4-Attachment B Scope of Work.docx

Scope of Work for Contract #NC26-3 Attachment : B

1. Introduction This Scope of Work is in support of establishing a contract for U-Th-Pb geochronology in order to obtain crystallization ages of intrusive (magmatic) rocks. The Utah Geological Survey is poised to receive funding that will allow statewide sampling of intrusive units for which the crystallization (CZ) age is an essential piece of information for evaluating certain types of mineral resource potential within the state. Given the number of samples that are planned for the next 3-5 years, we are seeking a contract with a laboratory that is able to provide the full workflow for U-Th-Pb dating on zircon, including mineral separation and preparation, imaging, analysis, and age calculations delivered within 4 months from receipt of whole rock samples at the laboratory.

This Scope of Work will be issued under U-Pb Crystallization Ages for Igneous Rocks.

1.1 Background

The Utah Geological Survey is tasked with providing timely scientific information about Utah’s resources, including mineral resources. The increase in attention on domestic mineral resources, including critical mineral resources, calls for a statewide assessment of Utah’s known mineral systems and potential mineral resources. In pursuit of these goals, the UGS has received federal and state funding to characterize mineral systems related to magmatic mineral systems. Within the study area for this project, there are 28 critical mineral focus areas including 14 known critical minerals: aluminum; antimony; arsenic; beryllium; bismuth; fluorspar; indium; manganese; platinum; palladium; scandium; tellurium; tungsten; zinc. Of these, beryllium, platinum, palladium, and tellurium are currently in production and established resources exist for fluorspar, indium, and zinc. A further 12 critical minerals are known to occur within the critical mineral systems present in the project area: barite; cobalt; gallium; germanium; lithium; niobium; REEs; rhenium; strontium; tantalum; tin; and vanadium. Non-critical mineral commodities known in the project area include: cadmium; clay; copper; gem-quality variscite; gold; halloysite clay; iron; lead; mercury; molybdenum; phosphorus; silver; thallium; uranium; yttrium; and zeolite. Of these, copper, molybdenum, gold, silver, iron, and halloysite clay have been recently in or are currently in production.

To further assess the potential for economic production of the commodities above, the UGS is collecting foundational geologic data on these mineral systems, of which the CZ age of magmatic units is an essential component. To obtain the CZ age, rocks collected in the field must be prepared and analyzed via a method known as U-Th-Pb geochronology on the mineral zircon.

1.2 Scope of Work

This Scope of Work focuses on the cost associated with obtaining the CZ age of magmatic rocks in Utah. The intention is to identify a laboratory that can conduct the entire workflow for U-Th-Pb dating on zircon, including:

· Mineral separation and preparation

· Imaging

· U-Th-Pb analysis

· Data and age calculations

· Timeline

· Return of materials

1.3 Requirements

Specific tasks for each milestone include:

· Mineral separation and preparation

· Crushing, pulverizing, water-table

· Heavy Liquid Mineral Separation

· Frantz Magnetic Separation, Wig-L-Bug, Acid Washing

· Mineral mounts

· Imaging

· Back-scatter electron (BSE) images are required for all samples to ensure that the correct minerals are analyzed.

· Cathodoluminescence (CL) images are required for all analyses of zircons to ensure that laser pits are located in optimal portions of crystals.

· U-Th-Pb analysis

· Analytical methods for U‐Th‐Pb geochronology of zircon by Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA‐ICPMS)

· 50 spot analyses per sample (mineral yield allowing)

· Cleaning shots, analyze standards, and analyze unknowns

· No charge to be incurred for analyses of standards or for analyses that are discarded due to instrument malfunction.

· Data and age calculations

· Provide data from each spot analysis, including all standards and QAQC shots

· Provide a crystallization age calculation for each sample (provide isochron diagrams including all age populations as well as the age used for CZ age calculation, i.e. show inheritance as well as CZ population).

· Provide preliminary assessment of any complications to U-Th-Pb systematics, e.g. Pb loss, etc.

· Timeline

· Receipt of spot analysis data, age calculation and supporting data, and BSE and CL imaging within 4 months of whole rock samples being received at the lab.

· Return of materials

· Return mineral mounts to Utah Geological Survey within 2 months of completing analyses

2. Compliance PI will be required to provide a report for each whole rock sample detailing instrumentation, methodology for analysis and data reduction, final weighted mean age at 2 sigma including MSWD, a brief description of grains and analysis for the zircon yield in the sample including total number of spots analyzed and explanation for less than 50 spots per sample, individual spot data, standard and QAQC data, Concordia and/or Tera-Wasserburg plots of the entire zircon population and separately of the population used for age calculation, histogram of spot ages, and weighted average best age plots. Instrumentation and methodology explanations can be grouped for multiple samples where samples underwent the same workflow. These reports for each sample are considered the final deliverable and are required within 4 months of receipt of the whole rock samples at the laboratory.

3. Project Deliverables PI will be required to provide a report for each whole rock sample including:

· Details on instrumentation, [a single description for instrumentation may be included in a report detailing results of multiple samples that underwent the same workflow]

· Description of methodology for analysis and data reduction, [a single description for methodologies may be included in a report detailing results of multiple samples that underwent the same workflow]

· Final weighted mean age at 2 sigma including MSWD

· Brief (~150 words) description of analysis and results in each sample including:

· Number of spots analyzed

· Number of analyses discarded during data reduction and filtering and justification

· Explanation for less than 50 spots per sample (e.g., low zircon yield)

· Notes on any complications to the age calculation (e.g., Pb loss)

· Data

· Spot data

· Standard and QAQC data

· Plots

· Concordia and/or Tera-Wasserburg plots of the entire zircon population

· Concordia and/or Tera-Wasserburg plots of the zircon population used for age calculation

· Histogram of individual spot ages

· Weighted average best age plot of individual spot ages

The report for each sample is considered the final deliverable for that sample and is required within 4 months of receipt of the initial whole rock sample at the laboratory. The mineral mount for each sample must be returned to the Utah Geological Survey within 2 months of delivering the final report.

4. Project Timeline

· The final report for each sample is due within 4 months of receipt of the whole rock sample at the laboratory.

· The mineral mount(s) for each sample are due to be returned to the Utah Geological Survey within 2 months of delivering the final report.

5. Project Budget The total per-sample cost for the workflow detailed in 1.3 and deliverables detailed in 3 should not exceed $1200. Additional costs may be discussed on a per-sample basis where unexpected complexity in the workflow arises (e.g., low zircon yield).