3D seismic analysis of circular evaporite dissolution structures, Eastern Mediterranean

Abstract

Buried circular collapse structures above a tabular evaporitic body are recorded by recently acquired 3D seismic data on the Levant Basin and continental margin, offshore Israel (Eastern Mediterranean). The structures formed during the Pliocene as buried Messinian (late Miocene) evaporites underwent extensive dissolution in a submarine, deep-water setting. Three-dimensional seismic analysis is used to describe the detailed morphology of the structures and the associated overburden, allowing the reconstruction of their origin and development. It is proposed that evaporite dissolution led to the collapse of the weakly lithified overburden, and this deformed with a series of concentric extensional faults. From the structural analysis of the overburden, the estimated maximum duration of the dissolution event is 0.75–1 Ma. The mechanism proposed for the creation of the circular collapse structures is subjacent dissolution of the more soluble evaporites in the Messinian evaporites, as a result of focused vertical fluid flow at the base of the evaporitic series. Rapid release of overpressured fluids, as, for example, during an earthquake, is thought to have initiated the focused fluid flow, which impinged on the evaporitic seal to the point where dissolution occurred, creating the localized circular collapse structures in the overburden.

Sequence stratigraphy, seismic stratigraphy, and seismic structures of the lower intermediate confining unit and most of the Floridan aquifer system, Broward County, Florida

“…Although the eastern limit of this seismic-sag structure is not fully imaged on plate 21 (because of a lack of any seismic-reflection data eastward of this limit), the western side of the seismic-sag structure has a notable concentration of zones of high-probability for faulting (pl. 21), indicating that this seismic-sag structure includes extensional ring faults in its outer perimeter (Bertoni and Cartwright, 2005).…”

“…21). If imaged in three dimensions, a less-faulted cylindrical core of the seismic-sag structure would be surrounded by extensional ring faults (Bertoni and Cartwright, 2005). The two high-probability fault zones above seismic sequence Ar7 diminish within the thin overlying seismic sequence representing deltaic sediments of the lower part of the Peace River Formation.…”

A seismological study of shallow weak micro-earthquakes in the urban area of Hamburg city, Germany, and its possible relation to salt dissolution

“…Eliasen and Talbot, 2005;Epstein, 2001;Bertoni and Cartwright, 2005;McDonnell et al, 2007;Loucks et al, 2004).…”

“…Submarine circular sinkhole structures have partly reached even larger dimensions up to 2 km (e.g. McDonnell et al, 2007;Bertoni and Cartwright, 2005).…”

Late Tertiary faulting along the coastal plain of Israel

“…Detailed studies of salt motion in the Eastern Mediterranean and its associated processes were recently published by Bertoni and Cartwright [2005, Gradmann et al [2005], Martinez et al [2005], and Netzeband et al [2006].…”