Geol. Pa läont. Mitt. Innsbruck, ISSN 0378--6870, Band 25, S. 1-242, 2001

QUATERNARY MORPHODYNAMICS AND NEOTECTONICS OF THELOWER ENGADINE (/AUSTRIA)

Rufus J. Bertle & Peter Schlusche (1937-1981)

The results of the investigations of P. Schlu­ from the S-charl valley. The age of the different sche, who died in 198 1 are presented in this lakes is pre-Daun, around Egesen and around abstract for the firsttime. The investigations took 2000 B.C. (last age is indicated by carbon dating place from 1959 to 1980 in the area of the Lower - Probenanalysen B-996, B-976, B-2027, B- Engactine valley and included detailed mapping 2028, B-977, B-978, B-2029, all data measured and C-14 dating. Schlusche was the pioneer of in Bern). Increased fluvial Sedimentation around neotectonic investigations in Austria (TOLLMANN 1500 B.C. can be correlated with the Santorin­ 1987, p. 135). event. The Engactine valley, located in the western The main morphological features of the Lower part of the BasternAlps, is striking in W-E direc­ Engactine valley are the so called "Dorfterrassen" tion from the Maloja-Paß in the We st to Landeck which show a complex sedimentological struc­ in the East. The main structural features along the ture due to polyphase development and the con­ Engactine valley are the W-E trending Engactine fluentvalleys which reach the main valley sever­ Line (TRÜMPY 1972, SCHMID & FROITZHEIM al hundred meters above the recent river bed 1993) and the Lower Engactine window (BERTLE resulting in deep gorges of the confluents in the in prep.), which is located at the Austrian-Swiss direction of the main river En (lnn). border region. The neotectonic activity is dominated by two In the westem part of the Engadine valley, in main systems - one striking E-W (Engadine the region of St. Moritz, Quaternary evolution is Line, see also ScHMID & FROITZHEIM 1993 for the well known, whereas the region between part above/west of ) and the other one strik­ and Landeck is still a missing gap from recent ing N-S (Reschen Line and parallel faults, investigations except the excellent, but unpub­ SCHLUSCHE & BERTLE in prep., BERTLE in prep.). lished work of Schlusche ( data collected from Slope movements in the valleys are controlled by 1959-1981). The results of Schlusche are pre­ these two fault systems resulting in rock slides in sented for the frr st time here. areas where Bündnerschiefer crop out. Morphodynamics of the Lower Engactine is Recent geothermal activity (mineralised dominated by adaption of glacial erosion and springs of Scuol, Val Sinestra, Prutz) along the filling on the neotectonic movements along Engactine valley correlates with major fault sys­ prominent tectonic structures. During and after tems. glacial regression (post-Gschnitz) fluvial processes like filling of lak:es, which were dammed by rock falls and later floods caused by References the break: down of the dams. Three different stages of lak:e evolution in the main valley BERTLE, R. J. (2000): Zur Geologie und Geochronologie between Scuol and Pfunds are documented and um Alp Trida (/Schweiz) einschließlich in­ two other stages of lak:e evolution are known genieurgeologischer Fragen der Gebirgsauflösung und

Geol. Paläont. Mitt. lnnsbruck, Band 25, 2001 31 des Permafrosts. - Unveröffentl. Dipl.-Arb. Univ. Wien, TOLLMANN, A. (1987): Geologie von Österreich, Band ill, 395 S. Deuticke Verlag, Wien. BERTLE, R. J. (in prep): Geologische Karte M 1 : 100.000 TRÜMPY, R. (1972): Zur Geologie des Unterengadins. - In: des Unterengadiner Fensters mit Erläuterungen. Ergebnisse der wissenschaftlichen Untersuchungen im CADISCH, J., EUGSTER, H. & WENK, E. (1968): Geologi­ Schweizerisches Nationalpark, Band XII:Oekologische scher Atlas der Schweiz 1 : 25.000, Blatt 44 Scuol, Untersuchungen im Unterengadin, 71-87, 88-96. Schuls-. - Schweiz. Geol. Komm. (mit Erläuterungen), Bem 1968. SCHLUSCHE, P. & BERTLE, R. J. (in prep.): Zur Quartär­ geologie und Neotektonik im Unterengadin. Authors' address: SCHMID, S.M. & FROITZHEIM, N. (1993): Oblique slip and cand. phil Peter Schlusche (Wien, 1937-1981); Mag. Rufus block rotation along the Engactine line. - Eclog. Geol. 1. Bertle, Institut of Geology, Univ. Vienna, Althansfraße Helv., 86, S. 569-593, Basel l993. 14, A -1090 Wien, Austria

32 Geol. Paläont. Mitt. Innsbruck, Band 25, 2001