HR: 0830h
AN: V51A-06    [Abstracts]
TI: Time Series Periodicity for Lava Compositions of Shield Volcanoes Above Hot Spots
AU: * Sharapov, V
EM: vik@uiggm.nsc.ru
AF: Institute of Geology, 3 Koptyug Pr., Novosibirsk, 630090 Russian Federation
AU: Zhmodik, A
AF: Institute of Geology, 3 Koptyug Pr., Novosibirsk, 630090 Russian Federation
AB: Thoileitic sheets for the Siberian Platform trapps and basalts of Hawaii and Iceland have similar time series for lava profiles in the following respects: 1. periodicity 2. interruption of distribution functions both at the suit boundaries and within continuous discharge of active volcanoes 3. presence or absence of time trends 4. substantial difference in distribution function types for profiles resulted from fissure conduit located at 30-40 km distance from each other. Wavelet analysis shows the functions for tholeiitic shield volcanoes are similar for the time intervals form 20 to 20000 years. Spectral characteristics of petrogenous and trace components as well as isotope ratios show coherent and incoherent values for frequency spectra. The main tendencies for evolution of compositions in completed sequences are similar. The spatial zoning depends on structural and geodynamic conditions of a lava sheet formation and its size. The trapps of the Siberian Platform can be regarded as unique structures from this viewpoint. The most various are time and spatial series for the Hawaiian Island. Two types of time series evolution can be distinguished: `Icelandic' and `Hawaiian'. It is interesting to note, that for the Western Siberian Slab the former type is typical, and for the Siberian Platform - the latter. The reasons for this phenomenon are still not clear. This work was supported by the RFBR (Grants No. 04-05-64276, No. 04-05-64107, and No. 04-05-64332).
DE: 8400 VOLCANOLOGY
DE: 8494 Instruments and techniques
SC: Volcanology, Geochemistry, Petrology [V]
MN: 2005 Joint Assembly