THE STRUCTURE OF THE EASTERN ALPS: FROM EDUARD SUESS TO PRESENT-DAY KNOWLEDGE.

Based on scattered earlier observations of other researchers and his own fieldwork, Eduard Suess analyzed the tectonic origin of the Alps and developed a number of basic concepts in his influential book "Die Entstehung der Alpen ("The Origin of the Alps"; published in 1875) and some concepts are still applied today. Suess based his ideas on the tectonic development of the Alps largely on the interplay between field observations and comparison with other mountain ranges. He therefore introduced and used a specific comparative methodology in the field of tectonics. The tectonic structure of the Alps, which he finally compiled in a map in year 1909, is quite similar to the present-day tectonic concept. The further development of ideas on the structure and origin of the Eastern Alps can be characterized by refinement of stratigraphic and structural observations, application of new tectonic concepts like plate tectonics since the early Seventies of the last century, by application of specific newly-developed geochronological and petrological methods mainly on metamorphic rocks, and then by increasingly detailed geophysical observations on the deep structure, and finally by application of experiments and numerical modeling. All these latter methods, specifically when validated by careful field observations and integrated into current knowledge, resulted in increasingly deeper understanding of the crustal and lithosphericscale structure and the tectonic development of the Eastern Alpine orogen. However, the present knowledge is still far from a full three-dimensional understanding of the overall structure and of the mountain building processes behind. The main reasons for this, aside from the lack of observations, are complications resulting from the oblique convergence and plate collision as well as by the lateral retreat of the subduction acting on a remnant land-locked basin in the eastern lateral extension of the Eastern Alps. [ABSTRACT FROM AUTHOR]