• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Quaternary geochronology >Cosmogenic and nucleogenic Ne-21 in quartz in a 28-meter sandstone core from the McMurdo Dry Valleys, Antarctica
【24h】

Cosmogenic and nucleogenic Ne-21 in quartz in a 28-meter sandstone core from the McMurdo Dry Valleys, Antarctica

机译：来自McMurdo Dryalys的28米砂岩核心，南极洲的28米砂岩核心中的富含核原和核原性Ne-21

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

We measured concentrations of Ne isotopes in quartz in a 27.6-m sandstone core from a low-erosion-rate site at 2183 m elevation at Beacon Heights in the Antarctic Dry Valleys. Surface concentrations of cosmogenic Ne-21 indicate a surface exposure age of at least 4.1 Ma and an erosion rate no higher than ca. 14 cm Myr(-1) Ne-21 concentrations in the upper few centimeters of the core show evidence for secondary spallogenic neutron escape effects at the rock surface, which is predicted by first-principles models of cosmogenic-nuclide production but is not commonly observed in natural examples. We used a model for Ne-21 production by various mechanisms fit to the observations to distinguish cosmic-ray-produced Ne-21 from nucleogenic Ne-21 produced by decay of trace U and Th present in quartz, and also constrain rates of subsurface Ne-21 production by cosmic-ray muons. Core samples have a quartz (U-Th)/Ne closure age, reflecting cooling below approximately 95 degrees C, near 160 Ma, which is consistent with existing apatite fission-track data and the 183 Ma emplacement of nearby Ferrar dolerite intrusions. Constraints on Ne-21 production by muons derived from model fitting are consistent with a previously proposed value of 0.79 mb at 190 GeV for the cross-section for Ne-21 production by fast muon interactions, but indicate that Ne-21 production by negative muon capture is likely negligible.
机译：在南极干燥谷的信标高度下，在27.6米的砂岩核中，在27.6米的砂岩核中测量了27.6米的砂岩核心中的NE同位素的浓度。化学原性NE-21的表面浓度表明表面暴露年龄至少为4.1 mA，侵蚀率不高于CA. 14厘米MYR（-1）NE-21核心在核心的较高厘米中浓度显示在岩石表面上的次级椎间力中子逸出效应的证据，这是通过富集核素生产的第一原理模型来预测的，但不一定地观察到在自然的例子中。我们通过各种机制使用了对NE-21生产的模型，其适用于将宇宙射线产生的NE-21区分通过腐烂的核心NE-21，以石英中的痕量U和TH产生，并且还限制了地下NE的速率-21由宇宙射线μs制作。核心样本具有石英（U-TH）/ NE闭合年龄，反映低于约95摄氏度的冷却，靠近160 mA，这与现有的磷灰石裂变轨迹数据一致，并且在附近的铁雷犬入侵的183 mA施加183 mA施加。由模型配件的MUONS产生的NE-21产生的约束与先前提出的0.79 MB，190 GEV的先前提出的值，对于NE-21生产的横截面，通过快速的μS互动，但表明NE-21由负μ子产生捕获可能会忽略不计。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号