Reply to Discussion on ‘Breakup continents at magma poor rifted margins: a seismic v. outcrop perspective’. Journal of the Geological Society, London , 175, 875-882

Abstract

Dr. Giancarlo Molli constructively replied to our paper ‘Breakup continents at magma poor rifted margins: a seismic v. outcrop perspective’ (Molli 2020) with a twofold argument (i) criticizing the collection of data, and, more importantly, (ii) questioning our discussion on the syn-tectonic behavior of basalts in the study area. 1. Regarding the first point, G. Molli produced a new, high quality interpretative map and a set of retro-deformed sections of the Levanto-Bonassola area to support the idea that Alpine deformation was underestimated by our work. At least three high-quality, detailed maps of the area were published (Decandia and Elter 1969; Barrett 1982; Cortesogno et al. 1987) and, in addition, there are a number of maps produced in the frame of PhD thesis (among which Molli 1995) that are, at present, not yet published. The fact that none of these maps are perfectly identical one to each other does not surprise any field geologist, as each geological map mainly derives from the balance of missing data (cover) and outcrops, especially in highly-anthropized areas, as is the case for the Levanto-Bonassola area. For example, if the maps of Cortesogno et al. (1987) and Decandia and Elter (1969) are compared for the area north of the Bonassola village, it can be seen that different solutions were proposed introducing or not prominent Alpine structures. This example is striking, in particular if one considers the period in which these distinguished geologists worked, because it shows how different maps gave priority to specific primary or late features that were often functional to the proposed framework. For what concerns our work, we wish to stress the concept that the map in Decarlis et al. (2018) was functional to a broader discussion and we therefore highlighted primary structures. The choice of prioritizing some observations (nature of contacts …