Related Experiment Video
Updated: Oct 22, 2025
07:20
Laboratory and Field Protocol for Estimating Sheet Erosion Rates from Dendrogeomorphology
Published on: January 7, 2019
7.9K
A Single-Year Cosmic Ray Event at 5410 BCE Registered in 14C of Tree Rings
F Miyake1, I P Panyushkina2, A J T Jull3,4
1Institute for Space-Earth Environmental Research Nagoya University Nagoya Japan.
Geophysical Research Letters
|August 26, 2021
Summary
Researchers discovered a significant carbon-14 (¹⁴C) increase in ancient tree rings, indicating an extreme solar energetic particle (SEP) event around 5410 BCE. This finding provides new evidence of past cosmic ray radiation events.
Area of Science:
- Paleoclimatology
- Solar physics
- Radiometric dating
Background:
- Annual 14C data in tree rings serve as a proxy for past extreme solar energetic particle (SEP) events.
- Previous extreme SEP events have been identified around 774/775 CE, 992/993 CE, and ~660 BCE.
Purpose of the Study:
- To report a newly identified rapid increase of 14C concentration in tree rings.
- To investigate the potential cause of this 14C variation as an extreme SEP event.
Main Methods:
- Analysis of annual 14C concentration in tree rings from California, Switzerland, and Finland.
- Comparison of the 14C signature with known SEP events.
Main Results:
- A significant increase of ~6‰ in 14C concentration was observed in tree rings dated to 5411-5410 BCE.
- The 14C variation signature closely resembles those of previously confirmed extreme SEP events.
- The event occurred during a period of high solar activity, 60 years after a major 14C excursion.
Conclusions:
- The 14C data strongly suggest an extreme solar energetic particle (SEP) event occurred around 5410 BCE.
- This event represents a significant influx of cosmic ray radiation into Earth's atmosphere.
Related Concept Videos
02:48Radioactive Decay and Radiometric Dating
35.5K
Radioactivity is a spontaneous disintegration of an unstable nuclide and is a random process, as all the nuclei in the sample do not decay simultaneously. The number of disintegrations per unit time is called the activity (A), which is directly proportional to the number of nuclei in the sample. The decay constant (λ) is an average probability of decay per nucleus in unit time.
35.5K
01:50Global Climate Change
26.0K
Throughout its ~4.5 billion year history, the Earth has experienced periods of warming and cooling. However, the current drastic increase in global temperatures is well outside of the Earth’s cyclic norms, and evidence for human-caused global climate change is compelling. Paleoclimatology, the study of ancient climate conditions, provides ample evidence for human-caused global climate change by comparing recent conditions with those in the past.
26.0K
01:10Carbon-13 (¹³C) NMR: Overview
6.7K
Carbon-13 is a naturally occurring NMR-active isotope of carbon with a low natural abundance of 1.1%. In contrast, carbon-12 is the most abundant isotope of carbon with zero nuclear spin. Therefore, it is NMR inactive. The gyromagnetic ratio of carbon-13 is smaller than that of protons. As a result, carbon-13 resonance is about 6000 times weaker than proton resonance. For a given magnetic field strength, the resonance frequency of carbon-13 is about one-fourth of the resonance frequency for...
6.7K
02:56The Fossil Record
26.3K
The fossil record documents only a small fraction of all organisms that have ever inhabited Earth. Fossilization is a rare process, and most organisms never become fossils. Moreover, the fossil record only exhibits fossils that have been discovered. Nevertheless, sedimentary rock fossils of long-lived, abundant, hard-bodied organisms dominate the fossil record. These fossils offer valuable information, such as an organism's physical form, behavior, and age. Studying the fossil record helps...
26.3K
01:11Atomic Nuclei: Larmor Precession Frequency
1.9K
The earth's gravitational field produces a 'twisting force' perpendicular to the angular momentum of a spinning mass (such as a spinning top) that causes the mass to 'wobble' around the gravitational field axis in a phenomenon called precession. Similarly, the magnetic moment (μ) of a spinning nucleus precesses due to an external magnetic field directed along the z-axis. The precession of the magnetic moment vector about the magnetic field is called Larmor precession,...
1.9K
01:10¹H NMR of Labile Protons: Temporal Resolution
1.3K
Protons bonded to heteroatoms such as nitrogen and oxygen exhibit a range of chemical shift values. This is due to the varying degree of hydrogen bonding between the proton and the heteroatom in other molecules. The extent of hydrogen bonding affects the electron density around the proton, thereby giving different chemical shift values for the protons in the proton NMR spectrum.
The –OH proton in alcohols typically appears in the range of δ 2 to 5 ppm but can vary depending on the specific...
The –OH proton in alcohols typically appears in the range of δ 2 to 5 ppm but can vary depending on the specific...
1.3K