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Journal articles on the topic 'K-Ar and 40Ar'

Author: Grafiati

Published: 7 July 2024

Last updated: 31 July 2025

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1

Lanphere, Marvin A. "Comparison of Conventional K–Ar and 40Ar/39Ar Dating of Young Mafic Volcanic Rocks." Quaternary Research 53, no. 3 (2000): 294–301. http://dx.doi.org/10.1006/qres.1999.2122.

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AbstractK–Ar and 40Ar/39Ar ages have been measured on nine mafic volcanic rocks younger than 1 myr from the Snake River Plain (Idaho), Mount Adams (Washington), and Crater Lake (Oregon). The K–Ar ages were calculated from Ar measurements made by isotope dilution and K2O measurements by flame photometry. The 40Ar/39Ar ages are incremental-heating experiments using a low-blank resistance-heated furnace. The results indicate that high-quality ages can be measured on young, mafic volcanic rocks using either the K–Ar or the 40Ar/39Ar technique. The precision of an 40Ar/39Ar plateau age generally is

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2

Clauer, Norbert, and Abraham Lerman. "A Kinetic Explanation for Combined Potassium Gains and Radiogenic 40Argon Losses of Diagenetic Illite-Rich Clay Separates." Geosciences 12, no. 5 (2022): 186. http://dx.doi.org/10.3390/geosciences12050186.

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In this study, a kinetic model sketches the concomitant K gain and radiogenic 40Ar loss of clay separates recovered from progressively buried sediments. Published K-Ar ages of clay separates from the Mahakam Delta, the Texas Gulf Coast, and the North Sea were used to constrain the modeling. As compared with analytical results, the model simulates changes relative to depth or to deposition time of the K-Ar ages from fine- and coarse-grained clay crystals. The decrease in the K-Ar ages of detrital-rich coarse-grained fractions (>2 μm) is bracketed with depth by K addition rates between 0.2 an

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3

Clauer, Norbert, and Abraham Lerman. "A Kinetic Explanation for Combined Potassium Gains and Radiogenic 40Argon Losses of Diagenetic Illite-Rich Clay Separates." Geosciences 12, no. 5 (2022): 186. http://dx.doi.org/10.3390/geosciences12050186.

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In this study, a kinetic model sketches the concomitant K gain and radiogenic 40Ar loss of clay separates recovered from progressively buried sediments. Published K-Ar ages of clay separates from the Mahakam Delta, the Texas Gulf Coast, and the North Sea were used to constrain the modeling. As compared with analytical results, the model simulates changes relative to depth or to deposition time of the K-Ar ages from fine- and coarse-grained clay crystals. The decrease in the K-Ar ages of detrital-rich coarse-grained fractions (>2 μm) is bracketed with depth by K addition rates between 0.2 an

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4

Plint, H. E., and M. R. McDonough. "40Ar/39Ar and K–Ar age constraints on shear zone evolution, southern Taltson magmatic zone, northeastern Alberta." Canadian Journal of Earth Sciences 32, no. 3 (1995): 281–91. http://dx.doi.org/10.1139/e95-023.

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New 40Ar/39Ar analyses of hornblende, muscovite, biotite, and K-feldspar constrain the timing of deformation and cooling of the southern Taltson magmatic zone, which underwent lower granulite to upper amphibolite grade deformation, in part synchronous with voluminous 1.99–1.92 Ga magmatism. New data are combined with existing K–Ar dates into a regional cooling framework to provide thermotemporal constraints on the deformational history. 40Ar/39Ar hornblende ages of ca. 1900 Ma are interpreted to record relatively rapid cooling following ductile thrusting on the Andrew Lake shear zone, and youn

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5

Carter, Jack, Ryan B. Ickert, Darren F. Mark, Marissa M. Tremblay, Alan J. Cresswell, and David C. W. Sanderson. "Production of <sup>40</sup>Ar by an overlooked mode of <sup>40</sup>K decay with implications for K-Ar geochronology." Geochronology 2, no. 2 (2020): 355–65. http://dx.doi.org/10.5194/gchron-2-355-2020.

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Abstract. The decay of 40K to the stable isotopes 40Ca and 40Ar is used as a measure of time for both the K-Ca and K-Ar geochronometers, the latter of which is most generally utilized by the variant 40Ar∕39Ar system. The increasing precision of geochronology has forced practitioners to deal with the systematic uncertainties rooted in all radioisotope dating methods. A major component of these systematic uncertainties for the K-Ar and 40Ar∕39Ar techniques is imprecisely determined decay constants and an incomplete knowledge of the decay scheme of 40K. Recent geochronology studies question wheth

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6

Sato, Megumi, Hironobu Hyodo, Kei Sugiura, Tatsuki Tsujimori, and Tetsumaru Itaya. "Regional-Scale Paleoproterozoic Heating Event on Archean Acasta Gneisses in Slave Province, Canada: Insights from K–Ar and 40Ar/39Ar Chronology." Minerals 14, no. 4 (2024): 397. http://dx.doi.org/10.3390/min14040397.

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Slave Province in Canada is an Archean granite–supracrustal terrane at the northwestern corner of the Canadian Shield. It is bordered by the Thelon–Taltson orogen (2.0 to 1.9 Ga) to the southeast and the Wopmay orogen (1.9 to 1.8 Ga) to the west. Acasta gneisses, exposed in the westernmost Slave Province, and the Wopmay rocks, located close to the gneisses, were systematically collected for K–Ar and laser step-heating 40Ar/39Ar single-crystal analyses of the biotite and amphibole. The K–Ar biotite ages of the four Wopmay samples range from 1816 ± 18 Ma to 1854 ± 26 Ma. The 40Ar/39Ar biotite an

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7

Jeans, C. V., J. G. Mitchell, M. J. Fisher, D. S. Wray, and I. R. Hall. "Age, origin and climatic signal of English Mesozoic clays based on K/Ar signatures." Clay Minerals 36, no. 4 (2001): 515–39. http://dx.doi.org/10.1180/0009855013640006.

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AbstractThe K/Ar characteristics of 53 clay assemblages (Triassic–Cretaceous), representing the detrital, volcanogenic and arid-facies clay mineral associations, are interpreted in relation to their mineralogy, chronostratic age and geological origins. The K-bearing mineral components of the 1–2 μm, 0.2–1 μm and <0.2 μm fractions of each clay assemblage together display one of two characteristic patterns of K2O and 40Ar values (the K/Ar signature of the assemblage) on a 40Ar/K2O correlation diagram. Interpretation of the K/Ar signatures indicates that: (1) all of these clay assemblages are

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8

Yudin, Denis, Nikolay Murzintsev, Alexey Travin, Taisiya Alifirova, Egor Zhimulev, and Sofya Novikova. "Studying the Stability of the K/Ar Isotopic System of Phlogopites in Conditions of High T, P: 40Ar/39Ar Dating, Laboratory Experiment, Numerical Simulation." Minerals 11, no. 2 (2021): 192. http://dx.doi.org/10.3390/min11020192.

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Typically, 40Ar/39Ar dating of phlogopites from deep-seated xenoliths of kimberlite pipes produces estimates that suggest much older ages than those when these pipes were intruded. High-pressure (3 GPa) laboratory experiments enabled the authors to explore the behaviour of argon in the phlogopite structure under the conditions that correspond to the mantle, at the temperatures (from 700 to 1000 °С), far exceeding closure temperature of the K/Ar isotopic system. “Volume diffusion” remains foremost for describing the mobility of argon in phlogopite at high pressures. The mantle material age can

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9

Renne, Paul R. "Progress and Challenges in K-Ar and40Ar/39Ar Geochronology." Paleontological Society Papers 12 (October 2006): 47–66. http://dx.doi.org/10.1017/s1089332600001340.

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K-Ar and more recently the40Ar/39Ar variant are well established dating methods. The40Ar/39Ar method requires irradiation with neutrons, posing some complications that are greatly outweighed by the benefits. The40Ar/39Ar method is particularly powerful due to the availability of internal reliability criteria, the ability to analyze single crystals, and the amenability of the analyses to automation.40Ar/39Ar dating has the capability for unsurpassed precision and is applicable to the broadest range of geologic environments and time scales of any radioisotope dating technique. For chronostratigr

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10

MARASCHIN, Anderson, Ana Maria MIZUSAKI, Paulo VASCONCELOS, Ruth HINRICHS, Luiz DE ROS, and Sylvia Dos ANJOS. "DEFINIÇÃO DA IDADE DEPOSICIONAL DA FORMAÇÃO AÇU (BACIA POTIGUAR, NORDESTE DO BRASIL) 40 39 ATRAVÉS DA DATAÇÃO." Pesquisas em Geociências 37, no. 2 (2010): 85. http://dx.doi.org/10.22456/1807-9806.22649.

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Crescimentos autigênicos precoces de K-feldspato são abundantes nos arenitos fluviais cretácicos da Formação Açu (Bacia Potiguar), um dos mais importantes reservatórios onshore de hidrocarbonetos do Brasil. Estes crescimentos foram formados diretamente ao redor de K-feldspatos detríticos, em condições superficiais (eodiagênese inicial). A continuidade física entre crescimentos e grãos detríticos impossibilitou sua separação visando a aplicação do método convencional 40K- 40Ar. Assim, optou-se em aplicar o método 40 39 Ar- Ar diretamente nos crescimentos autigênicos de K-feldspato. Como resulta

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11

KANEOKA, Ichiro. "Age Determinations by the K-Ar and 40Ar-39Ar Methods." Journal of Geography (Chigaku Zasshi) 94, no. 7 (1986): 676–81. http://dx.doi.org/10.5026/jgeography.94.676.

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12

Bounliyong, Patthana, Hirochika Sumino, and Antonio Arribas. "Large Amount of Excess Argon in Hydrothermal Quartz from the Vangtat Orogenic Gold Belt, Southern Laos: New In-Sight from K-Ar and Noble Gas Isotope Analyses." Minerals 12, no. 10 (2022): 1205. http://dx.doi.org/10.3390/min12101205.

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K-Ar dating and 3He/4He and 40Ar/36Ar analyses were conducted on samples of hydrothermal quartz from the Thongkai-Ok Au deposit in the Vangtat orogenic Au belt of southern Laos to study the presence of excess argon in hydrothermal quartz and to better understand the origin of the ore-forming fluids. The K-Ar age of two hydrothermal quartz separates yielded apparent dates of 1040 and 1385 Ma. These ages are significantly older than the estimated age of Vangtat Au mineralization (~200 Ma) and other regional geologic events, indicating the presence of an extraordinary amount of excess argon in th

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13

Zhang, Wan-Feng, De-Wen Zheng, Guo-Qing Liu, Yi-Gang Xu, and Ying-De Jiang. "Optimization of irradiation parameters for 40Ar/39Ar dating by Argus VI multi-collector mass spectrometry." Journal of Analytical Atomic Spectrometry 36, no. 7 (2021): 1374–80. http://dx.doi.org/10.1039/d1ja00055a.

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In <sup>40</sup>Ar/<sup>39</sup>Ar dating, <sup>39</sup>Ar<sub>K</sub> generated is dependent on irradiation conditions, and the accumulation fast neutron fluence is a critical parameter for <sup>40</sup>Ar/<sup>39</sup>Ar dating.

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14

Hemming, Sidney R., Tanzhuo Liu, Paul Northrup, et al. "Synchrotron Microanalytical Characterization and K/Ar Dating of the GL-O-1 Glauconite Reference Material at the Single Pellet Scale and Reassessment of the Age of Visually Mature Pellets." Minerals 13, no. 6 (2023): 773. http://dx.doi.org/10.3390/min13060773.

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The K/Ar chronology of glauconite pellets is a long-used method for directly dating marine sedimentary deposits. Many papers have explored the processes that form glauconite and the factors that lead to greater reliability in the ages. Although K/Ar ages of glauconite are generally in agreement with other measures of stratigraphic age, there are examples of occurrences with ages too old and examples with ages too young. This paper seeks to build on the accumulated knowledge of glauconite, using synchrotron radiation to non-destructively characterize individual pellets and then consecutively me

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15

Richards, Lachlan, Fred Jourdan, Alan Stephen Collins, and Rosalind Clare King. "Deformation recorded in polyhalite from evaporite detachments revealed by <sup>40</sup>Ar ∕ <sup>39</sup>Ar dating." Geochronology 3, no. 2 (2021): 545–59. http://dx.doi.org/10.5194/gchron-3-545-2021.

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Abstract. The Salt Range Formation is an extensive evaporite sequence in northern Pakistan that has acted as the primary detachment accommodating Himalayan orogenic deformation from the north. This rheologically weak formation forms a mylonite in the Khewra Mine, where it accommodates approximately 40 km displacement and is comprised of intercalated halite and potash salts and gypsiferous marls. Polyhalite [K2Ca2Mg(SO4)4⚫2H2O] grains taken from potash marl and crystalline halite samples are used as geochronometers to date the formation and identify the closure temperature of the mineral polyha

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16

Singer, Brad S., Robert P. Ackert,, and Hervé Guillou. "40Ar/39Ar and K-Ar chronology of Pleistocene glaciations in Patagonia." Geological Society of America Bulletin 116, no. 3 (2004): 434. http://dx.doi.org/10.1130/b25177.1.

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17

Wang, Fei, Ri-Xiang Zhu, Lie-Kun Yang, Huai-Yu He, and Ching-Hua Lo. "40Ar/39Ar analyses on Quaternary K–Ar standard BB-24: Evaluations." International Journal of Mass Spectrometry 270, no. 1-2 (2008): 16–22. http://dx.doi.org/10.1016/j.ijms.2007.11.002.

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18

Holm, Paul Martin. "Radiometric age determinations in the Kærven area, Kangerdlugssuaq, Bast Greenland Tertiary igneous Province: 40Ar/39 Ar, Kl Ar and Rb/Sr isotopic results." Bulletin of the Geological Society of Denmark 38 (February 18, 1991): 183–201. http://dx.doi.org/10.37570/bgsd-1990-38-18.

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The Kærven syenite complex was emplaced as part of the magmatic activity related to continental rifling in the Paleogene. Radiometric age determinations have been carried out on samples from selected parts of the complex, which consists of more !han 10 significant units. Five amphiboles and two alkali feldspar have been analysed by the 40Arl'9Ar method with stepwise heating, five amphiboles and one biotite K/Ar analyses are presented together with Rb/Sr isotope analysis of 6 amphiboles, 2 biotites, 3 alkali feldspars and 32 whole rocks. The results reveal that a Iate, probably 36 Ma, thermal e

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19

Uysal, I. Tonguç, Claudio Delle Piane, Andrew James Todd, and Horst Zwingmann. "Precambrian faulting episodes and insights into the tectonothermal history of north Australia: microstructural evidence and K–Ar, <sup>40</sup>Ar–<sup>39</sup>Ar, and Rb–Sr dating of syntectonic illite from the intracratonic Millungera Basin." Solid Earth 11, no. 5 (2020): 1653–79. http://dx.doi.org/10.5194/se-11-1653-2020.

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Abstract. Australian terranes concealed beneath Mesozoic cover record complex Precambrian tectonic histories involving a successive development of several Proterozoic to Palaeozoic orogenic systems. This study presents an integrated approach combining K–Ar, 40Ar–39Ar, and Rb–Sr geochronologies of Precambrian authigenic illites from the recently discovered Millungera Basin in north-central Australia. Brittle deformation and repeated fault activity are evident from the sampled cores and their microstructures, probably associated with the large-scale faults inferred from interpretations of seismi

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20

Balogh, Kadosa, and Imre Kádár. "Changes in the structure and formal K-Ar age of soil minerals in response to mineral fertilization." Agrokémia és Talajtan 62, no. 1 (2013): 81–98. http://dx.doi.org/10.1556/agrokem.62.2013.1.6.

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Ismeretes, hogy trágyázás hatására a talaj agyagásványai megváltoztatják szerkezetüket. Továbbá az is, hogy az Alföld fiatal üledékein mérhető formális K-Ar „korok” legtöbbször mezozoosak. Azaz lényegében megőrizték képződésük korát, mely a lepusztulás, elszállítódás és lerakódás folyamán csak nagyon keveset változhatott. Következésképpen a talajműveléssel járó ásványátalakulás megváltoztatja a formális K-Ar korokat is. Ennek a valószínűsíthető effektusnak a kimutatására tettünk kísérletet annak reményében, hogy a K-Ar módszer alkalmassá tehető azoknak az elváltozásoknak az integrális mérésére

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21

Guan, Yao, Yingzhi Ren, Xiaoming Sun, Zhenglian Xiao, and Zhengxing Guo. "Helium and Argon Isotopes in the Fe-Mn Polymetallic Crusts and Nodules from the South China Sea: Constraints on Their Genetic Sources and Origins." Minerals 8, no. 10 (2018): 471. http://dx.doi.org/10.3390/min8100471.

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In this study, the He and Ar isotope compositions were measured for the Fe-Mn polymetallic crusts and nodules from the South China Sea (SCS), using the high temperature bulk melting method and noble gases isotope mass spectrometry. The He and Ar of the SCS crusts/nodules exist mainly in the Fe-Mn mineral crystal lattice and terrigenous clastic mineral particles. The results show that the 3He concentrations and R/RA values of the SCS crusts are generally higher than those of the SCS nodules, while 4He and 40Ar concentrations of the SCS crusts are lower than those of the SCS nodules. Comparison

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22

Guillou, Herve. "Combined K-Ar and 40Ar/39Ar dating of the top Jaramillo boundary." Quaternary International 279-280 (November 2012): 180–81. http://dx.doi.org/10.1016/j.quaint.2012.08.277.

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23

McDougall, Ian, and Peter Wellman. "Calibration of GA1550 biotite standard for K/Ar and 40Ar/39Ar dating." Chemical Geology 280, no. 1-2 (2011): 19–25. http://dx.doi.org/10.1016/j.chemgeo.2010.10.001.

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24

Hart, Craig JR, and Mike Villeneuve. "Geochronology of Neogene alkaline volcanic rocks (Miles Canyon basalt), southern Yukon Territory, Canada: the relative effectiveness of laser 40Ar/39Ar and K-Ar geochronology." Canadian Journal of Earth Sciences 36, no. 9 (1999): 1495–507. http://dx.doi.org/10.1139/e99-049.

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Miles Canyon basalt is an informal term used to describe numerous exposures of young alkaline olivine basalt flows in southern Yukon. The volcanic rocks are part of the Northern Cordilleran volcanic province. K-Ar and Ar-Ar whole-rock dates indicate that the Miles Canyon succession of flows at the Whitehorse Rapids are clearly Late Miocene in age (ca. 8.4 Ma). The largest exposure of the Miles Canyon basalt occurs at the Alligator Lake volcanic complex where two nearly concordant Pliocene Ar-Ar dates indicate eruption at ca. 3.2 Ma. K-Ar analyses from other sites yield dates of 2.4 and 7.1 Ma

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25

Cogliati, Simone, Sarah C. Sherlock, Alison M. Halton, et al. "Expanding the toolbox for dating basaltic lava sequences: 40Ar–39Ar dating of silicic volcanic glass from interbeds." Journal of the Geological Society 178, no. 1 (2020): jgs2019–207. http://dx.doi.org/10.1144/jgs2019-207.

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40Ar–39Ar dating of glass shards from silicic tuffs of the Ellensburg Formation (NW, USA) interbedding basaltic lavas yielded accurate, precise, reproducible plateau and isochron ages that are within error at the 2σ level. The age-spectra have flat plateaus and the inverse isochrons have atmospheric 40Ar/36Ar at the 2σ level. Ages of 12.00 ± 0.24, 11.37 ± 0.15, 10.67 ± 0.21 and 10.70 ± 0.18 Ma are consistent with the stratigraphy of four of the dated layers; the age of 10.77 ± 0.18 Ma for a fifth layer is at odds with the stratigraphy. This discrepancy arises due to the effect of glass alterat

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Clauer, Norbert. "The K-Ar and 40Ar/39Ar methods revisited for dating fine-grained K-bearing clay minerals." Chemical Geology 354 (September 2013): 163–85. http://dx.doi.org/10.1016/j.chemgeo.2013.05.030.

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Clauer, N., J. Środoń, J. Francu, and V. Šucha. "K-Ar dating of illite fundamental particles separated from illite-smectite." Clay Minerals 32, no. 2 (1997): 181–96. http://dx.doi.org/10.1180/claymin.1997.032.2.02.

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AbstractFundamental particles of illite-smectite from bentonites were separated into classes by high-speed centrifugation after infinite osmotic swelling of mixed-layer crystals, achieved by Na-exchange and dispersion in distilled water. In samples free of detrital contamination, the thinnest fundamental particles yield older K-Ar ages than the thicker fundamental particles. This implies that they do not preferentially lose radiogenic 40Ar due to size, and that the illitization process is a crystal growth mechanism (not nucleation plus growth). As a result, any K-Ar age of fundamental illite p

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28

Dunlap, W. James, Christian Teyssier, Ian McDougall, and Suzanne Baldwin. "Ages of deformation from K/Ar and 40Ar/39Ar dating of white micas." Geology 19, no. 12 (1991): 1213. http://dx.doi.org/10.1130/0091-7613(1991)019<1213:aodfka>2.3.co;2.

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Gilbert, Lisa A., and K. A. Foland. "The Mont Saint Hilaire plutonic complex: occurrence of excess 40Ar and short intrusion history." Canadian Journal of Earth Sciences 23, no. 7 (1986): 948–58. http://dx.doi.org/10.1139/e86-096.

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Mont Saint Hilaire is an approximately 10 km2 alkaline plutonic complex in the Monteregian petrographic province of Quebec. The complex consists of an older, western half of alkali gabbros and an eastern portion of nepheline syenites and magmatic breccias. The intrusives were emplaced at depths of no more than a few kilometres into Paleozoic sedimentary rocks through the underlying Grenville basement. 40Ar/39Ar analyses of amphibole yield complex age spectra in which the apparent ages decrease with increasing heating temperature. Conventional K–Ar analyses of amphibole, pyroxene, and feldspar

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Franz, Gerhard, Masafumi Sudo, and Vladimir Khomenko. "<sup>40</sup>Ar/<sup>39</sup>Ar dating of a hydrothermal pegmatitic buddingtonite–muscovite assemblage from Volyn, Ukraine." European Journal of Mineralogy 34, no. 1 (2022): 7–18. http://dx.doi.org/10.5194/ejm-34-7-2022.

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Abstract. We determined 40Ar/39Ar ages of buddingtonite, occurring together with muscovite, with the laser-ablation method. This is the first attempt to date the NH4-feldspar buddingtonite, which is typical for sedimentary–diagenetic environments of sediments, rich in organic matter, or in hydrothermal environments, associated with volcanic geyser systems. The sample is a hydrothermal breccia, coming from the Paleoproterozoic pegmatite field of the Korosten Plutonic Complex, Volyn, Ukraine. A detailed characterization by optical methods, electron microprobe analyses, backscattered electron ima

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Isava, V., M. Grove, J. B. Mahoney, and J. W. Haggart. "Testing local and extraregional sediment sources for the Late Cretaceous northern Nanaimo basin, British Columbia, using 40Ar/39Ar detrital K-feldspar thermochronology." Geosphere 17, no. 6 (2021): 2234–61. http://dx.doi.org/10.1130/ges02395.1.

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Abstract Detrital K-feldspar 40Ar/39Ar thermochronology was conducted on clastic sedimentary rock samples collected from northern exposures of the Upper Cretaceous Nanaimo Group on Vancouver Island and adjacent Gulf Islands of British Columbia to constrain the denudation history of the local Coast Mountains batholith source region and determine the origin of extraregional sediment supplied to the basin. Strata of the northern Nanaimo Group deposited between 86 and 83 Ma (Comox and Extension formations) exhibit a 130–85 Ma age distribution of detrital K-feldspar 40Ar/39Ar ages that lack age max

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Kaufman, Darrell S., Robert C. Walter, Julie Brigham-Grette, and David M. Hopkins. "Middle Pleistocene age of the Nome River glaciation, northwestern Alaska." Quaternary Research 36, no. 3 (1991): 277–93. http://dx.doi.org/10.1016/0033-5894(91)90003-n.

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AbstractDuring the middle Pleistocene Nome River glaciation of northwestern Alaska, glaciers covered an area an order of magnitude more extensive than during any subsequent glacial intervals. The age of the Nome River glaciation is constrained by laser-fusion 40Ar/39Ar analyses of basaltic lava that overlies Nome River drift at Minnie Creek, central Seward Peninsula, that average 470,000 ± 190,000 yr (±1σ). Milligram-size subsamples of the lava were dated to identify and eliminate extraneous 40Ar enrichments that rendered the mean of conventional K-Ar dates on larger bulk samples of the same f

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di Brozolo, Filippo Radicati, Pio Di Girolamo, Bruno Turi, and Massimo Oddone. "40Ar-39Ar and K-Ar dating of K-rich rocks from the Roccamonfina Volcano, Roman comagmatic Region, Italy." Geochimica et Cosmochimica Acta 52, no. 6 (1988): 1435–41. http://dx.doi.org/10.1016/0016-7037(88)90213-x.

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Glasmacher, Ulrich A., Alain Tremblay, and Norbert Clauer. "K-Ar dating constraints on the tectonothermal evolution of the external Humber zone, southern Quebec Appalachians." Canadian Journal of Earth Sciences 40, no. 2 (2003): 285–300. http://dx.doi.org/10.1139/e02-105.

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In the external Humber zone, the emplacement episodes of allochthonous nappes and related low-grade metamorphism are mainly based on paleontological ages from the St. Lawrence Lowlands. In fact, Late Ordovician flysches are affected by thrusting, and it is not clear if the nappe imbrication is the result of the Taconian or the Acadian deformation. Along the Chaudière River transect, fourteen shales and phyllites of Cambrian to Ordovician age were sampled for determination of the KAr values of their < 2 µm-size fractions. To interpret the KAr data, mineral composition and clay mineral crys

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Strutinski, Carol, Adrian Puște, and Rodica Stan. "The metamorphic basement of Romanian Carpathians: a discussion of K-Ar and 40Ar/39Ar ages." Studia Universitatis Babes-Bolyai, Geologia 51, no. 1-2 (2006): 15–21. http://dx.doi.org/10.5038/1937-8602.51.1.2.

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Radhakrishna, T., H. Maluski, J. G. Mitchell, and M. Joseph. "40Ar/39Ar and K/Ar geochronology of the dykes from the south Indian granulite terrain." Tectonophysics 304, no. 1-2 (1999): 109–29. http://dx.doi.org/10.1016/s0040-1951(98)00288-1.

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Stuart, F. M. "The exhumation history of orogenic belts from 40Ar/39Ar ages of detrital micas." Mineralogical Magazine 66, no. 1 (2002): 121–35. http://dx.doi.org/10.1180/0026461026610017.

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AbstractThe exhumation history of mountain belts can be derived from radiometric dating of detrital mineral grains in proximal and distal post- and synorogenic sediments. The application of single-crystal dating techniques avoids the averaging effect that characterizes multi-grain and whole-rock techniques and allows the identification of populations of grains with distinct thermal histories. Of the major single crystal dating methods available, 40Ar/39Ar dating of detrital K-bearing minerals, in particular white mica, is perhaps the most versatile and widely applied technique. For a closure t

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Smith, P. E., D. York, R. M. Easton, Ö. Özdemir, and P. W. Layer. "A laser 40Ar–39Ar study of minerals across the Grenville Front: investigation of reproducible excess Ar patterns." Canadian Journal of Earth Sciences 31, no. 5 (1994): 808–17. http://dx.doi.org/10.1139/e94-074.

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40Ar–39Ar ages have been determined on single grains of biotite and amphibole from rocks on a 40 km traverse across the Grenville Front (GF) in the Temagami area, Ontario. Minerals in the vicinity of the GF contain excess Ar in varying amounts characterized by both anomalously high integrated and plateau ages. The excess Ar in biotite varies with distance from the GF, such that the overall age distribution along the GF forms an asymmetric wave-like pattern (an argonami) with two age maxima, one on either side of the GF. The integrated age maxima are 2.34 Ga for biotite and 3.21 Ga for amphibol

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39

Webster, Ewan R., Douglas A. Archibald, David R. M. Pattison, Jessica A. Pickett, and Joel C. Jansen. "Tectonic domains and exhumation history of the Omineca Belt in southeastern British Columbia from 40Ar/39Ar thermochronology." Canadian Journal of Earth Sciences 57, no. 8 (2020): 918–46. http://dx.doi.org/10.1139/cjes-2019-0131.

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A large geochronological data set comprising 40Ar/39Ar and K–Ar (hornblende, muscovite, biotite, and K-feldspar), Rb–Sr (muscovite), fission track (zircon and apatite) and U–Pb (zircon and monazite) dates has been compiled for the southern Kootenay Arc and western Purcell anticlinorium in the Omineca Belt of the Canadian Cordillera in southeastern British Columbia. New 40Ar/39Ar data for hornblende, muscovite, biotite, and alkali feldspar are presented and combined with data from other studies. We integrate these data with recent advances in the geology of the region to define three partially

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Rogers, Raymond R., Carl C. Swisher III, and John R. Horner. "40Ar/39Ar age and correlation of the nonmarine Two Medicine Formation (Upper Cretaceous), northwestern Montana, U.S.A." Canadian Journal of Earth Sciences 30, no. 5 (1993): 1066–75. http://dx.doi.org/10.1139/e93-090.

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The age of the nonmarine Two Medicine Formation of northwestern Montana is currently based upon correlations with K–Ar-dated Western Interior ammonite zones. 40Ar/39Ar dating of biotite and plagioclase separated from four bentonites and one crystal-rich tuff permits for the first time direct determination of the age of Two Medicine strata. Biotite and plagioclase from a bentonite 10 m below the top of the Two Medicine Formation yield concordant 40Ar/39Ar ages of 74 Ma, while biotite and plagioclase from two bentonites and a crystal-rich tuff from approximately 100 m above the base of the forma

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Kontak, D. J., and R. F. Cormier. "Geochronological evidence for multiple tectono-thermal overprinting events in the East Kemptville muscovite–topaz leucogranite, Yarmouth County, Nova Scotia, Canada." Canadian Journal of Earth Sciences 28, no. 2 (1991): 209–24. http://dx.doi.org/10.1139/e91-020.

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The East Kemptville muscovite–topaz leucogranite, located in Yarmouth County, Nova Scotia, Canada, is host rock to the only producing primary tin deposit in North America (56 Mt, 0.165% Sn). Previous geochronological studies include (i) Rb–Sr whole-rock analyses of the quartz–topaz greisens, which indicated a date of 337 ± 5 Ma, and (ii) 40Ar/39Ar analyses of greisen muscovite, which indicated apparent plateau dates of ca. 300 Ma. However, the pervasive development of deformational fabrics at East Kemptville suggests that both the Rb–Sr whole-rock and 40Ar/39Ar muscovite ages are at best minim

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SAITO, Kazuo, Soichi OSOZAWA, and Ken-ichi ISHIKAWA. "40Ar-39Ar and K-Ar ages of the igneous blocks in the Setogawa and Mikasa Groups." JOURNAL OF MINERALOGY, PETROLOGY AND ECONOMIC GEOLOGY 87, no. 7 (1992): 255–64. http://dx.doi.org/10.2465/ganko.87.255.

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Uto, Kozo, and Osamu Ishizuka. "The current state and the future of K-Ar and 40Ar/39Ar dating of volcanic rocks." Journal of the Japanese Association for Petroleum Technology 64, no. 1 (1999): 63–71. http://dx.doi.org/10.3720/japt.64.63.

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TAKAGI, Tetsuichi, and Atsushi KAMEI. "40Ar-39Ar and K-Ar geochronology for plutonic rocks in the central Abukuma Plateau, northeastern Japan." Journal of Mineralogical and Petrological Sciences 103, no. 5 (2008): 307–17. http://dx.doi.org/10.2465/jmps.071120.

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Reuter, A., and R. D. Dallmeyer. "K-Ar and 40Ar/39Ar dating of cleavage formed during very low-grade metamorphism: a review." Geological Society, London, Special Publications 43, no. 1 (1989): 161–71. http://dx.doi.org/10.1144/gsl.sp.1989.043.01.10.

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Guillou, Hervé, Sébastien Nomade, Juan Carlos Carracedo, et al. "Effectiveness of combined unspiked K–Ar and 40Ar/39Ar dating methods in the 14C age range." Quaternary Geochronology 6, no. 6 (2011): 530–38. http://dx.doi.org/10.1016/j.quageo.2011.03.011.

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Rouchon, Virgile, Jean-Claude Lefèvre, Xavier Quidelleur, Gilles Guérin, and Pierre-Yves Gillot. "Nonspiked 40Ar and 36Ar quantification using a quadrupole mass spectrometer: A potential for K–Ar geochronology." International Journal of Mass Spectrometry 270, no. 1-2 (2008): 52–61. http://dx.doi.org/10.1016/j.ijms.2007.11.009.

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Kligfield, Roy, Johannes Hunziker, R. D. Dallmeyer, and Steven Schamel. "Dating of deformation phases using K-Ar and 40Ar/39Ar techniques: results from the northern apennines." Journal of Structural Geology 8, no. 7 (1986): 781–98. http://dx.doi.org/10.1016/0191-8141(86)90025-8.

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Berry, R. F., and Ian McDougall. "Interpretation of 40Ar/39Ar and K/Ar dating evidence from the Aileu Formation, East Timor, Indonesia." Chemical Geology: Isotope Geoscience section 59 (January 1986): 43–58. http://dx.doi.org/10.1016/0168-9622(86)90056-4.

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Bai, Xiu-Juan, Rong-Guo Hu, Ying-De Jiang, Xiao Liu, Bin Tang, and Hua-Ning Qiu. "Refined insight into 40Ar/39Ar progressive crushing technique from K–Cl–Ar correlations in fluid inclusions." Chemical Geology 515 (June 2019): 37–49. http://dx.doi.org/10.1016/j.chemgeo.2019.03.037.

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