Abstract:
Chirpan Bunar Cave is located in the area of Granit village in Bratya Daskalovi municipality – Stara Zagora district. It is one of the few open caves in the Upper Thracian plain. The cave has formed in limestones of the marlstone-limestone association made of bioclastic limestone. The cave is relatively small and has a permanent karst spring. Since April 2016, it has been the subject of research and speleo-microclimatic monitoring. Field measurements of speleoatmospheric parameters of the cave were carried out twice a year – in spring and autumn. In the cave gallery, 5 points for measuring the air temperature, the available water, the relative humidity of the air have been established. The temperature of the speleoatmosphere is measured with the dry thermometer of an Assmann psychrometer. The temperatures of the available cave waters and sediments are measured with a dry mercury thermometer. The relative humidity of the air is determined using an aspiration psychrometer and a psychrometric table. Following a subsequent analysis, the speleo-microclimatic zones in the cave were located. Three main typically distributed speleo-microclimatic zones, and one local zone, have been determined in the cave: entrance zone, transitional zone and internal zone, as well as a local sub-zone of the internal zone. The ventilation regimes in the cave have also been investigated. The natural ventilation and temperature regimes in the cave have been affected by the anthropogenic impact. Field studies were conducted in the Srednogorsko-Thracian karst region.