However, the diapiric
core of the hills together with small thickness of the Quaternary cover shows (Fig.
Prehnite pseudomorphs after glauberite are widespread within the diapiric
amygdules of the first and second flows.
In this case, possible origins for these microstructures include compaction and diapiric
These investigations led towards the conclusions that the originally developed structure in the compressional tectonic settings was modified by the plastic and diapiric
nature of the Pre Cambrian rock salt and features of extensional tectonics have been superimposed on those of compressional tectonics.
and Marinenko J.W., 1989, Diapiric
transfer of melt in Kilauea Iki lava Lake, Hawaii: a quick, efficient process of igneous differentiation: Geological Society of America Bulletin, v.
In addition, the shales associated with the rollover faults are commonly over-pressured and diapiric
, adding to structural development in the overburden and increasing the seal on faults.
The regional geology has been reviewed by Francois (1987) in a comprehensive synthesis, surveyed by Gauthier and Francois (1989) In a following paper, Francois (in de Magnee and Francois, 1988) has laid particular stress on the role played by Roan evaporites and their diapiric
ascent in various kinds of tectonic ruptures of the Kundelungu covering, followed by collapse brecciation, to explain peculiarities like the dislocation of the three lower Roan groups in a megabreccia and the cropping out of this megabreccia as fragments, often of large size, which can be mingled with blocks of the Kundelungu Supergroups, as in cases of partial scraping of an anticline flank.
The salts, which were most likely formed in a single evaporitic basin, at present constitute independent bodies and are characterised by an intense tectonic compression with diapiric
folds, sometimes quite close together.
The Ma'reb/Jawf area was mostly covered in sand but included a diapiric
salt anticline with some associated bituminous shales.
uplift of an MIS3 marine deposit in SW Spain: Implications for Late Pleistocene sea level reconstruction and palaeogeography of the Strait of Gibraltar.
Compare, for example, thermal modelling studies indicating that diapiric
ascent of magma in the crust is impossible (Weinberg 1996; Petford 1996) with structural studies of felsic plutons indicating diapir-like emplacement (Sylvester 1964; Paterson and Vernon 1995).
To the south there is a related set of outcrops orientated along the southern block of the northeast-southwest tectonic and diapiric
axis of Nazare-Leiria-Pombal.