• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 1
  • Tagged with
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Large 14C excursion in 5480 BC indicates an abnormal sun in the mid-Holocene

Miyake, Fusa, Jull, A. J. Timothy, Panyushkina, Irina P., Wacker, Lukas, Salzer, Matthew, Baisan, Christopher H., Lange, Todd, Cruz, Richard, Masuda, Kimiaki, Nakamura, Toshio 31 January 2017 (has links)
Radiocarbon content in tree-rings can be an excellent proxy of the past incoming cosmic ray intensities to the Earth. Although such past cosmic ray variations have been studied by measurements of 14C contents in tree rings with ≧10 year time resolution for the Holocene (1), there are few annual 14C data. There is a little understanding about annual 14C variations in the past with the exception of a few periods including the AD774-775 annual 14C excursion (2). Here, we report the result of 14C measurements using the bristlecone pine tree rings for the period from 5490 BC to 5411 BC with 1-2 year resolution, and a finding of an extraordinarily large 14C increase (20‰) from 5481 BC to 5471 BC (the 5480 BC event). The 14C increase rate of this event is much larger than that of the normal Grand Solar Minima. We propose the possible causes of this event are a special phase of grand solar minimum, or a combination of successive solar proton events and a normal grand solar minimum.

Page generated in 0.0672 seconds