Document Type
Honors Project - Open Access
Abstract
Late Paleozoic clastic sedimentary rocks in the Inner Hornsund Trough (IHT) in southern Svalbard represent an archive of regional tectonic events and are key to accurate paleogeographic reconstructions of the Arctic. To tap this archive, ~1800 detrital zircon grains were separated and analyzed from six total samples of sedimentary rock, including samples from both sides of the Hornsund fjord. Two samples came from the Marietoppen formation (Late Devonian), and four from the Adriabukta formation (Late Devonian and/or earliest Carboniferous). Detrital zircon U-Pb age spectra from both units are similar, with the majority of analyzed grains falling in the 1.0-2.0 Ga range and exhibiting distinct peaks at ca. 1.65, 1.45, and 1.1 Ga. Relatively small populations also occur at ca. 2.7 and 3.2 Ga. These ages are comparable to those derived from Neoproterozoic metasedimentary rocks of the Southwestern Basement Province (SBP) that nonconformably underlie Paleozoic and younger rocks of the Inner Hornsund Trough, as well as the Northwestern Basement Province of more northerly Svalbard. This relationship suggests that studied samples of the Marietoppen and Adriabukta formations likely represent reworked locally- and/or regionally-derived material. These results from the Marietoppen and Adriabukta formations are distinct from previously published age spectra from the Andrée Land Basin of northern Svalbard. The zircon ages obtained are also distinct from more distal potential sources in the Arctic (e.g., northern Greenland and the Canadian Arctic). Our new 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, perhaps because the Southwest and Northern basement provinces were not yet juxtaposed. Alternatively, each of these basins may have been locally sourced and disconnected from each other, but otherwise in a relative arrangement similar to today.
Recommended Citation
Riccardi, Noah, "Provenance of Clastic Rocks in the Inner Hornsund Trough, Svalbard" (2025). Geology Honors Projects. 27.
https://digitalcommons.macalester.edu/geology_honors/27
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