Gravity modelling along the Southern Segment of the European geotraverse from the Gulf of Genoa to the Swiss Molasse Basin

Cassinis, R.; Cassano, E.; Cappelli, Vincenzo

doi:10.1016/0040-1951(90)90265-a

Cited by 9 publications

(2 citation statements)

References 6 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Little is known about possible general differences between the lithospheres of the European and the African/Adriatic plates though in several gravity studies (see e.g. Kahle et al 1980;Lyon-Caen & Molnar 1989;Cassinis, Cassano & Vincenzo 1990) this was considered a possible explanation of some deficiencies in the gravity models. Differences in the lithospheric structures seem more likely than differences in the velocity-density relationships applying to these two…”

Section: Discussionmentioning

confidence: 99%

“…To reduce the errors introduced by lateral variations of the near-surface structures inaccountable by 2.5-D gravity modelling, the effects of the sediments of the Po Plain, the Molasse Basin, and the larger Alpine valleys were calculated with 3-D models Schwendener 1984;Cassano et al 1990;Kissling & Schwendener 1990) and subtracted from the measured Bouguer gravity. The resulting gravity is termed observed gravity anomaly and compares with the gravity effect of the broader lithospheric structures accounted for by 2.5-D gravity modelling with a technique following Talwani, Worzel & Landisman (1959) and Cady (1980) (Fig.…”

Section: G R a V I T Y Modellingmentioning

confidence: 99%

See 1 more Smart Citation

Gravity interpretation of a unified 2-D acoustic image of the central Alpine collision zone

Holliger

Kissling

1992

Geophysical Journal International

View full text Add to dashboard Cite

Four individual deep seismic reflection profiles across the eastern and southern Swiss Alps have been combined along the trend of the Bouguer gravity anomalies onto the European Geotraverse. The profiles were migrated ray theoretically with the migration velocity model derived from a smoothed reinterpretation of the seismic wide-angle profiles running parallel to the strike of the Alpine arc. The contours of this velocity model were ray theoretically depth migrated together with the combined digitized line drawings of the seismic reflection profiles. The resulting acoustic image depicts the subduction of parts of the lower crust of the European plate beneath the Adriatic promontory of the African plate at a low angle of 15". Based on the interpretation of the seismic data, orogenic crustal thickening is attributed to the stacking of crystalline nappes onto the upper crust of the European plate and wedging of the European and Adriatic middle and lower crusts the latter being ill-constrained by the seismic evidence alone. The south-vergent thrusting of the Southern Alps can be accounted for by the observed downbending of the Adriatic Moho and the lower crust in conjunction with the inferred wedging at mid-crustal levels. Using the geometric constraints provided by seismic data, gravity modelling of the Alpine lithosphere/asthenosphere system relative to stable central European platform clearly favours a gently inclined subduction zone reaching down to at least 200 km depth. Such a gently dipping subduction zone is at odds with prominent models on Alpine geodynamics which favour a near-vertical orientation of the subducting lithosphere ('Verschluckung'). In agreement with the wedging hypothesis indirectly inferred from the seismic data the short wavelength part of the Alpine gravity anomaly requires a middle crust of anomalously high density in the axial zone of the orogen. Both seismic and gravimetric evidence therefore suggest that late-orogenic lithospheric shortening and crustal thickening was governed by the mechanical decoupling of the upper, middle and lower parts of the crust. The amount of subducted lower crustal material cannot be constrained by gravity modelling since its gravity effect cannot be separated from the effect of the subducting slab.

show abstract

Section: Discussionmentioning

confidence: 99%