TECTONICS AND GLOBAL CHANGE - INFERENCES FROM LATE CENOZOIC SUBSIDENCE AND UPLIFT PATTERNS IN THE ATLANTIC MEDITERRANEAN REGION

Quantitative subsidence analysis for a number of rifted basins in the northern Atlantic/Mediterranean region provides evidence for rapid phases of Plio-Quaternary subsidence. The observed acceleration in tectonic subsidence occurs after a phase of general quiescence in subsidence in these basins and deviates from predictions of stretching models. The latter indicate a decay of subsidence with time after Mesozoic-Tertiary basin formation and a slow tectonic subsidence in Plio-Quaternary times. A possible explanation for the observed patterns of anomalous subsidence could be an increase in the level of intraplate compression in the northern Atlantic region. Intraplate stress changes in the Plio-Quaternary are related to the dynamics of African/Eurasian collision processes and a reorganization of spreading directions in the Atlantic, possibly reflecting a plate reorganization of global nature. It seems that the Plio-Quaternary record reflects a period of increased levels of neotectonic activity, interplaying with periods of (de)glaciation. Stress-induced topography in the onshore parts of continental margins, coupled with the stress-induced subsidence in the offshore deeper parts of the basins, could have contributed to recent phases of uplift in Fennoscandia, augmenting the uplift induced by glacial unloading. Estimates of ice thicknesses are directly inferred from the observed uplift ignoring other driving mechanisms whereas topography plays a crucial role in the dynamics of glaciation. It is, therefore, important to quantify the interplay of rapid tectonic uplift and subsidence phases with climatic effects during the Plio-Quaternary.