Geological map of the central part of Narni-Amelia Ridge (Central Apennines, Italy)

Abstract

These explanatory notes are companion of a 1:12,500 geological map and present new stratigraphic and structural data gathered from the under-investigated Narni-Amelia Ridge (Central Apennines, Italy). Here Meso-Cenozoic rocks of the Umbria-Marche-Sabina sedimentary succession crop out, deeply influenced in its tectonic-stratigraphic evolution by the Early Jurassic Tethyan rifting. Geological mapping was accompanied by facies analysis and by a dense network of stratigraphic/ sedimentologic logs. Several Jurassic structural highs flanked by deeper-water basins were identified through palaeoescarpments analysis and allowed to reconstruct the Mesozoic palaeogeography of the study area. Unexpected fine-grained calcarenites made up of neritic material were found embedded in the upper Pliensbachian-Bajocian deposits (sedimented after the drowning of the Calcare Massiccio carbonate platform), providing new data for restoring the Jurassic palaeogeography of the Central Apennines. Evidence of an Early Cretaceous extensional phase, which is well-documented in the southernmost part of the Narni Ridge, was also recognised in the study area. Here the Marne a Fucoidi (Aptian-Albian) rest unconformably on the Hettangian shallow-water carbonates of the Calcare Massiccio, as a result of rejuvenation and erosion of the Early Jurassic margin of the Amelia intra-basinal high.

The aluminum and iron mines of the Comino Valley-Sora area (Central Apennines, Italy): sites of the geological memory

“…Simbruini-Western Marsica - Colacicchi & Praturlon, 1965;Mostardini & Merlini, 1986;Chiocchini et al, 2008Chiocchini et al, , 2012Chiocchini et al, , 2019, while the downthrown blocks deepened, entering in pelagic conditions (i.e. La Meta-Mainarde; Ghisetti & Vizzani, 1998;Festa et al, 2006; for comparable paleogeographic settings in Central Italy, see Cantelli et al, 1978;Colacicchi & Bigozzi, 1995;Galluzzo & Santantonio, 2002;Rusciadelli et al, 2009;Rusciadelli & Ricci, 2013;Cipriani, 2016Cipriani, , 2019Fabbi et al, 2016;Romano et al, 2018aRomano et al, , 2018bRomano et al, , 2019Cipriani & Bottini, 2019aCitton et al, 2019;Cipriani et al, , 2020.…”

Architecture and permeability structure of the Sibillini Mts. Thrust and influence upon recent, extension-related seismicity in the central Apennines (Italy) through fault-valve behavior

“…2D). Basin margin successions also host breccias and isolated olistoliths of Calcare Massiccio carbonate sourced from the steep margins of PCPs (Galluzzo and Santantonio, 2002;Pierantoni et al, 2013;Cipriani, 2016Cipriani, , 2019Cipriani et al, 2020; Fig. 2D).…”

“…Orogenic compression in the study area has been shown to be strongly conditioned by the rheological contrasts associated with (1) Juras-sic paleogeographic inheritances such as horsts and grabens and (2) lithological heterogeneities within the deformed clay-rich multilayer carbonate succession (e.g., Pierantoni et al, 2013;Cipriani, 2016Cipriani, , 2019Santantonio et al, 2016;Curzi et al, 2020a). In the following, we elaborate on the mechanical role potentially played by lithological/stratigraphic features on strain partitioning within complex deformation zones, indeed the case of the STF.…”

Geological mapping reveals the role of Early Jurassic rift architecture in the dispersal of calciturbidites: New insights from the Central and Northern Apennines

“…The northern sector (Amelia Mts) displays a complex pattern of morphostructural highs (Mt St Pellegrino, Fornole and Amelia PCPs), surrounded by deeper‐water basins being the North‐ward branches of the Narni Basin (Cipriani, 2019—see also Figure 1a). While the southernmost part of the Amelia Mts is devoid of any resedimented neritic deposits (see Fornole section in Figures 1a and 4), thin calciclastic levels were found in the ‘Calcari e Marne a Posidonia ’ of the Foce and Amelia sections (Figure 4).…”

“…Centamore, Chiocchini, Deiana, Micarelli, & Pieruccini, 1971; Farinacci, Malantrucco, Mariotti, & Nicosia, 1981). The map database considered for this paper includes the Narni‐Amelia, Sabini, and Sibillini (Mt Pennino) Mountain ridges, and relies in addition on information from the area covered by Sheet 347 «Rieti» of the 1:50,000 geological map of Italy (Cipriani, 2016, 2019; Galluzzo & Santantonio, 2002; Servizio Geologico d'Italia, in press) (Figure 1). This paper is centred on a geothematic field survey, aimed at the detection and mapping of preserved palaeoescarpment tracts and of marginal basin unconformities related to the Jurassic phase of normal faulting.…”