Bottom simulating reflector
The Bottom Simulating Reflector (, the seabed simulating reflector '), short BSR , is in seismic profiles occurring horizon strong reflection of seismic waves , which runs parallel to the overlying ocean floor and seems to reproduce it. In many cases, the BSR cuts the geological structures of the subsurface that can be seen in the seismic profile, such as the stratification . The formation of such a reflection horizon can have various causes, which have their cause in the change in physical properties of the seabed sediments .
The BSR often marks the lower limit of a sediment layer containing gas hydrate on the passive continental slopes . In this, the pressure and temperature conditions prevail under which gases (e.g. methane ) and water form stable hydrates. This gas hydrate stability zone, which is up to a few 100 m thick, is usually found at a depth of 900 to 1000 meters.
Other possible causes are phase transitions of frequently occurring minerals, such as the transition from Opal A to Opal CT, the conversion from smectite to illite or an abrupt change in the abundance of authentic carbonates .
Individual evidence
- ^ RD Hyndman, GD Spence: A Seismic Study of Methane Hydrate Marine Bottom Simulating Reflectors . In: Journal of Geophysical Research - Solid Earth . tape 97 , 1992, pp. 6683-6698 ( online abstract ).
- ↑ Christian Berndt, Stefan Bünz, Trevor Clayton, Jürgen Mienert and Martin Saunders: Seismic character of bottom simulating reflectors: examples from the mid-Norwegian margin . In: Marine and Petroleum Geology . tape 21 , no. 6 , 2004, p. 723-733 , doi : 10.1016 / j.marpetgeo.2004.02.003 .