Clastic Provenance of the Inner Hornsund Trough, Svalbard: Insights into Devonian Paleogeography and Regional Correlations

Students: Edwin Sis Figueroa, Owen Mckeon

Faculty Mentor: Owen Anfinson

Geology

College of Science, Technology, and Business

The late Paleozoic clastic sedimentary rocks of the Inner Hornsund Trough in southern Svalbard preserve a record of regional tectonic events critical for reconstructing the Arctic's Devonian paleogeography. For this study, approximately 1800 detrital zircon grains were separated and analyzed from six samples—two from the Marietoppen Formation (Devonian) and four from the Adriabukta Formation (Late Devonian to Early Carboniferous?). Detrital zircon U-Pb age spectra obtained from these units are characteristically similar, with the majority of analyzed grains falling within the 1.0–2.1 Ga range and exhibiting distinct peaks at approximately 1.9, 1.7, 1.45, and 1.1 Ga. Relatively small populations are also present at 2.7 and 3.2 Ga, and a single sample near the top of the Adriabukta Formation contains a small number of Paleozoic ages. These ages are comparable to those derived from the Neoproterozoic metasedimentary rocks of the Southwestern Basement Province, which nonconformably underlie the Paleozoic and younger strata of the Inner Hornsund Trough, as well as the Northwestern Basement Province. This relationship suggests that the Marietoppen and Adriabukta formations likely represent reworked locally or regionally derived material. Our results are distinct from previously published age spectra from the Andrée Land Basin of Northern Svalbard and from more distal potential sources in the Arctic (e.g., Northern Greenland and the Canadian Arctic). These results invite two possible interpretations. One explanation is that late Paleozoic strata of the Inner Hornsund Trough and the Andrée Land Basin were geographically separated, potentially due to the Southwest and Northern basement provinces not yet being juxtaposed. Alternatively, these basins may have been locally sourced and disconnected from each other while maintaining a relative arrangement similar to today. These results provide further insight into the provenance and paleogeography of Svalbard, which has been linked to various Arctic and Cordilleran terranes.