Proceedings of the 4th New World 

Luminescence Dating and Dosimetry 

Workshop, Denver, Colorado, May 31 

June 2, 2006 

Richard A. Wise, Editor 

Open-File Report 2006-1351 

 

 

U.S. Department of Interior 

U.S. Geological Survey
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ii
Introduction to the Luminescence Workshop 

 By Mahan, Shannon A. ......................................................................................................1 

 

Methodological Aspects and Dose Distribution 

Some unexplored methodological aspects and some applications of luminescence dating 

By Singhvi, Ashok and others.............................................................................................2 

 

A theoretical model for a new dating protocol for quartz , based on thermally transferred 

OSL (TT-OSL) 

By Pagonis, Vasilis; Wintel, A.G; Chen, R.; Wang, X.L. ................................................3 

Equivalent dose distributions from maad data sets 

 By Lepper, Kenneth; Denton, Anne................................................................. 4 

Reduction of uncertainties in the measurement of equivalent doses and anomalous fading 

rates in irsl dating of feldspar 

By Lamothe, M.; Auclair,M................................................................................................5 

The luminescence efficiency of cosmic radiation at the surface of Mars and in the 

Martian Regolith-A study with quartz and feldspar 

 By Kalchgrugber, R.; Benton, E.R.; Sawakuchi, G.O.; Mckeever, S.W.S. .......................6 

Low temperature effects on the OSL process of Martian simulants 

By Blair, M.W.; Kalchgruber, R.; Yukihara, E.G.; Mckeever, S.W.S...............................7 

 

Using low intensity blue light to stimulate high and mid-latitude waterlain sediments 

By Pierson, J.; Forman, S.L.; Gomez, Z. ...........................................................................8 

Measuring feldspars osl in a helium atmosphere: potential for improved reproducibility. By 

Huot, S.; Murray, 

A.S.......................................................................................................................................9 

Applications to Dating Sediments (Eastern and Midwestern U.S.A) 

 

iii
The sand ridges of Currituck County, Northeastern North Carolina 

By Burdette, K.; Mallinson, D; Brook, G; Mahan, S.A...................................................10 

Optically stimulated luminescence ages of marine isotope stage 5, 3 and 1 coastal 

lithosomes: North Carolina 

By Mallinson, David; Burdette, Kevin; Mahan, S.A.; Brook, George...........................11 

Luminescence dating of paleoliquifaction features in the Wabash River Valley area of 

Indiana 

By Mahan, S.A.; Crone, A.J.............................................................................12 

OSL chronologies for Aeolian activity in the context of lake-level fluctuations, drainage 

reorganization and glacial retreat, North-Central Minnesota 

By Nicoll, Kathleen; Demko, T.M.; Marlow, Lisa, M. ...........................................................13 

Dating ephemeral stream and alluvial fan deposits on the central great plains: comparing 

multiple-grain osl, single-grain osl, and radio carbon ages 

By Hanson, Paul..................................................................................................14 

Archeological Applications 

OSL dating of sediments from paleoindian sites in Brazil 

By Feathers, James.............................................................................................................15 

Using OSL to date fine-grained ceramics 

By Casson, M.A.; Feathers, J.K. .......................................................................................16 

Luminescence dating of ancient monumental architecture at Chavín Dé Huántar, Peru 

By Johnson, J.A.; Feathers, J.K.; Kembel, S.R. ................................................................17 

Applications to Dating Sediments (Midwest U.S. to Colorado) 

Eolian sand depositional records from Western kansas and Nebraska, and Eastern 

Colorado, U.S.A: a potential landscape response to droughts in the past 10,000 years 

By Forman, S.L.; Marìn, L.; Gomez, J. .......................................................................18 

iv
Luminescence chronology for Late Quaternary and Holocene records of Eolian 

deposition from a “Mega-Trench” across the Anton Scarp, Eastern Colorado 

By Gomez, J.; Noe, D.; Froman, S. ...............................................................19 

Applications to Fluvial Sediments Grand Wash/Grand Canyon 

Using OSL geochronology to correlate stream and hillslope deposits to climate change in 

eastern Grand Canyon tributaries 

By Dejong, B.; Pederson, J.; Rittenour, T.; Goble, R........................................................20 

Using osl to solve the riddle of variable incision rates across the Colorado Plateau 

By Pederson, J.; Rittenour, T.; Cragun, S.; Goble, R........................................................21 

OSL chronology from Colorado River tributaries in the Western Grand Canyon and 

Grand Wash trough: comparison to u-series ages and application to fluvial deposits

≥300 ka 

By Rittenour, T.; Sharp, W.; Pederson, J.; O’Brien, G.; Goble, R. ...............................22

 v
INTRODUCTION 

By Shannon Mahan 

 Optically stimulated luminescence 

(OSL) is one of a class of measurements known 

as stimulated phenomena. Such phenomena may 

be stimulated thermally or optically and the 

reader is referred to works by Aitken (1998) and 

Botter-Jensen and others (2003) for more detail. 

In recent years OSL has become a popular 

procedure for the determination of environmental 

radiation doses absorbed by archeological and 

geological materials in an attempt to date these 

materials. The first OSL measurements on 

quartz and feldspar were made using an argon 

ion-laser (Huntley et al., 1985). However, the 

development of cheaper stimulation systems 

based first on filtered lamps and then on lightemitting diodes (LEDs) (Spooner, et al., 1990; 

Botter-Jensen, and others, 1999) has led to a 

massive expansion in OSL dating applications. 

The abstracts in this volume represent 

presentations from a workshop held in May-June 

2006, at the Denver Federal Center, Denver, 

Colorado, in which OSL methodologies and 

applications were summarized and integrated to 

provide a current synthesis of the OSL science 

being applied throughout North America. 

 The workshop, sponsored by the U.S. 

Geological Survey Crustal Imaging and 

Characterization Team and North Dakota State 

University, was open to all scientists interested 

in OSL dating techniques and radiation 

dosimetry. Participants included thirty-six 

research scientists and students in geology,

archaeology, and physics from the U.S. 

Geological Survey, Los Alamos National Labs, 

Kentucky Geological Survey, eight universities 

in the United States, one university in Canada, 

one university in India, and Riso National Labs 

of Denmark. 

 The workshop included two keynote 

speakers: Dr. Ashok Singhvi (Physical 

Research Laboratory, Ahmedabad, India) spoke 

on “Some Unexplored Methodological Aspects 

and Some New Applications of Luminescence 

Dating”, while Dr. Jim Feathers (University of 

Seattle, WA) spoke on OSL Dating of Sediments 

From Paleoindian Sites in Brazil”. The 

workshop encouraged everyone to interact more 

to develop a broader perspective on the types of 

research and the problems encountered when 

reporting OSL ages. This meeting follows the 

first North American Luminescence Dating 

Workshop held in Tulsa, OK, by Oklahoma State 

University (2001), in Albuquerque, NM, by Los 

Alamos National Labs (2002), and in Halifax, 

Nova Scotia, by Dalhousie University (2004, 

with a name change to New World 

Luminescence Dating Workshop). These 

workshops were interspersed with the 

international meetings on luminescence that were 

held in Reno, NV, (2002), and Cologne, 

Germany; (2005). 

 References:

1.] Aitken, M.J., 1998. An Introduction to 

Optical Dating. Oxford University Press, 

Oxford, 267 p. 

[2.] Bøtter-Jensen, L, McKeever, S.W.S, and 

Wintle, A.G., 2003. Optically Stimulated 

Luminescence Dosimetry. Elsevier Science 

B.V., Amsterdam, 355 p. 

 [3.] Huntley, D.J., Godfrey-Smith, D.I., 

Thewalt, M.L.W., 1985. Optical Dating of 

Sediments, Nature, vol. 313, p. 105-107. 

[4.] Spooner, N.A., Aitken, M.J., Smith, B.W., 

Franks, M., McElroy, C., 1990. Archaeological 

dating by infrared stimulated luminescence using 

a diode array, Radiation Protective Dosimetry, 

vol. 34, p. 83-86. 

[5.] Bøtter-Jensen, L., Duller, G.A.T., Murray, 

A.S., Banerjee, D., 1999. Blue light emitting 

diodes for optical stimulation of quartz in 

retrospective dosimetry and dating. Radiation 

Protective Dosimetry, vol. 84, p. 335-340. 

Nov 2001 23 abstracts/presenters 

Aug. 2003 23 abstracts/presenters 

July 2004 23 abstracts/presenters 

May/June 2006 22 abstracts/presenters 

 

 1
SOME UNEXPLORED METHODOLOGICAL ASPECTS AND SOME APPLICATIONS OF 

LUMINESCENCE DATING Singhvi, A.K.1

, Mayya, Y.S.2, Sastry, M.D.3, Juyal, N.4, Morthekai, P.5, 

.Murari, M.K.6

, Nagar, Y.C.7, Jaiswal, M.K.8, Stokes, S.8, Jain, V. 9, 1singhvi@prl.res.in, 2

mayyays@magnum.barc.ernet.in, 3mdsastry@yahoo.co.in, 4navin@prl.res.in, 5pmorthek@prl.res.in, 6

madhav@prl.res.in,, 7ycnagar@prl.res.in, 8mkjosl@gmail.com , 9vjain@els.mq.edu.au

 The presentation will deal with the methodological 

aspects and new applications of luminescence dating so 

as to provoke a discussion on some of these ideas. 

Some of the factors described below can be a potential 

source of systematic errors which have been 

overlooked, so far. 

 A. Methodological Aspects: 

1. Natural Sensitivity Correction for SAR De Values 

The SAR protocol is now used extensively and we 

have investigated two aspects of systematic errors 

within its application in some detail. The first one 

relates to the change in the sensitivity during the 

measurement of natural signal. Presently the sensitivity 

is tracked only after the measurement of natural signal 

and it is therefore not clear if the natural signal and 

regenerated signal are measured with the same 

sensitivity. Our measurements indicate that such 

changes in sensitivity can be up to 30% and hence can 

cause systematic errors of the same magnitude. We 

have been using a natural sensitivity correction factor 

(NCF) with good results. 

2. The Standard Growth Curve in SAR 

We also examined the concept of a Standard Growth 

Curve (SGC) on a large number of samples and found 

that samples which provide a regression coefficient of 

0.9 in the SGC are likely to provide sensible SGC 

based De values. One point remains as to how the 

identification of samples with poor recycling ratios be 

identified apriori for samples where only the 

normalized natural is measured. While this needs to be 

investigated further, it appears that samples providing a 

reasonable regression value in their SGC are also the 

samples that are well behaved with respect to their 

recycling ratios. 

3. Component Specific Paleodose 

We examined the initial work on components of quartz 

BGSL. An effective deconvolution algorithm was 

developed and we applied this to the derive component 

of specific SAR ages. Initial studies indicate that the 

ages based only on the fast component provide a tighter 

distribution when compared to the conventional SAR 

ages. The application and implication of this for poorly 

bleached and/or feldspar contaminated samples, will be 

discussed. 

4. Age determination using Single Grains 

Possibilities for analyzing single grains brought hope 

for identifying the most bleached grains. However, it 

also brought back the difficulties in dosimetry that 

have been so far ignored. Most of the beta dose is 

provided by a few hotspots of K rich feldspar grains. 

At low K concentration, the distance between hotspots 

can be compared to a beta range that gives only the 

heterogeneity of the beta dose. This implies that the 

least De values can correspond both to the most 

bleached grains and to grains that see the lowest dose 

rate and perhaps the use of average dose rate in such 

cases may not be appropriate. This aspect has been 

investigated mathematically and some results and an 

analysis protocol will be presented 

 B. New Applications: 

1. Direct and Indirect Dating of Gypsum using 

Luminescence and ESR 

Chemical precipitates such as Gypsum, (CaSO4.2H2O) 

are climatic event markers indicating periods of 

desiccations. However, their dating was not possible 

with the conventional methods. We were successful in 

dating these deposits via the traces of quartz in them 

and the dating of gypsum itself with ESR. In addition, 

techniques such as XRD, Fourier transform infrared 

spectroscopy and Thermogravimetry helped 

development of methodologies to date gypsum samples 

as well as to deduce information on their formation 

pathways. Successful applications have been obtained 

at White Sands, New Mexico (USA), the Thar Desert 

and from Australian. The ESR ages match with 

stratigraphic controls provided by the sediment 

contexts overlying and underlying the gypsum beds. 

2. Analysis of Tsunami Sands 

Analysis of recent (2004) tsunami sands using 

component specific analysis of the BLSL of quartz 

indicated low paleodose values of 0.6 Gy, reaffirming 

the suggestion that OSL can be a potential method for 

the dating of paleo-tsunami deposits. Given the 

catastrophic nature of the event, such low values 

suggest that most of sediment was derived from the 

shelf region where daylight exposure during tidal 

reworking would have bleached the geological signal 

of the sands to a low value. 

 

 2
 3

A THEORETICAL MODEL FOR A NEW DATING PROTOCOL FOR QUARTZ BASED ON 

THERMALLY TRANSFERRED OSL (TT-OSL).#V. Pagonis1

, A.G. Wintle2, R. Chen3, X.L. Wang4

1

vpagonis@mcdaniel.edu; 2aqw@aber.ac.uk; 3chenr@tau.ac.il; 4wxl@loess.llqg.ac.cn. 

 Introduction: Although the optically stimulated 

luminescence (OSL) signal in quartz has been 

established as the basis of an accurate and precise 

luminescence dating method [1], its use is limited by 

the saturation of the measured OSL signal. However, 

another OSL signal has been proposed as the basis 

of a new OSL dating procedure [2]. The newlystudied signal is the thermally-transferred OSL (TTOSL) that is measured after irradiated quartz is 

optically bleached and then preheated [3]. Using the 

TT-OSL signal, the dating range for fine-grained 

quartz extracted from Chinese loess can be extended 

by almost an order of magnitude [2]. 

Wang et al. [2] used a TT-OSL signal obtained 

after a high temperature preheat (260°C for 10 s) 

following an optical bleach at 125°C for 270 s to 

deplete the fast and medium OSL components. They 

used the subsequent TT-OSL signal measured for 90 

s at 125°C in order to avoid the effect of re-trapping 

of electrons in the 110°C trap. The luminescence 

sensitivity related to this TT-OSL measurement was 

determined by the OSL response to a subsequent test 

dose. 

In this paper, we use the model of Bailey [4] to 

fit the experimental data for the OSL and TT-OSL 

signals that were obtained when using the protocol 

of Wang et al. [2], and we compare directly the 

experimental results with the results from the model. 

 The model: The original Bailey [4] model used 

in the present simulation consists of 5 electron traps 

and 4 hole centers. In terms of OSL-traps, the model 

contains traps for the fast and medium-OSL 

components of quartz (OSLF and OSLM), but does 

not contain traps for the slow-OSL components of 

quartz. The absence of these additional energy levels 

does not limit the applicability of the present model, 

since the phenomena described here involve 

exclusively the fast and medium OSL traps. The 

values of E and s for these traps were taken from the 

updated experimental data set of Singarayer and 

Bailey [5]. 

 Results: The complete sequence of steps in the 

new TT-OSL protocol was simulated using the 

Bailey model with modified parameters, and the 

simulated normalized L/T dose response graphs for 

both conventional OSL and TT-OSL are shown in 

the figure, together with a set of experimental data 

for fine grain quartz from Chinese loess [3]. From 

these dose response curves, the advantage of using 

the TT-OSL signal for older samples can be seen. L/T OSL

0

5

10

15

20

25

30

calculated 

experiment

Regenerated dose, Gy

0 1000 2000 3000 4000 5000

L/T TTOSL 0.0

0.1

0.2

0.3

0.4

0.5

0.6

experiment

calculated

 Conclusion: The simulation presented here 

provides a mathematical description of the high 

temperature charge transfer processes taking place 

during the new TT-OSL protocol. By modifying the 

parameters in the original Bailey [4] model, it is 

possible to get a good quantitative agreement 

between the experimental and simulated OSL and 

TT-OSL dose response curves. 

 References:

[1] Aitken, M. J., 1998. "An Introduction to Optical 

Dating." Oxford University Press, Oxford. 

 [2] Wang, X.L., Lu, Y.C. and Wintle, A.G., 2006. 

Recuperated OSL dating of fine grained quartz in 

Chinese loess. Quaternary Geochronology (in press). 

 [3] Wang, X.L., Wintle, A.G. and Lu, Y.C., 2006. 

Thermally-transferred luminescence in fine-grained 

quartz from Chinese loess: basic observations. 

Radiat. Meas. (in press). 

[4] Bailey, R. M., 2001. Towards a general kinetic 

model for optically and thermally stimulated 

luminescence of quartz. Radiat. Meas. 33, 17-45. 

[5] Singarayer, J., and Bailey, R.M., 2003. Further 

investigations of the quartz optically stimulated 

luminescence components using linear modulation. 

Radiat. Meas. 37, 451-458. 
EQUIVALENT DOSE DISTRIBUTIONS FROM MAAD DATA SETS. Kenneth Lepper1

 and Anne 

Denton2

. 1Department of Geosciences, North Dakota State University, 218 Stevens Hall, Fargo, ND, 58105 

(ken.lepper@ndsu.edu); 2

Department of Computer Sciences, North Dakota State University, 258 IACC, Fargo, 

ND, 58105 (anne.denton@ndsu.edu). 

Background: Over the past decade a great deal 

of attention and developmental effort has been 

focused on equipment, experimental procedures, 

and analytical tools for use with quartz sand. SAR 

data collection procedures and equivalent dose (De) 

distribution analysis, in particular, are increasing 

the accuracy and reproducibility of OSL ages as 

well as extending its utility to numerous 

depositional environments. 

There are deposits, however, from which it is 

difficult to isolate clean quartz sand due to the 

mineralogy of the sediments or depositional 

constraints on the sediment grain size distribution. 

In these situations OSL dating has been carried out 

on poly-mineral fine silts (4-11 microns). The most 

widely utilized experimental procedures for data 

collection from fine-grained samples has been 

multi-aliquot additive dose, or MAAD. This 

method required data collection from numerous 

aliquots in order to calculate one age. Using 

conventional MAAD methods it was impractical to 

collect statistically meaningful De data sets. In 

cases where multiple ages were determined from 

one field sample, reproducibility was often poor. 

Methods: In order to extend the remarkable 

advantages of dose distribution analysis to dating of 

fine-grained polymineral sediments, we have 

developed an analytical method for generating 

equivalent dose distributions from data collected by 

standard MAAD procedures. 

 Results: The fine-grained dose distributions 

obtained exhibit meaningful, interpretable shape 

characteristics and in many cases exhibit 

remarkable structural similarities to quartz sand 

distributions from the same fluvial sediment 

samples. This talk will present the conceptual 

framework for the analytical method, compare 

polymineral fine-grained De distributions with 

quartz sand De distributions obtained from the same 

field samples, as well as discuss the approach(s) for 

selecting a representative dose from the finegrained distributions. 

Conclusion: Dose distribution analysis has the 

same potential to improve age accuracy and 

reproducibility for polymineral fine silts as it has 

for quartz sand. We anticipate that an analytical 

method capable of generating dose distributions 

from conventional MAAD data, such as the one we 

have developed, can be applied retroactively to a 

wealth of existing data in the luminescence dating 

community and used to re-examine numerous data 

sets that have defied sensible interpretation without 

the benefit of dose distribution analysis. 

 4
REDUCTION OF UNCERTAINTIES IN THE MEASUREMENT OF EQUIVALENT DOSES AND 

ANOMALOUS FADING RATES IN IRSL DATING OF FELDSPAR. M. Lamothe and M. Auclair. 

Laboratoire de luminescence Lux, Département des sciences de la Terre et de l’atmosphère, Université du 

Québec à Montréal, PO 8888, Succ. Centre-Ville, Montréal, Québec, H3C 3P8, Canada. 

lamothe.michel@uqam.ca

 Introduction: The application of the Single 

Aliquot regeneration (SAR) procedure for dating 

feldspar, as developed in the Montréal laboratory, 

is based on an elaborate sequence of laboratory 

measurements. These were described by Lamothe 

et al. at the first NALDW in Tulsa [1,2]. Our 

procedures have been recently improved and some 

of these developments are described below. 

 Equivalent dose: After preheating and optically 

stimulating the feldspar aliquots, an internal 

halogen (“white”) light is now used for bleaching 

before each irradiation step. This procedure has a 

significant effect on the reduction of sensitivity 

changes. However, to limit thermal transfer, further 

thermal and optical IR stimulation steps are 

necessary to fully drain the dating trap, before the 

administration of the next radiation dose. 

In order to increase the overall reproducibility in 

the equivalent dose measurements, we have carried 

out a systematic analysis of our procedures to 

identify the main sources of IRSL variability. The 

parameters that seem to generate the most 

variability are those affecting the reproducibility of 

the preheat temperature, as well as that of the 

heating rate. There is no critical variability in the 

“optical environment” (diodes, filter optics, PM 

stability, etc.). We also compared the variability of 

the sensitivity-corrected luminescence for 

homogeneous aliquots (mostly fine grains) between 

those preheated in the Risø and Daybreak readers, 

and others preheated in an external oven. 

This investigation confirms that the thermal 

stability of the luminescence readers is a critical 

factor in the reproducibility of the natural 

luminescence intensity of feldspar. For example, 

using low heating rates in the order of 1°C/sec 

increases significantly the reproducibility of 

luminescence measurements. It is further found 

that, using 24 aliquots, one could determine the 

sensitivity-corrected natural luminescence within a 

standard deviation for the mean of less than 0.5 %, 

using an external oven for preheating. 

 Anomalous fading: The fading tests developed 

in our laboratory [3] require another large number 

of measurements. Several data points are needed to 

find a reliable fading rate value, and as each 

measurement carries a significant uncertainty, the 

error in the assessment of the g value could be 

relatively large for some heterogeneous material 

(i.e. 10-15%), and low precision corrected ages are 

commonly calculated. At each step, a similar 

bleach is introduced in the procedure to empty the 

traps not drained by the IR stimulation but that are 

sensitive to visible light. The occupancy of these 

non-IR sensitive traps is of consequence to the 

measured anomalous fading rate. Again, the 

thermal dependence of IRSL following preheating 

may generate unwanted scatter and a different 

procedure is being developed. Herein, the decay of 

luminescence is assessed by documenting the ratio 

SS/SD, from two luminescence measurements, a 

“prompt” short shine (SS) following preheating 

and a shine down (SD) after some time delay. This 

approach integrates method B of Huntley and 

Lamothe [4] and the SAR approach of Auclair and 

others [3]. 

 References: 

[1] Lamothe, M., Duller G.A.T., Huot, S., Wintle 

A.G., 2001. Measuring a laboratory radiation dose 

in feldspar using SAR. 1st North American 

Luminescence Dating Workshop, Tulsa, 

Oklahoma, November 2001. 

 [2] Huot, S., Lamothe, M., 2003. Variability of 

infrared stimulated luminescence properties from 

fractured feldspar grains. Radiation Measurements 

37, 499-503 

[3] Auclair, M., Lamothe, M., Huot, S., 2003. 

Measurement of anomalous fading for feldspar 

IRSL using SAR. Radiation Measurements 37, 

487-492.

[4] Huntley, D.J., Lamothe, M., 2001. Ubiquity of 

anomalous fading in K-feldspars and the 

measurement and correction for it in optical dating. 

Canadian Journal of Earth Sciences 38, 1093-1106. 

 5
THE LUMINESCENCE EFFICIENCY OF COSMIC RADIATION AT THE SURFACE OF MARS AND IN 

THE MARTIAN REGOLITH – A STUDY WITH QUARTZ AND FELDSPAR. R. Kalchgruber1

, E.R. 

Benton2

, G.O. Sawakuchi3 and S.W.S. McKeever4. 1-4Radiation Dosimetry Laboratory, Oklahoma State University, 

Venture 1, Suite 201, 1110 S. Innovation Way Drive, Stillwater, OK 74074 1

(rkalchg@okstate.edu); 2

(eric@erilresearch.com); 3(sawakuc@okstate.edu); 4(swsm@okstate.edu). 

Introduction: Pictures taken by the Mars Orbiter 

Camera show that the surface of Mars has been, and 

continues to be, shaped by fluvial, eolian and glacial 

processes. To understand the planet's 

geomorphologic and climatic history we need 

information about the age of these events. In this 

context, efforts are being made to create a miniature 

dating device for in situ luminescence dating of 

Martian sediments [1]. A direct measure for the 

absorbed dose is the optically stimulated 

luminescence signal (OSL) from the minerals. 

However, the other necessary component for an insitu luminescence dating device for Mars is the 

knowledge of the radiation environment on the 

surface of Mars and in the Martian regolith. The main 

source for the dose rate on Mars is galactic cosmic 

rays (GCR). Since the equivalent dose will be 

determined in relation to an X-ray or beta source in a 

robotic instrument, the relative efficiency of the GCR 

in producing OSL relative to the on-board radiation 

source needs to be determined. We present 

experiments with mineral mixtures that are used as 

Martian soil simulants, and irradiation with simulated 

cosmic rays. 

Samples and Instrumentation: Experiments 

were carried out with quartz and various feldspar 

minerals. Furthermore we devised two mineral 

mixtures as surrogates for Martian sediments. The 

two mixtures are known as OSU-Mars-1 and OSUMars-2. The compositions (in vol. %) are described 

in the following table; further details can be found in 

[2]. 

Mars 1 Mars 2 

Andesine 22 % 15 %

Labradorite 22 % 15 %

Bytownite 22 % 15 %

Augite 15 % 5 %

Diopside 15 % 5 %

Hematite 5 % 5 %

Obsidian 40 %

Measurements were conducted using a Risø 

TL/OSL-DA-15 reader, Risø National Laboratory, 

with a bialkali PM tube (Thorn EMI 9635QB) and 

Hoya U-340 filters (290-370 nm). The built-in 

90Sr/90Y beta source gives a dose rate of ~100 mGy/s. 

Optical stimulation was carried out with blue LEDs 

(470 nm), delivering 45 mW/cm2

 to the sample; IR 

stimulation was from an IR LED array at 

875 ± 80 nm with 36 mW/cm2

 power at the sample. 

The heating rate used was 5 °C/s. 

Experiments: The GCR spectrum consists of 

approximately 85 % protons, 12 % alpha particles 

and 1 % heavier nuclei, and about 2 % electrons and 

positrons [3]. Dose rates expected on the Martian 

surface (dependent upon altitude) are typically on the 

order of 200–300 mSv/year ([4]; ~80 mGy/year). At 

a depth of 700 g/cm2

, the dose rate is expected to be 

reduced to approximately 0.5 mGy/year [5]. 

 The minerals described above were irradiated 

with a variety of heavy ion beams at HIMAC, Japan, 

and NSRL, Brookhaven. Among others, the minerals 

were irradiated with known doses of 1 GeV protons, 

150 MeV/u He, 500 MeV/u and 200 MeV/u Fe. 

During the irradiations, small containers with the 

mineral mixtures were sandwiched between columns 

of Martian soil simulant of various thickness, 

simulating a variety of burial depths in the Martian 

regolith. As a reference, additional experiments were 

carried out with water instead of Martian regolith. 

The OSL signals induced by the single types of ions 

were measured and compared to 90Sr beta irradiations 

to determine the luminescence efficiency of different 

types of radiation. 

Results: The experiments indicate that there is a 

significantly lower efficiency for heavy charged 

particles compared to 90Sr beta irradiations. With 

increasing ionization density, described by the linear 

energy transfer of a particle, more charge carriers are 

released in the same crystal volume. The limited 

number of crystal defects leads to an increasing 

number of instantaneous recombinations. The result 

is a smaller percentage of trapped charges and a 

lower luminescence signal for heavy charged 

particles when compared to beta radiation or X-rays. 

The experiments and results will be presented in 

detail. 

 References: [1] McKeever S.W.S. et al. (2003) 

Radiat. Meas., 37, 527-534. [2] Kalchgruber R. et al. (in 

press) Radiat. Meas. [3] Benton, E.R. and Benton, E.V. 

(2001). Nucl. Instr. and Meth. in Phys. Res. B 184, 255-

294. [4] Saganti, P.B., et al. (2004). Space Sci. Rev. 110, 

143-156. [5] Pavlov, A.K., et al. (2002). Planetary and 

Space Science, 50, 669-673.

 6
LOW TEMPERATURE EFFECTS ON THE OSL PROCESS OF MARTIAN SIMULANTS. M. W. Blair1

, R. 

Kalchgruber2

, E. G. Yukihara2, and S. W. S. McKeever2. 1Los Alamos National Laboratory, Earth and 

Environmental Sciences Division, EES 2 MS J495, Los Alamos, NM 87545 (e-mail:mblair@lanl.gov); 2

Oklahoma 

State University, Physics Department, 145 PS II, Stillwater, OK 74078. 

Introduction: As the technology within the field 

of OSL dating continues to improve, the OSL 

technique is being applied in many new situations. 

Some new situations for OSL dating involve 

sediments from low temperature environments. 

Terrestrial sediments from ice cores [1] fall into this 

category, and the project to develop OSL dating for 

Martian studies [2] involves low temperature 

conditions as well. 

The current work explores some of the effects that 

irradiation and/or stimulation temperature may have 

on expected Martian minerals. We investigated if 

stable temperature control is necessary for an in-situ 

instrument or if experiments can be conducted at 

ambient temperature. 

Equipment and Samples: We use the lowtemperature TL/OSL system developed at Oklahoma 

State University. The system can irradiate (with 35 

keV X-rays), stimulate with a green laser (532 nm), 

and measure RL, TL, and OSL in the temperature 

range -150 to +200°C. 

Two different Martian soil simulants, named OSU 

Mars-1 and OSU Mars-2, were used in this study. For 

a detailed description of these simulants see 

Kalchgruber et al. [3]. 

Methods: To measure the luminescence 

efficiency of the simulants, the RL of the sample was 

monitored under constant irradiation as the sample 

was cooled from room temperature to -100°C 

Optically-active traps with a peak temperature below 

room temperature were also identified. The samples 

were irradiated at –100°C with 10 Gy and heated to 

room temperature at a heating rate of approximately 

0.3 oC/s. The same procedure was repeated with a 

laser bleach for 300 s at –125 oC after irradiation. 

The effect of varying the irradiation and stimulation 

temperature was studied as well. First, irradiations 

were performed at various temperatures while the 

stimulation temperature was held constant (25°C). 

Then, the irradiation temperature was held constant 

(25°C) while the stimulation temperature was varied. 

Finally, the irradiation and measurements 

temperatures were varied simultaneously. The final 

set of experiments tested recovering a known dose 

under various conditions. The temperatures for 

known dose irradiation, regeneration dose irradiation, 

and stimulation were all varied as outlined in Table 1. 

The dose ratio (recovered/given) for both simulants 

was also calculated. 

Results: Both simulants showed changes in RL 

over the studied temperature range. The increases 

could be a result of thermal quenching or the 

presence of multiple recombination centers. Both soil 

simulants show an optically-active peak near -30°C, 

and OSU Mars-1 shows an additional peak near 

20°C. However, none of the traps were completely 

bleached by optical wavelengths. Variation of the 

stimulation and irradiation temperatures affected the 

simulants in different ways, but competition effects 

induced by the low temperature traps seem to be the 

dominant effect. 

The known dose could be effectively recovered 

under various circumstances as detailed in Table 1. 

Table 1. Results of dose recovery experiments. 

Known 

Dose T 

(°C) 

Reg. 

Dose 

T 

(°C) 

OSL 

T 

(°C) 

Dose 

Ratio 

OSU 

Mars-1 

Dose 

Ratio 

OSU 

Mars-2 

25 25 25 1.01±0.25 1.02±0.14 

-100 -100 -100 1.07±0.77 0.98±0.11 

-100 25 25 1.01±0.04 0.94±0.32 

25 -100 -100 0.33±0.64 0.26±0.01 

-100* 

-50 

25 

-100 -100 0.60±0.09 0.39±0.15 

-100* 

-50 

25 

25 25 0.95±0.52 1.04±0.28 

*1.7 Gy delivered at each temperature 

Conclusions: Stable temperature control is 

necessary for a robotic OSL dating instrument 

deployed to Mars. First, the irradiation and 

stimulation temperatures need to be controlled. Also, 

the influence of low temperature traps needs to be 

considered in the luminescence process and 

appropriate heating procedures must be developed. 

Finally, the stimulation temperature used in the dose 

recovery process needs to be at least as high as the 

highest temperature experienced during natural 

irradiation. 

References: [1] Lepper et al. (2001) Radiat. Meas.

33, 445-455. [2] McKeever et al. (2003)

 7
USING LOW INTENSITY BLUE LIGHT TO STIMULATE HIGH-AND MID-LATITUDE WATERLAIN 

SEDIMENTS. J. Pierson1

, S. L. Forman1, and J. Gomez1. 1 University of Illinois at Chicago, Department of Earth 

and Environmental Sciences (M/C 186), 845 West Taylor Street, Chicago, Illinois 60607-7059 1 

(jpierson@uic.edu). 

Introduction: An accurate assessment of 

paleodose is necessary to generate a credible age 

estimate in luminescence dating studies. This is 

particularly difficult to achieve for sediments with a 

trapped electron population that is not fully 

diminished with sunlight exposure upon deposition. 

Preferentially accessing the “fast component”, the 

luminescence derived from highly photosensitive and 

thermally stable traps, would yield a credible 

chronometer for sediments that are partially solar 

reset. For quartz, one of the most photosensitive 

components is related to the 325°C TL peak, 

suggesting that its parent traps are thermally stable 

over geologic time 

scales (lifetime >3 x 107

 years at 20°C) [1], [2]. 

These same traps have been shown to be extremely 

photosensitive, resetting in ~10 seconds when 

exposed to high-intensity (~25 mW/cm2

) blue light 

(470 ± 20nm) [3], making them preferred targets for 

luminescence dating. 

Separating the fast component from the rest of the 

luminescence signal has been achieved by using 

curve-fitting techniques to deconvolute the OSL 

signal e.g. [2], [4]. Unfortunately this approach is 

impractical for luminescence dating because of the 

long stimulation times needed for peak resolution and 

the inability of the fitting algorithm to distinguish 

between nearly coincidental components. Isolation of 

the fast component has been attempted 

experimentally in other recent studies by using 

intense (115-230 mW/cm2

) infrared (830 ± 10nm) 

laser light to stimulate sediments at temperatures 

between 100°C and 200°C [5], [6]. However the 

long stimulation times (>1500 seconds) needed to 

reduce the fast component at elevated temperatures 

also makes this approach impractical for 

luminescence dating studies. 

Proposal: We suggest using a blended approach 

to isolate the fast component of the quartz signal 

using low intensity blue (470 ± 20nm) photostimulation. The traps responsible for the fast 

component are more sensitive to blue light, requiring 

less intense illumination to produce a measurable 

luminescence signal. The emissions from the mixedsignal, continuous-wavelength OSL (CW-OSL) 

curves, commonly used for dating, are spread over an 

extended time period by decreasing photo-stimulation 

intensity and thus increasing resolution. Any 

significant excess in the luminescence intensity 

attributable to the less photosensitive components 

would be reflected in the CW-OSL decay curve 

shape. As a result, processes that could create these 

excesses, such as incomplete optical bleaching, can 

be monitored and compensated for analytically, given 

an appropriate model. An examination of the 

differences between the CW-OSL decay curves 

generated from natural, unaltered sample portions 

and those generated from laboratory irradiated 

aliquots, after complete optical bleaching, provides 

the basis for this model. Laboratory experiments 

designed to test the veracity of the proposed model 

suggest that this approach could successfully 

compensate for residual luminescence in sediments 

with as little as 10 seconds of sunlight exposure with 

deposition. Optical ages based on these model 

calculations for quartz extracts from poorly solar 

reset sediments are consistent with known 

depositional ages. Successful application is limited 

to sediments that retain no electrons within the most 

photosensitive traps at burial, with natural CW-OSL 

decay curves that exhibit sufficient component 

resolution and can be adequately described by the 

proposed model. 

Our presentation will feature the description and 

application of the proposed model, including results 

from supporting laboratory experiments and 

conditions under which this approach is valid. 

References: [1] Wintle, A. G., and Murray, A. S. 

(2000) Radiation Measurements, 32, 387-400. [2] 

Bulur, E., Bøtter-Jensen, L., and Murray, A. S. 

(2000) Radiation Measurements, 32, 407-411. [3] 

Agersnap-Larsen, N., Bulur, E., and McKeever, S. 

W. S. (2000) Radiation Measurements, 32, 419-425. 

[4] Singarayer, J. S., and Bailey, R. M. (2003) 

Radiation Measurements, 37, 451-458. [5] Jain, M., 

Murray, A. S., and Bøtter-Jensen, L. (2003) 

Radiation Measurements, 37, 441-449. [6] Jain, M., 

Murray, A. S., Bøtter-Jensen, L., and Wintle, A. G. 

(2005) Radiation Measurements, 39, 309-318. 

 8
MEASURING FELDSPARS OSL IN A HELIUM ATMOSPHERE: POTENTIAL FOR IMPROVED 

REPRODUCIBILITY Sébastien Huot and Andrew S. Murray, Nordic Laboratory for Luminescence Dating, 

Department of Earth Sciences, Aarhus University, Risø National Laboratory, DK-4000 Roskilde, Denmark. 

sebastien.huot@risoe.dk and andrew.murray@risoe.dk

Introduction: Anomalous fading hampers 

accurate luminescence dating with feldspars by 

introducing a significant source of systematic error. It 

also acts as a substantial source of uncertainty in the 

age calculation, even if a correction model is applied. 

The level of instrumental measurement 

reproducibility provides a lower limit to the 

achievable precision. It is suggested here that poor 

thermal reproducibility during heat treatment stages 

is a major source of dispersion in the subsequent 

OSL, thus reducing the precision of any fading 

measurements based on these signals. 

 Methods: Analysis was performed on coarse Kfeldspars grains, separated with a heavy liquid 

solution (< 2.58 g/cm3

) and etched with 10% HF and 

mounted on stainless steel disk. Optical 

measurements were performed with infrared LEDs 

and detected with a combination of BG39 & 7-59. 

Heat treatments of 250oC/60s were identical for both 

dose and test dose [1,2,3,4], and were undertaken in a 

Risø TL/OSL DA-15 reader, either in a nitrogen or 

helium atmosphere. Fading measurements followed 

the procedure recommended by Auclair et al. [2], 

with a preheat performed before storage. Results are 

presented for samples collected from various 

locations (Russia, Portugal, Taiwan, Denmark). 

Observations: A simple superposition of glow 

curves recorded during preheating can show 

significant variability in the position of the peak 

maximum. Peak shift is especially pronounced during 

the first heating although it is also observed after 

delayed measurements. We find that what looks like 

an outlier OSL measurement often corresponds to an 

unusual preheat glow curve. 

Prompts luminescence measurements, where the 

OSL is measured immediately after a dose – preheat 

sequence, may show very good reproducibility, of the 

order of 0.5 – 1.0 % RSD. The reproducibility of 

delayed luminescence measurements (where the OSL 

is measured after a significant delay after a dose – 

preheat sequence) is often worse. For example, in 

sample H22546 (Russia), we observed a good 

reproducibility for the prompt measurements, 

averaging at 0.41 % RSD (σ = 0.09, n = 12 aliquots). 

The reproducibility is worse the delayed 

measurements (90 hours), with a RSD of 2.6 % (σ = 

1.6, n = 12 aliquots). 

Steps can be taken to improve the thermal 

reproducibility. For instance, reducing the heating 

rate should reduce the thermal lag between the 

heating plate and the grains. A longer duration of 

preheat should help to minimize variations in thermal 

contact. We have found that the most significant 

improvement is achieved by replacing the gas 

atmosphere in the sample chamber with helium, 

rather than the more usual nitrogen. Helium has a 

thermal conductivity [151 mW/(m·K)] that is 6x 

greater than nitrogen [26 mW/(m·K)]. It is known 

that essentially all the energy transfer from the heater 

plate to the sample disc takes place through the 

surrounding gas atmosphere (very large thermal lag is 

observed under vacuum) [5]. Hence, using a gas with 

a higher thermal conductivity helps reduce the 

thermal lag [6]. We have been able to observe 

significantly lower RSD from delayed measurements 

when heating is performed in helium (0.6 %), 

compared to a nitrogen atmosphere (2.6 %). 

 References: 

[1] Lamothe, M., Duller, G.A.T., Huot, S., Wintle, 

A.G., 2001. Measuring a laboratory radiation dose in 

feldspar using SAR. In 1st North American 

Luminescence Dating Workshop, Tulsa, United 

States, abstracts with program, p. 14. 

[2] Auclair, M., Lamothe, M., Huot, S., 2003. 

Measurement of anomalous fading for feldspar IRSL 

using SAR. Radiation Measurements 37, 487-492. 

[3] Huot, S., Lamothe, M., 2003. Variability of 

infrared stimulated luminescence properties from 

fractured feldspar grains. Radiation Measurements 

37, 499-503. 

[4] Blair, M.W., Yukihara, E.G., McKeever, S.W.S., 

2005. Experiences with single-aliquot OSL 

procedures using coarse-grain feldspars. Radiation 

Measurements 39, 361-374. 

[5] Huxtable, J., 1978. Fine grain dating. PACT 2, 7-

11. 

[6] Betts, D.S., Couturier, L., Khayrat, A.H., Luff, 

B.J., Townsend, P.D., 1993. Temperature distribution 

in thermoluminescence experiments. I. Experimental 

results. Journal of Physics D: Applied Physics 843-

848.

 9
THE SAND RIDGES OF CURRITUCK COUNTY, NORTHEASTERN NORTH CAROLINA. Burdette, K.1

, 

Mallinson, D.2

, Brook, G.3, Mahan, S.4. 1Department of Geology, University of Delaware, Newark, De 19716 

(keburd@udel.edu); 2

Department of Geology, East Carolina University, Greenville, NC 27858; 3Department of 

Geography, University of Georgia, Athens, Ga 30602 (gabrook@uga.edu); 4

U.S. Geological Survey, MS 974, Box 

25046, Federal Center, Denver, Co 80225 (smahan@usgs.gov). 

Introduction: The depositional characteristics and 

ages of two sand ridges in southern Currituck County on 

the North Carolina coastal plain of the U.S. midAtlantic continental margin were investigated. Optically 

stimulated luminescence (OSL) ages show that the Land 

of Promise Ridge was deposited between 65.3 ± 10.2 

and 59.7 ± 10.2 ka, and the Powells Point Ridge 

between 54.9 ± 6.3 and 43.2 ± 7.9 ka. Three OSL ages 

indicate dune reactivation before and after the onset of 

the Last Glacial Maximum Sampling: Sandy 

depositional strata were chosen for sampling based on 

sharp, well-defined discontinuities indicative of (i) a 

change in transport processes, and (ii) a lack of postdeposition bioturbation. The samples were 

collected at the “top, middle, and bottom” of 

each sandy unit. Methods: Thirteen samples were analyzed at the 

University of Georgia (UGA) Luminescence Dating 

Laboratory and three duplicate samples were analyzed 

at the United States Geological Survey (USGS) 

Luminescence Dating Laboratory in Denver, Colorado 

using the single-aliquot regenerative dose (SAR) 

protocol. 

At the UGA lab, dose rate calculations relied on the 

thick source ZnS (Ag) alpha counting technique for U 

and Th. Potassium was measured by ICP90 using the 

Sodium Peroxide Fusion technique at the SGS Lab in 

Toronto, Canada. In the USGS lab, the bulk samples 

were counted on a high-level resolution gamma ray 

spectrometer for measurements of U, Th, and K. These 

measurements were checked with Instrumental Neutron 

Activation Analyses (INAA) obtained from Jim Budahn 

at the USGS TRIGA reactor. 

Results/Conclusions: Importantly the UGA 

luminescence ages increase with depth at all four sites if 

age uncertainties are taken into account. The same 

applies to the USGS age data set. However, the ages 

from the two laboratories do differ but not outside of the 

uncertainties of the determinations. 

The OSL ages cluster in marine isotope stage (MIS) 

3 of the Taylor Dome δ18O ice core record [4] (Table 1). 

However, the age distribution, with 8 ages lying 

between ca. 40-55 ka, and 7 between 40-51 ka, suggests 

a major ridge formation episode centered at 40-50 ka, 

approximately coinciding with the warmest interval of 

climate during MIS 3 in the Taylor Dome record at ca. 

47 ka. This major phase of ridge formation was 

apparently followed later by dune reactivation from 

~29- to ~10 ka, with ages constrained by TCK-13 and 

TCK-4, which were collected above paleosols.

Table 1. Luminescence Ages from Currituck Co. 

Sample Expected Age Age (ka) 

Lane Pit 

TCK-1 MIS 5a 65.3±10.2 

TCK-2 MIS 5a 59.6±10.2 

54.26±6.73* 

TCK-3 MIS 5a 81.8±8.8 

#330 Bluff

TCK-4 Early Holocene 12.5±2.7 

TCK-5 Early Holocene 48.2±9.2 

26.37±2.32* 

TCK-6 Early Holocene 51.7±7.8 

41.92±4.02* 

TR Equipment Pit 

TCK-7 MIS 5a 28.2±6.2 

TCK-8 MIS 5a 43.2±7.9 

TCK-9 MIS 5a 45.2±5.6 

Green Acres Pit 

TCK-13 Early Holocene 33.7±4.6 

TCK-11 Early Holocene 48.8±6.2 

TCK-12 Early Holocene 50.6±7.3 

TCK-10 Early Holocene 54.9±6.3 

*-indicate ages analysed by the USGS lab 

References: 

[1] Mixon, R.B., 1985. Stratigraphic and geomorphic 

framework of uppermost Cenozoic Deposits in the 

southern Delmarva Peninsula, Virginia and Maryland. 

US Geological Survey Professional Paper 1067-C, pp. 

53. 

[2] Muhs, D.R., Wehmiller, J.F., Simmons, K.R., York, 

L.L., 2004. Quaternary sea-level History of the United 

States. In: Gillespie, A.R., Porter, S.C., Atwater, B.F. 

(Eds.), The Quaternary Period in the United States. 

Elsevier, Amsterdam, 147-183. [3] Oaks, R., 1964. 

Post Miocene Stratigraphy and Morphology, Outer 

Coastal Plain, Southeastern Virginia. Unpublished 

Ph.D. Dissertation, Yale University, USA. 

[4] Steig, E.J., Morse, D.L., Waddington E.D., Stuiver, 

M., Grootes, P.M., Mayewski, P.A., Twickler, M.S., 

Whitlow, S.I., 2000. Wisconsinan and Holocene 

Climate History from an Ice Core at Taylor Dome, 

Western Ross Embayment, Antarctica. Geografiska 

Annaler 82A, 213-235. 

 10
OPTICALLY STIMULATED LUMINESCENCE AGES OF MARINE ISOTOPE STAGE 5, 3 AND 1 

COASTAL LITHOSOMES: NORTH CAROLINA, USA. 

'David Mallinson, 2

Kevin Burdette, 3Shannon Mahan, 4George Brook 'Dept. of Geology, East Carolina 

University, Greenville, NC 27858, 2

Dept of Geology, University of Delaware, Newark, DE 19716, 3USGS 

Luminescence Dating Lab, USGS Federal Facility, Denver, CO 80225, 4

Dept of Geography, University of 

Georgia, Athens, GA 30602 

Introduction: The ridges, scarps, and associated 

coastal and nearshore depositional units along the 

passive margin coastal plain of the eastern U.S. 

have been a subject of study and debate for 

decades. It is apparent that these siliciclastic 

deposits are coastal features formed in response to 

sea-level highstands. The ridges and scarps have 

previously been defined as paleoshorelines based 

on their geomorphological and geological 

characteristics. As such, they can potentially 

provide important data points for Pleistocene sea 

level curves, and improve the understanding of 

global ice volume changes, paleoclimate, and 

glacio-hydro-isostasy during the Pleistocene. 

Sampling: Samples for OSL analyses were 

acquired from exposures in borrow pits in the case 

of the Hickory Scarp, or from natural cut banks in 

the case of the Suffolk Scarp, and one location on 

Powell's Point Ridge. In the case of the Kitty 

Hawk beach ridges, a 0.8 m deep pit was dug into 

the flank of each sampled beach ridge. Samples 

were obtained by scraping away ~10 cm of soil 

and hammering a 6.35-cm diameter black opaque 

PVC tube horizontally into the pit wall. The 

sediment cylinder recovered was capped and 

wrapped with black plastic for transport. 

Additional sediment was collected from inside the 

core hole for moisture and dose rate 

determinations. Samples were double sealed in 

airtight bags to prevent loss of moisture. 

Thirteen samples were analyzed at the 

University of Georgia (UGA) Luminescence 

Dating Laboratory. OSL analysis was carried out 

in subdued red-light conditions. Three duplicate 

samples were dated at the USGS Luminescence 

dating Laboratory in Denver, CO under sodium 

vapor low-intensity light conditions. Samples 

were analyzed using Duller's ANALYST 

PROGRAM [1]. 

Results and discussion: Newly acquired 

optically-stimulated luminescence (OSL) ages 

using quartz from a variety of coastal features on 

the North Carolina coastal plain provide age 

control for paleoshoreline formation and relative 

sea level position during the late Pleistocene. Two 

samples from the Suffolk Scarp, and one sample 

from the adjacent shelf deposits of the 

Norfolk Formation yield dates corresponding to 

Marine Isotope Stage 5A (OSL ages of 81.8 ± 8.8 

to 68.6 ± 7.2 ka). Features east of the Suffolk 

Scarp/Ridge, including Dillon's Ridge, Hickory 

Scarp, the Currituck Ridges, and Roanoke Island 

yield ages corresponding to MIS 3, and may 

correlate to highstands associated with DansgaardOeschger cycles [2-4]. The Kitty Hawk beach 

ridges, on the modern Outer Banks, yield ages of 

ca. 3 to 2 ka. 

Conclusions: OSL ages are consistent with 

many previously reported U-series and AAR ages. 

The SPECMAP oxygen-isotope curve and GISP2 

ice core data are used to place these deposits in the 

context of global climate and sea level change. 

The occurrence of the MIS 3 shorelines suggests 

either that glacio-isostatic uplift of the study area 

is large (>30 m), or MIS 3 sea level was 

significantly higher than recorded by coral reef 

terraces, or some combination of those two 

factors. The age of the Kitty Hawk beach ridges 

places the Holocene (MIS 1) shoreline well west 

of its present location at ca. 3 ka. 

References: 

[1] Duller, G.A.T., 1999. Luminescence 

Analyst computer programme V2.18. Department 

of Geography and Environmental Sciences, 

University of Wales, Aberystwyth. 

[2] Chappell, 1, 2002. Sea level changes 

triggered rapid climate shifts in the last glacial 

cycle: new results from coral terraces. 

Quaternary Science Reviews 21, 1229-1240. 

[3] Lambeck, K., Chappell, J., 2001. Sea 

Level change through the last glacial cycle._ 

Science 292, 679-686. 

[4] Yokoyama, Y., Esat, T.M., Lambeck., K., 

Fifield, L.K., 2000. Last ice age millennial scale 

climate changes recorded in Huon Peninsula 

Corals. Radiocarbon 42, 383-401. 

 11
LUMINESCENCE DATING OF PALEOLIQUIFACTION FEATURES IN THE WABASH RIVER 

VALLEY AREA OF INDIANA Shannon A. Mahan, U.S. Geological Survey, MS 974, Denver Federal 

Center, Denver, CO 80225, smahan@usgs.gov, and Anthony J. Crone, U.S. Geological Survey, MS 966, 

Denver, CO 80225. crone@usgs.gov

Introduction: In the winter of 1811-1812, the 

central Mississippi Valley was sparsely populated 

and contained few man-made structures, and as a 

result, the great New Madrid earthquakes (M 7.5-

8) caused minimal damage. These earthquakes 

stimulated seismic hazard studies throughout the 

central U.S., which eventually led to the discovery 

of large sand blows caused by liquefaction that 

occurred during prehistoric earthquakes in the 

lower Wabash River Valley of southern Indiana 

and Tllinois [1]. As part of continuing efforts to 

characterize the seismic hazard in the central U.S., 

the U.S. Geological Survey (USGS) is working to 

better understand the causes and the chronology of 

paleoearthquakes throughout the region, including 

the Wabash River Valley. 

Sand blows are lenticular sand bodies that were 

erupted onto paleo-ground surfaces and were fed 

by sand-filled dikes that were sourced from 

subjacent liquefied sand beds. Previous studies in 

the Wabash River Valley area have bracketed the 

ages of the sand blows using radiocarbon samples 

collected from exposures of Holocene alluvium in 

river banks. We collected samples at two sites on 

the Wabash River: Peankishaw Bend, and the 

Black River site. Sand blows and sand dikes in the 

cut bank exposures at these sites have been dated 

using radiocarbon [2]. We are using optically 

stimulated luminescence (OSL) dating from these 

`calibration sites' to test the possibility of using 

OSL to date sand blows where either conflicting 

radiocarbon data exist or where there is no datable 

organic material in the exposed section. 

Methods: We analyzed fine sand-sized quartz 

grains using blue-light OSL dating by single 

aliquot regeneration features (SAR) [3] with bluelight excitation. Dose recovery and plateau tests 

ensured that the sediments were responsive to 

optical techniques and that the proper 

temperatures were used to produce the equivalent 

dose values. We made our blue-light OSL 

measurements on an automated Riso "Minisys" 

TL/OSL DA-15A reader equipped with blue lightemitting diodes (470 ± 30 nm) for illumination 

and a 90Sr/90Y beta source for irradiation. We 

measured OSLsignals after they passed through 

three 3 -mm Hoya U-340 filters, for 40 seconds at 

125°C with an EMI 9235 photomultiplier tube. 

Estimation of the equivalent dose: Lomax 

and others [4] review the different methods of 

estimating the equivalent dose and propose that 

the arithmetic mean is an inappropriate measure to 

describe the equivalent dose if the histogram 

shows a broad and positively skewed distribution. 

The weighted mean, on the other hand, 

underestimates the equivalent dose of older 

samples and might be erroneously biased toward 

low equivalent-dose values in a distribution [5]. 

The central age model accounts for individual 

error but uses standard errors of log doses, which 

are independent of the size of the dose [6]. 

Bateman and others [7] used the high probability 

peak to calculate a mean equivalent dose by fitting 

a normal distribution to the data for their samples 

affected by pedoturbation. Lomax and others [4] 

fitted a Gaussian curve over the weighted 

histogram, and all values outside of this curve 

were removed from the data set, Imtil the 

remaining data could be fitted with a R2

 value of 

at least 0.95. 

We compare these different approaches to 

calculate the equivalent dose and evaluate the 

resulting ages with the radiocarbon evidence. 

References: [1]Obermeier, S.F., Bluer, N.R, 

Munson, C.A., Munson, P.J., Martin, W.S., 

McWilliams, K.M, Tabaczynski, D.A., Ohm, 

J.K, Rubin, M., and Eggert, D.L., 1991, 

Science, v. 251, p. 1061-1063. 

[2] Munson, P.J., and Munson, C.A., 1996, U.S. 

Geological Survey contract report, National 

Earthquake Hazards Reduction Program 

Grant 14-08-0001-G2117, 137 p. 

[3] Murray, A.S., Wintle, A.G., 2000, Radiation 

Measurements, v. 32, p. 57-73. 

[4] Lomax, J., Hilgers, A., Twidale, C.R, Bourne, 

J.A., and Radtke, U., 2006, Quaternary 

Geochronology, in press. 

[5] Galbraith, R.F., Roberts, R.G., and Yoshida, 

H., 2005, Radiation Measurements, v. 39, p. 289-

307. 

[6] Galbraith, R.F., Roberts, R.G., Laslett, G.M, 

Yoshida, H., and 0lley, J.M., 2006, Archaeometry, 

v. 41, no. 2, p. 339-364. 

[7] Bateman, MD., Fredrick, C.D., Jaiswal, M.K., 

and Singhvi, A.K, 2003, Quaternary Science 

Review, v. 22, p. 1169-1176. 

 12
OSL CHRONOLOGIES FOR AEOLIAN ACTIVITY IN THE CONTEXT OF LAKE-LEVEL 

FLUCTUATIONS, DRAINAGE REORGANIZATION AND GLACIAL RETREAT, NORTHCENTRAL MJNNESOTA. 

Kathleen Nicoll', Timothy M. Demko2

, and Lisa M. Marlow2. 1 Oxford University Centre for the Environment, S. Parks Road, Oxford OX13QY UK and (after 8/2006) Department of Geography, University of Utah 

260 S. Central Campus Dr. Rm. 270 Salt Lake City, UT 84112-9155 (kathleen.nicoll@gmail.com); 2 Department of Geological Sciences, University of Minnesota-Duluth, 217 Heller Hall, 1114 Kirby Drive, 

Duluth, Minnesota 55812 (tdemkona,umn.edu).

Introduction: Dunes and stratified eolian sediments are a significant component of the postglacial 

landscape across the mid-continent. During the 

1970s, a benchmark study in north-central Minnesota inferred a period of eolian activity 8,000 — 

5,000 years ago (i.e., the Altithermal Hypsithermal 

periods), based upon radiocarbon dates on charcoal 

and organic material preserved within paleosols 

developed in dunes [1]. We revisited a classic locality at Lake Winnibigoshish (N 47°27'; W 94°12'), 

and sample other dune-forms to hypothesis-test 

whether eolian landform development occurred during the middle Holocene. Optical luminescence 

techniques can better resolve Minnesota's eolian 

chronologies by directly dating the emplacement of 

bed forms; sediments are typically oxidized and lack 

preserved organic materials suitable for 14C dating. 

Sampling: After extensive field reconnaissance 

and GPR (ground-penetrating radar) imaging of 

subsurface contexts, we described stratigraphic relationships at 8 sites across north-central Minnesota. 

Using natural exposures and hand-dug pits, we targeted >20 contexts for optical dating. Samples were 

collected with PVC tubes and lightproof bags. 

Methods: Under amber light, samples were wetsieved and treated with dilute HC1 to remove carbonates, and then floated in 2.7 g/cm3

 sodium polytungstate to isolate heavy minerals, which were 

identified by XRD (x-ray diffraction). We used a 

standard pretreatment to refine the sample: 1) initial 

etch and removal of feldspars using 10% HF for 1 

hour; 2) etch with 48% HF in a mechanical shaker 

for ~50 minutes; 3) react with 47% HC1 to remove 

fluorides; 4) re-sieving to remove the <75 gm fraction; 5) infrared stimulation test (IRSL) to verify 

removal of feldspar grains; and 6) possible repeat of 

refinement steps to assure sample purity. 

The primary luminescence techniques employed 

included a preheat plateau test and single aliquot 

regenerative-dose measurements (OSL SAR) [2] on 

prepared quartz of the average grain size represented 

in the sediment sampled. Measurements were 

conducted using a RISO TL/OSL DA-15 reader 

(470 nm, 2 U-340 filters). The SAR protocol used 

four regenerative dose points (5, 10, 20, 40 Gy) with 

an initial preheat (PHI) of 260°C/10 sec, after which 

the natural dose (L.) was measured using 90% blue 

diodes (60 sec) at 125°C. The irradiations were 

followed by a preheat (PH2) of 260°C/10 sec, and a 

small test dose. 

Values for dose rate (Dr) were calculated from 

ICP-MS and AAS measurements of the concentrations of K, U and Th in bulk sample splits treated 

with an HF-HNO3 HC1O4 digestion, and dilution 

[3]. The in situ water content was measured after 

oven-drying the sediment at 100°C. 

Conclusion/References: Replicate optical dates 

suggest there was a period of dune mobilization 

during the late Pleistocene (13-12 ka), followed by a 

cessation. Eolian dynamism then peaked after 8 ka, 

which is a time period characterized by aridity 

across the mid-continent region [4]. These new dates 

from Minnesota can be compared with other 

published records from the Great Lakes region [5]. 

[1] Grigal, D.F., Severson, R.C., Goltz, G.E. (1976) 

Evidence of eolian activity in north-central 

Minnesota 8,000 to 5,000 yr ago. GSA Bulletin 

87:1251-1254. 

[2] Murray, A.S. and Wintle, A.G. (2000) Luminescence dating of quartz using an improved singlealiquot regenerative-dose protocoL Radiation 

Measurements 32:57-73. 

[3] Adiamec, G. and Aitken, M.J. (1998) Dose-rate 

conversion factors: update. Ancient TL 16:37-50. 

[4] Dean, W.E., Ahlbrandt, T.S., Anderson, RY., 

and Bradbury, J.P. (1995) Regional Aridity in 

North America during the middle Holocene. The 

Holocene 6:145-155. 

[5] Arbrogast, A.F., Wintle, A.G., and Packman, 

S.C. (2002) Widespread middle Holocene dune 

formation in. the eastern Upper Peninsula of 

Michigan and the relationship to climate and outletcontrolled lake leveL Geology 30:55-58. 

 13
DATING EPHEMERAL STREAM AND ALLUVIAL FAN DEPOSITS ON THE CENTRAL GREAT 

PLAINS: COMPARING MULTIPLE-GRAIN OSL, SINGLE-GRAIN OSL, AND RADIOCARBON AGES. 

Paul R. Hanson, School of Natural Resources, University of Nebraska-Lincoln, 114 Nebraska Hall, Lincoln, NE 

68588-0517, phanson2@unl.edu

Introduction: This research compares the use of 

luminescence (both multiple-grain and single-grain 

methods) and radiocarbon dating techniques for 

providing age control for ephemeral stream and 

alluvial fan deposits in western Nebraska. Age 

estimates were determined for channel, overbank, 

and alluvial fan deposits using the multiple-grain 

luminescence (37 ages), single-grain luminescence 

(13 ages), and radiocarbon (4 ages) dating 

techniques. 

Results and Discussion: The multiple-grain data 

showed problems associated with partial bleaching 

based on their high degree of equivalent dose (De) 

spread, and the poor correspondence of these ages 

with those from relative age estimates. The singlegrain results confirmed these bleaching problems, 

showing that all of the alluvial fan and channel and 

some of the overbank samples had highly 

asymmetrical histograms (Fig. 1) and much younger 

ages relative to those determined using the multiplegrain techniques. 

Based on the single-grain ages, multiple-grain 

ages were over-estimated by ~ 1,500-800 and 1,500-0 

years for channel and overbank sediments, 

respectively. Furthermore, sediments that likely were 

deposited in the 20th century had multiple-grain ages 

of ~ 1,500-1,400 years BP, while the ages from 

single-grain dating were 150-70 years BP. Four 

radiocarbon ages from detrital charcoal were 

analyzed to provide independent age control for the 

optical methods. In two cases 14C ages corresponded 

with age estimates from the multiple-grain and 

single-grain techniques. However, in two others 

single-grain or multiple-grain ages suggested the 

radiocarbon ages were over-estimated by ~ 750-650 

years. Based on these comparisons, the single-grain 

optical dating technique provides the most consistent 

ages for these alluvial deposits, and those that best 

agree with the relative age control in this field area. 

These results suggest that the single-grain technique 

may be useful in improving late-Holocene alluvial 

chronologies in the central Great Plains, and in 

similar alluvial settings. 

Figure 1. Single-grain equivalent dose distributions 

for representative overbank (upper histogram), 

channel (middle histogram), and alluvial fan (lower 

histogram) samples from western Nebraska. 

Rocky Hollow 5-5

n = 249 Bin Width = 0.5 Gy

0

10

20

30

40

50

60

70

80

-4.5 -3.5 -2.5 -1.5 -0.5 0.5 1.5 2.5 3.5 4.5 5.5 6.5 7.5 8.5 9.5 10.5

Rocky Hollow 5D-1 

n = 249 Bin Width = 0.5 Gy

0

5

10

15

20

25

30

35

40

-3.5 -1.5 0.5 2.5 4.5 6.5 8.5 10.5 12.5 14.5 16.5 18.5 20.5 22.5 24.5 26.5 28.5 30.5

McPheeter 0.5

n = 171 Bin Width = 0.5 Gy 

0

5

10

15

20

25

30

-1.5

0

1.5

3

4.5

6

7.5

9

10.5

12

13.5

15

16.5

18

19.5

21

22.5

24

25.5

27

 14
OSL DATING OF SEDIMENTS FROM PALEOINDIAN SITES IN BRAZIL. James K. Feathers, University 

of Washington, jimf@u.washington.edu

 

Introduction: In the ongoing debate about human 

colonization of the New World, increased attention 

has been paid to South American evidence. This is 

not only because the oldest, widely accepted site is 

located in South American, but also because the 

largest – by an order of magnitude – sample of 

paleoindian skeletons is found in Brazil. These 

skeletons have been shown to be morphologically 

distinct from modern Native Americans. Brazilian 

physical anthropologists have argued that they 

represent an earlier migration to the New World than 

that from which modern Native Americans are 

descended. A large portion of these skeletons are 

found in the limestone rockshelters of Lagoa Santa in 

Minas Gerais state. 

 A problem with South American paleoindian 

evidence is poor documentation, particularly in terms 

of reliable dating. In conjunction with a research 

project being conducted in Lagoa Santa by the 

University of São Paulo, our laboratory has been 

attempting to obtain OSL dates from sediments in the 

rockshelters. 

 The limestone in which the rockshelters are formed 

is overlain by a shale that includes pockets of 

quartzite cobbles. Most sediment in the rockshelters 

is either of anthropogenic origin or represents 

colluvium that has washed into the shelters from the 

eroding shale. The amount of sand-sized quartz, 

while not abundant, is sufficient for OSL dating, 

particularly if single-grain measurements are 

employed. In many of the shelters, the sediments are 

largely of paleoindian age, as evidenced from 

artifacts and radiocarbon dates. The possibility of 

mixture of the sediments and questions about the 

reliability of the radiocarbon dates has led to the 

application of OSL. 

 Methods: Equivalent dose (De) is determined by 

single-grain analysis using the SAR protocol. 

Attempting to understand the De distributions that 

result from single-grain analysis is the focus of 

research, particularly experimenting with mixture 

models to isolate single-age populations. 

Radioactivity is measured by alpha counting, beta 

counting, and on site dosimetry. 

 Results: Many of the measurements have not been 

completed as of this writing. Work is concentrating 

at three shelters: Lapa Vermelha (which is wellknown for containing the reputed oldest human 

skeleton in the New World), Boleiras and Lapa do 

Santo. Samples from Lapa Vermelha are 

distinguished from samples from the other two sites 

by displaying high over-dispersion in the De

distributions. Some simplified De (t) plots suggest 

the problem is not partial bleaching, but probably 

relates to turbation, a conclusion supported by the 

widespread occurrence of insect burrows in the 

sediments. This is being tested by looking at recently 

collected samples from a portion of the rockshelter 

where the insect burrows are absent. Samples from 

the other two sites, while showing moderate 

dispersion, probably represent single-aged 

populations. Over-dispersion values may be 

overestimated if no account is taken of spatial 

heterogeneity in the dose delivered by the 90Sr beta 

source. We have found a systematic variation in the 

calibration of the source for single grains, varying by 

a factor of almost two from one end of the singlegrain disk to the other. 

 Using the central-age model to determine De for 

age calculations, broad agreement at all three sites is 

obtained when comparison is made with radiocarbon 

dates. The agreement at Lapa Vermelha, where the 

central age model may be less appropriate, is only 

rough because of uncertainties in the association of 

the radiocarbon dates, obtained 30 years ago, with the 

OSL samples. But at Boleiras samples dated 9.7 to 

12.1 ka by radiocarbon compare with OSL samples 

dated 8.4 to 11.4. One OSL age is anomalously low 

and not in stratigraphic agreement with the others. 

At Lapo do Santo, an OSL age of 9.2 ka compares to 

a radiocarbon range of 9.8-10.2. (All radiocarbon 

dates are calibrated.) 

This work is funded by the National Science 

Foundation 

 15
USING OSL TO DATE FINE-GRAINED CERAMICS. M. Aksel Casson, University of Washington, 

casson@u.washington.edu, and James K. Feathers, University of Washington, jimf@u.washington.edu

 

Introduction – Luminescence dating was first 

developed in the context of dating archaeological 

ceramics. Research has largely shifted to dating 

unconsolidated sediments, but ceramic dating 

remains important for archaeology. Dating of finegrained ceramics using TL often results in less than 

satisfactory results, because of high scatter, illdefined equivalent dose (De) plateaus, sensitivity 

changes between first and second glow outs, and 

anomalous fading. Our laboratory in the last two 

years has been applying single-aliquot OSL to finegrained ceramics. OSL measures the fastest 

bleaching component and single-aliquot methods 

have higher precision than is possible with multialiquot TL. 

 The double SAR method was developed for dating 

fine-grained sediment samples [1,2]. The method 

involves at each measurement step of the SAR 

protocol, two exposures, an initial infrared followed 

by blue light. The rationale is that the infrared 

exposure will remove most of the feldspar signal so 

that the blue exposure produces a signal from mainly 

quartz, thereby getting around the problem of 

anomalous fading. 

 Effectiveness of infrared exposure – Feldspar 

also responds to blue light, and part of the 

uncertainties in the double SAR method is how much 

the initial infrared exposure reduces the feldspar 

signal. Is the blue stimulated signal really free from 

anomalous fading? Two approaches to insuring that 

the infrared exposure fully reduces the feldspar signal 

have been tried: (1) conducting the infrared exposure 

at higher temperatures [3] and (2) prolonging the 

infrared exposure [4]. We have experimented with 

both approaches and have found that heating above 

60°C for the infrared exposure or prolonging the 

infrared exposure to longer than 100 seconds makes 

little difference in the resulting blue-stimulated 

signal. Preliminary fading tests indicate that the blue 

signal does not fade, while the infrared signal does. 

 Alpha efficiency – De values from TL, IRSL and 

blue OSL from the same sample often differ 

significantly. This should not be surprising, given 

that alpha efficiency is likely to vary between quartz 

and feldspar. We have attempted to measure alpha 

efficiency, using b-value, for IRSL, OSL as well as 

TL. An alpha “equivalent dose” has been measured 

using an SAR protocol. This is compared to the De

obtained using beta irradiation, also using SAR. The 

b-value does not vary significantly for several 

samples tested from that obtained using multi-aliquot 

data. The results show that b-value differs 

significantly among all three, being generally high 

for IRSL and generally low for OSL, while 

somewhere in between for TL, probably varying 

depending on relative amounts of quartz and feldspar 

(see figure). 

 Ages – A comparison of ages for the same sample 

calculated using TL, IRSL and OSL suggests that 

OSL should become an important complement to TL 

in assessing the age of prehistoric ceramics. 

[1] Banerjee, D., Murray, A.S., Bøtter-Jensen, L, 

Lang, A. (2001). Equivalent dose estimation using a 

single aliquot of polymineral fine grains. Radiation 

Measurements 33:73-94.

[2] Roberts, H.M., Wintle, A.G. (2001). Equivalent 

dose determinations for polymineralic fine-grains 

using the SAR protocol: application to a Holocene 

sequence of the Chinese Loess Plateau. Quaternary 

Science Reviews 20:859-863. 

 [3] Jain, M., Singhvi, A.K. (2001). Limits to 

depletion of blue-green light stimulated luminescence 

in feldspars: implications for quartz dating. 

Radiation Measurements 33:883-892. 

[4] Wang, X., Lu, Y, Zhao, H. (2006). On the 

performances of the single-aliquot regenerative-dose 

protocol for Chinese loess: fine quartz and 

polymineral grains. Radiation Measurements 41:1-8. 

 16
LUMINESCENCE DATING OF ANCIENT MONUMENTAL ARCHITECTURE AT CHAVÍN DE 

HUÁNTAR, PERU. J.A. Johnson1

, J.K. Feathers2, S. R. Kembel3. 1,2University of Washington, Box 

353100, Seattle, WA 98195-3100 (1

anamgorm@u.washington.edu, 2jimf@u.washington.edu), 3Dept of 

Anthropology, Univ of Pittsburgh, Pittsburgh, PA 15213 (silvia@kembel.com) 

Introduction: Monumental architecture is a 

common feature of ancient Peruvian archaeological 

sites, but our understanding of the chronology of 

these complex monuments has been limited by 

difficulties in obtaining reliable dates for monument 

construction episodes. Primarily, these difficulties 

have been caused by a paucity of carbon or ceramic 

materials in clear association with architectural 

construction events. At the Peruvian formative site 

of Chavín de Huántar, located in the central Peruvian 

Andes, we have attempted to address these 

limitations by utilizing OSL methods to directly date 

multiple monumental construction events. 

 The site chosen is in some ways ideal for this 

project, as the relative sequence of construction 

events at Chavín is quite well understood, and 

extensive radiocarbon samples have been obtained 

directly from architectural features at the site. This 

information will provide independent evidence with 

which the dates we have obtained can be evaluated, 

allowing us to check the validity of our OSL dates 

before applying the method to the numerous 

monumental sites where such information is 

unavailable. The site chosen also posed several 

unique challenges to the collection, processing, and 

analysis of OSL samples, and this paper discusses 

these challenges and our solutions to them in detail. 

 Sample Collection: Mortar seams in stone-andmortar architectural walls were targeted for sampling. 

Preservation concerns and the small width of mortar 

seams restricted collected samples to unusually small 

volumes. Samples were collected with small 

diameter tubes driven into wall faces, and dosimeters 

were placed at maximum depth. Wall geometry and 

precise sample provenience were recorded in detail. 

Rock fragments from wall stones were collected to 

aid in laboratory estimation of dosimetry. 

 Sample Processing: Laboratory processing was 

governed by the concern for isolating samples of 

known depth from wall surface. Degree of 

compression as a product of collection was estimated 

mathematically, and samples were segmented to 

isolate subsamples expected to have been at least 15 

cm deep in wall matrix. 

 De Analysis: Single-grain SAR OSL was used on 

quartz grains to obtain equivalent dose estimates. 

Partial bleaching was identified and 

addressed with the use of the minimum age model. 

Sample sizes were quite small in many cases due to 

small sample volume and the scarcity of “bright” 

grains during analysis. Feldspars and fine-grained 

OSL were also attempted in some cases, but failed to 

produce any useable signal. 

 Dr Analysis: Complex wall geometry at 

collection points made estimation of dose rate an 

involved process. Radioactivity of collected mortar 

and stones was measured directly, and an estimate of 

each sample’s composite dose rate was derived from 

these measures using digital imaging software and 

the geometric configuration of wall surfaces at 

sampling locations. To help gauge potential error in 

projecting these surface-derived estimates to depth, 

this process was repeated for each sample using a 

second, hypothetical, sample placement, and the two 

surface estimates were compared. Dosimeters 

collected from sample locations have provided an 

additional check on dose rate estimates. 

 Results: Full results are available for a sample 

taken from the Ofrendas Gallery at Chavín, and this 

sample’s age falls within error terms of known 14C 

dates for this same construction episode. Numerous 

other samples will be finished soon, and will be 

discussed in detail. These data will also be 

systematically compared with forthcoming 14C data 

from Chavín to assess the potential of OSL for dating 

archaeological monument construction episodes in 

Peru. 

Table 1. Comparison of OSL and 14C Dates for 

 the Ofrendas Gallery 

OSL Sample Minimum Age 

UW1175 1101± 285 

 14C Sample 1σ Cal. Range (BC) 

GX1128 [1] 970-790 

TX18 [1] 1440-1120 

 References: [1] Lumbreras, L.G. (1993) Chavín de 

Huántar: Excavaciones en la Galeria de las Ofrendas. 

Materialien zur Allgemeinen und Vergleichenden 

Archaologie bd. 51. P. von Zabern, Mainz Am Rhein. 

 17
EOLIAN SAND DEPOSITIONAL RECORDS FROM WESTERN KANSAS AND NEBRASKA, 

AND EASTERN COLORADO: A POTENTIAL LANDSCAPE RESPONSE TO DROUGHTS IN 

THE PAST 10,000 YEARS. S. L. Forman, L. Marín and J. Gomez, Luminescence Dating Research 

Laboratory, Univ. of Illinois at 

Chicago, Chicago, IL 60607-7059. 

The Great Plains are dominated by presently 

stabilized dune fields that are indicators of 

extreme drought in the late Holocene. This study 

focused on evaluating geomorphological, 

stratigraphic and chronological evidences of 

dune reactivation for stabilized ergs in 

southwestern Kansas and southeastern Colorado 

adjacent to the Arkansas and Cimarron Rivers. 

Dunes occur on multiple-aged terraces, with 

modified star dunes at the upper valley margin 

and reverse and transverse dunes at lower 

topographic positions. Parabolic and blow dunes 

are also common and appear to reflect the latest 

period of dune reactivation. This complex of 

eolian landforms reflects a 

variety of paleowinds with 

dominant directions from the 

northwest and northeast and 

secondary directions from the 

southeast and southwest. 

Multiple stratigraphic 

exposures reveal eolian sand 

separated by up to three 

paleosols indicating repeated 

eolian activity followed by 

landscape stability. Most 

paleosols show minimal 

horizonation with either a sole 

A horizon and/or a weak 

cambic B, indicating 

pedogenesis for < 1 ka. The 

chronology of eolian-sand 

depositional events is 

constrained by optical stimulated luminescence, 

single aliquot regeneration method (SAR) on 

150-250 micron quartz grains. The oldest eolian 

sand stratigraphically above high fluvial terrace 

gravels yielded SAR ages of ca. 8000-6000 yr, 

indicating significant eolian activity in the early 

Holocene. Basal eolian sand from a stratigraphic 

exposure within Arkansas River dune field 

yielded the SAR age of 1490 ± 130 yr BP, 

indicating pervasive late Holocene reactivation. 

Widespread dune reactivation occurred at 230 ± 

20 and 190 ± 15 yr BP, possibly coincident with 

a multi-decadal (?) tree-ring identified drought in 

the 19th century. There is compelling evidence 

that these systems in Colorado, Nebraska and 

Kansas reactivated <300 yr ago. Independent 

confirmation of the timing of dune movement is 

derived from analyses of mosaiced and 

georeferenced aerial photograph time series 

spanning the past 70 years. Pure quartz aliquots 

from eolian sand associated with dune 

movements in the 1930’s and later in the 20th

century were dated by optically stimulated 

luminescence using two different single aliquot 

regeneration (SAR) protocols. Initial analyses 

were completed using standard SAR protocols 

with blue excitation (BL) of quartz aliquots. 

Subsequent analyses used a modified SAR 

protocol by adding a high-temperature step under 

blue excitation (BL-IR) with a prior infrared (IR) 

“wash” step. There is a variable response of 

quartz aliquots to these protocols with the BL-IR 

treatment for all samples yielding concordant 

ages. IR excitation yielded the greatest range of 

responses with quartz grains from Colorado 

yielding an older component, from west Kansas, 

an age underestimate and from Nebraska ages 

consistent with BL and BL-IR protocols. This 

study indicates that a pre-infrared wash step and 

an elevated temperature step under blue 

excitation minimized spurious feldspathic 

components and potential recuperation affects. 

SAR protocols are significantly robust to resolve 

ages for eolian sands deposited in the past 

century on the Great Plains, USA. 

 18
 

LUMINESCENCE CHRONOLOGY FOR LATE QUATERNARY AND HOLOCENE RECORDS OF 

EOLIAN DEPOSITION FROM A “MEGA-TRENCH” ACROSS THE ANTON SCARP, EASTERN 

COLORADO, USA. Jeaneth Gomez1

, David Noe2 and Steven L. Forman1 1Luminescence Dating Research 

Laboratory, Univ. of Illinois at Chicago, Chicago, IL 60607-7059. 2

Colorado Geological Survey 1313 

Sherman St, Rm 715, Denver, CO 80203 

Introduction: The Anton Scarp is an enigmatic, 

potentially tectonic structure, buried by late 

Quaternary sediments on the High Plains of eastern 

Colorado, approximately 160 km east of Denver. A 

mega-trench with tiered sidewalls was excavated into 

the lower slope of this scarp, revealing multiple 

eolian sedimentary units. 

Geochronology: Single and multiple aliquot 

regeneration protocols on the fine and coarse 

fractions were used under green, infrared and bluelight excitation to yield luminescence ages. 

Independent chronologic control is provided by the 

presence of paleo-indian (~11-13 ka) artifacts in the 

upper part of the trench. The lowest observed 

stratum is a well-developed paleosol with a meterthick carbonate-rich, argillic horizon (see Fig. 1). 

Periglacial sand wedges are intruded into the 

paleosol. These wedges show distinctive vertical beds 

of silty sand associated with cracking of sediments 

upon freezing and subsequent infilling by the eolian 

transport of grains. The wedges also exhibit sidewall 

collapse structures with melting of permafrost and 

subsequent colluvial deposition. The presence of 

these periglacial features indicates at least a 12°C 

temperature depression from the current mean. 

Quartz grains from the sand wedge infill yielded the 

optical age of 20,365 ± 1635 yr (UIC1677IR), 

consistent with much colder climates during the Last 

Glacial Maximum. 

The top of the lowest paleosol is eroded, marked 

by a lag of rounded pebbles, and grades into a 

horizontally-stratified very coarse to medium sand. 

Quartz grains from above the truncated paleosol 

surface yielded the optical age of 13,035 ± 910 yr 

(UIC1675IR). A correlative bed of eolian strata, 

which caps a sandy fluvial channel deposit associated 

with landscape erosion, yielded a similar age of 

13,150 ± 900 yr (UIC1679IR). A prominent 

compound paleosol occurs in the upper 1 m of the 

eolian/fluvial sand unit, which is buried by a 

conspicuous loess. Fine grains from the basal 10 cm 

of this loess yielded optical ages of 7020 ± 460 yr 

(UIC1676IR) and 7750 ± 500 yr (UIC1680IR), 

and 6120 ± 395 yr (UIC1676GR) and 6660 ± 710 yr 

(UIC1680GR) by infrared or green stimulation, 

respectively. 

Conclusion: This Holocene loess appears only 

within the area of a filled depression at the base of 

the scarp, and may be correlative to Bignell and 

younger loess in western Nebraska. 

Figure 1. Partial stratigraphy from trench 

 19
 

USING OSL GEOCHRONOLOGY TO CORRELATE STREAM AND HILLSLOPE DEPOSITS TO 

CLIMATE CHANGE IN EASTERN GRAND CANYON TRIBUTARIES. B. DeJong1

, J. Pederson1, T. 

Rittenour1

 and R. Goble2.

 1Department of Geology, Utah State University, Logan, UT 84322 (bddejong@cc.usu.edu; 

bolo@cc.usu.edu, tammyr@cc.usu.edu); 2

Department of Geosciences, University of Nebraska, Lincoln NE 68588 

(rgoble@unlnotes.unl.edu) 

Introduction: The Pleistocene stratigraphy of 

eastern Grand Canyon (EGC) provides insight into 

desert landscape responses to climate change. For 

example, hillslope and fluvial deposits in the Lava 

Chuar and Comanche tributary drainages record 

strong cycles of aggradation and incision in response 

to changing sediment production, storage, and 

transport. Anders et al. [1] produced a chronology for 

these tributaries and the mainstem Colorado River 

using OSL and cosmogenic dating methods. Results 

show different responses of the tributary drainages 

and the mainstem river that may indicate responses to 

differing controls; namely local climate forcing for 

tributaries and glaciation in the headwaters for the 

Colorado. 

Hillslope and stream components of the Lava 

Chuar and Comanche drainages offer a unique 

opportunity to explore the timing and mechanisms of 

tributary sedimentation. For example, field relations 

in the short, steep Comanche drainage indicate the 

massive colluvial C3 deposit grades to the fluvial S3 

deposit, suggesting contemporaneous fluvial and 

hillslope deposition. By contrast, the younger S2 

deposit has no correlative hillslope deposit and issues 

from gullies cut into the S3. The goals of this project 

are to develop a more robust chronology for these 

deposits using OSL in order to determine temporal 

patterns in deposition along the length of drainages. 

Sampling/Methods: OSL samples were collected by 

pounding metal tubes into fluvially re-worked 

colluvium and fluvial terraces. Priority was placed 

on collecting samples from the basal portions of 

deposits in order to determine the onset of deposition 

and to test for transience. Additional sand was 

collected for dose rate analysis and water content 

determination. OSL samples were processed at the 

University of Nebraska and analyzed using a 

modified single aliquot regenerative-dose (SAR) 

protocol [2] with a 280oC bleach after each cycle [3]. 

Results: The transport mechanisms associated with 

hillslope colluvium and terrace materials in EGC 

tributaries are expected to produce partially bleached

sediment. For example, fluvial sediments are often 

transported under turbid water conditions in these 

ephemeral streams. Similarly, sand lenses in 

hillslope colluvium are the result of fluvial reworking 

of debris flow material during small pulses of stream

flow activity. These difficult bleaching conditions are 

reflected both in equivalent dose (De) distributions

and in the rejection rate for disks. Despite these 

challenges, the SAR OSL dating method is yielding 

preliminary ages for samples collected in EGC 

tributary deposits (fig. 1). For example, results 

indicate two new distinct deposits (S2o, S3o) that 

reveal a picture of surprisingly complicated 

stratigraphy and unexpected timing of sedimentary 

responses. 

Figure 1. Schematic cross-section of terraces in 

eastern Grand Canyon showing preliminary OSL 

ages 

Conclusion/References: Preliminary OSL 

results suggest that a high-resolution picture of 

tributary sedimentation can be produced for the 

tributaries studied. This will help to explore the 

potential transience of tributary sedimentation and 

uncover a stratigraphy that is apparently more 

complicated than field observations suggest. Further 

fleshing out this record will ultimately provide a 

window to help us better understand dryland 

responses to climate change 

 [1] Anders, M.D., Pederson, J.L., Rittenour, 

T.M., Sharp, W.D., Goss, J.C., Karlstrom, K.E., 

Crossey, R.C., Goble, R.J., Stockli, L., and Guang, Y. 

(2005) Pleistocene geomorphology and 

geochronology of eastern Grand Canyon: Linkages of 

landscape components during climate changes: 

Quaternary Science Reviews 24, 2428-2448. 

[2] Murray, A.S., Wintle, A.G. (2000) 

Luminescence dating of quartz using an improved 

single aliquot regenerative-dose protocol: Radiation 

Measurements 32, 57-73. 

[3] Murray, A.S., Wintle, A.G. (2003) The single 

aliquot regenerative dose protocol: potential for 

improvements in reliability: Radiation Measurements 

37, 377-381. 

 20
 21

USING OSL TO SOLVE THE RIDDLE OF VARIABLE INCISION RATES ACROSS THE 

COLORADO PLATEAU. J. Pederson1

, T. Rittenour1, S. Cragun1, and R. Goble2. 1Dept. of Geology, Utah 

State University, Logan, UT 84322 (bolo@cc.usu.edu, tammyr@cc.usu.edu); 2

Dept. of Geosciences, University 

of Nebraska, Lincoln, NE 68588 (rgoble@unlnotes.unl.edu). 

Introduction: Optical dating is superior to 

other geochronometers for studying the history of 

fluvial systems that are strongly controlled by climate oscillations and marked by fill-terrace records. The depositional ages obtained are suited to 

studying climate controls, as well as for deciphering the signature of the longer-term incision that 

creates terrace records. 

For example, OSL-augmented studies in the 

Colorado Plateau highlight a geomorphic riddle 

about spatially-variable incision rates in this region that lacks active faulting. Here we summarize our studies involving OSL dating, describe the 

apparent patterns of incision along the river, and 

provide hypothetical explanations. 

Methods/approach: We are combining careful 

mapping, stratigraphic work, and topographic surveys with OSL dating that is complimented locally 

by cosmogenic and U-series dating methods. Thus 

far our study sites ranging from Lake Mead to the 

Rocky Mountain headwaters have produced reconstructions of fluvial history over 105

 yr timescales 

that allow us to quantify the trend of incision integrated over climate oscillations (our sites utilizing 

OSL are bold in figure). Single-aliquot regenerative dose OSL analyses were done at the University

of Nebraska laboratory. 

Results: Highly variable incision rates are apparent from the combined results of our studies 

and other recent incision estimates in the central 

Plateau based on cosmogenic or Ar-Ar volcanic

ages (fig). Changes in the western Grand Canyon 

have been described as a result of mild normal 

faulting in that area. But specifically confounding 

is an apparent ~400 km reach of high incision 

rates in the Glen Canyon region. 

Discussion: Some common tectonic controls 

on baselevel can be ruled out for this region. We

therefore submit two hypothetical mechanisms that

remain to create reaches of high incision: a) epeirogenic rock uplift regionally enhanced by erosional unloading; and b) transient knickzone dynamics due to drainage-integration events in combination with reaches of measurably low bedrock 

resistance. Finally, part of the solution to the riddle lies in problematic comparisons of studies with

different approaches in terms of what exactly is 

being dated, how rates are calculated geometrically, and different timescales of rate calculation. 
 22

OSL CHRONOLOGY FROM COLORADO RIVER TRIBUTARIES IN THE WESTERN GRAND 

CANYON AND GRAND WASH TROUGH: COMPARISON TO U-SERIES AGES AND 

APPLICATION TO FLUVIAL DEPOSITS ≥300 KA. T. Rittenour1

, W. Sharp2, J. Pederson1, G. O’Brien1, 

and R. Goble3

. 1Dept of Geology, Utah State Univ, Logan UT 84322 (tammyr@cc.usu.edu; bolo@cc.usu.edu; 

gobrien@cc.usu.edu); 2

Berkeley Geochronology Center, Berkeley CA 94709 (wsharp@bgc.org); 3Dept of Geosciences, Univ of Nebraska, Lincoln NE 68588 (rgoble@unlnotes.unl.edu). 

Introduction: Small fluvial systems in the arid 

southwestern US may provide insight into catchment response to past climate-related changes in 

precipitation and sediment supply. Recent research 

by Anders et al. [1] in the eastern Grand Canyon 

has produced the first detailed reconstruction of 

tributary and hillslope response to local climate 

change, and suggests an out-of-phase relationship 

with the adjoining Colorado River, controlled by 

glaciation of its headwaters. The goals of this research are to reconstruct the catchment-basin response of two geomorphically different Colorado 

River tributaries ~300 km downstream from the 

sites of Anders et al [1]. OSL and U-series results 

are presented here. 

Travertine Grotto, in western Grand Canyon, is 

a small steep drainage basin (~10 km2

, 170 m/km 

gradient). Fluvial sediments are characterized by 

inter-fingered travertine drapes within alluvium, 

with decreased clastic content near the top of terrace 

fills. Grand Wash is a large, low-gradient catchment (~4000 km2

, 17m/km gradient) that drains the 

Grand Wash Trough, the first extensional basin 

west of the Colorado Plateau. Fluvial sediments are 

inset into the Miocene basin fill with basal straths 

below the modern wash level. 

Sampling: OSL samples were collected from 

terrace fills using light-proof metal tubes. Where 

possible, samples were collected from the base and 

top of terrace deposits to determine the timing of 

aggradation. At Travertine Grotto, samples for Useries analysis were also collected from laminated 

travertine drapes within the fluvial sediments. 

Methods: Samples for OSL dating were processed at the University of Nebraska and analyzed 

using the quartz single-aliquot regenerative (SAR) 

technique [2] modified to include a 280°C bleach 

following each cycle [3]. Samples for TIMS Useries dating were analyzed by W. Sharp at the 

Berkeley Geochronology Center. 

Results: The final OSL and U-series ages from 

Travertine Grotto and preliminary OSL ages from 

Grand Wash are summarized in Figure 1. In Travertine Grotto, the T3 terrace has the greatest sampling density, with OSL and U-series ages showing 

good correspondence, suggesting the OSL technique 

is working well for these fluvial sediments. 

In Grand Wash, preliminary OSL ages range 

from 3-350 ka. The oldest terrace (T5) is producing 

an age of ~350 ± 40ka (~280 Gy equivalent dose), 

stretching the limits of SAR OSL dating. However, 

regenerative doses up to ~500 Gy do not show saturation, suggesting ages up to 600 ka could be obtained, assuming dose-rate calculations are accurate. 

Conclusion/References: Geomorphic, stratigraphic and geochronologic investigations of Travertine Grotto and Grand Wash have produced detailed reconstructions of the Pleistocene-Holocene 

terrace chronologies. Correlations to local and regional climate change are still premature, but suggest fluvial aggradation during inter-glacial climates. OSL results are stratigraphically consistent 

and agree with U-series ages from the same deposits. Moreover, the 350 ka sample from T5 in Grand 

Wash is not near saturation and appears to be reliable, despite its old age. 

[1] Anders, M.D., Pederson, J.L., Rittenour, T.M., 

Sharp, W.D., Gosse, J.C., Karlstrom, K.E., Crossey, R.C., 

Goble, R.J., Stockli, L., and Guang, Y. (2005), Quaternary Science Reviews 24, 2428-2448. 

[2] Murray, A.S., Wintle, A.G. (2000), Radiation 

Measurements 32, 57-73. 

[3] Murray, A.S, Wintle, AG (2003), Radiation Measurements 37, 377–381. 

Figure 1. Terrace 

cross-sections and 

summarized OSL and 

U-series chronologies.