Determination of Experimental Parameters during Measurement of 40Ar Content in K-Ar Dilution Method
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摘要:
K-Ar稀释法中40Ar含量的测量需经过样品熔融释气、气体纯化富集、质谱测量等步骤，随着新型设计的双真空加热炉和气体纯化系统的应用，实验流程逐渐由人工操作向自动化程序控制转变。为建立完整的K-Ar稀释法中40Ar含量测量方法，相关参数还需多次条件实验得以确定。本文以空气标准为对象，通过活性炭冷指释放和吸附空气标准，确定活性炭冷指最佳加热释气时间为500s，液氮条件下最佳吸附时间为200s，在此条件下，加热炉熔融产生的40Ar气体可以完全转移和释放，避免发生同位素分馏；根据不同熔融温度下相同质量样品释放40Ar强度，确定黏土矿物、黑云母、白云母等类型样品加热炉熔融温度设置为1400℃，角闪石熔融温度为1500℃，基性岩熔融温度为1550℃，钾长石熔融温度为1600℃，不同类型样品采用对应熔融温度，保证样品完全熔融释气。对10组SK01透长石标准进行测量，得到K-Ar年龄结果与40Ar-39Ar定年标准值相一致，结果表明所得条件参数可满足K-Ar稀释法中40Ar含量的准确测量。
Abstract:BACKGROUND The measurement of 40Ar content in K-Ar dilution method includes sample melting and releasing gas, gas purification and enrichment, mass spectrometry measurement. With the application of a newly designed double vacuum furnace and gas purification system, the experiment process gradually changes from manual operation to automatic program control, but the parameters are unclear.
OBJECTIVES To determine the parameters by conditional experiments and establish a complete measurement method of 40Ar content in K-Ar dilution method.
METHODS Parameters were determined by releasing and absorbing an air standard in activated carbon cold finger with different times, melting different types of samples with different temperatures of the double vacuum furnace. The method reliability was verified by K-Ar dating for SK01 sanidine standard.
RESULTS The optimal heating release time for activated carbon cold finger was 500s, and the adsorption time was 200s. Using these conditions, the gas produced by the melting in the furnace can be completely transferred and released to avoid isotope fractionation. The corresponding melting temperature was used for different types of samples to ensure that the samples were completely melted and outgassed, the melting temperature of the furnace for clay minerals, biotite, and muscovite should be set to 1400℃, and 1500℃ for amphibole, 1550℃ for basic rock, and 1600℃for potassium feldspar. The K-Ar dating of 10 sets of SK01 sanidine standards showed that the results were consistent with 40Ar-39Ar dating ages.
CONCLUSIONS The obtained condition parameters meet the accurate measurement of 40Ar content using the K-Ar dilution method.
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Key words:
- K-Ar dilution dating /
- 40Ar content /
- heating release time /
- absorption time /
- melting temperature
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表 1 500s释气时间下不同倍数空气标准Ar同位素强度和比值测量结果
Table 1. Measurement results of argon signal intensity and isotope ratio for multiple air standard with release time of 500 seconds
气量倍数 40Ar强度
(fA)38Ar强度
(fA)36Ar强度
(fA)40Ar/36Ar ±1σ 38Ar/36Ar ±1σ 1倍 56592.78 36.94 182.89 309.44 0.57 0.2020 0.0073 2倍 112399.77 73.53 362.33 310.22 0.49 0.2029 0.0063 3倍 169247.80 110.93 545.72 310.14 0.56 0.2033 0.0064 4倍 225219.87 147.59 726.73 309.91 0.57 0.2031 0.0065 5倍 280371.37 183.89 905.77 309.54 0.59 0.2030 0.0067 6倍 338437.87 222.61 1093.53 309.49 0.69 0.2036 0.0068 7倍 394567.74 259.81 1275.90 309.25 0.72 0.2036 0.0070 
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表 2 200s吸附时间下不同倍数空气标准Ar同位素强度和比值测量结果
Table 2. Measurement results of argon signal intensity and isotope ratio for multiple air standard with absorption time of 200 seconds
气量倍数 40Ar强度
(fA)38Ar强度
(fA)36Ar强度
(fA)40Ar/36Ar ±1σ 38Ar/36Ar ±1σ 1倍 55178.41 36.18 177.65 310.60 0.47 0.2037 0.0058 2倍 110750.53 72.41 356.94 310.28 0.58 0.2029 0.0061 3倍 168592.95 110.23 543.39 310.26 0.49 0.2029 0.0062 4倍 223359.57 146.32 720.41 310.04 0.56 0.2031 0.0063 5倍 279351.85 183.42 901.74 309.79 0.65 0.2034 0.0065 6倍 334247.19 220.98 1077.47 310.21 0.55 0.2051 0.0062 7倍 390138.68 255.91 1256.78 310.43 0.49 0.2036 0.0059
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表 3 SK01透长石标准K-Ar年龄测量结果
Table 3. K-Ar dating measurement results of SK01 sanidine standard
序号 样品质量
(mg)K含量
(%)40Ar/38Ar 38Ar/36Ar 40Ar*
(mol)40Ar*/40Ar
(%)40Ar*/40K 年龄
(Ma)±1σ
(Ma)1 2.660 8.54 1.4789 1161.5321 3.98×10-10 82.01 0.001615 27.59 0.50 2 3.754 8.54 1.9712 1286.0419 4.03×10-10 87.75 0.001632 27.88 0.47 3 4.697 8.54 2.4149 1180.5998 4.00×10-10 89.15 0.001624 27.73 0.50 4 5.076 8.54 2.5758 1046.1088 3.93×10-10 88.58 0.001592 27.20 0.52 5 5.401 8.54 2.7420 1037.8445 3.96×10-10 89.19 0.001604 27.40 0.49 6 5.916 8.54 2.9846 1049.7771 3.97×10-10 90.18 0.001612 27.53 0.50 7 5.957 8.54 3.0537 953.3207 4.01×10-10 89.47 0.001625 27.75 0.55 8 7.042 8.54 3.5488 962.7716 4.01×10-10 91.03 0.001625 27.75 0.53 9 8.072 8.54 4.0389 781.7466 3.95×10-10 90.36 0.001602 27.36 0.55 10 8.176 8.54 4.1622 746.9079 4.01×10-10 90.22 0.001627 27.79 0.47
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[1] 刘建强, 陈立辉, 钟源, 等. 小兴安岭逊克地区小兴安岭逊克地区第四纪高镁安山岩的岩石学、K-Ar年代学及火山地质特征[J]. 岩石学报, 2017, 33(1): 31-40.
Liu J Q, Chen L H, Zhong Y, et al. Petrological, K-Ar chronological and volcanic geological characteristics of Quaternary Xunke high-Mg# andesites from the Lesser Khingan Range[J]. Acta Petrologica Sinica, 2017, 33(1): 31-40.
[2] 向安平, 佘宏全, 陈毓川, 等. 内蒙古红花尔基钨钼矿云英岩化白云母Ar-Ar定年及其地质意义[J]. 岩矿测试, 2016, 35(1): 108-116. http://www.ykcs.ac.cn/article/doi/10.15898/j.cnki.11-2131/td.2016.01.017
Xiang A P, She H Q, Chen Y C, et al. Ar-Ar age of muscovite from the greisenization alteration zones of the Honghuaerji tungsten polymetallic deposit, Inner Mongolia, and its geological significance[J]. Rock and Mineral Analysis, 2016, 35(1): 108-116. http://www.ykcs.ac.cn/article/doi/10.15898/j.cnki.11-2131/td.2016.01.017
[3] Bui H B, Ngo X T, Yungoo S, et al. K-Ar dating of fault gouges from the Red River fault zone of Vietnam[J]. Acta Geologica Sinica (English Edition), 2016, 90(5): 1653-1663. doi: 10.1111/1755-6724.12808
[4] 毕丽莎, 梁晓, 王根厚, 等. 滇西澜沧江构造带中-南段澜沧群变质变形期次及Ar-Ar年代学约束[J]. 地球科学, 2018, 43(9): 3252-3266.
Bi L S, Liang X, Wang G H, et al. Metamorphism-deformation phases and Ar-Ar chronological constraints of the Lancang group in the middle and southern sections of the Lancangjiang tectonic belt, western Yunnan[J]. Earth Science, 2018, 43(9): 3252-3266.
[5] 张斌, 陈文, 孙敬博, 等. 南天山欧西达坂岩体热演化历史与隆升过程分析——来自Ar-Ar和(U-Th)/He热年代学的证据[J]. 中国科学: 地球科学, 2016, 46(3): 392-405.
Zhang B, Chen W, Sun J B, et al. The thermal history and uplift process of the Ouxidaban pluton in the South Tianshan Orogen: Evidence from Ar-Ar and (U-Th)/He[J]. Science China: Earth Sciences, 2016, 59(3): 349-361.
[6] Paul R R, Carl C S, Alan L D, et al. Intercalibration of standards, absolute ages and uncertainties in 40Ar/39Ar dating[J]. Chemical Geology, 1998, 145: 117-152. doi: 10.1016/S0009-2541(97)00159-9
[7] Terry L S, Ian M. Characterization and calibration of 40Ar/39Ar dating standards[J]. Chemical Geology, 2003, 198: 189-211. doi: 10.1016/S0009-2541(03)00005-6
[8] 桑海清, 王非, 贺怀宇, 等. K-Ar法地质年龄国家一级标准物质ZBH-25黑云母的研制[J]. 岩石学报, 2006, 22(12): 3059-3078.
Sang H Q, Wang F, He H Y et al. Intercalibration of ZBH-25 biotite reference material unitized for K-Ar and 40Ar-39Ar age determination[J]. Acta Petrologica Sinica, 2006, 22(12): 3059-3078.
[9] 张有瑜, 刘可禹, 罗修泉. 自生伊利石年代学研究——理论、方法与实践[M]. 北京: 科学出版社, 2016: 82-102.
Zhang Y Y, Liu K Y, Luo X Q. Geochronology of authigenic illite: Principle, methods and application[M]. Beijing: Science Press, 2016: 82-102.
[10] Norbert C, Horst Z, Nicole L, et al. Comparative 40Ar/39Ar and K-Ar dating of illite-type clay minerals: A tentative explanation for age identities and differences[J]. Earth-Science Reviews, 2012, 115: 76-96.
[11] Foland K A, Hubacher F A, Arehart G B. 40Ar/39Ar dating of very fine-grained samples an encapsulated-vial procedure to overcome the problem of 39Ar recoil loss[J]. Chemical Geology, 1992, 102(1-4): 269-276. doi: 10.1016/0009-2541(92)90161-W
[12] McDougall I, Harrison T M. Geochronology and thermo-chronology by the 40Ar/39Ar method (second edition)[M]. New York: Oxford University Press, 1999: 269.
[13] Wang F, Shi W B, Guillou H, et al. A new approach of unspiked K-Ar dating using laser fusion on microsamples[J]. Acta Geologica Sinica (English Edition), 2019, 93(2): 416.
[14] Peter W R, Richard W C, Paul R R, et al. Geochronology and thermochronology[M]. New Jersey: John Wiley & Sons, 2018: 233-234.
[15] 张万峰, 邱华宁, 郑德文, 等. 40Ar/39Ar定年自动去气系统的研制及其性能[J]. 地球化学, 2020, 49(5): 509-515.
Zhang W F, Qiu H N, Zhen D W, et al. An automatic degassing system for 40Ar/39Ar dating[J]. Geochimica, 2020, 49(5): 509-515.
[16] 邱华宁, 白秀娟, 刘文贵, 等. 自动化40Ar/39Ar定年设备研制[J]. 地球化学, 2015, 44(5): 477-484. doi: 10.3969/j.issn.0379-1726.2015.05.007
Qiu H N, Bai X J, Liu W G, et al. Automatic 40Ar/39Ar dating technique using multicollector ArgusⅥ MS with home-made apparatus[J]. Geochimica, 2015, 44(5): 477-484. doi: 10.3969/j.issn.0379-1726.2015.05.007
[17] 李军杰, 刘汉彬, 张佳, 等. 应用Argus多接收稀有气体质谱仪准确测量空气的Ar同位素组成[J]. 岩矿测试, 2016, 35(3): 229-235. http://www.ykcs.ac.cn/article/doi/10.15898/j.cnki.11-2131/td.2016.03.003
Li J J, Liu H B, Zhang J, et al. The accurate measurement of argon isotopes composition in air by Argus multi-collector noble gas mass spectrometer[J]. Rock and Mineral Analysis, 2016, 35(3): 229-235. http://www.ykcs.ac.cn/article/doi/10.15898/j.cnki.11-2131/td.2016.03.003
[18] Kim J, Jeon S. 40Ar/39Ar age determination using ArgusⅥ multi-collector noble gas mass spectrometer: Performance and its application to geosciences[J]. Journal of Analytical Science and Technology, 2015, 6(1): 4. doi: 10.1186/s40543-015-0049-2
[19] Jicha B D, Singerb S, Sobol P. Re-evaluation of the ages of 40Ar/39Ar sandine standards and supereruptions in the western U.S. Using a Noblesse multi-collector mass spectrometer[J]. Chemical Geology, 2016, 431: 54-66. doi: 10.1016/j.chemgeo.2016.03.024
[20] Harrison T M, Celerier J, Aikman A B, et al. Diffusion of 40Ar in muscovite[J]. Geochimica et Cosmochimica Acta, 2009, 73: 1039-1051. doi: 10.1016/j.gca.2008.09.038
[21] 邱华宁, 彭良. 40Ar-39Ar年代学与流体包裹体定年[M]. 合肥: 中国科学技术大学出版社, 1997: 206-218.
Qiu H N, Peng L. 40Ar-39Ar geochronology and fluid inclusion dating[M]. Hefei: China University of Science and Technology Press, 1997: 206-218.
[22] Sanderman H, Dickson W L. An ordovician, 40Ar/39Ar step-heating age for fabric age for fabric-forming hornblende in amphibolite, the Great Bend Complex, Central Newfoundland (NTS 2D/5)[J]. Geological Survey Report, 2019, 19(1): 85-96.
[23] 张佳, 刘汉彬, 李军杰, 等. 石英样品Ar-Ar定年测试过程中的相关问题及解决办法[J]. 铀矿地质, 2018, 34(3): 159-165. doi: 10.3969/j.issn.1000-0658.2018.03.005
Zhang J, Liu H B, Li J J, et al. Some problem and its solution in Ar-Ar dating measurement for quartz sample[J]. Uranium Geology, 2018, 34(3): 159-165. doi: 10.3969/j.issn.1000-0658.2018.03.005
[24] 李军杰. 自生伊利石中40K-40Ar和40Ar-39Ar定年方法的建立及其在苏里格气田成藏期的应用[D]. 北京: 中国科学院大学, 2017: 36-39.
Li J J. The establishment of 40K-40Ar and 40Ar-39Ar dating method of authigenic illite and the application in the determination of the pool-forming periods of sulige gas field[D]. Beijing: Beijing University of Chinese Academy of Sciences, 2017: 36-39.
[25] 刘汉彬, 李军杰, 张佳, 等. ArgusⅥ多接收稀有气体质谱仪在40Ar/39Ar高精度定年中的应用[J]. 质谱学报, 2018, 39(4): 407-415.
Liu H B, Li J J, Zhang J, et al. Application of ArgusⅥ multi-collector rare gas mass spectrometer in high-precision 40Ar/39Ar dating[J]. Journal of Chinese Mass Spectrometry Society, 2018, 39(4): 407-415.
[26] Dempsey E L. Improvements in noble gas separation methodology: A nude cryogenic trap[J]. Geochemistry, Geophysics, Geosystems, 2001, 2.
[27] 邱华宁. 新一代Ar-Ar实验室建设与发展趋势: 以中国科学院广州地球化学研究所Ar-Ar实验室为例[J]. 地球化学, 2006, 35(2): 133-140.
Qiu H N. Construction and development of new Ar-Ar laboratories in China: Insight from GV-5400 Ar-Ar laboratory in Guangzhou Institute of Geochemistry, Chinese Academy of Sciences[J]. Geochimica, 2006, 35(2): 133-140.
[28] 刘羽, 牛俐珺, 李永国, 等. 不同工况下活性炭吸附性惰性气体性能的初步研究[J]. 辐射防护, 2017, 37(4): 298-302.
Liu Y, Niu L J, Li Y G, et al. Study on adsorption performance of activated carbon for radioactive inert gases under different operating conditions[J]. Radiation Protection, 2017, 37(4): 298-302.
[29] 冯旭, 肖德涛, 丘厚康, 等. 活性炭高压吸附氡气技术研究[J]. 原子能科学技术, 2016, 50(4): 763-768.
Feng X, Xiao D T, Qiu H K, et al. Research on high pressure adsorption of radon on active carbon[J]. Atomic Energy Science and Technology, 2016, 50(4): 763-768.
[30] 高晶晶, 刘玉琳. 钾长石K-Ar定年若干问题的讨论[J]. 高校地质学报, 2006, 12(3): 375-377. doi: 10.3969/j.issn.1006-7493.2006.03.009
Gao J J, Liu Y L. Discussion on K-Ar dating of K-feldspar[J]. Geological Journal of China Universities, 2006, 12(3): 375-377. doi: 10.3969/j.issn.1006-7493.2006.03.009
[31] 李洁, 陈文, 刘新宇, 等. 新生代透长石SK01作为39Ar-40Ar法定年标准物质的均匀性检验[J]. 岩矿测试, 2013, 32(2): 213-220. doi: 10.3969/j.issn.0254-5357.2013.02.005
Li J, Chen W, Liu X Y, et al. Homogeneity test of Cenozoic sanidine SK01 as a national standard reference material for 39Ar-40Ar dating[J]. Rock and Mineral Analysis, 2013, 32(2): 213-220. doi: 10.3969/j.issn.0254-5357.2013.02.005
[32] 李洁. 新生代39Ar-40Ar年龄标准物质透长石SK01的研制[D]. 北京: 中国地质大学(北京), 2013: 23-59.
Li J. Research & development of Cenozoic sanidine SK01 as a national standard reference material for 39Ar-40Ar dating[D]. Beijing: China University of Geosciences (Beijing), 2013: 23-59.
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