Marine sequences and raised shorelines on Svalbard (Spitsbergen), Franz-Joseph Land, and Novaya Zemlya archipelagos have been described and dated by scientists of PMGE, VNII Okeangeologia, and AARI.

The ^I4C date of mollusk shells from the 10-m terrace of Chump Island has yielded the age of 10,020±110 years BP (LU-5146). U/Th dating of the same material has yielded the age of 15,500±1800 years BP (LU-5217). Radiocarbon age of marine mollusk shells from the 20-m terrace at Cape Forbes, George Island, is 9 060±130 years BP (LU-5147), and the U/Th date is ll,500±1500 years BP (LU-5218). The age of 30 m terrace at Jackson Island was estimated as 10,830±40 years BP (LU-5125) by radiocarbon, and as 3,900±600 years BP (LU-5220) by U/Th method. The 10-, 20-, and 30-m terraces have an age of ca 10 kyr.

On Svalbard, the shells of the same age can be found at various altitudes at the same localities. At the Wejde Fjord shore, by the new and earlier data, the shells dated 8,800 to 9,230 years BP occur in the range of 10 to 31 m asl (Sharin et al., 2006). Previous data show the same distribution. The 7,100 years old shells occur in sediments within 15 to 35 m interval of in the Smelledalen River valley, Age Island (Hjort et.al, 1995). Shells of this age are also common close to the present sea level.

Marine deposits with abundant foraminifer shells sampled at 59-60 m asl near Retovsky Lake near the Russkaya Gavan bay, Northern Island, Novaya Zemlya, have given the ¹⁴C age of 35,300±880 years BP (LU-5148) on marine mollusk shells, and the U/Th date is 23,100±1300 years BP (LU-5219).

The 20-25m marine terrace at the Bystraya River mouth near the Sporyi Navolok cape, Northern Island, Novaya Zemlya, was dated by shell fragments found in the debris. Their radiocarbon age is 22,040±400 years BP (LU-5495).

Two samples of mollusk shells from the contemporary cliff at Kabanyi Nos Peninsula, Southern Island, Novaya Zemlya, has shown the radiocarbon ages of 25,200±430 years BP (LU-5390) and 26,300±560 years BP (LU-5396). Surface deposits of the marine terrace at the altitude of 25 m in the same area have shown the radiocarbon age 20,800±210 years BP (LU-5391) on mollusk shells.

The published and new data do not support the hypothesis of glacioisostatic nature of the uplifts of islands around the Barents Sea.

Vigorous fault tectonism has been reported in these islands, which can explain the occurrence of diverse dates at similar altitudes and exposure of pre-Holocene deposits at the modern surface. At places, the blocks may experience downsagging.

Thus, existing indirect evidence in favour of a former ice sheet on the Barents Sea shelf, is offset by direct evidence against the glacioisostatic nature of crustal uplifts in the region.

Reference:

Anokhin V.M., Bolshiyanov D.Yu., Gusev E.A., Dymov V.A. New radiometric dates from the archipelagos of Novaya Zemlya, Franz-Joseph Land and Svalbard and discussion on the Late Pleistocene glaciation of the Barents Sea shelf. Correlation of Pleistocene Events in the Russian North. International Workshop Abstracts. 4-6 December 2006. Saint-Petersburg, 2006, p. 8.