Chloë Glover Grant D. Colip 20260220 spreadsheet https://doi.org/10.5066/P1KLX7Z2 This data release presents portable X-ray fluorescence (pXRF) data and physical properties (grain density, saturated bulk density, dry bulk density, and magnetic susceptibility) of 30 rock samples collected from an Earth MRI survey area in northeastern Washington, USA. Rock type information (age and lithology) are also included. The rock samples were initially collected for low-temperature thermochronology in May and June of 2025 and are composed mostly of felsic igneous or metamorphic rocks, many of which are Triassic-Eocene in age. The pXRF analysis is part of a larger project to determine the tectonic context and critical mineral potential of northeastern Washington State through structural and thermo-kinematic modelling. The 30 samples represented in this data release are also being processed and analyzed for low-temperature thermochronology (apatite helium and zircon helium). The thermochronology results will be used in thermal models to determine the tectonic deformation history, age and rate of faulting, erosional exhumation, and ultimately timing and process of critical mineral formation. The pXRF data will be used to constrain the model based on the presence and location of critical mineral resources at the surface. The results from these subsequent analyses and modeling will be published separately at a later date. The pXRF data presented here were collected in December 2025 using instrumentation housed in the Bascom Laser Diffraction Sedimentology Laboratory at the USGS Florence Bascom Geoscience Center (FBGC) in Reston, VA. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government. The pXRF dataset will be used to determine the presence and location of critical minerals in the Earth MRI survey area in northeastern Washington State, and the geologic history of their formation. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government. 20250528 20250605 ground condition Complete None planned -120.2290 -116.9826 48.9748 48.5197 ISO 19115 Topic Category geoscientificInformation None U.S. Geological Survey USGS Florence Bascom Geoscience Center FBGC Geology, Minerals, Energy, and Geophysics Science Center GMEGSC rock physical properties magnetic susceptibility sedimentology density geochemistry elemental XRF pXRF X-ray fluorescence thermochronology mag susc USGS Metadata Identifier USGS:698224eab66b018d00102deb None Washington Pacific Northwest Idaho Okanogan Highland None. Please see 'Distribution Info' for details. None. Users are advised to read the dataset's metadata thoroughly to understand appropriate use and data limitations. Grant D. Colip U.S. Geological Survey; Florence Bascom Geoscience Center Physical Scientist mailing and physical

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Reston Virginia 20192 United States (703) 648-6919 (703) 648-6953 The authors thank Lydia Staisch (USGS GMEGSC) for assistance in the field, Brandon Graham (USGS FBGC) for assistance with pXRF sample preparation, and GeoSep Services for sample crushing. These data have been peer reviewed and assessed for accuracy using processes described in the Process Step section of this metadata. The pXRF methodology employed to produce this dataset calculates errors associated with each measurement; this error is calculated internally by the pXRF instrument and is reported in the dataset. Data values from each analysis were checked to ensure that they fall within the expected ranges. For magnetic susceptibility data, mean and maximum values are reported from 10 replicates. Data were checked for duplication and omission. No other formal logical consistency reports were conducted. The dataset is considered complete for the information presented, as described in the abstract. Users are advised to read the rest of the metadata record carefully for additional details. No formal positional accuracy tests were conducted. No formal positional accuracy tests were conducted. Samples were initially collected for low-temperature thermochronology. Sample locations were chosen based on rock age, lithology, spacing across the study area, and quality of the outcrop. Each sample was collected in the field with a chisel, rock hammer, and/or sledge, then bagged, weighed, and shipped to GeoSep Services to be crushed and separated. Magnetic susceptibility was also collected in the field using a KT-10 magnetic susceptibility meter at 10 points on the outcrop. Magnetic susceptibility is reported as the mean of these 10 values, and the maximum of these 10 values. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government. 20250605 Chloe O. Glover U.S. Geological Survey; Geology, Minerals, Energy, and Geophysics Science Center Research Geologist mailing

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Portland Oregon 97201 United States N/A cglover@usgs.gov After samples were crushed and minerals picked for thermochronology by GeoSep Services, the additional pulverized material representative of the whole rock for each sample was returned for use in the pXRF analysis. The separated minerals for low-temperature Apatite-He and Zircon-He thermochronology were sent to the University of Colorado Boulder for analysis. Additional rocks from each sample were used to measure the grain density, saturated bulk density, and dry bulk density in Portland, Oregon. Samples were first dry brushed with a wire brush to remove detritus, plant material, and loose dirt from the rock, and labeled in permanent marker with their sample identifier. Each sample was weighed dry using a digital scale two times, and the mean of the two measurements were recorded as 'Wa', or “weight in air”, in grams. Samples were soaked in water overnight and subsequently re-weighed twice. The mean of the two weights was recorded as Ww, or “weight in water”, in grams. Samples were then removed from the water, patted dry lightly, and weighed twice on the digital scale. The mean of the two weights was recorded as Was, or “weight after saturation”, in grams. To calculate grain density, or D1, we use the equation D1 = Wa/(Wa-Ww). To calculate saturated bulk density, or D2, we use the equation D2 = Was/(Was-Ww). To calculate dry bulk density, or D3, we use the equation D3 = Wa/(Was-Ww). D1, D2, and D3 are recorded in the units [g^1cm^-3]. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government. 20250612 Chloe O. Glover U.S. Geological Survey; Geology, Minerals, Energy, and Geophysics Science Center Research Geologist mailing and physical

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Portland Oregon 97201 United States N/A cglover@usgs.gov pXRF analysis was conducted using a Bruker S1 Titan instrument housed in the Bascom Laser Diffraction Sedimentology Laboratory at the Florence Bascom Geoscience Center, U.S. Geological Survey, Reston, Virginia. The crushed, picked samples were pre-sieved using a #45 mesh (355 µm; medium sand) sieve to include only particles of this size or finer. These subsamples were then loaded into a plastic sample cup with Prolene film at the end facing the instrument window. Samples were analyzed in a lab setting with the instrument set up on a benchtop stand for consistency. All samples were run using the instrument’s built-in GeoExploration method, which uses three-phase testing over a run duration of 90 s (i.e., three energies of 30 s duration each) for each analysis. Triplicate analyses were run on each sample at slightly different orientations relative to the X-ray window to enhance data repeatability and representativeness. Data are presented as raw (unaltered) outputs. Variation in the number of significant digits reported between some samples is a result of the instrument output and should not be intepreted as an indicator of precision. Contact the authors of this dataset for more details about the parameters for this analysis. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government. 20251212 Grant D. Colip U.S. Geological Survey; Florence Bascom Geoscience Center Physical Scientist mailing and physical

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Reston Virginia 20192 United States (703) 648-6919 (703) 648-6953 gcolip@usgs.gov The comma separated value file containing the data (Washington_pXRF_density_magsusc_data.csv) is described in a data dictionary rather than directly in this metadata file. The files are as follows: - Washington_pXRF_density_magsusc_data.csv, which includes the raw data, and - Washington_DataDictionary.csv, which is a data dictionary describing the data in the other file. Washington_pXRF_density_magsusc_data.csv Washington_DataDictionary.csv GS ScienceBase U.S. Geological Survey mailing address

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Denver CO 80225 United States 1-888-275-8747 sciencebase@usgs.gov Unless otherwise stated, all data, metadata and related materials are considered to satisfy the quality standards relative to the purpose for which the data were collected. Although these data and associated metadata have been reviewed for accuracy and completeness and approved for release by the U.S. Geological Survey (USGS), no warranty expressed or implied is made regarding the display or utility of the data for other purposes, nor on all computer systems, nor shall the act of distribution constitute any such warranty. Digital Data https://doi.org/10.5066/P1KLX7Z2 None 20260220 Grant D. Colip U.S. Geological Survey; Florence Bascom Geoscience Center Physical Scientist mailing and physical

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Reston Virginia 20192 United States (703) 648-6919 (703) 648-6953 gcolip@usgs.gov FGDC Content Standard for Digital Geospatial Metadata FGDC-STD-001-1998