UNIGE document Scientific Article
previous document  unige:18873  next document
add to browser collection

The 1996 AD delta collapse and large turbidite in Lake Brienz

Schmidt, Oliver T.
Sturm, Mike
Anselmetti, Flavio S.
Published in Marine geology. 2007, vol. 241, no. 1-4, p. 137-154
Abstract In spring 1996 AD, the occurrence of a large mass-transport was detected by a series of events, which happened in Lake Brienz, Switzerland: turbidity increase and oxygen depletion in deep waters, release of an old corpse into surface waters and occurrence of a small tsunami-like wave. This mass-transport generated a large turbidite deposit, which is studied here by combining highresolution seismic and sedimentary cores. This turbidite deposit correlates to a prominent onlapping unit in the seismic record. Attaining a maximum of 90 cm in thickness, it is longitudinally graded and thins out towards the end of the lake basin. Thickness distribution map shows that the turbidite extends over ∼8.5 km2 and has a total volume of 2.72 * 106 m3, which amounts to ∼8.7 yr of the lake's annual sediment input. It consists of normally graded sand to silt-sized sediment containing clasts of hemipelagic sediments, topped by a thin, white, clay-sized layer. The source area, the exact dating and the possible trigger of this turbidite deposit, as well as its flow mechanism and ecological impact are presented along with environmental data (river inflow, wind and lake-level measurements). The combined results indicate that no particular cause (i.e., earthquake, explosion, flood, wind storm, lake-level change, seiche or sediment dredging) triggered the 1996 AD large turbidite deposit. Instead, it was due to a delta slope failure most likely caused by normal sediment accumulation.
Keywords gravity flowlimnogeologytsunamihigh-resolution seismicsediment core
Full text
Research groups ISE Climat
ISE Energie
ISE Pôle Sciences
ISE Villes et territoires
Limnology and Environmental Geology
Limnology and Geomicrobiology
(ISO format)
GIRARDCLOS, Stéphanie et al. The 1996 AD delta collapse and large turbidite in Lake Brienz. In: Marine geology, 2007, vol. 241, n° 1-4, p. 137-154. doi: 10.1016/j.margeo.2007.03.011 https://archive-ouverte.unige.ch/unige:18873

572 hits



Deposited on : 2012-03-19

Export document
Format :
Citation style :