2025/11/28 by Anna Sartell, Ulf Söderlund, Kim Senger +2 · 1 voice
Earth and Planetary Sciences · Biochemistry, Genetics and Molecular Biology · #Geological Studies and Exploration #Geological and Geochemical Analysis #Geomagnetism and Paleomagnetism Studies
paper · doi:10.1029/2024gc011842
Abstract The High Arctic Large Igneous Province (HALIP) formed in the circum‐Arctic during the Cretaceous. The timing and duration of emplacement of these mafic magmas are important for understanding the climatic and environmental effects, yet many uncertainties remain. The dating methods used vary greatly between different regions. For example, the mafic intrusions in Svalbard have mainly been dated using the 40 K/ 40 Ar method, which is more sensitive to overprinting at lower temperatures. This is problematic especially in the Arctic, where the Eocene Eurekan orogeny has impacted the intrusions post‐emplacement. Meanwhile, in the Canadian Arctic, 206 Pb/ 238 U dating on zirconium minerals has been the most common method employed, which requires much higher temperatures to be reset. We present a new compilation of ages for HALIP igneous and volcanic rocks in the circum‐Arctic, derived from a thorough review and reassessment of previously reported data. This compilation applies rigorous, method‐specific criteria to evaluate the reliability of existing HALIP age determinations, ensuring traceability and applicability for future data sets. By establishing a robust framework for assessing age data, this approach enhances the reliability of geological interpretations of HALIP magmatism, and highlights, for example, the spatial migration of peak magmatic activity through time in the High Arctic. To improve our understanding of the temporal evolution of the HALIP, we also present a new 206 Pb/ 238 U baddeleyite isotopic dilution thermal ionization mass spectrometry age from Svalbard. The new weighted mean 206 Pb/ 238 U age from Svalbard, 123.3 ± 1.6 Ma, is based on six samples belonging to one large sill. This age is in perfect agreement with existing published 206 Pb/ 238 U and 40 Ar/ 39 Ar ages, and suggests magma emplacement on Svalbard between 124.7 ± 0.3 and 120.2 ± 1.9 Ma ago.