Origin of an anhydrite sheath encircling a salt diapir and implications for the seismic imaging of steep-sided salt structures, Egersund Basin, Northern North Sea

摘要: The ingress of meteoric fluids into the crests salt structures typically results in formation anhydrite-dominated caprock. migration connate up margins has also been documented, although products related to this are rarely sampled deep subsurface. We use 3D seismic reflection and borehole data document geometry lithology a diapir. Seismic suggest that weld is developed along diapir stem, indicate stem consists an inner, c . 1500 m thick, halite-dominated zone, outer, 250 ‘sheath’. anhydrite may have formed early basin history, as depositional or crestal An alternative interpretation represents ‘lateral caprock’, which late history response NaCl-poor fluid dissolution halite. possibility lateral caprock form adjacent implications for understanding patterns vigour groundwater flow sedimentary basins. Furthermore, our study shows steep-sided be misidentified by several hundred metres if time-migrated used.