POST-3: Eustasy and sea-level changes in the footsteps of Eduard Suess (1 day bus excursion)

Eduard Carl Adolph Suess (1831 – 1914) was one of the most outstanding geologists of the 19th and beginning of the 20th century. From 1883 to 1900 he published three volumes of “Das Antlitz der Erde” (“The Face of the Earth”), the first comprehensive work on the geology of the world. With these volumes he became the founder of modern geology.

In the second volume of “The Face of the Earth”, published 1888, he developed and defined his theory on Eustasy  his “Eustatische Bewegungen” and the principles what we call today Sequence Stratigraphy. The idea on Sea level Fluctuations was born during his fieldwork in the large Neogene Basins in Austro-Hungary, especially in the northern Molasse-Basin, in the vicinity of the town of Eggenburg. Suess thought that mainly changes of the volume of sedimentary basins are causing sea-level fluctuations – named by him “Eustatische Bewegungen”. Deepening of the basins would be followed by a negative movement of the shoreline, what we would call a regression and the filling up of the basin with sediments he would call a positive movement of the shoreline, what we call nowadays a transgression. In that sense Suess was already seeing the causes of sealevel changes as we interpret them today by changes in the volume of oceanic basins. He also recognised, that climatic changes might be responsible for the changing sealevel.

In his alpine studies, writing about the Triassic and Jurassic transgression in the north of the continent, he interprets these facts as results of worldwide sealevel changes and distinguished here between different “Cycles”. He found out that there are several smaller cycles which create than a larger cycle. In this sense he postulated already 1888 the basic concepts of Sequence Stratigraphy.

The excursion within and around the picturesque town of Eggenburg will follow outcrops of Neogene sediments and collections in the Krahuletz museum.

The one-day bus field trip starts and ends in Vienna.

Physical conditions: light to medium; short walks along roads or trails.

Weather: maybe hot with up to 30 degrees, but may be also rainy.