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2TDK Railway, profile P18. Datings. Final Report.
Bosák, Pavel ; Zupan Hajna, N. ; Hercman, H. ; Horáček, I. ; Kdýr, Šimon ; Kogovšek, B.
Samples for datings were taken in the railway construction (2TDK) near village of Divača, Classical Karst on October 12, 2021: (1) vertebrate bones in cave 2TDK – 002 at the profile P18, cave entrance appeared during the construction operations on cleaned karst surface in a wall of karst depression. Samples of mammal bones and gastropods were collected in situ on cave bottom, and (2) pieces of speleothems occurring in non in situ position on artificially planated surface near the cave opening were collected. U-series: no numerical date was obtained as geochemistry of sample indicate open system, probably due to recrystallization of sample in soil cover. Paleomagnetism: The transition of N- and R-polarized samples cannot be identified more precisely as U-series radiometric dating yielded no numerical results. The transition easily can represent Brunhes/Matuyama boundary (at 773 ka) as well as any of older such transitions (e. g., base of Jaramillo, base of Olduvai). In any case the speleothem grew in a closed cave space with roof, probably as flowstone (inclusion of red soils above the base) and later as baldachin on eroded allogenic fill of the paleocave. Vertebrate paleontology: bone remains of small and larger vertebrates represent subrecent to Holocene species. Sorex alpinus represents the species quite rare in fossil record, but recetly limited to variegated woodland habitats with high surface humidity. A chamois Rupicapra rupicapra represents a resident species present in Slovenia throughout all stages of a glacial cycle, recently restricted to mountain habitats.
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Miocene-Pliocene age of cave Snežna Jama na Raduhi, Southern Alps, Slovenia
Mihevc, A. ; Horáček, I. ; Pruner, Petr ; Zupan Hajna, N. ; Čermák, Stanislav ; Wagner, Jan ; Bosák, Pavel
Snežna jama cave is 1,600 m long horizontal cave at about 1,500 m a.s.l. in Raduha Massif (Kamnik-Savinja Alps) rich in cave deposits (both allogenic sediments and massive flowstones). The cave size, shape and deposits show (1) formation of the cave in different conditions, and (2) its substantial age. A 4.8 m deep pit was excavated in allogenic sediments. Samples were taken both for palaeomagnetic analysis and palaeontological screening. Sediments consist of rhythmically arranged layers deposited in phreatic conditions. Fragments of rodent teeth and a well-preserved molar of genus Baranomys were identified. Fossil remains indicate mammalian zone MN 16 and MN 14. A high-resolution palaeomagnetic analysis revealed total of 3 principal normal polarized and 2 principal reverse polarized magnetozones. If we accept the palaeontologic calibration, the deposition took place within Gauss and Gilbert chrons, from about 2.6 to more than 5 Ma. Long sedimentation period is in concordance with the cave rocky relief that shows phreatic and epiphreatic morphology and predates the main uplift of the area for about 900 m.
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Palaeomagnetic research of fill of selected cave and karst sediments in Slovenia : progress report no. 8
Bosák, Pavel ; Pruner, Petr ; Zupan Hajna, N. ; Mihevc, A. ; Schnabl, Petr ; Šlechta, Stanislav ; Venhodová, Daniela ; Drahotová, Jana ; Man, Otakar ; Petráček, Jiří ; Komar, M. ; Horáček, I. ; Hajna, J. ; Rajlichová, Jana
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Rentgenově difrakční analýzy vzorků z výplní jeskyní ve Slovinsku
Bosák, Pavel ; Melka, Karel ; Zupan Hajna, N.
Na 21 vzorcích jeskynních sedimentů z různých jeskyní na Slovensku bylo stanoveno celkem 85 rentgenově difrakčních schémat. Nejzajímavější byly vzorky 15 a 16, které obsahovaly téměř výhradně smektit. Nepravidelně rozvrstvené struktury chloritu a smektitu byly zjištěny ve vzorcích 9 a 10. V některých vzorcích byly nalezeny příměsi magnetitu, hematitu, goethitu a boehmitu. Fylosilikáty byly většinou zastoupeny cloritem, slídou a slídnatými minerály, v menším množství kaolinitem a v jednom vzorku pravděpodobně i vermikulitem. Křemen a kalcit představovaly převažující minerály. Živec (většinou plagioklas) byl běžně zastoupen, ale v menším množství. Jeden vzorek (11) obsahoval amfibolit.
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