Structural and Stratigraphic Controls on Salient and Recesses Development along Thrust Belt Fronts: The Northern Apennine (Italy) Case Study

Scrocca, Davide ¹; Livani, Michele ¹; Arecco, Paola ²; Doglioni, Carlo ³
(1)Istituto di Geologia Ambientale e Geoingegneria (CNR), Rome, Italy. (2) Gas Plus Italiana S.p.A., Fornovo Taro, Italy. (3) Sapienza University, Rome, Italy.

The buried geometries of the Northern Apennines frontal thrust system were very well defined by seismic reflection data at the beginning of the ‘80s (e.g., Pieri and Groppi, 1981; Pieri 1983) that nicely imaged three different salients along the thrust front (i.e., from west to east, the Monferrato, the Emilia, and the Ferrara-Romagna arcs).

Notwithstanding, this structural configuration has served as a classic example for thrust tectonics and growth strata studies, several issues are still a matter of scientific debate.

One of these controversies regards the overall tectonic style with two conflicting hypotheses: the first suggests that the main detachment is located at the base of the Mesozoic sedimentary covers (e.g., Scrocca et al., 2007) while the second argues that the main thrusts, and particularly the basal detachment, also affect the Paleozoic basement and the upper crust (e.g., Boccaletti et al., 2004).

Another issue is related to the age of the most recent tectonic activity along the Apennine thrust front and its present-day seismotectonic behavior. Part of the scientific community (e.g., Burrato et al., 2003) considers still partially active the outermost structures of the Northern Apennines which in on the contrary considered inactive by other researchers (e.g., Picotti et al., 2007).

However, one the main open question regards the actual structural setting at the transition between salients and recesses (and the related causative processes) which has been interpreted alternatively as due to inherited heterogeneity in the upper crust of the subducted plate (e.g., Cuffaro et al., 2010) or to the dislocation of the thrust front by strike-slip faults (e.g., Costa, 2003).

In this contribution, based on the interpretation of an extensive dataset made up by recently acquired and already available seismic reflection profiles and well data, an updated 3D structural model of the system of salient and recesses along the Apennine thrust front buried below the Po Plain is proposed.

This new model brings some interesting implications for the comprehension of both structural and stratigraphic controls on salient and recesses development along thrust belt fronts. Moreover, it may also allow an improved assessment of both the seismotectonic and exploration potential of the study area.

AAPG Search and Discovery Article #90135©2011 AAPG International Conference and Exhibition, Milan, Italy, 23-26 October 2011.