pdf: http://rogov.zwz.ru/Molosto....rea.pdf

Authors suggested new magnetostratigraphic scheme of the Middle-Upper Jurassic of Volga area, based mainly upon their own observations on sections and drill cores. Unfortunately, these interesting data poorly integrated within biostratigraphical framework, because only symbols of fossils are given in logs of sections without any determinations. And at least in some cases presented magnetostratigreaphic correlations contradict strictly with results obtained from ammonite biostratigraphy.
Lets look at authors data from the oldest rocks:
Uppermost Bajocian Michalskii Zone characterized by frequent oscillations of normal and reverse polarity thus well corresponds with Spanish data.
Interpretation of the Ishmae Zone is controversial: at figs 7 and 8 it corresponds to differend magnetozones and different substages!
Callovian chart received from famous reference section Malinovy Ovrag seems to be close with data from Prosek section (still unpublished) and European succession
Reverse polarity of the whole Lower Volgian contradicts with both data by M.Piumenov and with ammonite biostratigraphy.
Partial corresponding of the Middle Volgian Panderi Zone with Richteri Subzone of the Middle Tithonian supported also by ammonite records, while correlation of the Virgatus Zone with uppermost Middle Tithonian could be valid if we will re-interpreting tethyan "Zaraiskites" from Bulgaria and Polish Carpathians as homoeomorphs of true Subboreal ones and possible derivations of Danubisphinctes.
Upper Volgian succession from Kashpir section (fig.8) well coincides with those from Northern Siberia (Housa et al., 2007; Zakharov, Rogov, 2008, etc) but surprisingly contradicts with U.Volgian scale given at fig. 10.
But, anyway, from these data supoports our idea: VOLGIAN STAGE SHOULD BELONGS TO THE JURASSIC SYSTEM