scholarly journals Large14C excursion in 5480 BC indicates an abnormal sun in the mid-Holocene

2017 ◽  
Vol 114 (5) ◽  
pp. 881-884 ◽  
Author(s):  
Fusa Miyake ◽  
A. J. Timothy Jull ◽  
Irina P. Panyushkina ◽  
Lukas Wacker ◽  
Matthew Salzer ◽  
...  
Keyword(s):  
Tree Rings ◽  
Time Resolution ◽  
Solar Minimum ◽  
Cosmic Ray ◽  
Solar Proton ◽  
The Past ◽  
Pine Tree ◽  
Unknown Phase ◽  
Increase Rate ◽  
Bristlecone Pine

Radiocarbon content in tree rings can be an excellent proxy of the past incoming cosmic ray intensities to Earth. Although such past cosmic ray variations have been studied by measurements of14C contents in tree rings with ≥10-y time resolution for the Holocene, there are few annual14C data. There is a little understanding about annual14C variations in the past, with the exception of a few periods including the AD 774−77514C excursion where annual measurements have been performed. Here, we report the result of14C measurements using the bristlecone pine tree rings for the period from 5490 BC to 5411 BC with 1- to 2-y resolution, and a finding of an extraordinarily large14C increase (20‰) from 5481 BC to 5471 BC (the 5480 BC event). The14C 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 an unknown phase of grand solar minimum, or a combination of successive solar proton events and a normal grand solar minimum.

scholarly journals Search for Annual 14C Excursions in the Past

Radiocarbon ◽  
2016 ◽  
Vol 59 (2) ◽  
pp. 315-320 ◽  
Author(s):  
Fusa Miyake ◽  
Kimiaki Masuda ◽  
Toshio Nakamura ◽  
Katsuhiko Kimura ◽  
Masataka Hakozaki ◽  
...  
Keyword(s):  
Cosmic Rays ◽  
Tree Ring ◽  
Cosmic Ray ◽  
Solar Proton ◽  
The Past ◽  
Continuous Measurements ◽  
Pine Tree ◽  
Short Timescale ◽  
Bristlecone Pine ◽  
Solar Proton Events

AbstractTwo radiocarbon excursions (AD 774–775 and AD 993–994) occurred due to an increase of incoming cosmic rays on a short timescale. The most plausible cause of these events is considered to be extreme solar proton events (SPE). It is possible that there are other annual 14C excursions in the past that have yet to be confirmed. In order to detect more of these events, we measured the 14C contents in bristlecone pine tree-ring samples during the periods when the rate of 14C increase in the IntCal data is large. We analyzed four periods every other year (2479–2455 BC, 4055–4031 BC, 4465–4441 BC, and 4689–4681 BC), and found no anomalous 14C excursions during these periods. This study confirms that it is important to do continuous measurements to find annual cosmic-ray events at other locations in the tree-ring record.

Altitudinal differences in ?13c of bristlecone pine tree rings

1992 ◽  
Vol 79 (4) ◽  
pp. 178-180 ◽  
Author(s):  
S. W. Leavitt ◽  
A. Long
Keyword(s):  
Tree Rings ◽  
Pine Tree ◽  
Bristlecone Pine

scholarly journals More Rapid 14C Excursions in the Tree-Ring Record: A Record of Different Kind of Solar Activity at About 800 BC?

Radiocarbon ◽  
2018 ◽  
Vol 60 (4) ◽  
pp. 1237-1248 ◽  
Author(s):  
A J Timothy Jull ◽  
Irina Panyushkina ◽  
Fusa Miyake ◽  
Kimiaki Masuda ◽  
Toshio Nakamura ◽  
...  
Keyword(s):  
Solar Minimum ◽  
Late Holocene ◽  
Solar Proton ◽  
Short Time Scale ◽  
Special Mode ◽  
Geomagnetic Data ◽  
Increase Rate ◽  
Different Types ◽  
Short Time ◽  
Hallstatt Period

ABSTRACTTwo radiocarbon (14C) excursions are caused by an increase of incoming cosmic rays on a short time scale found in the Late Holocene (AD 774–775 and AD 993–994), which are widely explained as due to extreme solar proton events (SPE). In addition, a larger event has also been reported at 5480 BC (Miyake et al. 2017a), which is attributed to a special mode of a grand solar minimum, as well as another at 660 BC (Park et al. 2017). Clearly, other events must exist, but could have different causes. In order to detect more such possible events, we have identified periods when the 14C increase rate is rapid and large in the international radiocarbon calibration (IntCal) data (Reimer et al. 2013). In this paper, we follow on from previous studies and identify a possible excursion starting at 814–813 BC, which may be connected to the beginning of a grand solar minimum associated with the beginning of the Hallstatt period, which is characterized by relatively constant 14C ages in the period from 800–400 BC. We compare results of annual 14C measurements from tree rings of sequoia (California) and cedar (Japan), and compare these results to other identified excursions, as well as geomagnetic data. We note that the structure of the increase from 813 BC is similar to the increase at 5480 BC, suggesting a related origin. We also assess whether there are different kinds of events that may be observed and may be consistent with different types of solar phenomena, or other explanations.

scholarly journals Theoretical and Experimental Aspects of Solar Flares Manifestation in Radiocarbon Abundance in Tree Rings

Radiocarbon ◽  
1992 ◽  
Vol 34 (2) ◽  
pp. 247-253 ◽  
Author(s):  
A. N. Kostantinov ◽  
V. A. Levchenko ◽  
G. E. Kocharov ◽  
I. B. Mikheeva ◽  
Stefano Cecchini ◽  
...  
Keyword(s):  
Tree Rings ◽  
Solar Flares ◽  
High Probability ◽  
Cosmic Ray ◽  
Cosmogenic Isotopes ◽  
The Past ◽  
Cosmic Ray Flux ◽  
Several Intervals

We describe our method of determining solar cosmic-ray flux and spectrum in the past, based on the comparison of different cosmogenic isotopes. For the period, AD 1781–1950, we have detected several intervals with a high probability of powerful solar flares.

What Is the Carbon Origin of Early-Wood?

Radiocarbon ◽  
2018 ◽  
Vol 60 (5) ◽  
pp. 1457-1464 ◽  
Author(s):  
Sabrina G K Kudsk ◽  
Jesper Olsen ◽  
Lasse N Nielsen ◽  
Alexandra Fogtmann-Schulz ◽  
Mads F Knudsen ◽  
...  
Keyword(s):  
Least Squares ◽  
Tree Ring ◽  
Tree Rings ◽  
Time Resolution ◽  
Calibration Curve ◽  
Cosmic Ray ◽  
Annual Variations ◽  
Late Wood ◽  
Annual Scale

ABSTRACTSubstantial amounts of annual radiocarbon (14C) data have recently been produced with the purpose of increasing the time resolution of 14C records used for constructing the calibration curve and for studying the occurrence of abrupt cosmic-ray events. In this study, we investigate if it is possible to resolve sub-annual scale changes in the atmospheric 14C content by measuring radiocarbon in early-wood and late-wood fractions from Danish oak. The tree-ring samples span the period 1954–1970 CE, hereby covering the peak of the bomb pulse. A least squares test comparing the atmospheric 14C content and the new sub-annual 14C record from Danish tree rings reveals that by measuring early-wood and late-wood fractions, it may be possible to resolve sub-annual variations in past atmospheric 14C levels.

Detection of solar proton events by using radiocarbon in tree-rings

2020 ◽  
Author(s):  
Nicolas Brehm ◽  
Marcus Christl ◽  
Hans-Arno Synal ◽  
Raimund Muscheler ◽  
Florian Adolphi ◽  
...  
Keyword(s):  
Carbon Cycle ◽  
Tree Ring ◽  
Tree Rings ◽  
Cosmic Ray ◽  
Solar Proton ◽  
Galactic Cosmic Rays ◽  
The Sun ◽  
Cosmogenic Radionuclides ◽  
Cosmogenic Nuclide ◽  
Solar Proton Events

<p>Our Sun erratically expels large amounts of energetic particles into the interplanetary space and towards Earth, which can be observed as so-called solar proton events (SPE). A strong SPE might cause major damage to satellites and could even disrupt transformers at the ground<sup>1</sup>. This rises the questions how often strong SPEs occur. Since direct observations of SPEs are limited to the last decades, cosmogenic radionuclides can be used to detect such events further back in time. The production rate of cosmogenic nuclides, such as radiocarbon, is primarily dependent on the incoming flux of highly energetic galactic cosmic rays (GCR). Under normal conditions, the Sun’s magnetic field carried by the (low energy) solar protons shields us from (high energy) GCRs, resulting in a lower production of cosmogenic radionuclides when the Sun is active. During a SPE, however, the sudden and drastic increase of high the energy solar protons themselves may lead to an elevated production of cosmogenic radionuclides on Earth. Only recently, such sharp increases in cosmogenic nuclide production occurring within less than one year have been detected in several radionuclide records (<sup>10</sup>Be, <sup>36</sup>Cl, <sup>14</sup>C) from ice core and tree ring records, and have been attributed to SPEs<sup>2,3</sup>.</p><p>Until now, only three SPE could confidently be detected in cosmogenic radionuclide records<sup>1,4,5</sup>. The reason for this is a general lack of accurately dated and annually resolved radionuclide records and/or the strong dampening of the production signal e.g. by the carbon cycle. To find and identify such events we measured radiocarbon in tree ring records at annual resolution with accelerator mass spectrometry (AMS). In this new, accurately dated and annually resolved <sup>14</sup>C record spanning the past about 1000 yr we found several new candidates for SPEs. Their timing and amplitude in terms of cosmogenic nuclide production was characterized by using a global carbon cycle box model. Once unambiguously identified such spiked production increases recorded in the absolutely dated tree ring record have a great potential to be used as a global tool to synchronize other not well dated (climate) records with cosmogenic radionuclides (e.g. <sup>10</sup>Be, <sup>36</sup>Cl).</p><p>1              Schrijver, C. J. et al. (2012) Estimating the frequency of extremely energetic solar events, based on solar, stellar, lunar, and terrestrial records. Journal of Geophysical Research: Space Physics <strong>117</strong></p><p>2              Miyake, F., Masuda, K. & Nakamura, T. (2013) Another rapid event in the carbon-14 content of tree rings. Nature communications <strong>4</strong>, 1748</p><p>3              Mekhaldi, F. et al. (2015) Multiradionuclide evidence for the solar origin of the cosmic-ray events of ᴀᴅ 774/5 and 993/4. Nature Communications <strong>6</strong>, 8611</p><p>4              Miyake, F., Nagaya, K., Masuda, K. & Nakamura, T. A (2012) signature of cosmic-ray increase in AD 774-775 from tree rings in Japan. Nature <strong>486</strong>, 240-242</p><p>5              O'Hare, P. et al. (2019) Multiradionuclide evidence for an extreme solar proton event around 2,610 B.P. ( approximately 660 BC). Proc Natl Acad Sci U S A <strong>116</strong>, 5961-5966</p>

New Single-Year Radiocarbon Measurements Based on Danish oak Covering the Periods AD 692–790 and 966–1057

Radiocarbon ◽  
2019 ◽  
Vol 62 (4) ◽  
pp. 969-987 ◽  
Author(s):  
Sabrina G K Kudsk ◽  
Bente Philippsen ◽  
Claudia Baittinger ◽  
Alexandra Fogtmann-Schulz ◽  
Mads F Knudsen ◽  
...  
Keyword(s):  
Tree Rings ◽  
Calibration Curve ◽  
Cosmic Ray ◽  
Relevant Information ◽  
The Past ◽  
One Year

ABSTRACTSingle-year measurements of radiocarbon (14C) in tree rings have led to the discovery of rapid cosmic-ray events as well as longer lasting anomalies, which have given new insights into the Sun’s behavior in the past. Here, we present two new single-year 14C records based on Danish oak that span the periods AD 692–790 and 966–1057, respectively, and consequently include the two rapid cosmic-ray events in AD 775 and 994. The new data are presented along with relevant information on the dendrochronological dating of the wood pieces, implying that these new measurements may contribute towards generating the next international calibration curve. The new data covering the AD 966–1057 period suggest that the increase in atmospheric 14C associated with the cosmic-ray event in AD 994 actually occurred in AD 993, i.e. one year earlier than the year reported in Fogtmann-Schulz et al. (2017) based on oak from southern Denmark. Careful reanalysis of the dendrochronology that underpins the new 14C records based on oak material from southern Denmark reveals that the cosmic-ray event reported in Fogtmann-Schulz et al. (2017) actually took place in AD 993.

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