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Palaeomagnetic research of cave fill in Hermanshöhle, Austria : final report
Bosák, Pavel ; Pruner, Petr ; Mock, A.
Zpráva je volně šiřitelná od roku 2015. Anotace: Detailed paleomagnetic analysis of sedimentary profile at Teichkluft showed that sediments are characterized by varying magnetic susceptibilities and NRM with increasing tendency of anisotropy parameter with increase of susceptibility. The component analysis identified 2 short R polarity intervals (0.41 m; 2.19–2.26 m) within samples with the N polarity. Rock magnetic and AMS measurements indicated mostly the presence of oblate, low coercivity magnetic fraction, presumably magnetite. However, the R polarity interval (2.19–2.26 m) revealed also other, higher coercivity fraction (maybe due to hematite/goethite content). The identity of this fraction is still unknown. The R polarity interval in 0.41 m represents a geomagnetic excursion without any doubt. The sedimentary profile with the R polarity interval in 0.41 m must be older than 162.7 ± 3.9 ka old topmost speleothem. The paleomagnetic directions (D, I) are very close to the present magnetic field. Therefore we assume deposition of studied sediments within the Brunhes chron (<780 Ka) and the excursion may be correlated with Jamaica-Pringle Falls (205–215 ka) or Calabrian Ridge 1 excursions (315–325 ka; Langereis et al. 1997). Other Th/U date was obtained at the tourist trail opposite to Teichkluft entrance (ca 495 ka +67/-41 ka) in an altitude corresponding to the top of the Teichkluft profile. This might indicate that the Teichkluft was completely or nearly completely filled twice (before 163 and ca 495 ka) and once completely excavated (between ca 205/325 and ca 495 ka). The fragments of cuticle of ring-like shape at the level of 2.30 m belongs to attemsiid millipedes. The probability that fragments represent Polyphematia moniliformis (Latzel, 1884; Diplopoda: Chordeumatida: Attemsiidae) known in the cave is high. It is supposed they are Tertiary relict (Mock and Tajovský 2008). It is not detected, if fragments represent relics of recent/subrecent animal
Plný tet: 0443832 Hermanshoehle_report_final -  PDF
Plný text: content.csg - PDF
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Výzkum vybraných travertinů na Slovensku : etapová zpráva č. 2 - Liptov
Bosák, Pavel ; Pruner, Petr ; Bella, P.
Zpráva je volně šiřitelná. Anotace: Bylo provedeno doplňující vzorkování 2 travertinových těles v Liptovské kotlině mezi Liptovským Mikulášem a Ružomberkem (Čerená a Liptovské Sliače–Skalie) pro paleomagnetický výzkum, Th/U datování a analýzu stabilních izotopů (O, C). Vzorky byly odebrány z pozic, u kterých paleomagnetická analýza vzorků z roku 2012 ukázala inverzní nebo přechodnou (inverzní – normální) polaritu. Báze travertinů na lokalitě Čerená lze datovat do období mezi 419 a 283 ka.
Plný tet: 0399071 - PDF
Plný text: content.csg - PDF
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Valley incision in the Nízké Tatry Mts. (Slovakia) estimated based on paleomagnetic and radiometric cave sediment datings
Kadlec, Jaroslav ; Bella, P. ; Čížková, Kristýna ; Granger, D. E. ; Hercman, H. ; Holúbek, P. ; Chadima, Martin ; Orvošová, M. ; Pruner, Petr ; Schnabl, Petr ; Šlechta, Stanislav
Up to eleven horizontal cave levels occur at different altitudes in Jánska, Demänovská and Mošnická karst valleys in the Nízke Tatry Mts. Most of the caves are filled with allochthonous sediments transported from the area formed mostly by granite. The cave levels were filled with fluvial sediments in dependence on the valleys incision caused by Neogene and Pleistocene uplift of the mountain range. The fluvial sediments are intercalated with, or capped, by flowstone layers in the caves. The paleomagnetic polarities measured both in clastic and chemogenic sediments indicate the age of deposition. Based on obtained polarity data we are able to distinguish cave sediments deposited during the Brunhes, Matuyama and Gauss chrons. The paleomagnetic interpretation was partly verified by U-series datings of flowstones preserved in the sedimentary sections. Except for the horizontal cave levels located in the karst valleys, additional large cave systems were found at extremely high altitudes in the Nízke Tatry Mts. 600–700 m above the lowest horizontal cave level.
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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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Výzkum sedimentů a speleotém ve Zbrašovských aragonitových jeskyních
Bosák, Pavel ; Šlechta, Stanislav ; Hercman, H. ; Pruner, Petr
Numerické datování termominerálních speleotém (koblih) z okolí lokality U krokodýla poskytlo poněkud starší data než dosud udávaná v literatuře: 123 až 127 tisíc let (s rozptylem 108 až 144 tisíc let). Speleotémy se tvořily v průběhu klimatického optima vrcholné poslední doby meziledové (eem), tj. v mořském izotopovém stupni (MIS) 5e. Jemnozrnné klastické sedimenty z výkopu U Krokodýla mají normální paleomagnetickou polaritu vzorků s téměř současnými paleomagnetickými směry. S ohledem na skutečnost, že sedimenty leží na bloku ze stěny utržených termominerálních speleotém, jsou pak jistě mladší než 108 tisíc let.
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Paleomagnetický výzkum sedimentárních výplní vybraných jeskyní v České republice : závěrečná zpráva k výjimce MŽP ČR
Bosák, Pavel ; Hercman, H. ; Kadlec, Jaroslav ; Pruner, Petr ; Schnabl, Petr ; Hlaváč, Jaroslav ; Drahotová, Jana ; Pavková, Jaroslava ; Petráček, Jiří ; Rajlichová, Jana ; Drbal, K. ; Komaško, A. ; Milka, D.
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