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

Dates

Publication Date
Time Period
2024

Citation

Wilson, F.H., O'Sullivan, P.B., 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.

Summary

This dataset contains U-Pb isotopic data and associated ages of zircons within the lithologic framework of igneous, metaigneous, and metasedimentary rocks collected from the Seldovia quadrangle in southcentral Alaska. The samples were collected as part of geological mapping and research conducted from 2020 to 2023 and funded by the Mineral Resources Program of the U.S. Geological Survey. Zircon grains were separated and analyzed by GeoSep Services (GSS). All analyses were conducted between 2021 and 2023 using laser-ablation-inductively-coupled-plasma-mass spectrometry (LA-ICP-MS) techniques. Also described in this report are the major and trace element geochemical analyses for samples collected as part of the mapping project. Analyses [...]

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Attached Files

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geochemistry_isotopeRatio_seldovia_wilsonOsullivan.csv 907 Bytes text/csv
geochemistry_seldovia_wilsonOsullivan.csv 21.84 KB text/csv
geochronology_U-Pb_seldovia_wilsonOsullivan.csv 221.39 KB text/csv
geochronologyChemistry_DataDictionary_seldovia_wilsonOsullivan.csv 32.51 KB text/csv
geochronologyChemistry_sampleSummary_seldovia_wilsonOsullivan.csv 4.17 KB text/csv
geochronologyChemistry_seldovia_wilsonOsullivan_metadata.html 205.24 KB text/html
GSS_Analytical_Methods.pdf 178.29 KB application/pdf
GSS_Supplementary_Table_S2.pdf 801.51 KB application/pdf

Purpose

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.

Additional Information

Identifiers

Type Scheme Key
DOI https://www.sciencebase.gov/vocab/category/item/identifier 10.5066/P1FDZG9X

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