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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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