Novel heating/cooling stage designed for fluid inclusion microthermometry of large stalagmite sections

•A novel heating/cooling stage was designed specifically for fluid inclusion measurements in stalagmites.•Samples of up to 17 × 35 mm2 can be analysed.•The stage covers a temperature range between − 15 and 35 °C.•The temperature accuracy is better than ± 0.1 °C with a precision of ± 0.02 °C.•The application of high NA microscope optics provides high-resolution images.

Liquid–vapour homogenisation temperatures of fluid inclusions in stalagmites are used for quantitative temperature reconstructions in paleoclimate research. Specifically for this application, we have developed a novel heating/cooling stage that can be operated with large stalagmite sections of up to 17 × 35 mm2 to simplify and improve the chronological reconstruction of paleotemperature time-series. The stage is designed for use of an oil immersion objective and a high-NA condenser front lens to obtain high-resolution images for bubble radius measurements. The temperature accuracy of the stage is better than ± 0.1 °C with a precision (reproducibility) of ± 0.02 °C.