Welcome to the USGS Luminescence Dating Laboratory Site. Information describing the principles of the dating technique, applications and types of dating, as well as more technical information for prospective customers can be found at this site.
What is Luminescence Dating?
Luminescence dating is a form of geochronology that measures the energy of photons being released. In natural settings, ionizing radiation (U, Th, Rb, & K ) is absorbed and stored by sediments in the crystal lattice. This stored radiation dose can be evicted with stimulation and released as luminescence. The calculated age is the time since the last exposure to sunlight or intense heat. The sunlight bleaches away the luminescence signal and resets the time 'clock'. As time passes, the luminescence signal increases through exposure to the ionizing radiation and cosmic rays. Luminescence dating is based on quantifying both the radiation dose received by a sample since its zeroing event, and the dose rate which it has experienced during the accumulation period (See the Luminescence Age Equation). The principal minerals used in luminescence dating are quartz and potassium feldspar.
Types of Luminescence Dating Techniques
- Thermal (TL)
- Optically Stimulated (OSL)
- Green Light (GSL) - Feldspar & Quartz
- Blue Light (BSL) - Quartz
- Red Light (RSL) - Volcanic Feldspar & Quartz
- Infrared Stimulated (IRSL) (IRSL)
- post-infrared infrared Stimulated (pIRIR) – Feldspar
Luminescence Age Equation, Equivalent Dose, and Dose Rate
Controlling Assumptions - TL and OSL Method
- Complete Zeroing - Exposure to sunlight or intense heat (>150°C) for an extended period of time
- Stable Luminescence Present - Plateau Test (TL only)
- Accurate Determination of the Dose Rate (DR) and Past Moisture Content
The Luminescence Age Equation: Age = DE / DR
DE is measured in grays (absorbed dose) and commonly known as the Equivalent Dose or paleodose
DR is measured in grays/ka and commonly known as the Dose Rate. Comprised of K , U, Th, Rb, and cosmic ray components
Determination of Equivalent Dose (DE)
- Additive Dose - usually multiple aliquots
- Partial Bleach - assumes a mix of grains with varying partial bleaches
- Total Bleach - assumes complete zero
- Regeneration - usually single aliquot or more rarely single grain
Determination of Dose Rate (DR)
- Neutron Activitation - U, Th, K , Rb
- γ Spectrometry - U, Th, K (Lab & Field)
- Atomic Absorption - K , Rb
- Alpha Counting - ZnS scintillation user for α
- Inductively Coupled Plasma - Mass Spectrometry (ICP-MS)
- Flame Photometry - K
Contributions to Sediments
The application of luminescence to dating archaeological or geological materials relies on determining two quantities. The first is the amount of radiation absorbed by the sample during the period since the event being dated, measured as De. To determine the age of the sample in years, De has to be divided by the radiation dose received by the sample each year – the dose rate.
There are four types of environmental radiation: alpha particles (α), beta particles (β), gamma rays (γ) and cosmic rays. The first three originate from naturally occurring elements in the sample itself and its surroundings. The most important of these sources are radioactive isotopes of uranium (U), thorium (Th) and potassium (K).
Once the concentrations of these three elements are known, conversion factors enable the calculation of the radiation dose rate (Adamiec and Aitken 1998). For example, 1% potassium in sediment will produce a gamma radiation dose rate of 0.243Gy per thousand years (Gy/ka), a beta dose rate of 0.782Gy/ka, but no alpha dose rate, as the decay of 40K does not result in the emission of alpha particles. Adding together the alpha, beta and gamma dose rates gives the total radiation dose rate.
Sampling
Excavation Process
- Excavate Back ∼20 cm
- Expose a fresh face
- Soft Sediment - auger/push in PVC or aluminum tubes
- Hard Sediment - carve out block
- Moisture and light tight, black cloth cover during collection
Sample Amount Requirements
- Need 100 mg silt (4-11 microns) and 1 gram of fine sand size (90-125 microns or dominant grain size) for OSL (corresponds to 10-100 grams initial sample)
- Usually an extra bulk sample is needed (about 400-600 grams) for moisture
Related Content
Active faulting on the Wallula fault zone within the Olympic-Wallowa lineament, Washington State, USA
Episodic bedrock erosion by gully-head migration, Colorado High Plains, USA
Quaternary alluvial fans of Ciudad Juárez, Chihuahua, northern México: OSL ages and implications for climatic history of the region
Active tectonics within the NW and SE extensions of the Pambak-Sevan-Syunik fault: Implications for the present geodynamics of Armenia
Identification and dating of indigenous water storage reservoirs along the Rio San José at Laguna Pueblo, western New Mexico, USA
Construction ages of the Upton Stone Chamber: Preliminary findings and suggestions for future luminescence research
Lithostratigraphic, borehole-geophysical, hydrogeologic, and hydrochemical data from the East Bay Plain, Alameda County, California
Paleodischarge of the Mojave River, southwestern U.S.A, investigated with single-pebble measurements of 10Be
User guide for luminescence sampling in archaeological and geological contexts
Variables and potential models for the bleaching of luminescence signals in fluvial environments
Luminescence dating of anthropogenic features of the San Luis Valley, Colorado: from stone huts to stone walls
Late Quaternary slip history of the Mill Creek strand of the San Andreas fault in San Gorgonio Pass, southern California: The role of a subsidiary left-lateral fault in strand switching
Related Content
- Publications
Filter Total Items: 62
Active faulting on the Wallula fault zone within the Olympic-Wallowa lineament, Washington State, USA
The Wallula fault zone is an integral feature of the Olympic-Wallowa lineament, an ∼500-km-long topographic lineament oblique to the Cascadia plate boundary, extending from Vancouver Island, British Columbia, to Walla Walla, Washington. The structure and past earthquake activity of the Wallula fault zone are important because of nearby infrastructure, and also because the fault zone defines part oAuthorsBrian L. Sherrod, Richard J. Blakely, John P. Lasher, Andrew P. Lamb, Shannon A. Mahan, Franklin F. Foit, Elizabeth BarnettEpisodic bedrock erosion by gully-head migration, Colorado High Plains, USA
This study explores the frequency of bedrock exposure in a soil-mantled low-relief (i.e. non-mountainous) landscape. In the High Plains of eastern Colorado, gully headcuts are among the few erosional features that will incise through the soil mantle to expose bedrock. We measured the last time of bedrock exposure using optically stimulated luminescence dating of alluvial sediment overlying bedrockAuthorsFrancis K. Rengers, G.E. Tucker, Shannon MahanQuaternary alluvial fans of Ciudad Juárez, Chihuahua, northern México: OSL ages and implications for climatic history of the region
Alluvial fans formed from sediments derived from erosion of the Juárez Mountains in northernmost México have a significant flood impact on the Ciudad Juárez, which is built on the fan system. The northern part of Ciudad Juárez is the most active; further south, older parts of the fan, upon which the rest of the city is built, were largely eroded by natural processes prior to human habitation and sAuthorsDavid Zúñiga de León, Stephen Kershaw, Shannon A. MahanActive tectonics within the NW and SE extensions of the Pambak-Sevan-Syunik fault: Implications for the present geodynamics of Armenia
This study analyzes the active tectonics within the northwestern and southeastern extensions of the Pambak-Sevan-Syunik fault (PSSF), a major right-lateral strike-slip fault cutting through Armenia. Quantifying the deformations in terms of geometry, kinematics, slip rates and earthquake activity, using cosmogenic 3He, OSL/IRSL and radiocarbon dating techniques, reveal different behaviors between tAuthorsJeff Ritz, A. Avagyan, M. Mkrtchyan, H. Nazari, P. H. Blard, A. Karakhanian, H. Philip, Sanda Balescu, Shannon A. Mahan, Sebastien Huot, P. Münch, M. LamotheIdentification and dating of indigenous water storage reservoirs along the Rio San José at Laguna Pueblo, western New Mexico, USA
An investigation into indigenous water storage on the Rio San José in western New Mexico was conducted in support of efforts by the Pueblo of Laguna to adjudicate their water rights. Here we focus on stratigraphy and geochronology of two Native American-constructed reservoirs. One reservoir located near the community of Casa Blanca was formed by a ∼600 m (2000 feet) long stone masonry dam that impAuthorsGary Huckleberry, T.J. Ferguson, Tammy M. Rittenour, Chris Banet, Shannon A. MahanConstruction ages of the Upton Stone Chamber: Preliminary findings and suggestions for future luminescence research
The Upton Chamber in Massachusetts, an earth-covered stone structure 3.4 meters (m) in diameter, with a corbelled stone dome, and a 4.3 m long entrance passageway, is studied with the aim of determining whether optically stimulated luminescence (OSL) dating methods can be used to establish the approximate construction date of the entranceway. Three samples, taken from soil behind the lowest stonesAuthorsShannon A. Mahan, Frederick Martin, Cathy TaylorLithostratigraphic, borehole-geophysical, hydrogeologic, and hydrochemical data from the East Bay Plain, Alameda County, California
The U.S. Geological Survey, in cooperation with the East Bay Municipal Utility District, carried out an investigation of aquifer-system deformation associated with groundwater-level changes at the Bayside Groundwater Project near the modern San Francisco Bay shore in San Lorenzo, California. As a part of the Bayside Groundwater Project, East Bay Municipal Utility District proposed an aquifer storaAuthorsMichelle Sneed, Patricia v.P. Orlando, James W. Borchers, Rhett R. Everett, Michael Solt, Mary McGann, Heather Lowers, Shannon MahanPaleodischarge of the Mojave River, southwestern U.S.A, investigated with single-pebble measurements of 10Be
The paleohydrology of ephemeral stream systems is an important constraint on paleoclimatic conditions in arid environments, but remains difficult to constrain quantitatively. For example, sedimentary records of the size and extent of pluvial lakes in the Mojave Desert have been used as a proxy for Quaternary climate variability. Although the delivery mechanisms of this additional water are still bAuthorsAndrew J. Cyr, David M. Miller, Shannon A. MahanUser guide for luminescence sampling in archaeological and geological contexts
Luminescence dating provides a direct age estimate of the time of last exposure of quartz or feldspar minerals to light or heat and has been successfully applied to deposits, rock surfaces, and fired materials in a number of archaeological and geological settings. Sampling strategies are diverse and can be customized depending on local circumstances, although all sediment samples need to include aAuthorsMichelle S. Nelson, Harrison J. Gray, Jack A. Johnson, Tammy M. Rittenour, James K. Feathers, Shannon MahanVariables and potential models for the bleaching of luminescence signals in fluvial environments
Luminescence dating of fluvial sediments rests on the assumption that sufficient sunlight is available to remove a previously obtained signal in a process deemed bleaching. However, luminescence signals obtained from sediment in the active channels of rivers often contain residual signals. This paper explores and attempts to build theoretical models for the bleaching of luminescence signals in fluAuthorsHarrison J. Gray, Shannon MahanLuminescence dating of anthropogenic features of the San Luis Valley, Colorado: from stone huts to stone walls
The Snake Nest Wall site and the Crestone Stone Huts are in the northern San Luis Valley, Colorado, and provide a unique opportunity to date high-altitude archeological sites of unknown age and origin using optically stimulated luminescence (OSL). We sampled sediment underlying foundation stones of these structures to establish a chronological framework for each site's construction. OSL dating ofAuthorsShannon Mahan, Rebecca A. Donlan, Barbara Maat KardosLate Quaternary slip history of the Mill Creek strand of the San Andreas fault in San Gorgonio Pass, southern California: The role of a subsidiary left-lateral fault in strand switching
The fault history of the Mill Creek strand of the San Andreas fault (SAF) in the San Gorgonio Pass region, along with the reconstructed geomorphology surrounding this fault strand, reveals the important role of the left-lateral Pinto Mountain fault in the regional fault strand switching. The Mill Creek strand has 7.1–8.7 km total slip. Following this displacement, the Pinto Mountain fault offset tAuthorsKatherine J. Kendrick, Jonathan C. Matti, Shannon A. Mahan