EGU General Assembly 2022
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Preliminary report on δ13Ccarb isotope excursion through the Silurian of Kurtuvėnai - 161 borehole, Northwest Lithuania

Tomas Želvys1, Andrej Spiridonov1, Anna Cichon-Pupienis1, Andrius Garbaras2, and Sigitas Radzevicius3
Tomas Želvys et al.
  • 1Vilnius University, Institute of Geoscience, Department of Geology and Mineralogy, Vilnius, Lithuania (
  • 2Department of Nuclear Research, Center for Physical Sciences and Technology, 10221 Vilnius, Lithuania
  • 3Department of Stratigraphical Geology, Institute of Geological Sciences, University of Wrocław, Pl. Maksa Borna 9, 50-205 Wrocław, Poland

Lithuania is located in the eastern part of the Silurian Baltic Basin which was located near the equator during the Silurian. Kurtuvėnai -161 borehole is located in the Northwest Lithuania. The Silurian geological section of investigated interval is composed of siliciclastic and carbonate deposits and represents deep marine environments.

Samples for stable carbon isotope analysis were collected from 1441 – 1316 m depth interval. The sampling intervals range from 0.2 up to 1m. The stable carbon isotope values from carbonates were measured using Thermo Gasbench II coupled with a Thermo Delta V isotope ratio mass spectrometer.

In the investigated interval 10 graptolites biozones were distinguished: Lapworthi Biozone is distinguished in the lowest part of the section and linked to the Adavere Regional Stage (uppermost Telychian); the centrifugus - belophorus biozones mark the Jaani Regional Stage; perneri - lundgreni biozones correspond to the Jaagarahu; and parvus - nassa biozones marks the Gėluva Regional Stage of the Wenlock.

According to the δ13Ccarb isotope analysis results, a positive excursion was detected in the lower part of the studied interval from 1422.8 m up to 1390.8 m depth. There, the δ13Ccarb maximum value is 3.87 ‰. This positive δ13Ccarb anomaly can be linked to the Ireveken positive stable carbon isotopes excursion and the centrifugus – belophorus biozones interval of the lower Wenlock. We can also observe a positive δ13Ccarb excusion in the upper part of Homerian (from 1327 m depth) which potentially can be the lower part of the Mulde positive stable carbon isotopic event.

In summary, the δ13Ccarb values varied from -1.35 ‰ up to 3.92 ‰ in studied interval of Kurtuvėnai-161 borehole. A more detailed biostratigraphic and lithological study is needed for a better understanding of the integrated stratigraphy of the Silurian geological section in the Kurtuvėnai-161 borehole in the future.

How to cite: Želvys, T., Spiridonov, A., Cichon-Pupienis, A., Garbaras, A., and Radzevicius, S.: Preliminary report on δ13Ccarb isotope excursion through the Silurian of Kurtuvėnai - 161 borehole, Northwest Lithuania, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-2950,, 2022.