10Be

Be-10 is a radioactive isotope of beryllium with mass number 10. It is produced in the Earth’s atmosphere by spallation of nitrogen and oxygen nuclei due to high-energy cosmic rays, and is also formed in exposed rocks by cosmic ray interactions. Be-10 decays to stable boron-10 by beta decay and has a half-life of about 1.387 million years. Its long half-life makes Be-10 useful for studying geological and environmental processes on timescales ranging from 10^5 to 10^6 years. In the atmosphere, Be-10 attaches to aerosols and is deposited to the surface through precipitation, becoming incorporated into ice cores, sediments, soils, and groundwater. Be-10 can also be produced in rocks themselves (in situ cosmogenic production), enabling surface exposure dating and erosion studies in landscapes.

Analytical measurement is typically performed by accelerator mass spectrometry (AMS), which detects Be-10 at very low abundances after chemical purification and separation of boron and beryllium from the sample matrix. Be-10 concentrations are often expressed as Be-10/Be or Be-10 concentration per unit mass, providing quantitative records of production rates and deposition.

Applications of Be-10 include determining exposure ages of rock surfaces and landforms, reconstructing erosion and sedimentation histories, dating groundwater and meteoric water recharge, and contributing to paleoclimate studies through Be-10 records in ice cores and sediments. These records reflect variations in cosmic ray flux driven by solar activity and geomagnetic field changes, making Be-10 a key cosmogenic nuclide in geoscience and climate research.