overlain by calceraceous sediments, clays and sands. You can see these sediments in the escarpment at Rognstranda, now as well-bedded limestones and schists. Between the gneisses and the sedimentary rocks there is a time gap, an important geological boundary between Precambrian and the Cambrian (Paleozoic and Mesozoic Eras).
A lot of fine fossils may be found at Rognstranda. But, the locality is protected, so you are not allowed to collect any fossils. Also, take care, look out for rock falls from the escarpmen
Tel: 91 38 84 45
Bamble Church is a large wooden structure dedicated in 1845.
The Olav church ruin (Skeidi church) are the ruins of a stone church built before 1150 in…
Great hiking area near Rognstranda in Bamble. Beautiful forests and flora.
Bamble is dominated by two types of landscape with completely different geological…
Welcome to the geosite in Steinvika
Langesund customs warehouse as it stands today was erected in 1869.
Workshop and gallery in Langesund.
Tollpakkboden is a log-built warehouse, the main part of which dates from the early 1700s.
The old guardhouse is now a customs museum, with artefacts found there from long ago.
Tangen Fort lies at the outermost point on Langesundtangen, south of the town of…
Valle, a gem of the archipelago with wealth of facilities, is located in the far south of…
Learn more about the natural history of our planet.