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Abstract. Reconstructions of palaeoseismicity are useful for understanding and mitigating seismic hazard risks. We apply cosmogenic 36Cl exposure-age dating and measurements of rare-earth elements and yttrium (REE-Y) concentrations to the palaeoseismic history of the Sparta Fault, Greece. Bayesian-inference Markov chain Monte Carlo (MCMC) modelling of 36Cl concentrations along a 7.2 m long vertical profile on the Sparta Fault scarp at Anogia indicate an increase in the average slip rate of the scarp from 0.8–0.9 mm yr−1 6.5–7.7 kyr ago to 1.1–1.2 mm yr−1 up to the devastating 464 BCE earthquake. The average exhumation of the entire scarp up to the present day is 0.7–0.8 mm yr−1. Modelling does not indicate additional exhumation of the Sparta Fault after 464 BCE. The Sparta Fault scarp is composed of fault breccia, containing quartz and clay-lined pores, in addition to host-rock-derived clasts of calcite and microcrystalline calcite cement. The impurities control the distribution of REE-Y in the fault scarp surface and contribute spatial variation to 36Cl concentrations, which precludes the identification of individual earthquakes that have exhumed the Sparta Fault scarp from either of these data sets. REE-Y may illustrate processes that localize slip to a discrete fault plane in the Earth's near-surface, but their potential use in palaeoseismicity would benefit from further evaluation. 

Abstract. In situ cosmogenic 14C (in situ 14C) in quartz provides a recently developed tool to date exposure of bedrock surfaces of up to ∼ 25 000 years. From outcrops located in east-central Sweden, we tested the accuracy of in situ 14C dating against (i) a relative sea level (RSL) curve constructed from radiocarbon dating of organic material in isolation basins and (ii) the timing of local deglaciation constructed from a clay varve chronology complemented with traditional radiocarbon dating. Five samples of granitoid bedrock were taken along an elevation transect extending southwestwards from the coast of the Baltic Sea near Forsmark. Because these samples derive from bedrock outcrops positioned below the highest postglacial shoreline, they target the timing of progressive landscape emergence above sea level. In contrast, in situ 14C concentrations in an additional five samples taken from granitoid outcrops above the highest postglacial shoreline, located 100 km west of Forsmark, should reflect local deglaciation ages. The 10 in situ 14C measurements provide robust age constraints that, within uncertainties, compare favourably with the RSL curve and the local deglaciation chronology. These data demonstrate the utility of in situ 14C to accurately date ice sheet deglaciation, and durations of postglacial exposure, in regions where cosmogenic 10Be and 26Al routinely return complex exposure results.