U-Pb Isotope Geochronology Data and Geochemical Analyses of Selected Rocks from the Seldovia Quadrangle, Southcentral Alaska

Publication Date

2024-08-30

Time Period

2024

Wilson, F.H., O'Sullivan, P.B., and Pongratz, A.L., 2024, U-Pb isotopic data and geochemical analyses of selected rocks from the Seldovia Quadrangle, Southcentral Alaska: U.S. Geological Survey data release, https://doi.org/10.5066/P1FDZG9X.

U-Pb isotopic ages of zircon grains aid in the interpretation of igneous intrusions and pathways following the original deposition of sedimentary rocks. The youngest zircon ages in any single sample also provide information about the maximum possible intrusion or formation age, as well as depositional age of any sedimentary rocks and, therefore, the geologic unit that contains it. Comparison of zircon age populations between samples provides a critical test of local to regional correlations of geologic units and aids in the reconstruction of geologic histories of large regions. In this study, the data were used to attempt to better understand the geologic history of the larger area of southcentral Alaska. The petrology, composition, emplacement settings, and distribution of these rocks facilitate regional correlations, help define their tectonic setting, and provide insights into their magma sources and petrogenesis. The origin and evolution of these rocks identifies some processes that can accompany subduction initiation along a continental margin. These data will be used in support of multiple geological maps, reports, and papers that describe the geological framework and mineral resource potential of these regions. Geochemical and Sr and Nd isotopic analysis of the samples of this study are used to help characterize the rocks and assist in determining their environment of eruption or emplacement. In conjunction with the geologic mapping and U-Pb isotope ages, an interpretation of this environment is suggested.

• Alaska Science Center (ASC)

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