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Abstract. The geological structure of the Central Apennines along a section line across the Lazio-Abruzzi carbonate platform has traditionally been interpreted using a thin-skinned thrust tectonic model, in which the sedimentary cover has been detached from an undeformed basement below. Such models have been used to predict that very large amounts of crustal shortening (e.g. 172 km over a section 173 km long) have occurred. Alternatively, in this paper we reinterpret the surface geology and well data along the same section line using a thick-skinned thrust tectonic model. Restoration of this section shows that the amount of shortening (37 km over a section 158 km long) is considerably lower than previously predicted; this is accomplished by open buckling of the carbonate platform, tighter folding of the basin scarp stratigraphy, and reactivation of pre-existing extensional faults. Age bracketing on thrust fault movement allows shortening rates for the two different models to be calculated; these are < 6 mm yr −1 for the new interpretation, but over 24 mm yr −1 for the equivalent thin-skinned model. This latter value is significantly greater than shortening rates reported for most other thrust belts, suggesting that thick-skinned tectonics is a more satisfactory explanation for the structure of this area. The two most important implications of this are that subthrust hydrocarbon plays are largely absent in the area, and Neogene contractional deformation in this part of the Apennines resulted in much less crustal shortening than previously predicted.

The alternative relationships that can exist between a mountain front and the adjacent foreland basin have been recognized for many years. However, seismic reflection data from such areas are commonly of poor quality and therefore structural models may contain large uncertainties. In view of scientific and commercial interest in mountain belts, we have reviewed the methods for discriminating between alternative interpretations using a case study from the Montagna dei Fiori in the central Apennines, Italy. In this area Mesozoic and Tertiary carbonate sediments are juxtaposed with a foredeep basin containing up to 7 km of Messinian and Plio-Pleistocene siliciclastic sediments. A new structural model for this area demonstrates how the structures in this area form a kinematically closed system in which displacement is transferred from the thrust belt to blind structures beneath the present-day foreland. Growth strata show that Pliocene shortening was initially rapid (15 mm a −1 ) followed by slower rates during the final stages of deformation. Variations in structural elevation indicate a component of basement involvement during thrusting, and this is further supported by magnetic modelling. The results illustrate the interaction of thin- and thick-skinned structures in the central Apennines, and the methods for discriminating between alternative structural models.

Traditional structural analysis in fold and thrust belts has focused on quantifying horizontal movements. In this paper, the importance of quantifying vertical movements is illustrated using a case study from Kurdistan, northern Iraq. The subsidence history of this area can be determined by analysis of the stratigraphic record from deep exploration wells. A phase of thermal subsidence from Middle Permian to Late Cretaceous (tectonic subsidence 1.8-1.9 km) was followed by flexural subsidence in the Late Cretaceous and Cenozoic (tectonic subsidence >0.6 km) in response to the closure of the Neo-Tethys Ocean. The main phase of continental collision during the Neogene resulted in the development of the Zagros fold and thrust belt; the amount of uplift at individual anticlines can be estimated from their amplitude (up to 3 km), but regional cross-sections indicate that approximately 1 km of additional basement-involved uplift is present NE of the Mountain Front. The timing of basement-involved uplift is interpreted to be coeval with the deposition of a Pliocene-Quaternary growth sequence adjacent to the Mountain Front. The amount of erosion resulting from the uplift can be estimated from vitrinite reflectance and cross-sections; these estimates show a similar pattern, with maximum erosion in the mountains NE of the Mountain Front (>1.5 km) and lesser erosion in the adjacent foreland basin (generally <0.8 km). The results provide a quantitative understanding of subsidence, uplift and erosion, and have been used to define prospective and high-risk areas for petroleum exploration.