https://theglowcurve.org/blog daily 0.75 2024-06-27 https://images.squarespace-cdn.com/content/v1/5b3e6b55e17ba3fda87d91dd/1540856927114-OKTJ6J5F1FYOO34VC0VZ/P6160739.JPG Blog https://theglowcurve.org/blog/2023/9/27/save-the-date-for-nwdlw-2024 monthly 0.5 2024-07-23 https://images.squarespace-cdn.com/content/v1/5b3e6b55e17ba3fda87d91dd/d08dcd7a-259f-40ff-8c6d-f484a98cf8a5/NWDLW2024-PIC.png Blog - SAVE THE DATE FOR NWLDW 2024! - Make it stand out Whatever it is, the way you tell your story online can make all the difference. https://theglowcurve.org/blog/2023/7/21/led2023 monthly 0.5 2024-07-23 https://images.squarespace-cdn.com/content/v1/5b3e6b55e17ba3fda87d91dd/fd9b6dda-59ff-4ce8-9abf-dac6791fdf19/copenhagen.jpg Blog - LED2023 - Make it stand out Whatever it is, the way you tell your story online can make all the difference. https://images.squarespace-cdn.com/content/v1/5b3e6b55e17ba3fda87d91dd/cff7d5a2-931d-4b2e-aca9-217a6af5edee/vikingships.jpg Blog - LED2023 - Make it stand out Whatever it is, the way you tell your story online can make all the difference. https://images.squarespace-cdn.com/content/v1/5b3e6b55e17ba3fda87d91dd/38d90268-d755-4721-8d93-b9e6d9d19a67/vikingchair.jpg Blog - LED2023 - Make it stand out Whatever it is, the way you tell your story online can make all the difference. https://theglowcurve.org/blog/2022/9/30/this-just-in-a-guide-for-interpreting-and-reporting-luminescence-dating-results monthly 0.5 2024-07-23 https://images.squarespace-cdn.com/content/v1/5b3e6b55e17ba3fda87d91dd/91986af4-3021-4529-99ae-7a1930ce0954/guide-pic2.png Blog - This just in! A guide for interpreting and reporting luminescence dating results. - Make it stand out Whatever it is, the way you tell your story online can make all the difference. https://theglowcurve.org/blog/2022/4/25/constraining-lateral-bedrock-erosion-of-the-buffalo-national-river-arkansas monthly 0.5 2024-07-23 https://images.squarespace-cdn.com/content/v1/5b3e6b55e17ba3fda87d91dd/b923eb42-8899-4822-b134-6ba67d9110e0/IMG_5728.jpg Blog - Constraining lateral bedrock erosion rates of the Buffalo National River, Arkansas - Make it stand out Whatever it is, the way you tell your story online can make all the difference. https://images.squarespace-cdn.com/content/v1/5b3e6b55e17ba3fda87d91dd/4bb5af6a-a3e1-4698-9454-5abe28e45854/IMG_9357.JPG Blog - Constraining lateral bedrock erosion rates of the Buffalo National River, Arkansas - Make it stand out Whatever it is, the way you tell your story online can make all the difference. https://theglowcurve.org/blog/2022/4/8/because-you-are-dying-to-know monthly 0.5 2024-07-23 https://images.squarespace-cdn.com/content/v1/5b3e6b55e17ba3fda87d91dd/d9787ac0-853d-46c9-8beb-6e4da38b7877/NB-2+Luminescence+depth+profile.png Blog - Because you are DYING to know... - Make it stand out Whatever it is, the way you tell your story online can make all the difference. https://theglowcurve.org/blog/2022/2/3/dating-limestone monthly 0.5 2024-07-23 https://images.squarespace-cdn.com/content/v1/5b3e6b55e17ba3fda87d91dd/1af21cef-38ef-400b-b902-d4fc3bff5a3b/limestone.JPG Blog - Dating limestone - Make it stand out Whatever it is, the way you tell your story online can make all the difference. https://theglowcurve.org/blog/2021/10/18/setting-up-our-new-toy monthly 0.5 2024-07-23 https://images.squarespace-cdn.com/content/v1/5b3e6b55e17ba3fda87d91dd/1634575959260-UZQKUQMS8X2DGZW1969X/244890960_587966482450556_4110115558384398792_n.jpg Blog - Setting up our new toy!! - Make it stand out Whatever it is, the way you tell your story online can make all the difference. https://theglowcurve.org/blog/2021/6/25/sampling-ancient-beach-ridges-in-the-great-basin monthly 0.5 2024-07-23 https://images.squarespace-cdn.com/content/v1/5b3e6b55e17ba3fda87d91dd/1624641838210-7U2ZS2HCOUZWJQKEPHBK/sampling-Lake+Valley.jpg Blog - Sampling ancient beach ridges in the Great Basin - Make it stand out Whatever it is, the way you tell your story online can make all the difference. https://theglowcurve.org/blog/2021/1/15/ages2-program-awards-for-geochronology-student-research2 monthly 0.5 2024-07-23 https://images.squarespace-cdn.com/content/v1/5b3e6b55e17ba3fda87d91dd/1610745787598-BV2HTA37VP7KC02DUH5X/DRILL-LAB.jpg Blog - AGeS2 Program - Awards for Geochronology Student Research2 https://theglowcurve.org/blog/2021/1/13/investigating-rates-and-mechanisms-of-lateral-erosion-in-a-small-bedrock-river-using-erosion-pins-structure-from-motion-photogrammetry-and-luminescence-dating monthly 0.5 2024-07-23 https://images.squarespace-cdn.com/content/v1/5b3e6b55e17ba3fda87d91dd/1610573090292-R5PI9XMJN3JCH4XYTNUS/Picture1.jpg Blog - Investigating rates and mechanisms of lateral erosion in a small bedrock river using erosion pins, structure-from-motion photogrammetry, and luminescence dating https://theglowcurve.org/blog/2020/10/30/a-glimpse-of-pluvial-lake-lahontan-in-the-high-desert monthly 0.5 2024-07-23 https://images.squarespace-cdn.com/content/v1/5b3e6b55e17ba3fda87d91dd/1604093818570-FKK5QZ5PGAU0W10R3WWK/JE-recon+map.png Blog - A glimpse of pluvial Lake Lahontan in the high desert Jessup Embayment, Carson Sink, Nevada. https://images.squarespace-cdn.com/content/v1/5b3e6b55e17ba3fda87d91dd/1604094187653-1728SHSL4EDC873C5VIH/DSC02536.JPG Blog - A glimpse of pluvial Lake Lahontan in the high desert Platy, angular volcanic shards forming a desert pavement atop a Sehoo highstand beach ridge. https://images.squarespace-cdn.com/content/v1/5b3e6b55e17ba3fda87d91dd/1604093960836-4Z2Z3C3PPZTNWQZJPI4X/DSC02560.JPG Blog - A glimpse of pluvial Lake Lahontan in the high desert Brad Sion, Assistant Research Professor, DRI, ruminating over Sehoo highstand beach gravels exposed in a beach ridge. https://images.squarespace-cdn.com/content/v1/5b3e6b55e17ba3fda87d91dd/1604093113777-3T8WSZVGS7F9YOGS3EZK/Jessup+B-pre-Sehoo+Beach.png Blog - A glimpse of pluvial Lake Lahontan in the high desert (TOP) Beach gravels below and above a well-developed paleosol. The paleosol suggests that the underlying gravels were likely deposited during a lake cycle that predates the most recent (Sehoo) cycle, which reached its maximum ~13,000 years ago. Ken Adams, Research Professor, DRI shown on the right. (BOTTOM) Interference ripples that formed in fine grain sediments on the lake floor. https://theglowcurve.org/blog/2020/8/25/tephra-in-the-lahontan-basin-a-reliable-chronostratigraphic-marker monthly 0.5 2024-07-23 https://images.squarespace-cdn.com/content/v1/5b3e6b55e17ba3fda87d91dd/1598378192176-DNZM1YTJ7YITPDM9YX06/IMG_20200723_100719.jpg Blog - Tephra in the Lahontan basin - a reliable chronostratigraphic marker? https://images.squarespace-cdn.com/content/v1/5b3e6b55e17ba3fda87d91dd/1598378151853-GYFECI5CXJY2ZPIDOEON/-3002682123766511721.jpg Blog - Tephra in the Lahontan basin - a reliable chronostratigraphic marker? https://theglowcurve.org/blog/2020/7/29/congrats-kathleen monthly 0.5 2024-07-23 https://images.squarespace-cdn.com/content/v1/5b3e6b55e17ba3fda87d91dd/1595949321362-WG8RVIKV30RZV1VDBHLE/KR-glowcurve.jpg Blog - Congrats Kathleen! https://theglowcurve.org/blog/2020/6/17/dating-dry-valley-deltas-down-under monthly 0.5 2024-07-23 https://images.squarespace-cdn.com/content/v1/5b3e6b55e17ba3fda87d91dd/1592408954174-LMF42UBIVWQSTGUQ71JT/20181223_165926.jpg Blog - Dating Dry Valley Deltas Down Under https://images.squarespace-cdn.com/content/v1/5b3e6b55e17ba3fda87d91dd/1592409024904-I3AETHS8O1UV8OGFD6UY/20191221_123150.jpg Blog - Dating Dry Valley Deltas Down Under https://theglowcurve.org/blog/2020/5/27/shining-some-light-on-rock-surfaces monthly 0.5 2024-07-23 https://images.squarespace-cdn.com/content/v1/5b3e6b55e17ba3fda87d91dd/1590603062076-JHQRD1L30S0R62PYUPSK/rock+signals3.png Blog - The science of light and lithology OSL, IRSL, and post-IR OSL signals from a range of rock types from Nevada. Click here for more information on luminescence signal types and how they are used. https://images.squarespace-cdn.com/content/v1/5b3e6b55e17ba3fda87d91dd/1590603031602-TMZ81ZZX026MX3RRNTF4/rock+signals2.png Blog - The science of light and lithology https://images.squarespace-cdn.com/content/v1/5b3e6b55e17ba3fda87d91dd/1590601119088-HSKSIC38SAQ940SLR0VY/Incandescent+Rocks+%282%29.jpg Blog - The science of light and lithology https://images.squarespace-cdn.com/content/v1/5b3e6b55e17ba3fda87d91dd/1590601363474-LTOUN1G74WR3LH3H5WKQ/drilled+rocks.png Blog - The science of light and lithology https://images.squarespace-cdn.com/content/v1/5b3e6b55e17ba3fda87d91dd/1590602996216-1DDZVV0XJFIAQ0LOHPY3/rock+signals1.png Blog - The science of light and lithology https://theglowcurve.org/blog/2020/4/16/luminescence-dating-ancient-pluvial-lake-shorelines-in-the-lahontan-basin-using-tufa monthly 0.5 2024-07-23 https://images.squarespace-cdn.com/content/v1/5b3e6b55e17ba3fda87d91dd/1587071478799-9DYGDJ2X0SGEGN7D6VHN/Jessup+Bay+sampling.png Blog - Luminescence dating ancient pluvial lake shorelines in the Lake Lahontan basin using.... tufa? The Jessup embayment preserves shoreline features mainly dating to the last (Sehoo) lake cycle in the Late Pleistocene. The sampled lithoid terrace at 1339 m asl, with tufa coated beach cobbles, may have started to form during the penultimate (Eetza) lake cycle ~100,000 years earlier (Adams & Wesnousky 1998; 1999). https://images.squarespace-cdn.com/content/v1/5b3e6b55e17ba3fda87d91dd/1587071397767-T2E7EYM7Z1K8IRPXSUAY/tufa+measurements.png Blog - Luminescence dating ancient pluvial lake shorelines in the Lake Lahontan basin using.... tufa? TOP. The sampled lithoid terrace in the Jessup embayment. Person for scale. BOTTOM LEFT. Lithoid tufa. BOTTOM CENTER. The IRSL signal from silt (<32 um) extracted from the tufa. BOTTOM RIGHT. A fading plot showing a moderate to high fading rate. https://theglowcurve.org/blog/2020/3/27/wishing-you-health-and-resilience monthly 0.5 2024-07-23 https://images.squarespace-cdn.com/content/v1/5b3e6b55e17ba3fda87d91dd/1585342680736-HS7TPVALMV4M4FJB7EZI/91483581_144551613618270_6103440795845525504_n.jpg Blog - Wishing you health and resilience https://theglowcurve.org/blog/2020/2/6/rock-surface-dating-using-luminescence-methods monthly 0.5 2024-07-23 https://images.squarespace-cdn.com/content/v1/5b3e6b55e17ba3fda87d91dd/1581010819545-8IWI2JT6W8QGUQOA2EFF/P1300035.JPG Blog - Rock surface dating using luminescence methods A Buehler precision saw with a 400 µm thick diamond wafer blade allows us to cut rock cores into sub-millimeter thick slices. These can be used to date the last time a rock surface has been exposed to sunlight, and to determine the depth of light penetration in a rock. https://theglowcurve.org/blog/2019/12/19/luminescence-signals-a-cheat-sheet monthly 0.5 2024-07-23 https://images.squarespace-cdn.com/content/v1/5b3e6b55e17ba3fda87d91dd/1576864278268-CMZSBP0NAWVZTCZA3Z3M/signals-2.jpg Blog - Luminescence signals - a cheat sheet https://theglowcurve.org/blog/2019/10/23/the-new-world-luminescence-portable-gamma-spectrometer-calibration-initiative monthly 0.5 2024-07-23 https://images.squarespace-cdn.com/content/v1/5b3e6b55e17ba3fda87d91dd/1571847940389-8L6R0ACIH6A9CNKT1PHC/PORTABLES.png Blog - The New World Luminescence Portable Gamma Spectrometer Calibration Initiative! https://images.squarespace-cdn.com/content/v1/5b3e6b55e17ba3fda87d91dd/1571847707759-68DQ8VSPH7EH7ELJ6Z9T/DSC02497.JPG Blog - The New World Luminescence Portable Gamma Spectrometer Calibration Initiative! https://images.squarespace-cdn.com/content/v1/5b3e6b55e17ba3fda87d91dd/1571848004982-X8M85OELAZ3AOLYPUKS1/CALIBRATING.png Blog - The New World Luminescence Portable Gamma Spectrometer Calibration Initiative! https://theglowcurve.org/blog/2019/9/25/field-photos-dos-and-donts monthly 0.5 2024-07-23 https://images.squarespace-cdn.com/content/v1/5b3e6b55e17ba3fda87d91dd/1572995092738-R7M8YI0XMOFCMX0CEOIR/scale.png Blog - Field photos: "Do’s" and "Don’ts"… https://images.squarespace-cdn.com/content/v1/5b3e6b55e17ba3fda87d91dd/1572993479135-EG5A60XIK78VU0X2PN70/Jan24-27-09+028.jpg Blog - Field photos: "Do’s" and "Don’ts"… https://images.squarespace-cdn.com/content/v1/5b3e6b55e17ba3fda87d91dd/1572995484773-WV365YQNAVQ2A021HWQN/SMILE.JPG Blog - Field photos: "Do’s" and "Don’ts"… https://images.squarespace-cdn.com/content/v1/5b3e6b55e17ba3fda87d91dd/1572994389750-ACGDS6JT5I1S4U748USR/kunteli.png Blog - Field photos: "Do’s" and "Don’ts"… Sampling fluvial silts and sands deposited by ancestral Son River, in the Son Valley, Madhya Pradesh, India. https://images.squarespace-cdn.com/content/v1/5b3e6b55e17ba3fda87d91dd/1572993620914-UTDBTMDP5529JQTU2YCT/Mar06-10-09+003.jpg Blog - Field photos: "Do’s" and "Don’ts"… https://images.squarespace-cdn.com/content/v1/5b3e6b55e17ba3fda87d91dd/1572993930148-3T9WAA9GQIF7T9OZ8AV6/pans.png Blog - Field photos: "Do’s" and "Don’ts"… https://images.squarespace-cdn.com/content/v1/5b3e6b55e17ba3fda87d91dd/1572994236042-MJK46NGLGD6M00306O8V/annotation.png Blog - Field photos: "Do’s" and "Don’ts"… https://images.squarespace-cdn.com/content/v1/5b3e6b55e17ba3fda87d91dd/1572995166508-Q4BNV3C89ORERUS7LET2/tasmania.jpg Blog - Field photos: "Do’s" and "Don’ts"… Ancient eolian sands exposed in a roadcut in Tasmania. Amy Robertson, of the Forest Practices Authority, Tasmania, for scale. Photo credit: Tim Barrows. https://images.squarespace-cdn.com/content/v1/5b3e6b55e17ba3fda87d91dd/1572993713564-G9K7GNGWJ8VV3LPN009F/shadows.png Blog - Field photos: "Do’s" and "Don’ts"… https://images.squarespace-cdn.com/content/v1/5b3e6b55e17ba3fda87d91dd/1572996050676-ZYRRBDVNREMQKLGTBJ8B/cavert3.png Blog - Field photos: "Do’s" and "Don’ts"… Sampling beach sands containing peat on Calvert Island, British Columbia, Canada. https://images.squarespace-cdn.com/content/v1/5b3e6b55e17ba3fda87d91dd/1572994628409-U22SYXOS2Q0WKZO8QP53/dhaba.png Blog - Field photos: "Do’s" and "Don’ts"… Sampling unsorted colluvial deposits comprised of weathered shale derived from local bedrock, Son Valley, Madhya Pradesh, India. https://images.squarespace-cdn.com/content/v1/5b3e6b55e17ba3fda87d91dd/1572993803896-VB14LR8V6C6ZTPZ7YZ6J/clean.png Blog - Field photos: "Do’s" and "Don’ts"… (LEFT) Before section cleaning. (RIGHT) After section cleaning. https://images.squarespace-cdn.com/content/v1/5b3e6b55e17ba3fda87d91dd/1572993533137-X8NV7AG0PEY6ZPLHQ1Z0/Jan24-27-09+027.jpg Blog - Field photos: "Do’s" and "Don’ts"… https://images.squarespace-cdn.com/content/v1/5b3e6b55e17ba3fda87d91dd/1572994563493-PWGJL6QFLGO1MYU0D5EG/calvert2.png Blog - Field photos: "Do’s" and "Don’ts"… Sampling waterlogged sands preserving paleosols in a bog on Calvert Island, British Columbia, Canada. https://theglowcurve.org/blog/2019/6/28/sampling-for-luminescence-dating-part-iii monthly 0.5 2024-07-23 https://images.squarespace-cdn.com/content/v1/5b3e6b55e17ba3fda87d91dd/1561587575681-MX8KT9LVAJOJ7JLK0QB6/h2o-2.png Blog - Sampling for luminescence dating – Part III The influence of water content on alpha, beta, gamma and total environmental dose rates at the site of sample W4014 (Neudorf et al., 2019). Water can absorb all three forms of radiation (alpha, beta and gamma), but it has the largest impact on alpha dose rates. The alpha dose rate error is an order of magnitude larger than the errors of all other dose rates, and have been removed from the graph for clarity. https://images.squarespace-cdn.com/content/v1/5b3e6b55e17ba3fda87d91dd/1561586841013-1GK5Q49KOA5BO962APP7/Snake+River%2C+ID.JPG Blog - Sampling for luminescence dating – Part III https://images.squarespace-cdn.com/content/v1/5b3e6b55e17ba3fda87d91dd/1561587083082-SXWNM68CAH6TWA3Y3TNJ/subaqueous.JPG Blog - Sampling for luminescence dating – Part III https://images.squarespace-cdn.com/content/v1/5b3e6b55e17ba3fda87d91dd/1561587748783-VSRCU30FQTNPH9GJUPGT/h20-3.png Blog - Sampling for luminescence dating – Part III The influence of water content on a sample age can depend on the grain size used for dating. Thompson et al. (2018) dated sample LED11-210 using both the 4-11 µm (FQ) and 90-180 µm (SA) quartz fractions. Water content has a slightly smaller influence on the larger grain size because i) the coarse quartz grains were treated with HF acid to remove the outer alpha-penetrated rind as is commonly done in coarse grain luminescence dating, and ii) radiation is not attenuated in fine grains as much as it is in coarser grains. The measured water contents include an error of 15% that is not plotted for clarity. https://images.squarespace-cdn.com/content/v1/5b3e6b55e17ba3fda87d91dd/1561588164083-OGG9ILGC9W37XI9EM4GE/h2o-5.png Blog - Sampling for luminescence dating – Part III The influence of water content on quartz and feldspar ages measured from the same sample (T4BATT03) (Smedley et al., 2017; 2019). Water content has a slightly larger influence on age estimates from quartz than from feldspar because a proportion of the total dose rate absorbed by feldspar grains comes from K-40 inside the grains. The grey shading covers ±5% error on the water content measurement. https://images.squarespace-cdn.com/content/v1/5b3e6b55e17ba3fda87d91dd/1561587882034-5TQSKOHZMH1FLVB0GN8V/h2o-4.png Blog - Sampling for luminescence dating – Part III Dose rate (parsed by radiation type) vs water content for the fine grain (LEFT) and coarse grain (RIGHT) samples of Thompson et al. (2018) in the previous figure. The measured water contents include an error of 15% that is not plotted for clarity. https://images.squarespace-cdn.com/content/v1/5b3e6b55e17ba3fda87d91dd/1561588600494-4EFN6842HYCSK35NDPNC/h2o-6.png Blog - Sampling for luminescence dating – Part III Dose rate (parsed by radiation type) vs water content is plotted for both quartz (LEFT) and feldspar (RIGHT) grains from sample T4BATT03 (previous figure). Again, the alpha contribution can be excluded from the dose rate for the quartz sample, because this sample has been treated with HF acid to remove the alpha-penetrating outer rind. The grey shading covers ±5% error on the water content measurement. https://images.squarespace-cdn.com/content/v1/5b3e6b55e17ba3fda87d91dd/1561587451747-Y1B3RSHFIFW7YEGBPBN0/h2o-1.png Blog - Sampling for luminescence dating – Part III (LEFT) Calculated age vs estimated water content for two dune samples from Tasmania (Neudorf et al., 2019). These sediments become saturated at a water content of ~20% (blue shaded region), and measured water contents of collected samples were 15 ± 3% (grey shaded region). The age estimate of the young sample (W4014) ranges from ~16 ka to ~19 ka, while the age estimate of the older sample (SB7) ranges from ~175 ka to ~210 ka – a difference of ~35 ka! (RIGHT) The change in absolute age with water content decreases as the age of a sample decreases. For instance, if we recalculate the ages of sample W4014 assuming this sample De value is only ¼ of its true value, then a 20% increase in assumed water content will increase the age by less than 1000 years. https://theglowcurve.org/blog/2019/5/16/sampling-for-luminescence-dating-part-ii monthly 0.5 2024-07-23 https://images.squarespace-cdn.com/content/v1/5b3e6b55e17ba3fda87d91dd/1558027353379-6C05T1E3HYSCGBQ0HDWX/sampling_ditch.png Blog - Sampling for luminescence dating – Part II Possible sample sites (circles) for luminescence dating an earthwork ditch exposed in an archaeological trench at Garden Creek (Wright, 2011, “Earthwork Update” https://gardencreekarchaeology.wordpress.com/page/3/). The yellow circle shows a sample site where the gamma dose rate field is likely to be homogeneous. All other sample sites (red) are located in heterogeneous gamma dose rate fields. The 30 cm scale is hypothetical, and may not be accurate. https://images.squarespace-cdn.com/content/v1/5b3e6b55e17ba3fda87d91dd/1558027208302-M3U05BZIMPYAF2Y8GOL5/IDEAL.png Blog - Sampling for luminescence dating – Part II https://images.squarespace-cdn.com/content/v1/5b3e6b55e17ba3fda87d91dd/1558026763259-NXCNASUMNET2EGIISXEV/Radiation_sources.png Blog - Sampling for luminescence dating – Part II The sources of radiation and their measured dose rates for alluvial sediments (sample DDU011) collected 0.7 m below the surface in the southern Great Basin, USA. Because the grains were etched in HF acid, we can ignore the external alpha contribution to the total dose rate. https://images.squarespace-cdn.com/content/v1/5b3e6b55e17ba3fda87d91dd/1558027784702-OONSPFD2ZARVRJYOX6F6/Sampling_hearth.png Blog - Sampling for luminescence dating – Part II Possible sample sites (circles) for luminescence dating an escavated pit hearth in western Nebraska (Photo from the lesson plan by Damita Hiemstra, “Arner Site: Out of the Prairies of Western Nebraska”, http://d1vmz9r13e2j4x.cloudfront.net/nebstudies/Lesson4c_Arner.pdf). The yellow and red circles indicate homogeneous and heterogeneous gamma ray dose fields, respectively. The 30 cm scale is hypothetical, and may not be accurate. https://images.squarespace-cdn.com/content/v1/5b3e6b55e17ba3fda87d91dd/1558029592509-VQEZ92M6VYWILRZA974Y/beta_microdos.png Blog - Sampling for luminescence dating – Part II A) Stitched microphotograph of a thin section of beach sand from MacCauley’s Beach, NSW, Australia (sample SP5) shown in cross-polarized light. B) A beta dose rate (in Gy/ka) map created from portable XRF measurements of a separate impregnated block of the same sample. The spatial variations in beta dose rate in this sample can explain the spread in De values (overdispersion = 35%) measured from 170 individual grains (Jankowski & Jacobs, 2018). https://images.squarespace-cdn.com/content/v1/5b3e6b55e17ba3fda87d91dd/1558026967893-I8G27WF4CJQ3BP8RM5NW/Radiatino.png Blog - Sampling for luminescence dating – Part II A schematic illustrating the sources of radiation in the sampling environment and their approximate travel distances. https://images.squarespace-cdn.com/content/v1/5b3e6b55e17ba3fda87d91dd/1558027141848-IFCGW9ZZCW0M6OBJ6RTX/non-ideal.png Blog - Sampling for luminescence dating – Part II https://theglowcurve.org/blog/2019/3/21/sampling-for-luminescence-dating monthly 0.5 2024-07-23 https://images.squarespace-cdn.com/content/v1/5b3e6b55e17ba3fda87d91dd/1553283546337-V44IF68JO1Z8FA9S3RKA/tube_options.png Blog - Sampling for luminescence dating - Part I Luminescence sample tubes of various sizes (LEFT). A steel cap may be placed on the end of the tube to protect it during hammering (RIGHT), and the tube ends can be sealed with a cap, opaque plastic or tape. Sample tubes are commonly stuffed with a paper, plastic or foam “plug” (RIGHT) prior to hammering the tube into the sediments. This ensures that the sediments remain compact, minimizing any mixing between sun-exposed grains and non-exposed grains during transport. If a sample is collected subaqueously, it is not advisable to use a plug, as this may force sediment-laden water back out the unplugged end, contaminating non-light-exposed sediments. https://images.squarespace-cdn.com/content/v1/5b3e6b55e17ba3fda87d91dd/1553283472905-2UQ7YWHESHER5LBATUVS/OSL_tube.png Blog - Sampling for luminescence dating - Part I https://images.squarespace-cdn.com/content/v1/5b3e6b55e17ba3fda87d91dd/1553286840052-P9REV0I7KVIEJER7TYWU/tarp.png Blog - Sampling for luminescence dating - Part I Luminescence sampling under a tarp IN NEWFOUNDLAND, CANADA. Tape was applied to creases susceptible to light penetration, and multiple layers of material was used. If you choose to sample this way, do it quickly and with lots of helping hands - You do not want to suffocate! PHOTO CREDIT: GREGORY MUMFORD https://images.squarespace-cdn.com/content/v1/5b3e6b55e17ba3fda87d91dd/1553286201716-M2ZATU6J9R7HO4HGPKQU/block+sample.png Blog - Sampling for luminescence dating - Part I A block sample collected from cohesive sandy silts along the Snake River, Idaho. PHOTO CREDITS: TOM BULLARD https://images.squarespace-cdn.com/content/v1/5b3e6b55e17ba3fda87d91dd/1553291693219-14QPPGZT3JJN8JX2H9VP/bricks.png Blog - Sampling for luminescence dating - Part I Drill core sampling brick from a late-Post medieval English building (Bailiff, 2007) (TOP). Method of sampling a megalithic wall (shown is Mykerinus pyramid, Egypt) (BOTTOM) (Liritzis, 2011). https://images.squarespace-cdn.com/content/v1/5b3e6b55e17ba3fda87d91dd/1553292581014-AAUXP59K3L0CATX7L7VM/modern_samples.png Blog - Sampling for luminescence dating - Part I Modern samples should be collected at sites with bleaching conditions thought to be representative of the ancient samples of interest. (TOP LEFT) A modern sandy gravel bar in the Snake River, Idaho. (TOP RIGHT). A vegetated sand bar in the Snake River, Idaho. (BOTTOM LEFT) Shallow-water river sediments adjacent to an archaeological site in Idaho. PHOTO CREDITS: CHRISTINA NEUDORF. (BOTTOM RIGHT) The crest of a sand dune on Calvert Island, British Columbia. PHOTO CREDIT: OLAV LIAN https://images.squarespace-cdn.com/content/v1/5b3e6b55e17ba3fda87d91dd/1553288626337-OQXPS6C62E83KVGPYZHR/rock_sampling.png Blog - Sampling for luminescence dating - Part I Rock surface sampling steps for luminescence dating. the ~9 mm diameter rock core was extracted from a granite boulder from Quadra Island, British Columbia, Canada. The rock slice is from granite sampled by Meyer et al. (2018). Slices can then be mounted into a luminescence reader and measured directly as shown by Freiesleben (2014) (FAR RIGHT). https://images.squarespace-cdn.com/content/v1/5b3e6b55e17ba3fda87d91dd/1553284792479-EAKLCXVUNFOBNEKFK53Y/auguring.png Blog - Sampling for luminescence dating - Part I Luminescence sampling by hand auger (LEFT). A beveled, light-tight core sampler (RIGHT). Photo credits: Amanda Keen-Zebert (left), christina neudorf (right) https://images.squarespace-cdn.com/content/v1/5b3e6b55e17ba3fda87d91dd/1553285685679-B0XX648WXAMA8A2347ER/core.jpg Blog - Sampling for luminescence dating - Part I Core sample sediments in a light-safe lab, ready for subsampling for luminescence dating AT THE UNIVERSITY OF THE FRASER VALLEY. PHOTO CREDIT: CHRISTINA NEUDORF https://images.squarespace-cdn.com/content/v1/5b3e6b55e17ba3fda87d91dd/1553285462059-0FZLRKPZQ9SHSEBLHM43/coring.png Blog - Sampling for luminescence dating - Part I Sediment cores collected by hand using ABS pipe (LEFT). ABS pipe is less prone to fracture than PVC pipe, especially in rocky substrates. Cores may be extracted using a tripod and winch system (LEFT-CENTER). A core catcher (RIGHT-CENTER & RIGHT) can prevent the loss of sediment during core extraction. pHOTO CREDITS: CHRISTINA NEUDORF https://theglowcurve.org/blog/2019/3/20/what-is-overdispersion monthly 0.5 2024-07-23 https://images.squarespace-cdn.com/content/v1/5b3e6b55e17ba3fda87d91dd/1553116831887-3Q3RF06YVFZQRACRNVGR/high-OD.png Blog - What is overdispersion? A De distribution, exhibiting a high (>30%) OD, plotted in a kernel density estimate (KDE) plot (LEFT) and a radial plot (RIGHT). The asymmetry of the distribution suggests partial bleaching. Grey shading in the radial plot marks ±2σ of the Central Age Model weighted mean De value (27.5 Gy), and the solid line marks the younger Minimum age model De value (19.2 Gy). Note that few grains fall within 2σ of the CAM weighed mean De value. Click here for details on how to read a radial plot. https://images.squarespace-cdn.com/content/v1/5b3e6b55e17ba3fda87d91dd/1553116499265-QS80TDCSWV2PCMKJMZH0/low-OD.png Blog - What is overdispersion? A De distribution, exhibiting a relatively low (<10%) OD, plotted as a kernel density estimate (KDE) (LEFT) and a radial plot (RIGHT). Two high outlying De values suggest that some grains may contain a residual signal prior to burial, however the low OD value, and symmetrical shape of the De distribution between ~3 and ~12 Gy suggest that the majority of grains have been well bleached prior to burial and that heterogeneities in the environmental dose rate field at the sample site are minimal. Grey shading in the radial plot marks ±2σ of the Central Age Model De value (10.2 Gy). Note that most grains fall within this shaded region. Click here for details on how to read a radial plot. https://theglowcurve.org/blog/2019/1/11/sources-of-error-in-luminescence-dating-some-specifics-on-the-fuzzies monthly 0.5 2024-07-23 https://images.squarespace-cdn.com/content/v1/5b3e6b55e17ba3fda87d91dd/1547253818078-EX050SONRMW6FWR7DB4N/DRC-error2.png Blog - Sources of error in luminescence dating... Some specifics on the fuzzies... https://images.squarespace-cdn.com/content/v1/5b3e6b55e17ba3fda87d91dd/1549924330472-XUKC61QYGNTPGZZ1YIKJ/rel_dose2.png Blog - Sources of error in luminescence dating... Some specifics on the fuzzies... A contour plot of the relative dose rate over a 10 x 10 mm single-grain disc irradiated in a luminescence reader at DRI. Correction factors generated from these data are used to correct single-grain data measured on this machine for non-uniform beta irradiation. https://images.squarespace-cdn.com/content/v1/5b3e6b55e17ba3fda87d91dd/1547254391431-O1HYDZO4R4T5DMYK4JXH/108N96E-WestWall-c.JPG Blog - Sources of error in luminescence dating... Some specifics on the fuzzies... https://images.squarespace-cdn.com/content/v1/5b3e6b55e17ba3fda87d91dd/1547253946052-2EUQI387TKF085CFJZXB/KFaliquot.jpg Blog - Sources of error in luminescence dating... Some specifics on the fuzzies... https://images.squarespace-cdn.com/content/v1/5b3e6b55e17ba3fda87d91dd/1547253447093-SSGEHF2HD1CZHBSPCA2M/sourceoferror-reader.png Blog - Sources of error in luminescence dating... Some specifics on the fuzzies... The components of a luminescence dating reader, modified from Fig. 1.1 of “Guide to The Risø TL/OSL Reader” (July, 2017). Sources of instrumental error include aliquot positioning on the sample carousel and on the heating plate, variations in heating rates, and fluctuations in brightness of the LED or laser stimulation sources. https://images.squarespace-cdn.com/content/v1/5b3e6b55e17ba3fda87d91dd/1547253364720-A5HZ0XDIOIPK46AFLIWQ/lightsource.png Blog - Sources of error in luminescence dating... Some specifics on the fuzzies... https://images.squarespace-cdn.com/content/v1/5b3e6b55e17ba3fda87d91dd/1547254344692-FWC98DIWVUA6N68N9U3H/gammaspec.jpg Blog - Sources of error in luminescence dating... Some specifics on the fuzzies... https://theglowcurve.org/blog/2019/1/9/how-accurate-is-an-optical-age monthly 0.5 2024-07-23 https://images.squarespace-cdn.com/content/v1/5b3e6b55e17ba3fda87d91dd/1547076798629-X7SG9MN4F45TBR5J2S1W/errors.png Blog - How accurate is an optical age? Optical ages vs their relative errors for young (<1000 yrs) and older (Mid-late Pleistocene) sediments. The highest relative errors are commonly associated with sediments of ~100 years in age or less. https://theglowcurve.org/blog/2018/11/29/cam-age-mam-age-fmm-age-can-i-just-have-an-age-please monthly 0.5 2024-07-23 https://images.squarespace-cdn.com/content/v1/5b3e6b55e17ba3fda87d91dd/1543532909790-1K56WS6TCXF7PTNPFMGT/MiddleSon-banks_radial.png Blog - CAM age, MAM age, FMM age…. Can I just have an age please? A single-grain (black dots) and multi-grain aliquot (white triangles) K-feldspar age distribution from a sample collected from alluvial sands in the Middle Son Valley, Andhra Pradesh, India (Neudorf et al.2014). The solid lines plot the ages of three FMM age components detected in the single-grain data that are interpreted to represent a mixture of older cutbank deposits and younger fluvial sands. The youngest (third) component is interpreted to represent bioturbation as roots penetrating overlying soils translocate grains from the surface down to the sample site. The shaded region marks ±2σ of the MAM De value calculated from the multi-grain aliquot data. Click here for an explanation on how to read a radial plot. https://images.squarespace-cdn.com/content/v1/5b3e6b55e17ba3fda87d91dd/1543532777938-8SCREABGVXF14HOZBNJY/clamgarden-radial.png Blog - CAM age, MAM age, FMM age…. Can I just have an age please? A multi-grain aliquot De distribution from a partially bleached sample collected below an intertidal indigenous clam garden wall on Quadra Island, BC, Canada (Neudorf et al., 2017). Grey shading in the radial plot marks ±2σ of the CAM De value (~5 ka), and the solid line marks the younger MAM De value (~4 ka). Click here for an explanation on how to read a radial plot. https://images.squarespace-cdn.com/content/v1/5b3e6b55e17ba3fda87d91dd/1543533752132-VMSP8DYME9TX6MICIEJG/OSL2c.JPG Blog - CAM age, MAM age, FMM age…. Can I just have an age please? This OSL sample tube has intersected an ant burrow. Sediment mixing can occur when roots or insects burrow into the substrate, bringing recently sun-bleached grains from the surface down into older sedimentary units. Photo credit: Christina Neudorf https://theglowcurve.org/blog/2018/11/29/single-grain-vs-multi-grain-analysis-which-one-should-i-use monthly 0.5 2024-07-23 https://images.squarespace-cdn.com/content/v1/5b3e6b55e17ba3fda87d91dd/1543528829490-EVR9B30WKDH20XN1LZR9/de_distributions.png Blog - Single-grain vs multi-grain analysis – which one should I use? (TOP LEFT) A highly spread multi-grain K-feldspar aliquot De distribution from partially bleached littoral sands near Great Slave Lake, NWT, Canada (Wolfe et al. 2018). Each aliquot consisted of ~100 grains. (TOP RIGHT) A multi-grain K-feldspar aliquot De distribution from coarse, subaqueous outwash fan deposits in north-central Quebec, Canada (Price et al. unpublished). The small spread suggests that the grain signals were re-set during transport in a shallow, proglacial stream prior to subaqueous deposition. Each aliquot consisted of ~70-100 grains. (BOTTOM LEFT) A multi-grain K-feldspar aliquot age distribution from well-bleached, terraced alluvial sands in the Middle Son Valley, India (Neudorf et al. 2014). Each aliquot consisted of ~30 grains. (BOTTOM RIGHT) A single grain quartz age distribution from alluvial sands in the Middle Son Valley, India underlying ash from the ~75 ka Toba supervolcanic eruption. The multi-grain K-feldspar aliquot age distribution (~30 grains per aliquot) from the same sample is shown as white triangles. Three solid lines mark the ages of three statistically significant components that may represent different aged sedimentary units that have been mixed during mass wasting and fluvial processes (Neudorf et al. 2014). Click here for instructions on how to read a radial plot https://images.squarespace-cdn.com/content/v1/5b3e6b55e17ba3fda87d91dd/1543528386944-DW7043RBGGQEROXJPOE1/SG_MG.png Blog - Single-grain vs multi-grain analysis – which one should I use? A quartz grain (TOP), a quartz multi-grain aliquot (BOTTOM LEFT), and a K-feldspar-rich multi-grain aliquot (BOTTOM RIGHT) extracted from alluvial sand from the Middle Son Valley, Madhya Pradesh, India. Photo credits: Christina Neudorf https://images.squarespace-cdn.com/content/v1/5b3e6b55e17ba3fda87d91dd/1543528546838-ASVLXHE9HNWAL6DV8O9O/QF-signals-radial.png Blog - Single-grain vs multi-grain analysis – which one should I use? (LEFT) The luminescence signal (measured in photon counts per 0.07 s) from a K-feldspar grain and a contaminating quartz grain (inset) detected through CN 7-59 and BG 39 optical filters (from Neudorf et al. 2012). (RIGHT) A multi-grain K-rich feldspar aliquot age distribution (white symbols) superimposed on a single-grain K-feldspar age distribution (solid symbols) from the same sample (from Neudorf et al. 2012). Note the averaging effect of the multi-grain distribution. Click here for instructions on how to read a radial plot. https://theglowcurve.org/blog/2018/10/29/how-to-read-radial-plots monthly 0.5 2019-10-23 https://images.squarespace-cdn.com/content/v1/5b3e6b55e17ba3fda87d91dd/1540855555634-VT3EXIDKEH9A3TGNOECW/radial.png Blog - How to read Radial Plots A radial plot. 95% of points should fall in grey shaded area if they are consistent with each other at 2 σ. The relative error is equal to the reciprocal of the precision. https://images.squarespace-cdn.com/content/v1/5b3e6b55e17ba3fda87d91dd/1540855831568-I682EC7NAJXQOW1SIF1U/radial2.png Blog - How to read Radial Plots How to read a radial plot (modified from Galbraith and Roberts, 2012). On the left is the 2 sigma error. The width of the bar on the left is controlled by the distribution of De. The bottom scale indicates a measure of the error of each De measurement. The relative error and precision of each point (De value) can be read off of the bottom scale that is plotted on a regular orthogonal x,y coordinate system. The De value of each point can be read off of the radial axis on the right. The measured burial dose that is modeled from the population of De values is also typically plotted. https://images.squarespace-cdn.com/content/v1/5b3e6b55e17ba3fda87d91dd/1569947066677-RMCEIVBDQ41IQRUXVXPG/abanicoplot.png Blog - How to read Radial Plots A De distribution containing low-precision values and two components plotted in an Abanico plot. See Dietz et al. (2016) for more details on abanico plots and Galbraith and Roberts (2012) for more indepth discussion on radial plots, kernel density estimates and other data visualization strategies. https://theglowcurve.org/blog/2018/10/29/paleodose-and-equivalent-dose-whats-the-difference monthly 0.5 2019-10-23 https://images.squarespace-cdn.com/content/v1/5b3e6b55e17ba3fda87d91dd/1540854856575-5E01HOUBGQDE2JFVKKI6/drc.png Blog - Paleodose and equivalent dose… what’s the difference? Typical “dose response” or “regeneration curve”. The natural signal is shown as a small box on the y-axis. The De value is the corresponding value for the sample’s regeneration curve on the x-axis. https://images.squarespace-cdn.com/content/v1/5b3e6b55e17ba3fda87d91dd/1543529678891-BGBKIG14WX01LU6SXRH2/c14.png Blog - Paleodose and equivalent dose… what’s the difference? A comparison between radiocarbon and luminescence (IRSL) ages from peat and beach sand, respectively on Calvert Island, BC, Canada. Photo credit: Christina Neudorf. https://theglowcurve.org/blog/2018/10/29/quartz-or-feldspar-which-mineral-should-i-date monthly 0.5 2020-04-17 https://images.squarespace-cdn.com/content/v1/5b3e6b55e17ba3fda87d91dd/1543526138325-DSLK18AN8MZXLXPU0OFS/table.png Blog - Quartz or Feldspar? Which mineral should I date? 1. This applies to the most commonly used luminescence signals, blue stimulated luminescence (quartz) and infrared-stimulated luminescence (feldspar). More recent signals (e.g., violet stimulated or thermally-transferred luminescence signals) are being investigated as means of extending the dating range of luminescence dating techniques. https://images.squarespace-cdn.com/content/v1/5b3e6b55e17ba3fda87d91dd/1540853080749-YXRTW67F32LODMR7H38E/Picture3.png Blog - Quartz or Feldspar? Which mineral should I date? Table 1. Advantages and disadvantages of dating quartz and feldspar. Modified from Lian (2007). https://theglowcurve.org/blog/2018/7/16/shedding-some-light-on-luminescence-dating monthly 0.5 2019-10-29 https://images.squarespace-cdn.com/content/v1/5b3e6b55e17ba3fda87d91dd/1543525152927-DGX2PAG4VN260DNSMCC9/india-artifacts.jpg Blog - SHEDDING SOME LIGHT ON LUMINESCENCE DATING Neolithic stone tools excavated from the Middle Son Valley, Madhya Pradesh, India, 2009. Photo credit: Christina Neudorf. https://images.squarespace-cdn.com/content/v1/5b3e6b55e17ba3fda87d91dd/1543523937391-RGRU28V53H6FYV8Y0VCC/Feb28-Mar05-09+618.jpg Blog - SHEDDING SOME LIGHT ON LUMINESCENCE DATING - What is OSL? Optically stimulated luminescence dating https://images.squarespace-cdn.com/content/v1/5b3e6b55e17ba3fda87d91dd/1543524859632-13XGWVFN55QQLN9YQK09/burial.jpg Blog - SHEDDING SOME LIGHT ON LUMINESCENCE DATING https://images.squarespace-cdn.com/content/v1/5b3e6b55e17ba3fda87d91dd/1543525050012-410FV50XNEXY5GX9YG1P/janardan.jpg Blog - SHEDDING SOME LIGHT ON LUMINESCENCE DATING Neolithic stone tools excavated from the Middle Son Valley, Madhya Pradesh, India, 2009. Photo credit: Christina Neudorf. https://images.squarespace-cdn.com/content/v1/5b3e6b55e17ba3fda87d91dd/1543524546751-B5X1RCXKR8NMHXHCP9ZS/hourglass2.jpg Blog - SHEDDING SOME LIGHT ON LUMINESCENCE DATING - How do we obtain an OSL age? https://theglowcurve.org/blog/category/De+distribution monthly 0.5 https://theglowcurve.org/blog/category/General+info monthly 0.5 https://theglowcurve.org/blog/category/Paleodose+estimation monthly 0.5 https://theglowcurve.org/blog/tag/What+is+OSL%3F monthly 0.5 https://theglowcurve.org/blog/tag/bleaching monthly 0.5 https://theglowcurve.org/blog/tag/precision monthly 0.5 https://theglowcurve.org/blog/tag/Radial+Plots monthly 0.5 https://theglowcurve.org/blog/tag/accuracy monthly 0.5 https://theglowcurve.org/blog/tag/photos monthly 0.5 https://theglowcurve.org/blog/tag/Feldspar monthly 0.5 https://theglowcurve.org/blog/tag/OSL+dating monthly 0.5 https://theglowcurve.org/blog/tag/post-IRIR monthly 0.5 https://theglowcurve.org/blog/tag/environmental+dose+rate monthly 0.5 https://theglowcurve.org/blog/tag/thermoluminescence monthly 0.5 https://theglowcurve.org/blog/tag/LM-OSL monthly 0.5 https://theglowcurve.org/blog/tag/single+grain monthly 0.5 https://theglowcurve.org/blog/tag/burial+history monthly 0.5 https://theglowcurve.org/blog/tag/beta+microdosimetry monthly 0.5 https://theglowcurve.org/blog/tag/age+calculation monthly 0.5 https://theglowcurve.org/blog/tag/sampling monthly 0.5 https://theglowcurve.org/blog/tag/OSL+age monthly 0.5 https://theglowcurve.org/blog/tag/minimum+age+model monthly 0.5 https://theglowcurve.org/blog/tag/overdispersion monthly 0.5 https://theglowcurve.org/blog/tag/CAM monthly 0.5 https://theglowcurve.org/blog/tag/multigrain+aliquot monthly 0.5 https://theglowcurve.org/blog/tag/regeneration+curve monthly 0.5 https://theglowcurve.org/blog/tag/field monthly 0.5 https://theglowcurve.org/blog/tag/Portable+gamma+spectrometer monthly 0.5 https://theglowcurve.org/blog/tag/MAM monthly 0.5 https://theglowcurve.org/blog/tag/CW-OSL monthly 0.5 https://theglowcurve.org/blog/tag/finite+mixture+model monthly 0.5 https://theglowcurve.org/blog/tag/error monthly 0.5 https://theglowcurve.org/blog/tag/De+calculation monthly 0.5 https://theglowcurve.org/blog/tag/OD monthly 0.5 https://theglowcurve.org/blog/tag/water+content monthly 0.5 https://theglowcurve.org/blog/tag/dose+response+curve monthly 0.5 https://theglowcurve.org/blog/tag/calibration monthly 0.5 https://theglowcurve.org/blog/tag/central+age+model monthly 0.5 https://theglowcurve.org/blog/tag/IRSL monthly 0.5 https://theglowcurve.org/blog/tag/FMM monthly 0.5 https://theglowcurve.org/blog/tag/equivalent+dose monthly 0.5 https://theglowcurve.org/blog/tag/OSL monthly 0.5 https://theglowcurve.org/blog/tag/natural+signal monthly 0.5 https://theglowcurve.org/blog/tag/Quartz monthly 0.5 https://theglowcurve.org/blog/tag/age+models monthly 0.5 https://theglowcurve.org/blog/tag/spread monthly 0.5 https://theglowcurve.org/blog/tag/sources+of+error monthly 0.5 https://theglowcurve.org/blog/tag/fieldwork monthly 0.5 https://theglowcurve.org/blog/tag/Paleodose monthly 0.5 https://theglowcurve.org/blog/tag/TL monthly 0.5 https://theglowcurve.org/blog/tag/luminescence+signals monthly 0.5 https://theglowcurve.org/blog/tag/sediment+mixing monthly 0.5 https://theglowcurve.org/blog/tag/statistical+analysis monthly 0.5 https://theglowcurve.org/blog/tag/dose+rate+heterogeneity monthly 0.5 https://theglowcurve.org/projects-gallery daily 0.75 2018-10-29 https://images.squarespace-cdn.com/content/v1/5b3e6b55e17ba3fda87d91dd/1540616614140-6QEJSFEKN5CV8OIO1IBG/buff+bluff.jpg <display = none> - Defining the role of heterogeneous lithology in bedrock channel incision and terrace formation in the Buffalo National River, Arkansas Because of its low relief, mid-continent location, and preserved alluvial sedimentary archive, the Buffalo River presents an opportunity to extend the range of landscape evolution studies to an under-represented end-member in the range of landscapes. This project will: i) create a quantitative reconstruction of the incision history of the Buffalo National River from the record of sediments stored in alluvial drapes on strath terraces and in subterranean caves ii) develop and interpret the sedimentary record of changes in fluvial processes operating in the Buffalo River catchment during the Quaternary Period and iii) define the ways that streams in catchments with heterogeneous lithologies in low-topography, mid-continent catchments, such as that of the Buffalo River, respond to base level fall. The features of interest for luminescence dating are former channel fills and gravel bars now perched above the channel as terraces. These sediments are mixed gravel, sand, and fines overlying bedrock straths and as such, the dosimetry is complex. Because the samples are heterogeneous this research requires in-situ measurements of gamma dose for an accurate assessment of dose rate. The research contributes to long-lived fundamental questions in geomorphology concerning the role of lithology in landscape evolution and the significance of unpaired stream terraces in interpretation of the geomorphic record. The outcomes of this research will contribute to understanding the ways that landscapes respond to base level fall that are central to interpreting spatial and temporal variation in sediment storage and erosion and therefore have implications for several societal concerns (e.g. soil loss, pollutant sequestration in soils and floodplains, and flood attenuation). These results will also facilitate reconstructions of the evolution of the Earth's surface in the mid-continent of North America which can provide baseline information from pre-human landscapes to contextualize human impacts and thus guide restoration and management. For more info, see the Buffalo River Geoscience webpage. https://images.squarespace-cdn.com/content/v1/5b3e6b55e17ba3fda87d91dd/1540616614140-6QEJSFEKN5CV8OIO1IBG/buff+bluff.jpg <display = none> - Defining the role of heterogeneous lithology in bedrock channel incision and terrace formation in the Buffalo National River, Arkansas Because of its low relief, mid-continent location, and preserved alluvial sedimentary archive, the Buffalo River presents an opportunity to extend the range of landscape evolution studies to an under-represented end-member in the range of landscapes. This project will: i) create a quantitative reconstruction of the incision history of the Buffalo National River from the record of sediments stored in alluvial drapes on strath terraces and in subterranean caves ii) develop and interpret the sedimentary record of changes in fluvial processes operating in the Buffalo River catchment during the Quaternary Period and iii) define the ways that streams in catchments with heterogeneous lithologies in low-topography, mid-continent catchments, such as that of the Buffalo River, respond to base level fall. The features of interest for luminescence dating are former channel fills and gravel bars now perched above the channel as terraces. These sediments are mixed gravel, sand, and fines overlying bedrock straths and as such, the dosimetry is complex. Because the samples are heterogeneous this research requires in-situ measurements of gamma dose for an accurate assessment of dose rate. The research contributes to long-lived fundamental questions in geomorphology concerning the role of lithology in landscape evolution and the significance of unpaired stream terraces in interpretation of the geomorphic record. The outcomes of this research will contribute to understanding the ways that landscapes respond to base level fall that are central to interpreting spatial and temporal variation in sediment storage and erosion and therefore have implications for several societal concerns (e.g. soil loss, pollutant sequestration in soils and floodplains, and flood attenuation). These results will also facilitate reconstructions of the evolution of the Earth's surface in the mid-continent of North America which can provide baseline information from pre-human landscapes to contextualize human impacts and thus guide restoration and management. For more info, see the Buffalo River Geoscience webpage. https://images.squarespace-cdn.com/content/v1/5b3e6b55e17ba3fda87d91dd/1540613983458-Z8IYD5L8ODOQ1S08TGJV/DSC06779.JPG <display = none> - Evolution of the Vaal River in the Vredefort Dome, South Africa Collaboration with Amanda Keen-Zebert (Desert Research Institute) and Stephen Tooth (Aberystwyth University). Mixed bedrock-alluvial anabranching rivers form some of the world’s most spectacular fluvial scenery but their dynamics remain poorly documented. Previous conceptual models have outlined how alluvial islands form on the underlying bedrock template but timescales of island development are largely unknown owing to limited geochronology. This study uses optically stimulated luminescence (OSL) dating to establish the growth rates and stability of alluvial islands on the Vaal River at Parys, South Africa. The Vaal traverses the World Heritage-listed Vredefort Dome, an eroded, ancient meteorite impact site. The river enters and exits the dome as a 150-170 m wide single channel flanked by sedimentary rocks, but changes to a distinctive 1.5 km wide anabranching river with 10-15 channels and numerous islands as it flows across granitoid rocks exposed in the dome's core. The numerous islands are formed of rock and/or alluvium, and support extensive native riparian tree communities, providing habitat diversity that contrasts with the surrounding semi-arid, grass- and shrub-covered terrain. We measured the age and aggradation rates of 9 islands in the anabranching reach using OSL. Single grain measurements of quartz were made using the single aliquot regenerative dose (SAR) approach. Equivalent dose populations have up to 60% overdispersion, common for fluvial samples, and the minimum age model was used to calculate final ages. Results demonstrate that the complex of alluvial islands is relatively young, with all having formed in the past 1000 years. The alluvial islands grow rapidly (mean vertical aggradation >0.28 cm/yr) during low to moderate floods (Q <2500 m3/s) owing to interactions between sediment deposition in the lee of bedrock outcrop, tree colonisation, and island coalescence. Islands tend to erode during larger floods through lateral erosion, vertical stripping, and dissection by newly-forming anabranches. The ages demonstrate that the alluvial islands are essentially dynamic, short-lived features that develop on a bedrock template that is underlying slower, long-term erosion. Our goal is to expand this dataset to include bedrock cored islands and place the age of formation of the islands in the context of the age of the broader floodplain within which the island complex exists. These findings will contribute to geoheritage education and to ongoing development of sustainable management plans for the tree-covered islands, many of which are threatened by altered flow regimes, invasive species, and encroaching tourism developments. https://images.squarespace-cdn.com/content/v1/5b3e6b55e17ba3fda87d91dd/1540616876752-75ZBWKNWW21XMFR7T927/bloody+canyon.png <display = none> - Late Pleistocene climatic oscillations and diffusive sediment transport on moraine hillslopes Collaboration with David Furbish, Dan Morgan, and Joshua Roering, Tyler Doane, and Amanda Keen-Zebert. Recent work on the sediment transport on hillslopes suggests a need to clarify the implications of ‘nonlocal’ versus ‘local’ transport processes and associated formulations of the sediment flux, as expected hillslope behavior under these two conditions is quite different. However, the supporting theory has outpaced experimental and field-based observations needed to inform the theory. This project is aimed at closing this gap, as implications for understanding hillslope evolution are far-reaching. The project will: (1) combine experiments with scaling analyses to clarify ingredients of rarefied particle-surface interactions during their downslope motions, as these influence key processes of sediment disentrainment; (2) explore theoretical formulations of nonlocal transport for two-dimensional topography that is convergent-divergent in planform; (3) combine field observations with modeling work centered on hillslopes in the Oregon Coast Range and moraines in the Sierra Nevada Mountains, specifically selected to reveal ingredients of nonlocal transport behavior; and (4) formulate descriptions of nonlocal transport with appropriate space-time averaging in order to take into account the discontinuous (patchy, intermittent) nature of sediment motions on steepland hillslopes, as is necessary for treating the sediment flux as a ‘smooth’ (time differentiable) quantity. https://images.squarespace-cdn.com/content/v1/5b3e6b55e17ba3fda87d91dd/1540616260400-92O5GE3OOA2FE7PFNAJ5/ARO+stir.jpg <display = none> - Relating luminescence partial bleaching to discharge In collaboration with the staff of the DRILL, Amanda Keen-Zebert is conducting research focused on the intersection OSL dating techniques, sediment transport, and hydrology. The research design includes field, physical lab experiments, and OSL techniques and addresses multiple objectives: 1. Defining a OSL bleaching statistic that relates the magnitude of partial bleaching of the luminescence signal in fluvial sediment systematically to the depositional context (flow rate; distance travelled in a watershed, stream, or bar) such that OSL bleaching statistics can be used as a paleoenvironmental proxy. 2. Differentiate the luminescence signal resetting characteristics of human-disturbed surfaces naturally reset sediments. 3. Elucidate the relationship between luminescence signal resetting, sensitivity, and sediment transport distance. A pilot study for this project was funded by a Short Term Innovative Research (STIR) Grant from the Army Research Office (ARO) and by internal funding from DRI that supported field work before and after a controlled dam release on the lower Colorado River. https://images.squarespace-cdn.com/content/v1/5b3e6b55e17ba3fda87d91dd/1540615907679-75ANP3SIH17M102NJJ2O/tephra.jpg <display = none> - Testing the impact of reworking on the isochronicity of tephras deposited in diverse sedimentary environments Collaboration with Amanda Keen-Zebert, Ken Adams (DRI) and Kathleen Rodrigues (AKZ’s PhD advisee at UNR/DRI). This work has 2 goals: to develop a thermoluminescence method to directly date eruption timing from volcanic glass, and to define the degree of re-working of tephras using luminescence resetting statistics (rather than age dating). We have conducted preliminary field work to collect tephra samples of known age from the Great Basin. Kathleen has successfully dated some of the tephras with thermoluminescence and has preliminary results that align with the correct age. She is working to reduce the error to refine the dating approach. (Photos from Ken Adams.) https://images.squarespace-cdn.com/content/v1/5b3e6b55e17ba3fda87d91dd/1540614702743-9KLF9N7E7Y94CMJR4I0J/stockton+bar.png <display = none> - Dating at the Stockton Bar: A modern chronostratigraphic re-appraisal of G.K. Gilbert’s bay mouth bar and spit complex in the Lake Bonneville Basin, Utah Collaboration between Amanda Keen-Zebert and Kathleen Nicoll, University of Utah. The goals of this research are to improve the understanding of bay mouth bar formation and to better develop the chronostratigraphy of the Bonneville Basin in order to reconstruct landform evolution and lake history as a function of hydroclimatic change. The research strategy combines geochronology (OSL, diagnostic artifacts) and Ground Penetrating Radar (GPR), field mapping, and sediment characterization to develop the chronostratigraphy of the Stockton Bar. We have conducted field work, analyzed a suite of preliminary OSL samples and diagnostic artifacts, and published those results in Journal of Archaeological Sciences. https://images.squarespace-cdn.com/content/v1/5b3e6b55e17ba3fda87d91dd/1540617963721-ZTGRZKJRCTX84696GK9L/SoilsFigure.jpg <display = none> - The geomorphic evolution of a complex of parabolic dunes along the eastern shore of Lake Michigan Collaboration with Bradley Johnson (Davidson College) and Amanda Keen-Zebert (DRI). Lake Michigan shoreline dunes are unique features of the landscape both geomorphologically and in terms of ecosystems. Despite a number of recent studies examining the geomorphic history of Lake Michigan dune complexes, there is disagreement about the timing and controls on dune activation, migration, and stabilization and the relationship between lake level and dune activity. In particular, it is uncertain if dune behavior is exclusively related to dune type and morphology or if there is a more gradational change in behavior associated with latitudinal climate variation. Several characteristics of the Green Point Dune Complex (GPDC) on the northeast coast of Lake Michigan make it an ideal site to investigate the controls on dune activation and stability in order to resolve the contradictions of previous studies. The accuracy of OSL dating in the region has been verified by previous studies that used radiocarbon ages as an independent control on OSL results. In this study, mapping, soils chronostratigraphy, and absolute age dating through OSL will be used to test the hypothesis that lake-plain dunes along the northeastern coast of Lake Michigan at the Green Point Dune Complex evolved similarly to lake-plain dunes to the south and that latitudinal climate variation played little role in the evolution of lake-plain dunes. The chronostratigraphy derived from the OSL results will be used to determine periods of dune activity and the timing of stabilization. Results will contribute to a more complete understanding of the timing and cause of dune activity along the eastern coast of Lake Michigan which will contribute to informing strategies for modern dune management. https://images.squarespace-cdn.com/content/v1/5b3e6b55e17ba3fda87d91dd/1540616881056-3L3FE0B7IJWBSLNTHIV7/buff+trench.jpg <display = none> - Defining the timescales of hillslope-channel connectivity in entrenched meander, bedrock channel systems Collaboration with Ben Odhiambo Kisila (University Mary Washington). This project has arisen out of the observation of hillslope erosion rates that are disconnected from channel incision rates in the entrenched meandering rivers like the Buffalo River. We will use a multi-geochronological approach to define the timescales of hillslope response to channel incision using OSL, 210Pb erosion rates, and 137Cs sediment fingerprinting. https://images.squarespace-cdn.com/content/v1/5b3e6b55e17ba3fda87d91dd/1540616886161-COI92G8776PZ0AZ7GNZK/jrd.jpg <display = none> - Tracing the long-term footprint of anthropogenic pollution in the landscape: Evaluation of evidence from a 5000 year-old industrialized landscape in southern Jordan Collaboration with Russ Adams (University of Waterloo), Hannah Friedman (Texas Tech University), Amanda Keen-Zebert (Desert Research Institute). The primary objective of this multi-disciplinary research project is to quantify the environmental legacy and biological consequences of industrialization, issues that both scientists and policy makers continue to grapple with in modern society. Two of key questions raised are: 1. What is the long-term environmental footprint of large scale mining and extractive metallurgy on the surrounding landscape and environment? and 2. What are the enduring consequences of these activities on humans? Research into the effects of mining and smelting is usually conducted at sites with less than a hundred years of this type of activity; within the Faynan Basin of southern Jordan we have the opportunity to investigate a landscape that has been impacted by nearly 5000 years of copper mining and smelting. This creates a unique natural laboratory for the study of how anthropogenic pollution moves across an active and complex landscape over time. Preliminary research has allowed us to develop a methodology for analysis of pollution with the examination of a small cluster of sites and the spread of residual pollution in the landscape surrounding them. This work will scale up this research to investigate the movement of pollution on a basin-scale level of analysis. This work builds on 25 years of archaeological investigation of early metallurgical research in the Faynan Basin by developing a comprehensive overview of the emergence of early copper industrialization and its impact on ancient populations and the environment. https://images.squarespace-cdn.com/content/v1/5b3e6b55e17ba3fda87d91dd/1540618079655-386BISV29019NJUM8333/coopers.JPG <display = none> - Refining the chronostratigraphy of the Cooper’s Ferry settlement Collaboration with Loren Davis (Oregon State University) and Amanda Keen-Zebert (DRI). Funded by the Lander Foundation. The Cooper’s Ferry Archaeology site, located on an alluvial terrace at the confluence of Rock Creek and the Salmon River in Idaho, is shedding new light on lithic technologies in the Western United States. At the site, the highest densities of artifacts are in pit features that appear to be dug into the lower stratigraphic units. Owing to a lack of suitable material for radiocarbon dating, we will use single grain optically stimulated luminescence (OSL) to define the chronology of older units into which the pits are dug to establish the maximum age of the occupation. In one of the pits at the site, variations in sediment color suggests multiple episodes of use. We expect that OSL dating of sediment within the pit will establish both the age of pit usage and that the feature post-dates the surrounding sediment, confirming that it is in fact a pit. We also expect that OSL equivalent dose (De) distributions in the sediments deposited naturally by the stream will be less scattered than the sediment within the pit, which we expect to have widely scattered equivalent dose distributions. https://theglowcurve.org/teamgallery daily 0.75 2024-02-27 https://images.squarespace-cdn.com/content/v1/5b3e6b55e17ba3fda87d91dd/1619110439221-4VWG2RBF55EO9X689XFB/christina.jpeg Team gallery - Christina Neudorf, PhD, Assistant Research Professor Christina is a Assistant Research Professor and Manager of the DRI Luminescence Laboratory (DRILL). Her research combines field observations and sedimentology, sampling, remote sensing (the interpretation of air photos, satellite imagery, Digital Elevation Models or LiDAR imagery), and geochronological methods to gain insights into the style and rate of landscape change and human/environment interactions in the Quaternary Period. Her research includes developing luminescence dating techniques to refine temporal records in archaeology and geology, and she is the writer of The Glow Curve Blog: https://theglowcurve.org/blog. You can view her full CV here and follow her on Twitter @tweencmn. https://images.squarespace-cdn.com/content/v1/5b3e6b55e17ba3fda87d91dd/1619110439221-4VWG2RBF55EO9X689XFB/christina.jpeg Team gallery - Christina Neudorf, PhD, Assistant Research Professor Christina is a Assistant Research Professor and Manager of the DRI Luminescence Laboratory (DRILL). Her research combines field observations and sedimentology, sampling, remote sensing (the interpretation of air photos, satellite imagery, Digital Elevation Models or LiDAR imagery), and geochronological methods to gain insights into the style and rate of landscape change and human/environment interactions in the Quaternary Period. Her research includes developing luminescence dating techniques to refine temporal records in archaeology and geology, and she is the writer of The Glow Curve Blog: https://theglowcurve.org/blog. You can view her full CV here and follow her on Twitter @tweencmn. https://images.squarespace-cdn.com/content/v1/5b3e6b55e17ba3fda87d91dd/1540621457567-GRW96V66DJF2BLVUYNQC/P1080273.JPG Team gallery - Kathleen Rodrigues, Postdoctoral Researcher, DRI Kathleen’s research interests are in developing new luminescence dating techniques. Her PhD dissertation project involved developing a luminescence approach to dating the eruption age of volcanic glass to better date tephras in the geomorphic record. Kathleen is also working on evaluating the assumptions involved in applying OSL to dating river terraces to find incision rates. She also contributes to a variety of luminescence dating projects in the DRI Luminescence Lab. https://images.squarespace-cdn.com/content/v1/5b3e6b55e17ba3fda87d91dd/1540621179232-SIOZYQL7WJBR798JHF96/DSCN2095.JPG Team gallery - Amanda Keen-Zebert, Assoc. Prof., Dir. DRI Luminescence Lab Amanda’s research interests are lie at the intersection geochronology and geomorphology. She uses luminescence dating to find the rates and timescales of geomorphic processes and their response to climate, tectonic, environmental, and anthropogenic change over the Quaternary. 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