Inversion Structures in a Foreland Area - Seismic Examples from the Adriatic Sea - Italy (original) (raw)
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Foreland tectonics in the southern Adriatic sea
1994
Two major deformation belts occur in the portion of the Adriatic Sea offshore the Gargano Promontory. The NE-SW trending Tremiti Deformation Belt, located north of the Gargano Promontory, originated during the Plio-Quaternary, while the E-W-trending South Gargano Deformation Belt, located south of the Gargano Promontory, formed in a time span from Eocene to Early Pliocene. These deformation belts may have originated by tectonic inversion of Mesozoic extensional faults. This inversion tectonics, of Tertiary age, can be related to the evolution of the fold-andthrust belts surrounding the Adriatic Sea.
Foreland deformational pattern in the Southern Adriatic Sea
1993
Two major deformation belts occur in the portion of the Adriatic Sea offshore the Gargano Promontory. Although these two belts display similar characters on seismic profiles, they are different in other respects. The NE-SWtrending Tremiti Deformation Belt, located north of the Gargano Promontory, originated during the Plio-Quaternary, while the E-W-trending South Gargano Deformation Belt, located south of the Gargano Promontory, formed in a time span that goes from Eocene to early Pliocene. On the ground of structural and stratigrafic evidence these deformation belts are interpreted as originated by tectonic inversion of Mesozoic extensional faults. This inversion tectonics, of Tertiary age, can be related to the evolution of the fold-and-thrust belts that surround the Adriatic Sea. A moderate seismic activity, recorded around the Tremiti Island, and historical seismological data suggest that the whole of study area is, at present, seismically active. Therefore, this portion of the Adriatic block still represents a preferental site of deformation.
Journal of Structural Geology, 2009
Integration of new field structural and geophysical data with existing information from the Apennines chain in Italy and its adjacent Adriatic foreland indicates that the styles of positive inversion tectonics and the modes of interaction between the extensional and the subsequent compressive structures vary. Starting from the Cretaceous, the contractional deformation induced by the mainly north-directed convergence of Africa/Adria with respect to the European plate promoted the closure of various arms of the Atlantic and the Neo-Tethys oceans, which opened in different times and with distinct orientations. The mosaic of continental blocks, carbonate platforms, rift basins and oceanic domains with several geometries and orientations with respect to the axis of the subsequent compression, and the resulting heterogeneities within the shallow sedimentary cover and the overall lithosphere, strongly influenced both the structural evolution of the Apennine orogenic belt and the intra-continental deformation within the Adriatic foreland.
Tectonics, 2001
Up to several kilometers deep sedimentary basins of Neogene to Quaternary age are found in the south Adriatic between the Apennines and the Dinarides/Albanides. They are the Apennines foredeep, the Central Adriatic Basin, and the South Adriatic Basin. Two regional seismic lines, 260 and 170 km long, across the entire system provide hitherto unavailable constraints on the kinematics and dynamics of basin development. The Apennine foredeep imaged along the lines, formed in middle to late Pliocene times through a rapid westward tilting of the basin floor. A paleobathymetry of few kilometers was created in which allochthonous bodies were emplaced and sediments deposited unaffected by deformation and farther rotations. The Central and South Adriatic Basins formed in Neogene to Quaternary times and are both characterized by strong subsidence in their central pans, gradually diminishing toward the edges in the SW and NE. Depocenters did not shift laterally through time. Subsidence rates increase through time, and subsidence continued also following the end of main shortening episodes in the Dinarides/Albanides. The Central and South Adriatic Basins form two crustal-scale synclines with subsidence concentrated in their central parts. Basins' geometries and subsidence patterns indicate that the Adriatic crust has undergone (episodes of) buckling since Miocene times. Wavelengths and amplitudes of such folds change along strike corresponding to mechanical changes of the folded medium. been adequately described and interpreted. The understanding of such processes has significant implications for hydrocarbon exploration and production in the Adriatic area [e.g., Finetti et al., 1987; Casero et al., 1991; Flores et al., 1991; Anelli et al., 1996]. Despite the very large body of data which has been acquired in the last decades in the Adriatic region, published seismic profiles only cover limited pans of the system and are mainly concentrated in its western pans, i.e., the Bradanic Trough, the Apennine foredeep, and the adjacent foreland [e.g., Casnedi, 1988; Cello et al., 1989; Casero et al., 1991; Flores et al., 1991;Argnani et al., 1996]. Profiles crossing the entire system, from the Apennines in the west to the Dinahdes in the east, are rare [see Anelli et al., 1996]. Consequently, subsidence kinematics are insufficiently known, and basinforming mechanisms are poorly understood. Generally accepted ideas consider the basins of the south Adriatic as foredeeps, that is, as basins related to the vertical load exerted by thrust belts and/or to further unspecified "hidden" loads applied to the deep termination of the subducting plate [e.g., Moretti and Royden, 1988; Kruse and Royden, 1994; De Alteriis, 1995]. These interpretations are mainly based on flexural studies on the Apennine foredeeps and are constrained by few, often poorly controlled, geological data. The analysis of new and more complete data sets raises fundamental questions about the validity of such models.
Tectono-sedimentary setting of the Po Plain and Adriatic foreland
RENDICONTI LINCEI, 2010
Based on the substantial drilling and 2D/3D seismic control achieved during a 60-year-long hydrocarbon exploration history, a detailed reconstruction of the Adria plate foreland shared by the converging Southalpine, Dinaric/Albanian and Apennines chains is presented. Eight depth converted seismic transects joining the opposing belt margins and three time-scaled maps of the evolving tectono-sedimentary framework illustrate the shallow crustal geometry and evolution of the study area. Its Cenozoic compressional architecture results overprinted to and somewhere strongly controlled by the late Permian to early Cretaceous extensional features generated during the Mesozoic rift. The effects of the Cenozoic shortening affected the foreland at different times and with variable directions of tectonic deformation. The Dinaric and Albanian chain compression operated since Paleocene to, respectively, early Miocene and Pleistocene. The western and eastern Southalpine comparts acted on the area since early Oligocene to Messinian and middle Miocene to Pleistocene, respectively, whereas the Apennines system involved it since middle-late Miocene to Pleistocene. The result is a fragmented post-Eocene tectonic evolution of the Adriatic foreland controlled by both the diachronous chain segment activity and their coeval competition. The effect of the opposite chain segment interference was a multiple system of differently evolving foredeeps not exclusively ruled by the chain load at their back. Time and amount of the foreland flexuring were moreover accompanied by formation of transversal positive belts that played the role of transfer zones.
Active tectonics of the Adriatic Region
Geophysical Journal International, 1987
Seismicity and fault-plane solutions show that the active deformation in the Adriatic region is very varied. West of Messina, N-S shortening occurs with slip vectors representative of the overall Africa-Eurasia motion. Along the length of peninsular Italy, NE-SW extension on normal faults is the dominant style of deformation, but changes t o N-S shortening in N. Italy. Inland central and northern Yugoslavia is deforming on strike-slip and thrust faults, and an intense belt of NE-SW shortening continues south along the coast from central Yugoslavia into Albania. South of Albania the shortening in coastal regions is in a more easterly direction. The most remarkable feature of the region is the low level of seismicity in the Adriatic Sea itself, compared with the intense activity in the hgh topographic belts that border it on the SW, NW and NE. The relatively rigid behaviour of the Adriatic allows its motion relative t o Eurasia to be described by rotation about a pole in N. Italy. Anticlockwise rotation about this pole accounts, in a general way, for the change in style and orientation of the deformation in the circum-Adriatic belts. Historical and recent seismicity account for approximately equal rates of extension in central Italy and shortening in southern Yugoslavia of about 2 mm yr-' ; however, these are uncertain by at least a factor of two, and are anyway likely t o be underestimates of the true motion, because of the unknown contribution of aseisniic creep.
2009
Southern Apulia (Adriatic foreland, Italy), has long been considered a "stable area" lying in between two active orogens, but in fact its tectonic framework is poorly known. To learn more about this topic, we carried out an original structural analysis on Pleistocene deposits. The results indicate that southern Apulia has been affected by mild but discernible brittle deformation throughout the Middle and Late Pleistocene. Joints prevail, whereas faults are rare and all characterized by small displacement. Horizontal extension dominates throughout the entire study area; the SW-NE to SSW-NNE direction is the most widespread. WNW-ESE extension prevails in the Adriatic side portion of the study area, but the dispersion of the measured plane directions is high, suggesting that the local strain field is not characterized by a strongly predominant trend. A Middle and Late Pleistocene, SW-NE to SSW-NNEoriented maximum extension is not surprising for the study area, as it is compatible with most of the available geodynamic models, whereas the different state of deformation affecting the Adriatic side of the study area requires further investigations. We tentatively interpreted this anomaly as reflecting some regional variation of the general geodynamic frame, for instance as the farthest evidence of ongoing compressional deformation across the W-verging Albanide-Hellenide foldand-thrust belt. RIASSUNTO Deformazione tardo-quaternaria dell'avampaese Adriatico meridionale (Puglia meridionale) da dati mesostrutturali: risultati preliminari. Late Quaternary deformation of the Adriatic foreland. Boll. SGI, accepted Di Bucci et al.
Marine and Petroleum Geology, 2013
The stress field at a specific location is the sum of regional stress, controlled by plate-scale tectonic processes, with local sources. Here we evaluate and discuss the different sources (from geodynamic to local scale) and the controlling factors (including the Jurassic paleogeography of the Adriatic passive margin) of present-day stress in the Adriatic Sea and Periadriatic regions of Italy using two kinds of numerical models: 3D mantle scale viscoelastic models and 2.5D lithosphere scale thin-shell models.
Inversion structure of dinaric age in the Adriatic foreland (Northern Italy)
An inversion structure located in the northern Adriatic foreland (Italy) has been investigated to understand the relationship between geometry, age of deformation and dolomitization process. The geometry of the inversion structure and the relationship between the tectonic deformation and the dolomitization have been investigated producing isochron maps, isopach maps, amplitude and continuity extractions. The structure is delineated by NE trending SE dipping reverse faults reactivated on older Mesozoic extensional faults during Cenozoic compression (Fig. 1A). The inversion structure is defined by two culminations, Agata culmination located to the south and Amira culmination to the north. The isopach maps showed that the growth of the structure was mostly pronounced on Agata culmination and that the culmination is an older Mesozoic extensional basin reactivated during Upper Cretaceous to Eocene inversion (Fig. 1B). The structure showed pervasive dolomitization on its higher Agata culm...