Journal articles: 'Bomb radiocarbon'

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Mouchet, Anne. "The Ocean Bomb Radiocarbon Inventory Revisited." Radiocarbon 55, no. 3 (2013): 1580–94. http://dx.doi.org/10.1017/s0033822200048505.

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Large discrepancies exist among data-based estimates and model reconstructions of the ocean bomb radiocarbon inventory. In order to resolve this gap, it has been proposed that the CO2 piston velocity should be revised downward (Sweeney et al. 2007; Müller et al. 2008). This article compares the transient 14C distributions in the ocean obtained with different formulations of the isotopic ratio commonly used in modeling studies. It is found that both the CO2 increase and the air-sea CO2 flux significantly contribute to the 1990 ocean bomb 14C inventory, by around 10% each. Moreover, these 2 processes explain more than 25% of the inventory difference between 1974 and 1990. These results imply that, as already argued by Naegler (2009), inventories based on observations that lack information about CO2 invasion are underestimated. Further, this work provides insight into the reasons for discrepancies among model results. It suggests that while a comprehensive isotopic formulation is needed when addressing the global 14C cycle, a simplified form is more relevant for model calibration and piston velocity assessment based on currently available bomb 14C inventories.

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Ayache, Mohamed, Jean-Claude Dutay, Anne Mouchet, Nadine Tisnérat-Laborde, Paolo Montagna, Toste Tanhua, Giuseppe Siani, and Philippe Jean-Baptiste. "High-resolution regional modelling of natural and anthropogenic radiocarbon in the Mediterranean Sea." Biogeosciences 14, no. 5 (March 13, 2017): 1197–213. http://dx.doi.org/10.5194/bg-14-1197-2017.

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Abstract. A high-resolution dynamical model (Nucleus for European Modelling of the Ocean, Mediterranean configuration – NEMO-MED12) was used to give the first simulation of the distribution of radiocarbon (14C) across the whole Mediterranean Sea. The simulation provides a descriptive overview of both the natural pre-bomb 14C and the entire anthropogenic radiocarbon transient generated by the atmospheric bomb tests performed in the 1950s and early 1960s. The simulation was run until 2011 to give the post-bomb distribution. The results are compared to available in situ measurements and proxy-based reconstructions. The radiocarbon simulation allows an additional and independent test of the dynamical model, NEMO-MED12, and its performance to produce the thermohaline circulation and deep-water ventilation. The model produces a generally realistic distribution of radiocarbon when compared with available in situ data. The results demonstrate the major influence of the flux of Atlantic water through the Strait of Gibraltar on the inter-basin natural radiocarbon distribution and characterize the ventilation of intermediate and deep water especially through the propagation of the anthropogenic radiocarbon signal. We explored the impact of the interannual variability on the radiocarbon distribution during the Eastern Mediterranean Transient (EMT) event. It reveals a significant increase in 14C concentration (by more than 60 ‰) in the Aegean deep water and at an intermediate level (value up to 10 ‰) in the western basin. The model shows that the EMT makes a major contribution to the accumulation of radiocarbon in the eastern Mediterranean deep waters.

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Grumet, Nancy S., Thomas P. Guilderson, and Robert B. Dunbar. "Pre-Bomb Radiocarbon Variability Inferred from a Kenyan Coral Record." Radiocarbon 44, no. 2 (2002): 581–90. http://dx.doi.org/10.1017/s0033822200031933.

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We report results from AMS radiocarbon measurements (δ14C) in corals recovered off the coast of Kenya. Bimonthly samples which span the pre-bomb era average −51 (±3.7; n=43), when age and Suess effect are corrected, and over the time of interest (1946–1954) do not exhibit any discernible seasonality. Relative to regional pre-bomb δ14C values in the western Indian Ocean, our results indicate 14C enrichment off the coast of Kenya. Furthermore, the absence of a distinct subannual δ14C signal suggests that open and coastal upwelling is negligible off the coast of Kenya. Unlike pre-bomb values south of the equator near Seychelles and Madagascar, our pre-bomb value are enriched by more than 10. The enrichment of pre-bomb Kenyan δ14C values relative to sites around Mauritius, northern Madagascar and Seychelles, suggest that the influence of depleted δ14C water transported in the SEC is limited to regions south of 3 to 4°S.

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Andrews, Allen H., Beverly K. Barnett, Robert J. Allman, Ryan P. Moyer, and Hannah D. Trowbridge. "Great longevity of speckled hind (Epinephelus drummondhayi), a deep-water grouper, with novel use of postbomb radiocarbon dating in the Gulf of Mexico." Canadian Journal of Fisheries and Aquatic Sciences 70, no. 8 (August 2013): 1131–40. http://dx.doi.org/10.1139/cjfas-2012-0537.

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Growth characteristics are poorly understood for speckled hind (Epinephelus drummondhayi), a tropical deep-water grouper of economic importance that is considered overfished. Age has been validated for early growth, but the validity of adult age estimates is unknown. A few studies of growth zones in otoliths have revealed maximum age estimates of 15–35 years, which have been uncritically assumed as longevity. To answer questions about adult age, bomb radiocarbon dating was used to provide validated age estimates. A novel aspect of this study was use of the postbomb radiocarbon decline period (ca. 1980–2004) to age younger fish, an approach that was validated with known-age otoliths. Bomb radiocarbon dating provided valid length-at-age estimates ranging from ∼5 years to more than 45 years. Age was unexpectedly greater than previous estimates for more than half the fish used in this study, and longevity may approach 60–80 years. This study extends the utility of bomb radiocarbon dating by more than 20 years and adds to the growing perspective that deep-water tropical fishes can be long-lived.

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Campana, Steven E., Lisa J. Natanson, and Sigmund Myklevoll. "Bomb dating and age determination of large pelagic sharks." Canadian Journal of Fisheries and Aquatic Sciences 59, no. 3 (March 1, 2002): 450–55. http://dx.doi.org/10.1139/f02-027.

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Despite their notoriety and role as apex predators, the longevity of large pelagic sharks such as the porbeagle (Lamna nasus) and shortfin mako (Isurus oxyrinchus) is unknown. Vertebral growth bands provide an accurate indicator of age in young porbeagle, but age validation has never been reported for any large shark species past the age of sexual maturity. Here, we report the first application of bomb radiocarbon as an age validation method for long-lived sharks based on date-specific incorporation of radiocarbon into vertebral growth bands. Our results indicate that porbeagle vertebrae recorded and preserved a bomb radiocarbon pulse in growth bands formed during the 1960s. Through comparison of radiocarbon assays in young, known-age porbeagle collected in the 1960s with the corresponding growth bands in old porbeagle collected later, we confirm the validity of porbeagle vertebral growth band counts as accurate annual age indicators to an age of at least 26 years. The radiocarbon signatures of porbeagle vertebral growth bands appear to be temporally and metabolically stable and derived mainly from the radiocarbon content of their prey. Preliminary radiocarbon assays of shortfin mako vertebrae suggest that current methods for determining shortfin mako age are incorrect.

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Andrews, Allen H., Daria Siciliano, Donald C. Potts, Edward E. DeMartini, and Stephannie Covarrubias. "Bomb Radiocarbon and the Hawaiian Archipelago: Coral, Otoliths, and Seawater." Radiocarbon 58, no. 3 (May 17, 2016): 531–48. http://dx.doi.org/10.1017/rdc.2016.32.

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AbstractCorals of the Hawaiian Archipelago are well situated in the North Pacific Gyre (NPG) to record how bomb-produced radiocarbon has been sequestered and transported by the sea. While this signal can be traced accurately through time in reef-building corals and used to infer oceanographic processes and determine the ages of marine organisms, a comprehensive and validated record has been lacking for the Hawaiian Archipelago. In this study, a coral core from Kure Atoll in the northwestern Hawaiian Islands was used to create a high-resolution bomb 14C record for the years 1939–2002, and was then used with other 14C measurements in fish otoliths and seawater to explore differences and similarities in the bomb 14C signal throughout the Hawaiian Archipelago. The Kure Atoll sample series produced a well-defined bomb 14C curve that, with some exceptions, was similar to other coral 14C records from the Hawaiian Archipelago. Subtle differences in the coral 14C records across the region may be explained by the large-scale ocean circulation patterns and decadal cycles of the NPG. The most rapid increase of 14C, in the 1950s and 1960s, showed similar timing across the Hawaiian Archipelago and provides a robust basis for use of bomb 14C dating to obtain high-precision age determinations of marine organisms. Reference otoliths of juvenile fish demonstrated the use of the post-peak 14C decline period as a viable reference in the age validation of younger and more recently collected fishes, and effectively extended the utility of bomb 14C dating to the latest 30 yr.

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Hüls, C. Matthias, Andreas Börner, and Christian Hamann. "WHEAT SEED (TRITICUM AESTIVUM L.) RADIOCARBON CONCENTRATION OVER THE LAST 75 YEARS." Radiocarbon 63, no. 5 (September 30, 2021): 1387–96. http://dx.doi.org/10.1017/rdc.2021.81.

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ABSTRACTHere we report radiocarbon measurements made on wheat seed tissue (Triticum aestivum L.; winter or spring type growth habit), from the seed archive of the IPK Gatersleben, Sachsen-Anhalt, Germany, which was harvested between 1946 and 2020. The results give an overview of 75 years of radiocarbon concentration evolution in agricultural plant products. The wheat tissue radiocarbon concentrations follow known pre- and post-bomb radiocarbon records, such as the atmospheric Jungfraujoch, Schauinsland, and NH1 datasets. Based on a Northern Hemisphere growing period from April to July, the Gatersleben seed tissue radiocarbon concentration indicates incorporation of fossil carbon of about 1% with respect to the high alpine, clean-air CO2 of the Jungfraujoch station between 1987 and 2019. We propose to use the pre- and post-bomb radiocarbon record of Gatersleben wheat as a reference in forensic investigations, such as the age estimation of paper by analyzing starch used in paper manufacture. Additionally, an advantage of the record reported here lies in its extensibility by adding new analyses from future harvests.

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Haltuch, Melissa A., Owen S. Hamel, Kevin R. Piner, Patrick McDonald, Craig R. Kastelle, and John C. Field. "A California Current bomb radiocarbon reference chronology and petrale sole (Eopsetta jordani) age validation." Canadian Journal of Fisheries and Aquatic Sciences 70, no. 1 (January 2013): 22–31. http://dx.doi.org/10.1139/cjfas-2011-0504.

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As petrale sole (Eopsetta jordani) is a valuable groundfish harvested in the California Current, proper ageing is important for its assessment and management. This study presents the first bomb radiocarbon reference chronology for the California Current and petrale sole age validation. Break-and-burn and surface ages are negatively biased by approximately 1 year and 2–3 years, respectively. The reference and validation curves are more variable and show a lag in the rate of radiocarbon increase in comparison to most other time series of bomb radiocarbon in marine systems. Upwelling in the California Current produces a lagged rate of increase in radiocarbon levels owing to the introduction and mixing of radiocarbon-depleted deep waters with surface waters that interact with the atmosphere. The variable and lagged rate of radiocarbon increase in the petrale sole data may be due to their spending a substantial portion of their first year of life in areas subject to variable upwelling, illustrating the importance of using reference curves for age validation that are region and species specific when possible.

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Stewart, R. E. A., S. E. Campana, C. M. Jones, and B. E. Stewart. "Bomb radiocarbon dating calibrates beluga (Delphinapterus leucas) age estimates." Canadian Journal of Zoology 84, no. 12 (December 2006): 1840–52. http://dx.doi.org/10.1139/z06-182.

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The ages of many mammals are estimated by counting growth layers in tooth sections, yet validation of age estimation techniques using free-ranging mammals has been problematic. Contrary to age estimates for most other animals in which it is assumed that one bipartite growth increment forms annually, beluga whale ( Delphinapterus leucas (Pallas, 1776)) age estimates have been calculated assuming that two growth layer groups (GLGs) form each year. Here we report the age validation for belugas based on date-specific incorporation of atomic bomb radiocarbon into tooth GLGs. Radiocarbon assays of dentinal layers formed in belugas harvested between 1895 and 2001 indicated that radiocarbon from atmospheric testing of nuclear weapons was incorporated into growing teeth and retained for the remaining life of the animal. Comparison of age determined by bomb radiocarbon with age determined by GLG counts indicated that GLGs form annually, not semiannually, and provide an accurate indicator of age for belugas up to at least 60 years old. Radiocarbon signatures of belugas were temporally and metabolically stable and were apparently derived more from the radiocarbon content of their prey than from water. Our understanding of many facets of beluga population dynamics is altered by the finding that this species lives twice as long as previously thought.

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Glynn, Danielle, Ellen Druffel, Sheila Griffin, Robert Dunbar, Michael Osborne, and Joan Albert Sanchez-Cabeza. "Early Bomb Radiocarbon Detected in Palau Archipelago Corals." Radiocarbon 55, no. 3 (2013): 1659–64. http://dx.doi.org/10.1017/s0033822200048578.

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In order to evaluate the variability in surface water masses in the Western Pacific Warm Pool, we report high-precision radiocarbon measurements in annual and seasonal bands from Pontes lutea corals collected from the Palau Archipelago (7°N, 134°E). Annual coral bands from 1945 to 2008 and seasonal samples from 1953 to 1957 were analyzed to capture the initial early input of bomb 14C from surface thermonuclear weapons testing in the Marshall Islands. Results show a pre-bomb average δ14C value of-54.9% between 1945 and early 1953. Beginning early in 1954, there is a rapid increase to a maximum of-23.1% at the start of 1955. Values continued to rise after 1957 to a post-bomb peak of 141% by 1976. The large initial rise in δ14C cannot be accounted for by air-sea CO2 exchange. Results therefore suggest that the primary cause of this increase is the lateral advection of fallout-contaminated water from the Marshall Islands to Palau via the North Equatorial Current and then to the North Equatorial Countercurrent.

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Campana, Steven E., John M. Casselman, and Cynthia M. Jones. "Bomb radiocarbon chronologies in the Arctic, with implications for the age validation of lake trout (Salvelinus namaycush) and other Arctic species." Canadian Journal of Fisheries and Aquatic Sciences 65, no. 4 (April 1, 2008): 733–43. http://dx.doi.org/10.1139/f08-012.

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Radiocarbon generated by atmospheric testing of nuclear weapons (bomb radiocarbon) produced a strong signal with an abrupt onset in the 1950s, which serves as a dated marker for tracing oceanic circulation and confirming age in animals forming growth bands. Here, we report the first prebomb and postbomb radiocarbon chronologies for marine and freshwater environments in the Canadian Arctic, extend the radiocarbon chronology for the northwest Atlantic Ocean, and use the onset of the bomb signal to validate our age interpretations of lake trout (Salvelinus namaycush) in Arctic lakes. Both surface and deepwater Arctic chronologies became detectable on or around 1958, similar to the year of onset elsewhere in the world. In contrast, the freshwater Arctic chronology increased sharply in 1957, with a peak value sixfold higher than the adjacent marine environment. The radiocarbon content of the adult otolith core validated our age interpretation criteria for Arctic lake trout to an age of at least 50 years. Otolith growth in such slow-growing fish was so low as to be unresolvable under conventional examination with a dissecting microscope. With these new radiocarbon reference chronologies, age validation of a large number of Arctic organisms should now be possible.

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Sierra, Carlos A. "Forecasting Atmospheric Radiocarbon Decline to Pre-Bomb Values." Radiocarbon 60, no. 4 (April 25, 2018): 1055–66. http://dx.doi.org/10.1017/rdc.2018.33.

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AbstractIn this manuscript, I present an estimation of the rate of decline in atmospheric radiocarbon and the amplitude of its seasonal cycle for the past four decades for the northern and southern hemispheres, and forecast the time required to reach pre-1950 levels (i.e. Δ14C<0‰). Using a set of 30 different exponential smoothing state-space models, the time series were decomposed into their error, trend, and seasonal components, choosing the model that best represented the observed data. According to the best model, the rate of change in Δ14C has decreased considerably since the 1970s and reached values below −5‰ per year since 2005. Overall, the time-series showed larger rates of radiocarbon decline in the northern than in the southern hemisphere, and relatively stable seasonal cycles for both hemispheres. A forecast of the exponential smoothing models predicts that radiocarbon values will reach pre-1950 levels by 2021 in the northern hemisphere with 20% probability, and by around 2035 in the southern hemisphere. However, at regional levels radiocarbon concentrations have already reached pre-1950 levels in several industrialized regions and cities around the world as a consequence of fossil-fuel emissions.

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Grammer, G. L., S. J. Fallon, C. Izzo, R. Wood, and B. M. Gillanders. "Investigating bomb radiocarbon transport in the southern Pacific Ocean with otolith radiocarbon." Earth and Planetary Science Letters 424 (August 2015): 59–68. http://dx.doi.org/10.1016/j.epsl.2015.05.008.

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Guilderson, Thomas P., E. Brendan Roark, Paul D. Quay, Sarah R. Flood Page, and Christopher Moy. "Seawater Radiocarbon Evolution in the Gulf of Alaska: 2002 Observations." Radiocarbon 48, no. 1 (2006): 1–15. http://dx.doi.org/10.1017/s0033822200035359.

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Oceanic uptake and transport of bomb radiocarbon as 14CO2 created by atmospheric nuclear weapons testing in the 1950s and 1960s has been a useful diagnostic for determining the carbon transfer between the ocean and atmosphere. In addition, the distribution of 14C in the ocean can be used as a tracer of oceanic circulation. Results obtained on samples collected in the Gulf of Alaska in the summer of 2002 provide a direct comparison with results in the 1970s during GEOSECS and in the early 1990s during WOCE. The open gyre values are 20–40% lower than those documented in 1991 and 1993 (WOCE), although the general trends as a function of latitude are reproduced. Surface values are still significantly higher than pre-bomb levels (∼ −105% or lower). In the central gyre, we observe Δ14C values that are lower in comparison to GEOSECS (stn 218) and WOCE P16/P17 to a density of ∼26.8 σt. This observation is consistent with the overall decrease in surface Δ14C values and reflects the erosion of the bomb-14C transient. We propose that erosion of the bomb-14C transient is accomplished by entrainment of low-14C water via vertical exchange within the Gulf of Alaska and replenishment of surface and subther-mocline waters with waters derived from the far northwest Pacific.

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Andrews, Allen H., Ashley Pacicco, Robert Allman, Brett J. Falterman, Erik T. Lang, and Walter Golet. "Age validation of yellowfin (Thunnus albacares) and bigeye (Thunnus obesus) tuna of the northwestern Atlantic Ocean." Canadian Journal of Fisheries and Aquatic Sciences 77, no. 4 (April 2020): 637–43. http://dx.doi.org/10.1139/cjfas-2019-0328.

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Estimates of age and growth of yellowfin (Thunnus albacares) and bigeye (Thunnus obesus) tuna remain problematic because validation of growth zone deposition (opaque and translucent) has not been properly evaluated. Otolith growth structure (zone clarity) can be poorly defined for tropical tunas, but the use of bomb radiocarbon dating has validated age estimates to 16–18 years for yellowfin and bigeye tuna. Use of the radiocarbon decline period — defined by regional coral and otoliths — provided valid ages through ontogeny. Yellowfin tuna aged 2–18 years (n = 34, 1029–1810 mm FL) and bigeye tuna aged 3–17 years (n = 12, 1280–1750 mm FL) led to birth years that were coincident with the bomb radiocarbon decline. The results indicate there was no age reading bias for yellowfin tuna and that age estimates of previous studies were likely underestimated for both species.

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Brock, Fiona, Nicholas Eastaugh, Thierry Ford, and Joyce H. Townsend. "Bomb-pulse Radiocarbon Dating of Modern Paintings on Canvas." Radiocarbon 61, no. 1 (July 11, 2018): 39–49. http://dx.doi.org/10.1017/rdc.2018.55.

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ABSTRACTRadiocarbon (14C) dating has previously been applied to modern paintings on canvas from the 20th century to identify potential modern forgeries, and dates indicate a time lag of several years between the harvesting of plant fibers for making canvas, and completion of a painting. This study investigated both the length of this time lag and the potential of 14C dating to inform about an individual artist’s mode of working (for example long-term storage or reuse of canvases, or extended reworking on a single canvas) and/or to establish a chronology for a corpus of work. Two pre-bomb and 16 post-bomb artworks by 17 mid-20th-century Scandinavian artists were 14C dated. The majority of post-bomb samples indicated a time lag of 2–5 years between the harvesting of the plants and completion of a painting, but some samples recorded lags of up to 10 years, and others produced much earlier results, potentially indicating the use of much older canvases or challenges removing contamination prior to dating. The importance of thorough pre-screening of canvas samples for both synthetic fibers and contaminants prior to dating, and selection of the most suitable calibration curve, are highlighted.

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Rinyu, Laszlo, Robert Janovics, Mihaly Molnar, Zoltan Kisvarday, and Adam Kemeny-Beke. "Radiocarbon Map of a Bomb-Peak Labeled Human Eye." Radiocarbon 62, no. 1 (July 25, 2019): 189–96. http://dx.doi.org/10.1017/rdc.2019.78.

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ABSTRACTThe 14C/12C ratio of living organisms is largely determined by the 14C/12C ratio of consumed diet as well as by the atmospheric 14C concentration together with the body’s metabolic processes. The measured 14C content of living matter compared to the atmospheric radiocarbon level can provide invaluable information about developmental processes. Our aim was to determine the 14C content of ten different tissues of the human eye using the 14C bomb-pulse dating signature. The 14C content of the atmosphere, so called 14C “bomb-pulse” has labeled humanity offering an opportunity to determine these special formation, turnover and substitution courses in biology. The results allowed us to construct a 14C map of the bomb-peak labeled human eye. According to the anatomical location of the tissues, an unexpected picture emerged as in moving from the outer parts towards the inner parts of the eye, the 14C content of each tissue decreased. The data presented here are compatible with the view that the oldest parts of the eye are the sclera, the limbus and the cornea, in this order, and moving further inside, the youngest tissue of the eye is the retina.

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Bruun, Sander, Johan Six, Lars S. Jensen, and Keith Paustian. "Estimating Turnover of Soil Organic Carbon Fractions Based on Radiocarbon Measurements." Radiocarbon 47, no. 1 (2005): 99–113. http://dx.doi.org/10.1017/s0033822200052231.

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In this paper, we examine 3 different models used to estimate turnover of soil organic carbon (SOC) fractions using radiocarbon measurements: one conventional carbon dating model and two bomb 14C models. One of the bomb 14C models uses an atmospheric 14C record for the period 22,050 BC to AD 2003 and is solved by numerical methods, while the other assumes a constant 14C content of the atmosphere and is solved analytically. The estimates of SOC turnover obtained by the conventional 14C dating model differed substantially from those obtained by the bomb 14C models, which we attribute to the simplifying assumption of the conventional 14C model that the whole SOC fraction is of the same age. The assumptions underlying the bomb 14C models are more applicable to SOC fractions; therefore, the calculated turnover times are considered to be more reliable. We used Monte Carlo simulations to estimate the uncertainties of the turnover times calculated with the numerically solved 14C model, accounting not only for measurement errors but also for uncertainties introduced from assumptions of constant input and uncertainties in the 14C content of the CO2 assimilated by plants. The resulting uncertainties depend on systematic deviations in the atmospheric 14C record for SOC fractions with a fast turnover. Therefore, the use of the bomb 14C models can be problematic when SOC fractions with a fast turnover are analyzed, whereas the relative uncertainty of the turnover estimates turned out to be smaller than 30% when the turnover time of the SOC fractions analyzed was longer than 30 yr, and smaller than 15% when the turnover time was longer than 100 yr.

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Davis-Foust, Shannon L., Ronald M. Bruch, Steven E. Campana, Robert P. Olynyk, and John Janssen. "Age Validation of Freshwater Drum using Bomb Radiocarbon." Transactions of the American Fisheries Society 138, no. 2 (March 2009): 385–96. http://dx.doi.org/10.1577/t08-097.1.

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McKay, Christopher P., Austin Long, and E. Imre Friedmann. "Radiocarbon dating of open systems with bomb effect." Journal of Geophysical Research: Solid Earth 91, B3 (March 10, 1986): 3836–40. http://dx.doi.org/10.1029/jb091ib03p03836.

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Broecker, Wallace S., Tsung-Hung Peng, Gote Ostlund, and Minze Stuiver. "The distribution of bomb radiocarbon in the ocean." Journal of Geophysical Research 90, no. C4 (1985): 6953. http://dx.doi.org/10.1029/jc090ic04p06953.

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Geyh, Mebus A. "Bomb Radiocarbon Dating of Animal Tissues and Hair." Radiocarbon 43, no. 2B (2001): 723–30. http://dx.doi.org/10.1017/s0033822200041382.

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Initially, radiocarbon dating by bomb 14C was used to check vintages of wine and whisky and to estimate the turnover times of carbon in various biological tissues. However, this technique has never been widely used for routine dating, although it has a wide field of application in geriatric medicine and forensic investigations. Fifteen years' experience in this field has shown the potential and limits of this technique. Taking into account the decisive biological factors, such as growth and aging, a complicated picture is obtained. Recent human bones cannot be dated with a constant precision. Despite an incomplete understanding of the process of incorporation of 14C into human bones, the present dating technique is still more precise than most estimates by geriatric experts, for conventional 14C dating follows that 14C dates of bone collagen represent the years of the termination of puberty rather than those of death.Another application is the identification of furs of illegally hunted animals on the “Red List of threatened species” of the World Conservation Union (IUCN). For court cases, the year the animals were killed must be precisely determined. Due to the long and variable turnover time of more than one year of leather hair is the best dating material for animals.

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Kumamoto, Yuichiro, Akihiko Murata, Chizuru Saito, Makio Honda, and Masashi Kusakabe. "Bomb radiocarbon invasion into the northwestern North Pacific." Deep Sea Research Part II: Topical Studies in Oceanography 49, no. 24-25 (January 2002): 5339–51. http://dx.doi.org/10.1016/s0967-0645(02)00194-7.

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Kalish, John M. "Pre- and post-bomb radiocarbon in fish otoliths." Earth and Planetary Science Letters 114, no. 4 (February 1993): 549–54. http://dx.doi.org/10.1016/0012-821x(93)90082-k.

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Kumamoto, Yuichiro, Akihiko Murata, Shuichi Watanabe, and Masao Fukasawa. "Decadal Changes of Bomb Radiocarbon in the Subtropical South Pacific Ocean Between 1992 and 2003." Radiocarbon 49, no. 2 (2007): 937–45. http://dx.doi.org/10.1017/s0033822200042806.

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A basin-scale repeat hydrography of the WOCE-P06 line along approximately 32°S has revealed decadal changes of bomb-produced radiocarbon in the subtropical South Pacific Ocean between 1992 and 2003. Surface δ14C decreased by about 30%. A δ14C decrease was also found in the upper thermocline from the surface to 400 m water depth. In the lower thermocline, from 400 m to 1100 m depth, however, δ14C increased, with a maximum increase of 25% at 700 m depth. This contrast between the upper and lower thermoclines resulted in an overall 10% increase of the specific column inventory of bomb 14C from 1992 to 2003. The global ocean inventory of bomb 14C was assessed based on the specific inventory increase in the subtropical South Pacific Ocean. The meridional distribution of bomb 14C in the early 1990s suggests that the bomb 14C increases observed along 32°S in 2003 were primarily caused by mixing along isopycnals.

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Andrews, Allen H., John H. Choat, Richard J. Hamilton, and Edward E. DeMartini. "Refined bomb radiocarbon dating of two iconic fishes of the Great Barrier Reef." Marine and Freshwater Research 66, no. 4 (2015): 305. http://dx.doi.org/10.1071/mf14086.

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Refinements to the methodology of bomb radiocarbon dating made it possible to validate age estimates of the humphead wrasse (Cheilinus undulatus) and bumphead parrotfish (Bolbometopon muricatum). Age for these species has been estimated from presumed annual growth zones in otoliths at ~30 and ~40 years respectively. The validity of these estimates was tested using bomb radiocarbon dating on the small and fragile otoliths of these species, and provided an opportunity to refine the method using advanced technologies. A regional Δ14C reference record from hermatypic coral cores from the Great Barrier Reef was assembled and Δ14C measurements from extracted otolith cores of adult otoliths were successful. Validated ages supported the accuracy of growth zone derived ages using sectioned sagittal otoliths.

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Kumamoto, Yuichiro, Akihiko Murata, Takeshi Kawano, Shuichi Watanabe, and Masao Fukasawa. "Decadal Changes in Bomb-Produced Radiocarbon in the Pacific Ocean from the 1990s to 2000s." Radiocarbon 55, no. 3 (2013): 1641–50. http://dx.doi.org/10.1017/s0033822200048554.

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In the 2000s, radiocarbon in dissolved inorganic carbon was measured during 7 revisit cruises along the lines of the World Ocean Circulation Experiment in the Pacific Ocean. Comparison of 14C data along these lines from the 1990s and 2000s revealed decadal changes of 14C concentration in the thermocline, most of which were due to temporal changes in the bomb-produced 14C. Vertical profiles and vertical-integrated inventories of the bomb 14C in the subarctic and equatorial regions did not change appreciably. In the southern subtropical region, 14C decreased in the upper thermocline from the surface to ∼500 m depth. In contrast, 14C increased in the lower thermocline below ∼500 m depth. The opposing directions in 14C change resulted in small temporal changes in the total inventory of bomb 14C. On the other hand, the water-column inventory significantly decreased in the northwestern subtropical region due to the 14C decrease in the upper thermocline. These decadal changes in bomb 14C indicate that the turnover time of thermocline circulation in the northwestern subtropical region is faster than that in the southern subtropical region, and imply an interbasin transport of bomb 14C from the North Pacific to other basins.

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Andrews, Allen H., John M. Kalish, Stephen J. Newman, and Justine M. Johnston. "Bomb radiocarbon dating of three important reef-fish species using Indo-Pacific Δ14C chronologies." Marine and Freshwater Research 62, no. 11 (2011): 1259. http://dx.doi.org/10.1071/mf11080.

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Demersal reef fishes of the Indo-Pacific are under increasing pressure as a fisheries resource, yet many of the important life history characteristics required for suitable management are poorly known. The three fish species, eightbar grouper (Hyporthodus octofasciatus), ruby snapper (Etelis carbunculus) and the spangled emperor (Lethrinus nebulosus), are important components of fisheries and ecosystems throughout the Indo-Pacific. Despite their importance, age and growth information is incomplete. Age has been estimated for E. carbunculus and L. nebulosus, but validated age beyond the first few years is lacking and for H. octofasciatus no age estimates exist. Bomb radiocarbon dating can provide age estimates that are independent of growth-zone counting, but only if appropriate reference Δ14C chronologies exist. In this study, a series of Δ14C records from hermatypic corals was assembled to provide a basis for bomb radiocarbon dating in the western Indo-Pacific region. Results provided (1) valid age estimates for comparison to age estimates from two facilities investigating growth-zones in otolith thin sections; (2) support for age estimation protocols using otolith thin sections; and (3) the information necessary for further refinement of age estimation procedures. Estimates of longevity from bomb radiocarbon dating agree with some prior studies: H. octofasciatus, E. carbunculus and L. nebulosus all being long-lived species with life spans of at least 43, 35 and 28 years respectively.

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Vitale, Sergio, Allen H. Andrews, Pietro Rizzo, Salvatore Gancitano, and Fabio Fiorentino. "Twenty-five-year longevity of European hake (Merluccius merluccius) from novel use of bomb radiocarbon dating in the Mediterranean Sea." Marine and Freshwater Research 67, no. 7 (2016): 1077. http://dx.doi.org/10.1071/mf15376.

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The high variability of growth and longevity estimates for European hake (Merluccius merluccius) reflects the existence of two opposing hypotheses on growth rates that differ by a factor of 2: (1) a fast-growing hypothesis (FGH) with a maximum age near 15 years; and (2) a slow-growing hypothesis (SGH) with a maximum age near 30 years. A recently established regional radiocarbon (14C) reference led to a first-time application of bomb 14C dating in the Mediterranean Sea to three of the largest-sized and potentially oldest-catch female European hake. Because age reading of otoliths is very subjective and poorly defined, these fish were aged blind with bomb radiocarbon (14C) dating as an independent estimate of validated age. The validated ages were compared with the theoretical maximum ages from the most reliable FGH and SGH von Bertalanffy growth functions. Among the three bomb 14C ages, the most diagnostic length-at-age was an alignment with the bomb 14C rise period for two of the three fish, providing validated ages of 22 years (74.5-cm total length) and 25 years (88-cm total length). The results provide estimates of length-at-age that are in agreement with the SGH and cannot be accounted for by the FGH.

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30

Mahadevan, Amala. "An analysis of bomb radiocarbon trends in the Pacific." Marine Chemistry 73, no. 3-4 (March 2001): 273–90. http://dx.doi.org/10.1016/s0304-4203(00)00113-4.

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31

Hamady, Li Ling, Lisa J. Natanson, Gregory B. Skomal, and Simon R. Thorrold. "Vertebral Bomb Radiocarbon Suggests Extreme Longevity in White Sharks." PLoS ONE 9, no. 1 (January 8, 2014): e84006. http://dx.doi.org/10.1371/journal.pone.0084006.

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32

Broecker, Wallace S., Stewart Sutherland, William Smethie, Tsung-Hung Peng, and Gote Ostlund. "Oceanic radiocarbon: Separation of the natural and bomb components." Global Biogeochemical Cycles 9, no. 2 (June 1995): 263–88. http://dx.doi.org/10.1029/95gb00208.

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33

Andrews, Allen H., Robert L. Humphreys, and Jeffery D. Sampaga. "Blue marlin (Makaira nigricans) longevity estimates confirmed with bomb radiocarbon dating." Canadian Journal of Fisheries and Aquatic Sciences 75, no. 1 (January 2018): 17–25. http://dx.doi.org/10.1139/cjfas-2017-0031.

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The longevity of blue marlin (Makaira nigricans) remains unresolved. The use of fin spines and sagittal otoliths for age reading has led to unconfirmed longevity estimates near 20–30 years. Age validation has been elusive because large individuals are uncommonly caught, and a technique that can be applied to structures that provide estimates of age was absent. The use of otolith chemical signatures has been limited by sagittal otoliths that are very small — whole otolith mass of adult blue marlin rarely exceeds 10 mg for the largest fish. Recent advances in the detection limits of radiocarbon (14C) with accelerator mass spectrometry — coupled with recently acquired knowledge of marine bomb 14C signals spanning the tropical Pacific Ocean — have led to an opportunity to age blue marlin from small amounts of otolith material. In this study, otoliths from a recently collected 1245 lb (565 kg) female blue marlin at a measured 146-inch (371 cm) lower jaw fork length were analyzed for 14C. Estimated longevity was either 12–21 or 32–44 years on the basis of bomb 14C dating. Using multiple lines of evidence, it was determined that the young age scenario was most likely, with evidence for an age close to 20 years using a series of deductions in the bomb 14C dating method.

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Yu, Shi-Yong, Ji Shen, and Steven M. Colman. "Modeling the Radiocarbon Reservoir Effect in Lacustrine Systems." Radiocarbon 49, no. 3 (2007): 1241–54. http://dx.doi.org/10.1017/s0033822200043150.

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The modern water (both pre- and post-atmospheric nuclear testing) of most lakes has an anomalously old apparent radiocarbon age due to what is commonly referred to as the “reservoir effect.” In contrast to marine settings, this14C-offset phenomenon is primarily caused by pre-aged carbon discharged to lakes by rivers and/or groundwater. In this paper, a 2-component box model based on the principle of14C mass balance in lake water and in the early diagenesis zone was formulated to address the relative importance of terrestrial inputs, autochthonous production, and biogeochemical processes in the14C reservoir of a lacustrine system. The model was tested using observed data from Lake Qinghai, the largest inland water body in China. Our inverse modeling using Markov chain Monte Carlo (MCMC) techniques yields best estimates of the δ14C of DIC in river (∼118% modern) and groundwater (∼76% modern), as well as the δ14C of DOC in river water (∼70% modern) during the post-bomb era. Assuming that these parameters remain constant over time, our modeling indicates that both the DIC and DOC pool of this lake have reservoir ages of about 1500 yr for the pre-bomb era, generally consistent with estimates obtained by extrapolation of the age-depth models of 2 sediment cores to the sediment surface.

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35

Kalish, John M. "Application of the bomb radiocarbon chronometer to the validation of redfish Centroberyx affinis age." Canadian Journal of Fisheries and Aquatic Sciences 52, no. 7 (July 1, 1995): 1399–405. http://dx.doi.org/10.1139/f95-135.

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Validation of methods used to estimate fish age is a critical element of the fish stock assessment process. Despite the importance of validation, few procedures are available that provide unbiased estimates of true fish age and those methods that are available are seldom used. The majority of these methods are unlikely to provide an indication of the true age of individual fish, data that are best suited to the validation process. Accelerator mass spectrometry analyses of radiocarbon in selected regions of Centroberyx affinis otoliths were used to validate the age estimation method for this species. Radiocarbon data from the otoliths of C. affinis with presumed birth dates between 1955 and 1985 described the increase in ocean radiocarbon attributable to the atmospheric detonation of nuclear weapons in the 1950s and 1960s. The results confirm the longevity of C. affinis and demonstrate the effectiveness of the bomb radiocarbon chronometer for the validation of age-estimation methods.

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Goslar, Tomasz, W. O. van der Knaap, Sheila Hicks, Maja Andrič, Justyna Czernik, Ewa Goslar, Satu Räsänen, and Heidi Hyötylä. "Radiocarbon Dating of Modern Peat Profiles: Pre- and Post-Bomb 14C Variations in the Construction of Age-Depth Models." Radiocarbon 47, no. 1 (2005): 115–34. http://dx.doi.org/10.1017/s0033822200052243.

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We present studies of 9 modern (up to 400-yr-old) peat sections from Slovenia, Switzerland, Austria, Italy, and Finland. Precise radiocarbon dating of modern samples is possible due to the large bomb peak of atmospheric 14C concentration in 1963 and the following rapid decline in the 14C level. All the analyzed 14C profiles appeared concordant with the shape of the bomb peak of atmospheric 14C concentration, integrated over some time interval with a length specific to the peat section. In the peat layers covered by the bomb peak, calendar ages of individual peat samples could be determined almost immediately, with an accuracy of 2–3 yr. In the pre-bomb sections, the calendar ages of individual dated samples are determined in the form of multi-modal probability distributions of about 300 yr wide (about AD 1650–1950). However, simultaneous use of the post-bomb and pre-bomb 14C dates, and lithological information, enabled the rejection of most modes of probability distributions in the pre-bomb section. In effect, precise age-depth models of the post-bomb sections have been extended back in time, into the “wiggly” part of the 14C calibration curve.Our study has demonstrated that where annual resolution is concerned, tissues of Sphagnum are the only representative material for 14C dating, although even samples of pure Sphagnum collected from a very thin slice of the peat section contain tissues grown in different years, so they integrate the atmospheric 14C signal over a period of time. This time period (0.5–8 yr, depending on the site) seems to correlate with the peat accumulation rate, but it also depends on how the sampled peat sections were handled. When constructing age-depth models, for some peat sections we used the strategy of multi-stage 14C dating. This led to a drastic reduction in the uncertainty of the age-depth models, by dating only a few additional samples in the profile.Our study is the first in which peat sections from the late pre-bomb time (AD 1900–1960) have been precisely dated at a high temporal resolution. In this time interval, 14C ages of all the samples dated were younger than those derived from the atmospheric calibration curve, apparently due to the effect of integration. Evidently, the determination of calendar ages based on 14C dating of single peat samples from that interval may be affected by a serious error if the possibility of integration is ignored.

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Andrews, Allen H., Robert T. Leaf, Laura Rogers-Bennett, Melissa Neuman, Heather Hawk, and Gregor M. Cailliet. "Bomb radiocarbon dating of the endangered white abalone (Haliotis sorenseni): investigations of age, growth and lifespan." Marine and Freshwater Research 64, no. 11 (2013): 1029. http://dx.doi.org/10.1071/mf13007.

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Understanding basic life-history characteristics of white abalone (Haliotis sorenseni), such as estimated lifespan, is critical to making informed decisions regarding the recovery of this endangered species. All predictive modelling tools used to forecast the status and health of populations following restoration activities depend on a validated estimate of adult lifespan. Of the seven Haliotis species in California, white abalone is considered to have the highest extinction risk and was the first marine invertebrate listed as an endangered species under the Federal Endangered Species Act (ESA). Lifespan was previously estimated from observations of early growth; however, no study has generated ages for the largest white abalone. To address questions of age and growth, bomb radiocarbon (Δ14C) dating was used on shells from large white abalone. Measured bomb Δ14C levels were compared to regional Δ14C reference records to provide estimates of age, growth and lifespan. Bomb radiocarbon dating indicated that growth was variable among individuals, with a maximum estimated age of 27 years. The findings presented here provide support for previous age and growth estimates and an estimated lifespan near 30 years. These age data support the perception of a critical need for restoring the remnant aging and potentially senescent population.

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Druffel, Ellen R. M. "Post-Bomb Radiocarbon Records of Surface Corals from the Tropical Atlantic Ocean." Radiocarbon 38, no. 3 (1996): 563–72. http://dx.doi.org/10.1017/s0033822200030095.

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Δ14C records are reported for post-bomb corals from three sites in the tropical Atlantic Ocean. In corals from 18°S in the Brazil Current, Δ14C values increased from ca. −58% in the early 1950s to +138% by 1974, then decreased to 110‰ by 1982. Shorter records from 8ºS off Brazil and from the Cape Verde Islands (17°N) showed initially higher Δ14C values before 1965 than those at 18ºS, but showed lower rates of increase of Δ14C during the early 1960s. There is general agreement between the coral results and Δ14C of dissolved inorganic carbon (DIC) measured in seawater previously for locations in the tropical Atlantic Ocean. Δ14C values at our tropical ocean sites increased at a slower rate than those observed previously in the temperate North Atlantic (Florida and Bermuda), owing to the latter's proximity to the bomb 14C input source in the northern, hemisphere. Model results show that from 1960–1980 the Cape Verde coral and selected DIG Δ14C values from the North Equatorial Current agree with that calculated for the North Atlantic based on an isopycnal mixing model with a constant water mass renewal rate between surface and subsurface waters. This is in contrast to Δ14C values in Bermuda corals that showed higher post-bomb values than those predicted using a constant water mass renewal rate, hence indicating that ventilation in the western north Atlantic Ocean had decreased by a factor of 3 during the 1960s and 1970s (Druffel 1989).

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39

Clarke, Laurence J., Sharon A. Robinson, Quan Hua, David J. Ayre, and David Fink. "Radiocarbon bomb spike reveals biological effects of Antarctic climate change." Global Change Biology 18, no. 1 (October 27, 2011): 301–10. http://dx.doi.org/10.1111/j.1365-2486.2011.02560.x.

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40

Druffel, Ellen R. M. "Bomb radiocarbon in the Pacific: Annual and seasonal timescale variations." Journal of Marine Research 45, no. 3 (August 1, 1987): 667–98. http://dx.doi.org/10.1357/002224087788326876.

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41

Peng, Tsung-Hung, Robert M. Key, and H. Göte Östlund. "Temporal variations of bomb radiocarbon inventory in the Pacific Ocean." Marine Chemistry 60, no. 1-2 (February 1998): 3–13. http://dx.doi.org/10.1016/s0304-4203(97)00089-3.

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42

Hua, Q., M. Barbetti, G. E. Jacobsen, U. Zoppi, and E. M. Lawson. "Bomb radiocarbon in annual tree rings from Thailand and Australia." Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms 172, no. 1-4 (October 2000): 359–65. http://dx.doi.org/10.1016/s0168-583x(00)00147-6.

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43

Peacock, Synte. "Debate over the ocean bomb radiocarbon sink: Closing the gap." Global Biogeochemical Cycles 18, no. 2 (June 2004): n/a. http://dx.doi.org/10.1029/2003gb002211.

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44

Sanchez, Phillip J., Jeffrey P. Pinsky, and Jay R. Rooker. "Bomb Radiocarbon Age Validation of Warsaw Grouper and Snowy Grouper." Fisheries 44, no. 11 (July 30, 2019): 524–33. http://dx.doi.org/10.1002/fsh.10291.

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45

Georgiadou, Elisavet, and Kristina Stenström. "Bomb-Pulse Dating of Human Material: Modeling the Influence of Diet." Radiocarbon 52, no. 2 (2010): 800–807. http://dx.doi.org/10.1017/s0033822200045811.

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The atmospheric testing of nuclear weapons during the 1950s and early 1960s produced large amounts of radiocarbon. This 14C bomb pulse provides useful age information in numerous scientific fields, e.g. in geosciences and environmental sciences. Bomb-pulse dating can also be used to date human material (e.g. in forensics and medical science). Bomb-pulse dating relies on precise measurements of the declining 14C concentration in atmospheric carbon dioxide collected at clean-air sites. However, local variations in the 14C specific activity of air and foodstuffs occur, which are caused by natural processes as well as by various human activities. As 14C enters the human body mainly through the diet, variations of 14C concentration in foodstuffs need to be considered. The marine component of the diet is believed to be of particular importance due to the non-equilibrium in 14C specific activity between the atmosphere and aquatic reservoirs during the bomb pulse. This article reviews the 14C concentration in marine foodstuffs during the bomb-pulse era, and models how the marine component in one's diet can affect the precision of bomb-pulse dating of human material.

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46

Brock, Fiona, and Gordon T. Cook. "Forensic Radiocarbon Dating of Human Remains." Archaeological and Environmental Forensic Science 1, no. 1 (July 16, 2017): 3–16. http://dx.doi.org/10.1558/aefs.30715.

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Radiocarbon dating is a valuable tool for the forensic examination of human remains in answering questions as to whether the remains are of forensic or medico-legal interest or archaeological in date. The technique is also potentially capable of providing the year of birth and/or death of an individual. Atmospheric radiocarbon levels are currently enhanced relative to the natural level due to the release of large quantities of radiocarbon (14C) during the atmospheric nuclear weapons testing of the 1950s and 1960s. This spike, or “bomb-pulse,” can, in some instances, provide precision dates to within 1–2 calendar years. However, atmospheric 14C activity has been declining since the end of atmospheric weapons testing in 1963 and is likely to drop below the natural level by the mid-twenty-first century, with implications for the application of radiocarbon dating to forensic specimens.

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47

Kastelle, Craig R., Daniel K. Kimura, and Betty J. Goetz. "Bomb radiocarbon age validation of Pacific ocean perch (Sebastes alutus) using new statistical methods." Canadian Journal of Fisheries and Aquatic Sciences 65, no. 6 (June 2008): 1101–12. http://dx.doi.org/10.1139/f08-038.

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We used bomb-produced radiocarbon (14C) to validate ages of Pacific ocean perch ( Sebastes alutus ), which are routinely estimated with the cut-and-burn method at the Alaska Fisheries Science Center (Seattle, Washington, USA). New statistical methods to compare Δ14C in validation samples with a reference chronology are introduced: (i) calculating confidence intervals around the LOESS-smoothed Δ14C reference chronology using simultaneous inference; (ii) purposely adding biases to the validation sample ages and then analyzing the sum of squared residuals of the validation samples’ Δ14C about the LOESS-smoothed reference chronology; and (iii) standardizing the Δ14C measurements from the validation sample to better fit the reference chronology. Standardized Δ14C measurements are particularly useful when researchers suspect that environmental and biological differences between the validation samples and the reference chronology may exist that affect the level, but not the timing, of Δ14C in the samples. These new methods can be applied simultaneously. Two previous bomb radiocarbon studies on canary rockfish ( Sebastes pinniger ) and black drum ( Pogonias cromis ) were reanalyzed, further illustrating the usefulness of these new methods.

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Wu, Yang, Stewart J. Fallon, Neal E. Cantin, and Janice M. Lough. "SURFACE OCEAN RADIOCARBON FROM A PORITES CORAL RECORD IN THE GREAT BARRIER REEF: 1945–2017." Radiocarbon 63, no. 4 (January 28, 2021): 1193–203. http://dx.doi.org/10.1017/rdc.2020.141.

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ABSTRACTWe present a high-resolution seawater radiocarbon (Δ14C) record from a Porites coral collected from Masthead Island in the southern Great Barrier Reef (GBR) covering the years 1945–2017. The Δ14C values from 1945–1953 (pre-bomb era) averaged –49‰. As a result of bomb-produced 14C in the atmosphere, Δ14C values started to rise rapidly from 1959, levelled off at ∼131‰ in the late 1970s and gradually decreased to ∼40.3‰ by 2017 due to the decrease in the air-sea 14C gradient and the overturning of the 14C ocean reservoir (i.e., surface ocean to subsurface ocean; atmosphere to surface ocean). The Masthead Island record is in agreement with previous 14C coral records from the southern GBR. A comparison between surface ocean and atmospheric Δ14C suggests that, since 2010, the main reservoir of bomb-derived 14C has shifted from the atmosphere to the surface ocean, potentially resulting in reversed 14C flux in regions where the CO2 gradient is favorable. The high-resolution Masthead coral Δ14C sheds light on long-term variability in air-sea exchange and GBR regional ocean dynamics associated with climate change and in conjunction with the previous records provides a robust seawater 14C reference series to date other carbonate samples.

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Hua, Quan, Mike Barbetti, Ugo Zoppi, David M. Chapman, and Bruce Thomson. "Bomb Radiocarbon in Tree Rings from Northern New South Wales, Australia: Implications for Dendrochronology, Atmospheric Transport, and Air-Sea Exchange of CO2." Radiocarbon 45, no. 3 (2003): 431–47. http://dx.doi.org/10.1017/s0033822200032793.

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We have analyzed by radiocarbon 27 consecutive single rings, starting from AD 1952, of a preliminarily cross-dated section (DFR 021) of Pinus radiata, which grew in Armidale, northern New South Wales, Australia. The bomb 14C results suggested the possibility of 2 false rings, and, consequently, 2 misidentified rings in the preliminary count for this section. This possibility was supported by a better ring-width correlation between the revised DFR 021 count and other Pinus radiata chronologies in the study region. This indicated that bomb 14C is a useful tool to complement the standard techniques of dendrochronology in tree species where annual rings are not always clearly defined.

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Krzemnicki, Michael S., and Irka Hajdas. "Age Determination of Pearls: A New Approach for Pearl Testing and Identification." Radiocarbon 55, no. 3 (2013): 1801–9. http://dx.doi.org/10.1017/s0033822200048700.

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For this radiocarbon study, 7 saltwater pearls and 3 shells from pearl oysters have been analyzed. The declared ages of the samples range from the mid-19th century to very recent formations. The analyzed data show the potential of the bomb peak time marker to provide additional information when testing pearls. The analyzed pearls could be distinctly separated in pearls of pre- and post-bomb peak ages, in agreement with the distinction based on the declared ages. The analyzed data further reveals the potential of this method to provide supporting evidence for the historic provenience of a pearl or as an indication of a natural or cultured formation of a pearl.

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Journal articles on the topic 'Bomb radiocarbon'

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