Overview
Main content
Fluid inclusions in stalagmites contain relics of drip water from which the surrounding calcite formed. The density of the enclosed water is directly related to the temperature at the time the inclusions sealed off from the cave environment. Assuming that the inclusions have not undergone any chemical and physical changes, and based on the well-known thermodynamic properties of water, the density of the enclosed water can be used to accurately and precisely determine stalagmite formation temperatures.
The density of fluid inclusion water can be determined by means of the liquid-vapor homogenization temperature using classical microthermometry. The measurements are performed on a microscope equipped with a heating-cooling stage. In addition, the microscope is coupled to a femtosecond laser that allows us to stimulate vapour bubble nucleation in monophase liquid fluid inclusions that are characteristic for stalagmites. This powerful method, also referred to as nucleation-assisted microthermometry, however, requires the presence of well-sealed fluid inclusions of appropriate size (>20-30 μm in the largest dimension), which is not the case for all stalagmites. For physical reasons, the method exhibits a lower temperature limit at around 9°C, limiting its applicability to stalagmites from tropical and subtropical climate zones or to warm periods at the higher latitudes.
Detailed information is provided in the following videos:
Introduction link
Sample selection and preparation
Lab setup
Microthermometric analysis
Theoretical background
