Deep crustal roots beneath the northern Apennines inferred from teleseismic receiver functions

Mele, Giuliana; Sandvol, Eric

doi:10.1016/s0012-821x(03)00185-7

Cited by 60 publications

(57 citation statements)

References 28 publications

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“…[35] A SW-NE receiver function transect obtained from teleseismically recorded earthquakes, found a 25 6 1 km thick crust under northern Corsica that thins to 20 6 2 km toward the Tuscany margin and increases to $50 km under the northern Apennines [Mele and Sandvol, 2003]. Contrucci et al [2005] modeled marine shots recorded on land $50 km north of the profile (line LISA-10 in Figure 1).…”

Section: Crustal Structure and Thinningmentioning

confidence: 99%

Early‐stage rifting of the northern Tyrrhenian Sea Basin: Results from a combined wide‐angle and multichannel seismic study

Moeller

Grevemeyer

Ranero

et al. 2013

Geochem Geophys Geosyst

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[1] Extension of the continental lithosphere leads to the formation of rift basins and ultimately may create passive continental margins. The mechanisms that operate during the early stage of crustal extension are still intensely debated. We present the results from coincident multichannel seismic and wide-angle seismic profiles that transect across the northern Tyrrhenian Sea Basin. The profiles cross the Corsica Basin (France) to the Latium Margin (Italy) where the early-rift stage of the basin is well preserved. We found two domains, each with a distinct tectonic style, heat flow and crustal thickness. One domain is the Corsica Basin in the west that formed before the main rift phase of the northern Tyrrhenian Sea opening ($8-4 Ma). The second domain is rifted continental crust characterized by tilted blocks and half-graben structures in the central region and at the Latium Margin. These two domains are separated by a deep ($10 km) sedimentary complex of the eastern portion of the Corsica Basin. Travel-time tomography of wide-angle seismic data reveals the crustal architecture and a subhorizontal 15-17 6 1 km deep Moho discontinuity under the basin. To estimate the amount of horizontal extension we have identified the pre-, syn-, and post-tectonic sedimentary units and calculated the relative displacement of faults. We found that major faults initiated at angles of 45 -50 and that the rifted domain is horizontally stretched by a factor of $ 1.3 ($8-10 mm/a). The crust has been thinned from $24 to $17 km indicating a similar amount of extension ($30%). The transect represents one of the best imaged early rifts and implies that the formation of crustal-scale detachments, or long-lived low-angle normal faults, is not a general feature that controls the rift initiation of continental crust. Other young rift basins, like the Gulf of Corinth, the Suez Rift or Lake Baikal, display features resembling the northern Tyrrhenian Basin, suggesting that half-graben formations and distributed homogeneous crustal thinning are a common feature during rift initiation.

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Section: Crustal Structure and Thinningmentioning

confidence: 99%

Early‐stage rifting of the northern Tyrrhenian Sea Basin: Results from a combined wide‐angle and multichannel seismic study

Moeller

Grevemeyer

Ranero

et al. 2013

Geochem Geophys Geosyst

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“…Geological [Carmignani et al, 1994;Jolivet et al, 1998;Collettini and Holdsworth, 2004] and geophysical [Keller et al, 1994;Barchi et al, 1998b;Collettini et al, 2006;Chiaraluce et al, 2007] data suggest that a significant amount of extension has been accommodated by east-dipping low-angle normal faults and associated antithetic structures (Figure 1). In the western sector of the Northern Apennines, Tyrrhenian islands and Tuscany, extension was active for enough time to change the geophysical character of the area: the Moho is shallow [Doglioni, 1991;Ponziani et al, 1995;Barchi et al, 1998b;Doglioni et al, 1998;Mele and Sandvol, 2003], heat flow is high [Mongelli and Zito, 1991] and magmatism is widespread [Peccerillo, 1999;Lavecchia and Stoppa, 1990;Serri et al, 1993]. The western sector is also affected by a widespread CO 2 degassing episode [Chiodini et al, 2000[Chiodini et al, , 2004.…”

Section: Geological Settingmentioning

confidence: 99%

Fault zone architecture and deformation processes within evaporitic rocks in the upper crust

et al. 2008

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Recently, in the Northern Apennines, geophysical data have identified the Triassic Evaporites (TE, anhydrites and dolomites) as the source region of the major extensional earthquakes of the area (M ∼ 6). In order to characterize fault zone architecture and deformation processes within the TE, we have studied exhumed evaporite‐bearing normal faults within the upper crust. The structure of large displacement (>100 m) normal faults is given by 1) a zoned fault core with a wider portion of fault‐parallel foliated Ca‐sulphates (ductile deformation), overprinted by an inner fault core (IFC) of localized brittle deformation, and 2) wide (dolostones) to absent (Ca‐sulphates) damage zones of fault fracture patterns. Fault rock assemblage within the IFC is characterized by fault breccia, gouge, and cataclasites of different grain size. Most of the deformation within the IFC is localized along thin and fault parallel principal slip surfaces (PSS) made of dolomite‐rich fine‐grained cataclasite. SEM analyses show an evolution from Ca‐ to St‐ to gypsum‐rich mineralization, due to episodic fluid flow events channeled along the fault zones during different stages of fault exhumation. The development of the observed fault geometry can be explained by a mechanical fault evolution model where initial faulting occurs along broad and ductile shear zones within the anhydrites and causes fracturing within the dolostones. Progressive deformation within the fault core leads to the development of fault parallel dolomite‐rich cataclastic layers. Their reactivation coupled with transient fluid overpressures can produce embrittlement and localization of brittle deformation within the IFC.

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“…Many of the NW-SE normal faults reactivate preexisting thrust planes, mostly SW dipping, formed during the buildup of the Apennines D'Agostino et al, 1998]. Balanced cross sections from published works [e.g., Spadini and Podladchikov, 1996;Faccenna et al, 1997;Mele and Sandvol, 2003] permit estimation of the stretching factor b across the Tyrrhenian margin. Assuming an overall symmetric extension across the Tyrrhenian basin ], the stretching factor in these balanced sections is evaluated as b = t i /t f (where t i is the initial thickness of the crust and t f is the thickness of the stretched crust), that is, the thickness difference between a stretched portion of the margin and the portion in correspondence with the tectonic divide, which represents the preextension crustal thickness (Figure 1).…”

Section: Structural Setting Of the Tyrrhenian Margin Of Central Italymentioning

confidence: 99%

Transverse systems along the extensional Tyrrhenian margin of central Italy and their influence on volcanism

2006

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[1] The Tyrrhenian margin of central Italy has undergone Plio-Quaternary extension, developing NW-SE normal faults and NE-SW faults. The NE-SW faults decrease in frequency toward NE with the stretching factor b, becoming negligible for b < 1.3. Plio-Quaternary volcanoes, aligned NW-SE, formed at the intersection among NE-SW and NW-SE faults; fissure eruptions are mostly controlled by NE-SW faults. Structural field data show normal motions for 76% of NW-SE Quaternary faults and transtensive for 73% of NE-SW Quaternary faults. Analogue experiments simulating the NE-SW Tyrrhenian extension show that transverse transtensive faults form with differential extension Db > 0.21. These data suggest that the NE-SW transtensive structures are transfer faults of the NW-SE normal faults due to relevant differential extension (Db > 0.21) within a stretched crust (b > 1.3). The minor dip-slip and strikeslip components of the NE-SW and NW-SE faults, respectively, possibly result from the NW-SE extension due to the southeastward slab retreat beneath the Calabrian arc. The NE-SW and NW-SE extensions in the central southern Tyrrhenian Sea account for the composite kinematics of the NE-SW structures, which, in turn, exert a twofold role in controlling volcanism. Where their dip-slip component forms basins, the associated decompression induces magma accumulation (developing central volcanoes) at the intersection among NW-SE and NE-SW systems. Where transfer faults are mainly strike slip, their inferred subvertical attitude enhances their permeability to magma, accounting for the observed NE-SW fissure eruptions. Regional extension, forming NW-SE faults, enhances the overall generation and rise of magma along the margin, but NE-SW structures focus magma rise and emplacement at shallower levels. Citation: Acocella, V., and R.

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Deep crustal roots beneath the northern Apennines inferred from teleseismic receiver functions

Cited by 60 publications

References 28 publications

Early‐stage rifting of the northern Tyrrhenian Sea Basin: Results from a combined wide‐angle and multichannel seismic study

Early‐stage rifting of the northern Tyrrhenian Sea Basin: Results from a combined wide‐angle and multichannel seismic study

Fault zone architecture and deformation processes within evaporitic rocks in the upper crust

Transverse systems along the extensional Tyrrhenian margin of central Italy and their influence on volcanism

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