Uranium, lead, and sulphur data for a Middle Pleistocene interglacial peat deposit from Norfolk, UK, suggest that uptake of these elements was synchronous and confined to a single early diagenetic episode, probably coeval with peat formation. Sulphur isotope data indicate that reducing conditions have been maintained within the deposit throughout its history. Both uranium and lead concentration profiles show a marked discontinuity near the middle of the bed, probably indicating an environmental change, possibly emergence. The lead isotope data are compatible with a single lead component below the discontinuity and two components above. Groundwater is thought to be the dominant source of lead with an additional airfall component present in the upper peat. The uranium and lead concentration profiles below the discontinuity and the sulfur isotope profile throughout the peat support the view that these elements were sequestered from upwelling groundwaters. The organic material is particularly suitable for 230 Th 238 U dating because it contains a negligible allogenic mineral component and very low 232Th activity. A sequence of consistent ages through the peat profiel (mean 317 ± 14 ka) over a wide range of uranium concentrations (7–65 mg g −1, strongly suggests that a discrete, short-lived, uranium-uptake event has been dated and that subsequent differential isotopic migration has not occurred. One sample, from immediately below the discontinuity, has an infinite apparent age, but there is strong evidence for sequestration of uranium from the peat into adjacent wood fragments found along the discontinuity. Calculated initial 234 U 238 U values of 1.2–1.3 support a groundwater origin for the uranium, rather than a marine origin resulting from a subsequent rapid transgression. The very restricted range of U/Pb ratios in the lower part of the peat bed, and the heterogeneity of the initial lead isotopic composition in the upper part, preclude UPb isochron dating. 210Po measurements (as a proxy for 210Pb) also indicate possible post-depositional migration of 222Rn which, if active over a significant period, would bias any UPb age estimate. The 230 Th 238 U ages are consistent with deposition during oxygen isotope Stage 9.