Plutonium Marker for the Great Acceleration by Intensified Human Activities

Area of Science:

• Environmental Science
• Geochemistry
• Nuclear Science

Background:

• Human activities surged in the mid-20th century, termed the Great Acceleration.
• Nuclear activities are a defining technological process of this era.
• Plutonium-239,240 (Pu) fallout from nuclear weapons tests is a potential chronostratigraphic marker, but its sediment accumulation dynamics are debated.

Purpose of the Study:

• To analyze plutonium-239,240 (Pu) in lake sediment cores to establish a precise timeline for the Great Acceleration.
• To investigate the accumulation dynamics of Pu from atmospheric deposition to sediment preservation in different lake environments.

Main Methods:

• Analysis of three sediment cores from two maar lakes with established chronologies.
• Measurement of plutonium-239,240 (Pu) concentrations within the sediment layers.

Main Results:

• The first significant increase in Pu-239,240 was observed in 1953, corresponding to the first high-yield thermonuclear test.
• Pu-239,240 peaked in 1963, aligning with the period of highest global nuclear testing.
• Pu scavenging and preservation dynamics differed between anoxic (Lake Sihailongwan) and oxic (Lake Huguangyan) lake environments.

Conclusions:

• Pu-239,240 deposition in lake sediments serves as a robust and permanent marker for the Great Acceleration.
• The identified Pu timeline (1953 increase, 1963 peak) accurately reflects major nuclear events and human impact.
• Lake sediments, particularly in anoxic environments, provide excellent archives for preserving this nuclear chronostratigraphic marker.