Inversion structures in a foreland domain: Seismic examples from the Italian Adriatic Sea

Abstract

Positive structural inversion within foreland domains ahead of thrust belts can create structures with significant hydrocarbon potential in mature and underexplored areas. Within this context, the Adriatic region represents a well-established hydrocarbon province constituting a foreland domain bounded by the Apennines, Southern Alps, and Dinaric fold-and-thrust belts. Newly reprocessed regional 2D seismic data and a renewed exploration interest in the area motivate a reappraisal of the regional structure and stratigraphy of the deformed Central Adriatic region of Italy (i.e., the Mid-Adriatic Ridge). Here, we developed and discussed examples of inversion structures that have different structural styles. The structural interpretations displayed on time-to-depth converted profiles had been validated by 2D structural-kinematic balancing and forward modeling. Our aim was to better define the geometry, style, and timing of the analyzed inversion-related folds. Positive inversion structures appeared locally as asymmetric harpoon-shaped anticlines riding over high-angle blind thrusts. More commonly, inversion structures were symmetric anticlines formed above conjugate faults. Retrodeformed cross sections showed that positive inversion involved symmetric graben and asymmetric half-graben that originated during the Triassic and Jurassic. That these inversion structures developed during basement-involved thrusting, as suggested for the Adriatic in general, was consistent with forward modeling. Regionally, the contractional structures belonging to the Mid-Adriatic Ridge can be explained in terms of intraplate deformation that chiefly acted through reactivation of Mesozoic normal faults.

Thick-Skinned and Thin-Skinned Tectonics: A Global Perspective

“…Trace of cross-section is shown in Figure 8(C1,C3). (B) Detailed cross-section of the Apennine chain and the Adriatic foreland adapted from [185,189] involving a thick-skinned tectonic style and basin inversion tectonics.…”

“…The geometry displayed in Figure 19B is compiled from [185,189] who included the deep structure for the first time and interpreted the structural style in terms of inversion tectonics. Several thrust faults repeat the Mesozoic-Cenozoic strata and reach deep down into the crystalline basement.…”

Thick-Skinned and Thin-Skinned Tectonics: A Global Perspective

“…The geometry displayed in Figure 19B is compiled from [176] and [180] who included the deep structure for the first time and interpreted the structural style in terms of inversion tectonics. Several thrust faults repeat the Mesozoic-Cenozoic strata and reach deep down into the crystalline basement.…”

Macro‐ and meso‐scale structural criteria for identifying pre‐thrusting normal faults within foreland fold‐and‐thrust belts: Insights from the Central‐Northern Apennines (Italy)

“…Steeply dipping and slightly overturned strata are locally observed within the forelimbs but they are related to dragging or minor fault‐propagation folding occurring in the thrust leading edge. These criteria, which are characteristic of fault‐bend folds generated by positive inversion, are critical to recognise contractional reactivation of PTNFs in curved thrust systems (Figure b,g) and when unravelling subsurface structures via seismic interpretation, as in mildly deformed forelands in which the early‐stage development of fault‐bend reactivation folds can be recognised (Figure ; Pace et al., ).…”