USGS Luminescence Laboratory

Task Objectives

The USGS Luminescence Dating Laboratory (Denver) offers three different kinds of luminescence dating. Traditional Thermoluminescence (TL) is offered for sediment samples which may vary in age from 1,000 years to 500,000 years. Optically Stimulated Luminescence (OSL) is offered for both Infrared Stimulated Luminescence (IRSL) on feldspars varying in age from 200 years to 450,00 years and blue-light OSL (blue OSL) on quartz varying in age from 10 years to 150,000 years. The newest technique of blue-light OSL is also offered for single aliquot (300-500 grains) analyses. The technique has undergone drastic technological advances, for instance, just five years ago an age with an accuracy of 10-20% was considered good. Today ages are routinely given with accuracies of 3-7%. With single grain analyses the accuracy can be given in 1- 5%.

The USGS Luminescence Lab provides a wide capability in luminescence dating. Sediments from eolian processes, such as dunes (both coastal and inland) or loess can be very well dated using luminescence. Sediments from fluvial processes, such as alluvium, colluvium, lacustrine and shallow marine, have also proven suitable for luminescence using blue-light OSL and IRSL. Even material from light starved environments such as glaciers can be dated using single grain or single aliquot blue-light OSL and IRSL.

The USGS Luminescence Dating lab offers critical geochronology aid to a wide variety of projects, both within the USGS and outside. The lab offers a "how-to" booklet that covers what luminescence dating is, examples in current literature of what deposits and artifacts can be dated, how to collect samples, cost, turnaround time, other North American luminescence labs and contacts and a list of past and current USGS projects luminescence dating has been applied to (successful or not).

The booklet can be obtained by e-mailing Shannon Mahan.

Statement of Work

Laboratory personnel respond to inquiries about the laboratory and maintain equipment. Analyses for USGS projects as well as outside requests are performed.

Highlights & Key Findings

Surficial Geologic Mapping Program: In the Mojave desert dating colluvium, alluvium and eolian sediments from 1,000- 300,000 years (with Dave Miller, GD, Menlo Park).
LA-Basin FoQUS Program: Dating shallow marine core sediment ranging in age from 1,000-550,000 years (with Dan Ponti, GD, Menlo Park).
Pacific Northwest Mapping Program: Dating deposits in and around the Seattle and Tacoma area, mainly glacial fluvial or glacial lacustrine of fine silt or sand in conjunction with paleo-mag chronology. Large session of findings expected at GSA in November 2003 (with Ray Wells, GD Menlo Park and Derek Booth and Kathy Troost, University of Washington).
Badlands National Park, SD: Dating Quaternary sediments within the Holocene eolian cliff-tops, Pleistocene eolian sands, fluvial and lacustrine layers beneath the eolian deposits (with Dr. E. Rawling, University of Wisconsin and Dr. R. Benton, Park paleontologist).
Mammoth sites near Greeley, CO: Fluvial deposits dating around 60,000 years in an effort to constrain mammoth occupation rates in North America (with Dr. S. Holen, Denver Museum of Nature and Science).
Cheyenne River, SD: Dating very young fluvial deposits (<500 years) with private consulting firm (em2) in an attempt to date flood cycles.
Lower Colorado River incision studies: Collaboration with a graduate student trying to date rates of incision around caves and local pediment surfaces near Glen canyon Dam. Cosmogenic, radiocarbon and U/Th dating being used as well. (with Cris Garvin of Dartmouth University and Tom Hanks, USGS).
Fulgurite Studies: First ever attempt to date fulgurites using luminescence. Special oral presentation at North American Luminescence meeting in August 2003 (with Dr. R Navarro, University of Mexico and Dr. A. Singhvi, Earth and Planetary Sciences Institute, India).
Convener and organizer of the 4th New World Luminescence Dating and Dosimetry Workshop, May 31-June 2, 2006, Denver, Colorado.

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