B--X-Ray Fluorescence (XRF) analysis of split sediment cores

Statement of Work I. GENERAL INFORMATION A. Introduction. X-ray fluorescence is a non-destructive elemental analysis sensitive to most elements from Aluminum to Uranium. Scans are typically performed on recovered sediment including bulk samples and sediment cores, and depending on the sample being scanned resolutions can range from 0.1mm to 10cm. The US Geological Survey, Earthquake Science Center, uses these data to differentiate earthquake triggered sediment density flows from climatic related triggers (i.e., intensive flooding), to determine fault activity and associated earthquake hazards through lacustrine paleoseismology. B. Background. Lacustrine paleoseismology develops records of pre-historic earthquakes by using shaking induced signals in the depositional record of a lake (i.e., through the generation of sediment density flows by strong ground motion). Because both flood and earthquake induced density flows can have similar physical appearance (in terms of deposit structure and similar grain size evolution), a separate independent dataset that does not rely on sedimentological character is needed to strengthen interpretations and help reduce potential overestimation of the number of earthquakes. There are several physical mechanisms that differ between climatic and earthquake generated density flows, such as delivery of oxygenated bottom water during floods that have been shown to produce a geochemically distinct pattern in the relative abundance of specific elements (for example Mn). These differences can be identified with XRF analysis and used to differentiate flood related deposits from earthquake related deposits. C. Scope. Purpose of the work is to obtain relative elemental abundances from split sediment cores collected in lakes from Alaska, California, Oregon, and Washington. II. WORK REQUIREMENTS A. Technical Requirements. 1. In consultation with the lab manger approximate 70 split cores will be scanned at 1mm sampling interval for detection of ‘light atomic weight’ elements (Al, Si, P, S, Cl, K, Ca, Ti, Cr, Mn, Fe), and detection of ‘medium atomic weight’ elements (Cu, Zn, Ga, Br, Rb, Sr, Y, Zr, Nb, Mo, Pb, Bi). Final number of core scan will be determined via consulation between USGS researchers and XRF lab personal. The lab will be responsible for -- 1 of 2 -- preparing the split cores for a successful analysis and will also provide a technician to conduct the XRF scan or assist USGS personal during scanning. USGS personal will deliver split cores to XRF lab. 2. Criteria for acceptance of Product or Service. XRF analysis results provided within 60 days of receipt of USGS cores. B. Deliverables. 1. Characteristics for work product described in II.A.1., identified by name and quantity. USGS will provide the split cores for XRF analysis. If applicable, the laboratory will conduct XRF specific preparations to get split cores suitable for scanning. The laboratory will provide results in the form of a spreadsheet table or data text including the USGS core identification, lab identification number (if applicable), and elemental abundances down core. 2. Delivery dates for work/product to be completed and point of delivery. Results will be emailed within 60 days of receipt of USGS cores. III. SUPPORTING INFORMATION A. Place of Performance. Vendor’s facility B. Period of Performance. September 1, 2026 to September 30, 2027. C. Government Furnished Property (GFP): None. D. Special Considerations. 1. Key personnel qualifications. N/A 2. Data Rights, Safety, Environment. Data will be released in accordance with USGS data release policies. 3. Security/Privacy issues. N/A -- 2 of 2 --