A test of the cosmogenic 3He production rate in the south‐west Pacific (39°S)
A test of the cosmogenic 3He production rate in the south‐west Pacific (39°S)
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西南太平洋（39°S）宇宙成因 3He 生产率的测试
DOI：
10.1002/jqs.2760
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发表时间：
2015
影响因子：
2.3
通讯作者：
Xun Li
中科院分区：
文献类型：
--
作者：
Shaun R. Eaves;G. Winckler;J. Schaefer;M. Vandergoes;B. Alloway;A. Mackintosh;D. Townsend;M. Ryan;Xun Li
使用原位宇宙成因核素计算表面暴露年龄，需要准确了解当地的产生率。在这里，我们报告了在西南太平洋地区校准宇宙成因3He产量的第一次尝试。我们给出了一个新的放射性碳年代学，它准确地测定了位于新西兰北岛中部(约830 m ASL；39°S)的Murimotu组的侵位时间，它发生在10.4-10.6 卡尔卡BP。从这次事件中暴露的大型安山岩块中分离出的辉石中的宇宙成因3He的测量结果表明，海平面上的高纬度产生率为120 ± 12个原子g−1 a−1(‘LM’标度)。这与最近的全球汇编是一致的，该汇编主要包括位于北半球的校准站点。因此，我们得出结论，全球编制的宇宙成因~3He产生率在西南太平洋是有效的。通过对新西兰石英中宇宙成因同位素10Be和14C的独立近端刻度，得到宇宙成因的3He/10Be和3He/14C的产额比分别为32.2 ± 3.2和10.6 ± 1.6。
Calculation of surface exposure ages, using in situ cosmogenic nuclides, requires accurate knowledge of local production rates. Here, we report the first attempt to calibrate cosmogenic 3He production in the south‐west Pacific region. We present a new radiocarbon chronology that precisely dates the emplacement of the Murimotu Formation, a large debris avalanche deposit in central North Island, New Zealand (ca. 830 m asl; 39°S), which occurred 10.4–10.6 cal ka BP. Measurements of cosmogenic 3He in pyroxene separated from large andesitic blocks exposed during this event yield a sea‐level high‐latitude production rate of 120 ± 12 atoms g−1 a−1 (‘Lm’ scaling). This is consistent with a recent global compilation, comprised predominantly of calibration sites located in the Northern Hemisphere. Thus, we conclude that the globally compiled cosmogenic 3He production rate is valid in the south‐west Pacific. Using independent, proximal calibrations of cosmogenic isotopes 10Be and 14C from quartz in New Zealand, we derive cosmogenic 3He/10Be and 3He/14C production ratios of 32.2 ± 3.2 and 10.6 ± 1.6, respectively.
影响因子：
2.7
作者：
Putnam, A. E.;Schaefer, J. M.;Kelley, S. E.
通讯作者：
Kelley, S. E.