U-Pb ages and concentrations of selected trace elements were analyzed in zircon crystals from nine samples of Cenozoic igneous rocks collected near Tonopah, Nevada. U-Pb ages were obtained from four samples, and trace element analyses were obtained from both the dated samples and an additional five samples.

The Cortez region in north-central Nevada hosts the second largest concentration of Carlin-type gold deposits in Nevada. The origin of these deposits is debated, and major questions remain concerning the role of magmatism in their formation. To understand the Mesozoic and Cenozoic magmatic history of the Cortez region, twenty-one samples of igneous rocks ranging from Jurassic to Eocene were sampled, including drill core from around several of the major deposits. Individual zircon grains from these samples were analyzed by Sensitive High Resolution Ion Microprobe (SHRIMP) for uranium lead ages and a suite of trace elements. Most samples are Eocene, in particular the dikes associated with Cortez mineralization. Although no Cretaceous rocks igneous rock are exposed, Cretaceous xenocrysts were found in some samples indicating the presence of Cretaceous rocks at depth.

The Cortez region in north-central Nevada hosts the second largest concentration of Carlin-type gold deposits in Nevada. The origin of these deposits is debated, and major questions remain concerning the role of magmatism in their formation. To understand the Mesozoic and Cenozoic magmatic history of the Cortez region, twenty-one samples of igneous rocks ranging from Jurassic to Eocene were sampled, including drill core from around several of the major deposits. Individual zircon grains from these samples were analyzed by Sensitive High Resolution Ion Microprobe (SHRIMP) for uranium lead ages and a suite of trace elements. Most samples are Eocene, in particular the dikes associated with Cortez mineralization. Although no Cretaceous rocks igneous rock are exposed, Cretaceous xenocrysts were found in some samples indicating the presence of Cretaceous rocks at depth.

This data set contains tables containing uranium-lead (U-Pb) isotopic data and the crystallization age of zircon from a metamorphic rock from the Manzano Mountains, New Mexico, collected in 2005. The bulk sample was processed into concentrated mineral separates of zircon at the University of Texas at Austin and analyzed by U.S. Geological Survey (USGS) research scientists at the Stanford-USGS Sensitive High Resolution Ion Microprobe with Reverse-Geometry (SHRIMP-RG) at Stanford University. The data table "geochronology_SHRIMP-RG_manzanoMtns_jones.csv" accompanying this data release reports the isotopic composition of uranium (U) and thorium (Th) measured in each grain, ratios of two isotopes of lead (207Pb and 206Pb) and two isotopes of uranium (235U and 238U), the age of each grain, and concentrations of selected trace elements measured in each grain. A second table "geochronology_sampleSummary_manzanoMtns_jones.csv" reports the sample location, rock characteristics, and interpreted age. Additionally, a third data table "geochronology_dataDictionary_manzanoMtns_jones.csv" is provided as a reference guide for the user.

This data set contains tables containing uranium-lead (U-Pb) isotopic data and the crystallization age of zircon from a metamorphic rock from the Manzano Mountains, New Mexico, collected in 2005. The bulk sample was processed into concentrated mineral separates of zircon at the University of Texas at Austin and analyzed by U.S. Geological Survey (USGS) research scientists at the Stanford-USGS Sensitive High Resolution Ion Microprobe with Reverse-Geometry (SHRIMP-RG) at Stanford University. The data table "geochronology_SHRIMP-RG_manzanoMtns_jones.csv" accompanying this data release reports the isotopic composition of uranium (U) and thorium (Th) measured in each grain, ratios of two isotopes of lead (207Pb and 206Pb) and two isotopes of uranium (235U and 238U), the age of each grain, and concentrations of selected trace elements measured in each grain. A second table "geochronology_sampleSummary_manzanoMtns_jones.csv" reports the sample location, rock characteristics, and interpreted age. Additionally, a third data table "geochronology_dataDictionary_manzanoMtns_jones.csv" is provided as a reference guide for the user.

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.

During the 2017 and 2018 field seasons, geologists from the Alaska Division of Geological & Geophysical Surveys (DGGS) conducted geologic mapping and sampling in the Richardson mining district southeast of Fairbanks, including parts of the Big Delta B-4, B-5, B-6, and C-6 quadrangles. The project area has produced approximately 122,000 ounces of gold, mostly from placer mines, and includes the Uncle Sam, Montecristo, Richardson, Tower, and Hilltop lode gold exploration properties. The goal of DGGS's work in this area is to conduct a mineral-resource assessment and to build an improved understanding of the area's geology and controls on gold mineralization to facilitate industry exploration targeting. Uranium-lead (U-Pb) zircon geochronology results presented in this report show that similarly textured quartz-feldspar porphyry intrusions in the project area were generated by both Paleocene (56.8 +/- 0.9 Ma; 18WCW149) and middle Cretaceous (92.0 +/- 0.7 Ma; 18AW002, known as the Democrat Dike) magmatic episodes. The ages of medium-grained plutonic rocks at Birch Lake (92.4 +/- 0.6 Ma; 18ET587) and Gold Run (93.7 +/- 0.7 Ma; 18ET580) lie within error of the age of the hypabyssal Democrat Dike, indicating that the present-day depth of exposure juxtaposes rocks that were buried at widely different crustal depths during the middle Cretaceous. Phaneritic granodiorite near the Democrat prospect yielded a zircon age of 110.7 +/- 1.3 Ma (18RN565), extending the magmatic history of the prospect into the Early Cretaceous. Amphibolite-facies augen orthogneiss yielded a Late Devonian zircon age of 364.5 +/- 6.0 Ma (18ET040), consistent with similar rocks in the Lake George assemblage. Detrital zircons analyzed from siliciclastic schist along the Richardson Highway (18AW021) contain prominent age populations at 1.8 and 2.6 Ga, consistent with a Laurentian cratonic source and consistent with other results from parautochthonous North America. Pelitic schist from the Hilltop prospect (18TJN372) yielded a relatively small number (n=32) of zircon grains that define small age populations between ca. 1.7 and 1.5 Ga. All components of this data release are available on the DGGS website: http://doi.org/10.14509/30555.

This data release includes raw detrital zircon U-Pb data for Paleoproterozoic metasedimentary rocks of the Gunnison block, central Colorado, USA. Detrital zircon U-Pb data for five samples of metasedimentary rock (totaling 1459 zircon U-Pb dates) were acquired via laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) at the University of Arizona LaserChron Center. The data provide constraints on the sediment provenance, maximum depositional age, and timing of metamorphism of these metasedimentary rocks, providing insights on the crustal and tectonic evolution of the Gunnison block and Yavapai Province.

This data release includes raw detrital zircon U-Pb data for Paleoproterozoic metasedimentary rocks of the Gunnison block, central Colorado, USA. Detrital zircon U-Pb data for five samples of metasedimentary rock (totaling 1459 zircon U-Pb dates) were acquired via laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) at the University of Arizona LaserChron Center. The data provide constraints on the sediment provenance, maximum depositional age, and timing of metamorphism of these metasedimentary rocks, providing insights on the crustal and tectonic evolution of the Gunnison block and Yavapai Province.