Postojna Cave Research Articles

The Story of the 1833 Fercher Survey, Postojnska Jama, Continues: An Additional Document and Newly Discovered Inscriptions

Publications, archived documents and inscriptions help with the reconstruction of the history of Postojnska jama. Until recently, the circumstances of the first mayor cave survey ever undertaken were not well known. It is the so called Fercher Survey conducted in winter 1833; a cooperation between the Mine Office in Idrija and the Cave Administration that surveyed the entire cave known at the time. Documents from the Archive of the Karst Research Institute and an inscription in the Tartarus of Postojnska jama gave a first insight into this story (Kempe, 2005). The survey suggested that (in what is now Male jama) a connection could be blasted to shorten the visitor route. Now a further letter dated 5th September, was found shedding light on this mining attempt begun in summer 1833. In the letter the Cave Administration massively attacks the Mine Office. They claim that either the survey was not accurate or that the breakthrough was attempted at a wrong site. In consequence they demanded their expenses back, threatening with an investigation by the precinct administration. We also found three more inscriptions of the Fercher Party, in Pisani rov and in the Old Cave, one by Fercher and two by the miner Tracha.

Psilochorus simoni (Berland, 1911) (Araneae: Pholcidae), a new record for slovenian spider fauna from Postonjska jama cave

An adult female Psilochorus simoni (Berland, 1911) (Pholcidae) was found in Postojna Cave, Slovenia. The species, which originates from subtropical America, has been introduced to Europe where it is generally associated with synanthropic habitats. This is the first record of this rare species in Slovenia and the second from a cave environment in Europe.

Methodology of radon monitoring and dose estimates in Postojna Cave, Slovenia.

Due to the specific work regime in the Postojna Cave, which depends primarily on the daily number of visitors, and on seasonal variations in air radon concentrations, an optimal methodology for radon and progeny measurement and dose calculation was sought. The program of measurement throughout the years was optimized, and now comprises 3-mo exposures of etched-track detectors, and twice a year, 8-10-d measurements using continuous monitors. Radon concentrations range from about 500 Bq m(-3) in winter to about 6,000 Bq m(-3) in summer, and equilibrium factors range from 0.42 to 0.69 in winter and from 0.33 to 0.86 in summer. Radiation doses from radon decay products for employees in the cave were calculated according to the ICRP 65 methodology. The basic input data are radon concentrations and equilibrium factors at two selected locations in the cave and the records of the time spent by a worker in the cave. Effective doses received by employees annually ranged from 0.02 to 8.4 mSv.

Bomb 14C time history recorded in two modern stalagmites — importance for soil organic matter dynamics and bomb 14C distribution over continents

Carbon 14 activity measurements made by Accelerator Mass Spectrometry on two modern stalagmites from the Han-sur-Lesse cave (Belgium) and from the Postojna Cave (Slovenia) permit the construction of 14C activity ( a 14C) time series over the last 50 years. A high precision chronology is given by annual laminae in the first stalagmite and by a specific mark (explosion in the Postojna Cave in 1944) in the second one. In both stalagmites, 14C activity increase due to nuclear tests in the atmosphere is remarkable. However, instead of a sharp peak like the one observed in the atmosphere around 1963–1964, the 14C activities of the stalagmite CaCO 3 show an abrupt increase, with an offset of 1–10 years, followed by a high activity plateau for the Han-sur-Lesse sample and a slight decrease for the Postojna sample. For both stalagmites, the variation of the a 14C amplitude between pre- and post-bomb period is much lower than the atmospheric record, which demonstrates the damping effect of the soil carbon reservoir. We have modeled the CaCO 3 activities using fractionation processes between atmosphere CO 2, soil CO 2 and organic matter (OM), dissolved inorganic carbon and stalagmite CaCO 3. In both cases studied, the model and former soil studies suggest that CO 2 from soil organic matter (SOM) decomposition, which has a slow turnover (i.e. >1 y), is of major importance in winter, when the development of speleothem is the most important. Combined with the fact that 80–90% of the stalagmite carbon comes from soil CO 2, this produces a damping effect on the speleothem a 14C. Consequently, the `geochemical time resolution', at least for speleothem carbon, is much lower than the structural resolution given by annual laminae alternations and is mainly controlled by soil carbon dynamics: a 14C and δ 13C are smoothed over several years. Differences between the 14C time series of the Han-sur-Lesse and Postojna stalagmites are likely to be due to the double amount of precipitation in Postojna, which produces a faster soil OM turnover and thus a `system' which is more sensitive to atmospheric changes.

The significance of E. A. Martel for speleology in Slovenia

Three times Martel visited karst in Carniola: in 1879, 1893 and 1896. The importance of his visits and later publications lies in fact that he informed the francophone public about our karst and caves; his visit stimulated the introduction of new technical means into the then Austrian speleology (folding boat, portable telephone); in 1893 due to his researches Postojnska jama became the longest cave in Europe; public found out about existence of caving society Anthron, which was the first Slovene and Slav society of the kind; he set up the foundations of international speleological co-operation and included into it Austrian speleologists; he informed the public about Putick and his researches of karst underground; unknowingly he helped to introduce the term “karst” into francophone public.