The views of the Jurassic eustatic fluctuations differ significantly: specialists either suggest multiple rises
and falls ("Haq's view") or question the idea of global falls ("Hallam's view"). For instance, it is unclear
whether there was a stage-long eustatic lowstand in the Aalenian. The presence of the noted alternatives
is a serious problem complicating interpretation of events in the geological history. This paper summarizes
the evidence of the Aalenian long-term shoreline shifts obtained in different regions of the
world since 2000, i.e., after the noted views appeared. This evidence deals with the stratigraphical architecture
of regions (interpreted in the present article), the established shoreline shifts (transgressions
and regressions), and the knowledge of the regional tectonic activity. The compiled information characterizes
"stable" regions located in the different parts of the world (Europe, Asia, Africa, North America,
South America, and Australia). It is established that there were no regressions in some of these regions in
the Aalenian, whereas regressions in the other regions can be explained by the influence of the tectonic
activity. There was no coherence of the basin-scale eustatically-driven regressions (in contrast, the longterm
Bajocian eustatic rise is proven by a coherence of regional transgressions). This finding contradicts
the idea of the stage-long eustatic lowstand in the Aalenian and, thus, favours the "Hallam's view". This
interpretation is in agreement with the present knowledge of the Earth's palaeoclimate and the past
plate tectonics. This study demonstrates efficacy of interregional correlation of sea-level changes for
resolution of the problem of the alternative views of the Jurassic eustasy. |
