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A terrestrial (lacustrine and fluvial) palaeoclimate record from Hoxne (Suffolk, UK) shows two temperate phases separated by a cold episode, correlated with MIS 11 subdivisions corresponding to isotopic events 11.3 (Hoxnian interglacial period), 11.24 (Stratum C cold interval), and 11.23 (warm interval with evidence of human presence). A robust, reproducible multiproxy consensus approach validates and combines quantitative palaeotemperature reconstructions from three invertebrate groups (beetles, chironomids, and ostracods) and plant indicator taxa with qualitative implications of molluscs and small vertebrates. Compared with the present, interglacial mean monthly air temperatures were similar or up to 4.0°C higher in summer, but similar or as much as 3.0°C lower in winter; the Stratum C cold interval, following prolonged nondeposition or erosion of the lake bed, experienced summers 2.5°C cooler and winters between 5°C and 10°C cooler than at present. Possible reworking of fossils into Stratum C from underlying interglacial assemblages is taken into account. Oxygen and carbon isotopes from ostracod shells indicate evaporatively enriched lake water during Stratum C deposition. Comparative evaluation shows that proxy-based palaeoclimate reconstruction methods are best tested against each other and, if validated, can be used to generate more refined and robust results through multiproxy consensus.

This study explores the potential of the ostracod Cyprideis torosa (Jones, 1850) as a brackish-water indicator for mapping freshwater/estuarine boundaries in Pleistocene interglacials in SE England. Ostracod species records from MIS 9 (Purfleet) and MIS 11 (Hoxnian) interglacial sites are mapped onto established palaeogeographies of the Thames-Medway river system, revealing distribution patterns indicative of a salinity gradient from west (freshwater) to east (brackish estuarine) in both cases. Comparisons with the ostracod biofacies of the present-day Thames Estuary suggest there may be no exact modern analogue for the Thames/Medway palaeoenvironments of the MIS 9 and MIS 11 interglacials. A similar conclusion is drawn from discussion of noding in C. torosa, which is common in the interglacial assemblages but extremely rare in the modern estuary. The value of mapping C. torosa onto estuarine palaeogeography is limited by taphonomic considerations because postmortem transport and mixing in a macrotidal estuary significantly influence the composition of ostracod assemblages. Nevertheless, its use in combination with other brackish-water taxa provides useful insights regarding the palaeosalinity regimes of the lower River Thames and River Medway during the MIS 9 and MIS 11 interglacials.

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