Journal of Asian Earth Sciences: X (Jun 2022)
Quaternary dating and instrumental development: An overview
Abstract
Reliable estimation of ages and temporal correlations through the Quaternary Period (<2.58 Myr) have led to a better understanding of paleoclimatic changes. Various dating techniques applicable through the Quaternary have received significant impetus from paleoclimate community for high-resolution climatic reconstructions that are supported by robust chronological controls. Radiometric dating of Quaternary samples/archives have extensively progressed due to significant instrumentation developments. The Quaternary studies involve several radiometric dating techniques which include cosmogenic and anthropogenically produced radioisotopes.Radiocarbon (14C) is a cosmogenically produced radionuclide that has been frequently used to date recent archives. Previously, conventional β counting method for radiocarbon dating required ∼ 1 g of carbon extracted from the samples. However, with the introduction and development of Accelerator Mass spectrometry (AMS), it became possible to date these natural archives with a much smaller sample quantity. In addition to its application in 14C dating, AMS also led to a breakthrough in application of other cosmogenic isotopic systems (10Be, 26Al) to understand various earth surface processes (e.g., glacial retreats, denudation rates). The 210Pb dating technique is mainly used to study anthropogenic forcing on annual to decadal climatic changes. The measurement technique for 210Pb commenced with α detectors and involved tedious chemical separation and longer measurement times in attaining secular equilibrium. However, the gradual adoption of β and γ detectors led to rapid analysis with relatively shorter analysis times. This contribution aims to provide an overview of frequently used radiometric (14C, 10Be, 26Al, 210Pb and 137Cs) dating techniques in Quaternary studies and discusses the significant instrumental developments.
