The Reid Lakes batholith (RLB) in southwestern McQuesten map area (115P) has previously been tentatively assigned a mid-Cretaceous age, although two K-Ar ages from the northwestern part of the batholith indicated that at least part of the body must be late Paleozoic or older. U-Pb dating of two lithologically distinct samples from the southeastern part of the RLB yields Early Mississippian crystallization ages (341.5 ± 0.7 Ma and 355.7 ± 0.9 Ma). A sample of the Moose Creek pluton, which is on the northeast side of the Tintina fault zone, but was previously interpreted to be part of the RLB, yielded a U-Pb age of 92.0 ± 0.3 Ma. The Moose Creek pluton is therefore correlated with the mainly 95-93 Ma South Lansing plutonic suite which intrudes rock units of Ancestral North America, whereas the RLB is a multi-phase, Early Mississippian intrusion into metamorphic rocks of the Yukon-Tanana terrane.

Six dikes that are closely associated with the Klaza epithermal vein system in the Mt. Nansen district yield early Late Cretaceous U-Pb zircon ages (78.2-76.3 Ma); this age is similar to that obtained from the porphyry stock that hosts the Cyprus Cu-Mo-Au porphyry occurrence immediately to the southeast. These results support the interpretation that epithermal veins in the Mt. Nansen district are likely genetically related to subvolcanic magmatism. Granodiorite of the Dawson Range batholith that underlies most of the Klaza property gives a U-Pb zircon age of 107.9±0.3 Ma. These dates overlap with previously reported mid-Cretaceous U-Pb zircon ages for felsic dikes associated with the Brown-McDade and related vein and breccia deposits in the Mt. Nansen mine. The new results, together with regional dating and Pb isotopic data from western Yukon, emphasize the metallogenic importance of the “early Late Cretaceous” magmatic-hydrothermal event in this region.

This dataset contains U-Pb isotopic data and ages, Hf isotope data, and trace element concentrations of zircon from igneous rocks collected from the Yukon-Tanana Upland, eastern Alaska. The sample suite was collected as part of geological mapping and supporting geochemical and geochronological analysis conducted from 2013 to 2019. Zircon was obtained from these igneous rocks to determine the crystallization age for the bedrock samples. The data tables accompanying this data release report the composition of uranium (U) and thorium (Th) measured in each grain, ratios of three isotopes of lead (206Pb, 207Pb, 208Pb), two isotopes of uranium (235U and 238U), and one isotope of thorium (232Th), as well as the age of each grain, plus trace element abundances from the same ablated aliquot, including P, V, Sr, high field strength elements (HFSE), and rare earth elements (REE). Reported Hf (and Lu) isotope data includes 176Hf/177Hf, 176Lu/177Hf, and 178Hf/177Hf ratios, calculated epsilon Hf values, and age-corrected isotope ratios and epsilon values.

This data set contains U-Pb isotopic data and ages, Hf isotope data, and trace element concentrations of zircon from igneous rocks collected from the western Alaska Range of south-central Alaska. The sample suite was collected as part of geological mapping and supporting geochemical and geochronological analysis conducted from 2011 to 2013. We also analyzed portions of remainders of previously collected igneous bedrock samples from the USGS archive, allowing expansion of the dataset to include igneous bodies that were not sampled during 2011–2013 field work or were outside the area of focused project field work. Zircon was obtained from these igneous rocks to determine the crystallization age for the bedrock samples. The data tables accompanying this data release report the isotopic composition of uranium (U) and thorium (Th) measured in each grain, ratios of three isotopes of lead (208Pb, 207Pb, and 206Pb), two isotopes of uranium (235U and 238U), one isotope of thorium (232Th), and the age of each grain, plus trace element abundances from the same ablated aliquot, including P, V, Sr, high field strength elements (HFSE), and rare earth elements (REE). Reported Hf (and Lu) isotope data includes 176Hf/177Hf, 176Lu/177Hf, and 178Hf/177Hf ratios, calculated epsilon Hf values, and age-corrected isotope ratios and epsilon values.

This data set contains U-Pb isotopic data and ages, Hf isotope data, and trace element concentrations of zircon from igneous rocks collected from the Yukon-Tanana Upland, eastern Alaska. The sample suite was collected as part of geological mapping and supporting geochemical and geochronological analysis conducted from 2013 to 2019. Zircon was obtained from these igneous rocks to determine the crystallization age for the bedrock samples. The data tables accompanying this data release report the composition of uranium (U) and thorium (Th) measured in each grain, ratios of three isotopes of lead (206Pb, 207Pb, 208Pb), two isotopes of uranium (235U and 238U), and one isotope of thorium (232Th), as well as the age of each grain, plus trace element abundances from the same ablated aliquot, including P, V, Sr, high field strength elements (HFSE), and rare earth elements (REE). Reported Hf (and Lu) isotope data includes 176Hf/177Hf, 176Lu/177Hf, and 178Hf/177Hf ratios, calculated epsilon Hf values, and age-corrected isotope ratios and epsilon values.

This dataset contains U-Pb isotopic data and ages, Hf isotope data, and trace element concentrations of zircon from igneous rocks collected from the western Alaska Range of south-central Alaska. The sample suite was collected as part of geological mapping and supporting geochemical and geochronological analysis conducted from 2011 to 2013. We also analyzed portions of remainders of previously collected igneous bedrock samples from the USGS archive, allowing expansion of the dataset to include igneous bodies that were not sampled during 2011–2013 field work or were outside the area of focused project field work. Zircon was obtained from these igneous rocks to determine the crystallization age for the bedrock samples. The data tables accompanying this data release report the isotopic composition of uranium (U) and thorium (Th) measured in each grain, ratios of three isotopes of lead (208Pb, 207Pb, and 206Pb), two isotopes of uranium (235U and 238U), one isotope of thorium (232Th), and the age of each grain, plus trace element abundances from the same ablated aliquot, including P, V, Sr, high field strength elements (HFSE), and rare earth elements (REE). Reported Hf (and Lu) isotope data includes 176Hf/177Hf, 176Lu/177Hf, and 178Hf/177Hf ratios, calculated epsilon Hf values, and age-corrected isotope ratios and epsilon values.

This dataset contains U-Pb isotopic data and ages, Hf isotope data, and trace element concentrations of zircon from igneous rocks collected from the western Alaska Range of south-central Alaska. The sample suite was collected as part of geological mapping and supporting geochemical and geochronological analysis conducted from 2011 to 2013. We also analyzed portions of remainders of previously collected igneous bedrock samples from the USGS archive, allowing expansion of the dataset to include igneous bodies that were not sampled during 2011–2013 field work or were outside the area of focused project field work. Zircon was obtained from these igneous rocks to determine the crystallization age for the bedrock samples. The data tables accompanying this data release report the isotopic composition of uranium (U) and thorium (Th) measured in each grain, ratios of three isotopes of lead (208Pb, 207Pb, and 206Pb), two isotopes of uranium (235U and 238U), one isotope of thorium (232Th), and the age of each grain, plus trace element abundances from the same ablated aliquot, including P, V, Sr, high field strength elements (HFSE), and rare earth elements (REE). Reported Hf (and Lu) isotope data includes 176Hf/177Hf, 176Lu/177Hf, and 178Hf/177Hf ratios, calculated epsilon Hf values, and age-corrected isotope ratios and epsilon values.

This data set contains fission track data and associated ages of apatite from igneous and sedimentary rocks, U-Pb isotopic data and associated ages of zircon from a subset of the igneous rock samples, and U-Pb isotopic data and associated ages of detrital zircon from a subset of the sedimentary rock samples. All samples were collected from the region surrounding Lake Clark and Lake Iliamna in southwestern Alaska. All samples were collected as part of geological mapping and research conducted in 2008 and funded by the U.S. Geological Survey Mineral Resources External Research Program. Apatite and zircon grains were separated and analyzed by Apatite to Zircon, Inc. (A2Z). All analyses were conducted in 2009 using standard fission track dating techniques and laser-ablation-inductively-coupled-plasma-mass spectrometry (LA-ICP-MS) techniques

This data set contains U-Pb isotopic data and associated ages of detrital zircon from sedimentary and metasedimentary rocks collected in northern Yukon, Canada. The samples were originally collected as part of geological mapping and research conducted by the Geological Survey of Canada. They were recovered from archived collections and sent to the U.S. Geological Survey for analysis of detrital zircon using U-Pb geochronology methods. Detrital zircon grains were separated and analyzed by GeoSep Services (GSS) in 2015 using laser-ablation-inductively-coupled-plasma-mass spectrometry (LA-ICP-MS) techniques.

This data set contains U-Pb isotopic data and associated ages of detrital zircon from sedimentary and metasedimentary rocks collected in northern Yukon, Canada. The samples were originally collected as part of geological mapping and research conducted by the Geological Survey of Canada. They were recovered from archived collections and sent to the U.S. Geological Survey for analysis of detrital zircon using U-Pb geochronology methods. Detrital zircon grains were separated and analyzed by GeoSep Services (GSS) in 2015 using laser-ablation-inductively-coupled-plasma-mass spectrometry (LA-ICP-MS) techniques.