RFI_SOW_AMS_Radiocarbon_Analyses_1.pdf

U.S. GEOLOGICAL SURVEY

ALASKA SCIENCE CENTER

STATEMENT OF WORK

1.0 INTRODUCTION

The USGS needs to acquire radiocarbon analyses of organic material from sediment samples.

2.0 BACKGROUND

The USGS is assessing tsunami hazards across Prince William Sound, Alaska. To do so, it needs to identify when tsunamis occurred in the past to evaluate the frequency and impacts of these events. Such age estimates can be precisely calculated from the results of accelerator mass spectrometer radiocarbon analyses on small samples of organic material from coastal deposits, marine sediment and lake deposits in south-central Alaska. The samples we submit for radiocarbon analysis will help us assess when tsunamis inundated certain shorelines throughout Prince William Sound, how large or extensive the waves were, and ultimately what scale of seismic and/or landslide events caused the tsunamis. This field-based research is one component of the Alaska Earthquake Hazards Project, which falls within the USGS Earthquake Hazards Program.

3.0 SCOPE

The contractor shall perform the tasks listed under Section 5.0 below in order to obtain radiocarbon estimates on samples submitted to support seismic hazards research in Alaska.

4.0 APPLICABLE DOCUMENTS

None.

5.0 TECHNICAL REQUIREMENTS

USGS will provide the contractor with samples not to exceed a quantity of 25 for a base year;

and a quantity not to exceed 100 samples for Option Year 1, if available, subject to continuing need and the availability of funds.

(a) As each batch of samples is received, contractor shall perform a series of sample pretreatments using standard methods for pretreating 14C samples (for example, Mook and van der Plassche, 1986; Jull, 2007). For most samples, pretreatment will consist of a series of heated acid-base-acid pretreatments to remove contaminants from samples as applicable to each type of sample of a particular size. Some small samples may require only the acid pretreatment. Some samples are small (1-5 mg) and will require careful monitoring of sample response to pretreatments to avoid destroying the sample. Contractor will consult with the USGS technical liaison if samples are so small that pretreatment may destroy the organic material.

(b) Contractor shall determine the 13C/12C ratio for each sample using in-line stable 13C analysis (for example, Glaser et al., 2005; Jull, 2007) at no additional charge, unless the split for the 13C analysis will reduce the size of the sample below what is needed for 14C analysis.

(c) Contractor shall convert the sample to graphite and analyze each sample in the accelerator mass spectrometer.

(d) Contractor shall ensure that each sample is measured for the amount of time required to obtain standard deviations on ages of less than +/-70 years on 500- to 10,000-year-old samples containing as little as 3 mg of carbon.

(e) Contractor shall discard any remaining samples.

References:

Glaser, B., 2005, Compound-specific stable-isotope (13C) analysis in soil science: Journal of Plant Nutrition and Soil Science, v. 168, p. 633-648.

Jull, A.J.T., 2007. Radiocarbon Dating: AMS Method, In: Elias, S.A. (Ed.), Encyclopedia of Quaternary Science. Elsevier, Amsterdam, pp. 2911-2918.

Mook, W.G., and van de Plassche, O., 1986. Radiocarbon Dating, In: van de Plassche, O.

(Ed.), Sea-Level Research—A Manual for the Collection and Evaluation of Data. Geo Books, Norwich, pp. 525-560.

6.0 DELIVERABLES

Contractor will complete 13C and 14C analyses within 3 months of receiving each batch of samples, unless unforeseen equipment failures at the accelerator facility delay analyses.

Contractor will deliver by email to the USGS technical liaison a written report that lists the results of 13C and 14C analyses and ages and describes any special preparation procedures used in performing the analyses. Results will be provided in a format (e.g., .xls, .csv) compatible with standard data applications (e.g., MS Excel) and include the following parameters: Receipt #; Date Reported; Submitter ID; Type of Material; Process; Accession #;

F Modern; Fm Err; d13C Corr; C-14 Age; C-14 Age Err; d13C; d13C Source.

7.0 Government Furnished Property: N/A

8.0 Place of Performance: Contractor’s facility

9.0 Period of Performance:

March 1, 2026 – February 28, 2027 (Base Year) March 1, 2027 – February 29, 2028 (Option Year 1, if available, subject to availability of continuing need and the availability of funds)