Cosmogenic ¹⁰Be surface exposure dating

Knowledge graph centered on Cosmogenic ¹⁰Be surface exposure dating with 73 nodes and 145 connections. Top connected: Crested Butte, Climate Change Impacts, Organic matter decomposition, Precipitation Variability, sediment transport.

Method synopsis

Standard method for determining exposure ages of rock surfaces using in-situ produced cosmogenic ¹⁰Be nuclides measured by accelerator mass spectrometry. Involves sample collection, quartz purification, chemical processing, and AMS measurement.

Synthesized from method descriptions across 2 papers using this protocol.

Procedure from a recent peer-reviewed implementation

Steps below were extracted from the most recent peer-reviewed implementation of this protocol in the corpus — Latest Pleistocene glacial chronology and paleoclimate reconstruction for the East River watershed, Colorado, USA (2024), Quaternary Research. Implementations in other papers (listed below) may differ.

1. Sample collection from moraine boulders
   Collected quartz monzonite and quartzite boulders with broad horizontal surfaces deposited on moraine crests. Sampled boulders on average 53 ± 23 cm (1σ) measured above ground surface. Sample thickness and mass ranged from 2–4 cm and 1–3 kg, respectively.
   Quantities: 24 total samples from 6 sites, boulder surfaces averaged 53 ± 23 cm heightDuration: Not specifiedConditions: Field sampling conducted at sites across East River watershed
   Equipment: sledgehammer, chisel, portable rotary drill
2. Topographic shielding measurement
   Data were collected in the field by measuring the angle above the horizon at 20° azimuthal increments using a compass and clinometer.
   Quantities: Measurements at 20° azimuthal increments (18 measurements per sample)Duration: Not specifiedConditions: Field conditions at sample locations
   Equipment: compass, clinometer
3. Sample preparation for cosmogenic analysis
   Samples were crushed and sieved to target grain size of 250–850 μm. Quartz grains were isolated using rare earth hand magnet, Outotec magnetic roll separator, froth flotation, and dilute acid treatment. Quartz purification accomplished by repeated etching in dilute hydrofluoric acid.

Typical Equipment

• sledgehammer
• chisel
• portable rotary drill
• compass
• clinometer
• rare earth hand magnet
• Outotec magnetic roll separator
• quartz crucible
• gas torch
• accelerator mass spectrometer

Output Measurements

• exposure ages in years
• ¹⁰Be concentrations

Papers Using This Protocol (2)

Species Studied With This Protocol

Places Where Used