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Salt sequences form an integral part of many sedimentary basins worldwide. Many of these basins have experienced igneous activity either syn-or post-deposition of the salt sequences. Despite this, little work has so far been undertaken to understand magma-salt interactions within the subsurface, and how aspects such as salt halokinesis may be influenced by igneous activity. Within this paper, we detail the first direct description of relationships and textures that are developed during intrusive igneous-salt interaction. We show that salt composition appears to play a dominant role in controlling where igneous intrusions invade laterally through salt sequences in a sedimentary basin. In particular, we illustrate that hydrous salts, such as carnallite, act as preferential horizons for lateral magma intrusion. This lithological control appears primarily related to the heating and subsequent dehydration reaction of carnallite, which causes the carnallite to behave as viscous fluidal horizons, resulting in the non-brittle emplacement of magma, and spectacular peperitic salt-magma mingling textures. We suggest that heating and transformation of carnallite and other hydrous salts into viscous fluidal horizons during igneous intrusion within a regional salt sequence may act as a possible trigger for contemporaneous halokinesis, by creating fluid-like viscous detachment layers. Over longer time scales, however, a solidified rigid boxwork of dikes and sills may create zones of increased mechanical strength that will locally inhibit further salt flow.

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The assessment of deformation types within the slope of a carbonate platform can be complicated by the\ud possible interaction of rooted (tectonically-induced) and superficial (gravity-driven) structures. An ideal\ud case study to document and distinguish tectonically- and gravity-driven structures is provided by the\ud Cretaceous slope-to-basin carbonates exposed in the Gargano Promontory, southern Italy. These carbonates\ud formed adjacent to the Apulian platform margin, which was oriented approximately NEeSW to\ud NWeSE along the southern and northern edges of the promontory, respectively. Slump-related folds are\ud characterised by axial planes typically oriented either sub-parallel or at small angles to the strike of the\ud inferred paleoslope. In fact, the strike of folds is roughly NEeSW in the southern portion of the study\ud area, whereas it is NWeSE in the northern part. Correspondingly, gravity-driven normal and reverse\ud faults strike sub-parallel and at acute angles to the adjacent Apulian paleoslope. Cretaceous tectonic\ud faults in the slope-to-basin carbonates form two principal sets striking NWeSE and WNW-ESE. The\ud former set is made up of normal faults and the latter one includes mainly oblique-slip normal faults.\ud Neither normal nor oblique-slip normal faults show any relationship with the geometry of the paleoslope.\ud The results obtained from this study may help the interpretation of subsurface data in those\ud geological contexts in which the interplay of gravitational and tectonic processes is responsible for\ud deformation

A detailed characterisation of submarine mass-transport deposits (MTDs), in terms of both emplacement processes and internal architecture of depositional products, is crucial to define the hydraulic properties of slope-to-basinal deposits. The Late Jurassic-Early Cretaceous basinal Maiolica Formation exposed in the Gargano Promontory (southern Italy) represents an ideal natural laboratory to study the complex stratigraphic architecture of ancient MTDs. This formation consists of undisturbed intervals of flat-lying, thin-bedded, cherty micritic limestone interbedded with intervals of lithologically similar, but chaotic strata that are characterized by significant internal distortion. The stratigraphic thickness of these deformed units, which are interpreted to represent several types of mass movements (e.g., slumps and, to a lesser extent, slides and debris flows), varies from several decimetres to tens of metres.\ud The internal deformation features comprise down-slope verging folds, together with both normal and reverse faults. In several places, the studied MTDs exhibit signs of reworking, as demonstrated by reactivation of the slump-related faults resulting in deformation of beds directly overlying the MTDs. Structural features within MTD’s, provide information about the direction of the mass movement, and hence the orientation of the paleoslope. Measurements in the eastern and north-eastern part of Gargano Promontory suggest flow is directed towards the E and N respectively. The internal architecture of studied MTDs is discussed in the context of triggering mechanisms related to the characteristics of the Cretaceous paleoslope of the Apulian Platform