Structure and dynamics of the Alps: A geophysical inventory

Miller, Heinz; Mueller, St.; Perrier, Guy

doi:10.1029/gd007p0175

Cited by 27 publications

(14 citation statements)

References 21 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The velocity of 8.7 km s-l at 90-100 km depth derived here (Fig. 8) is lower than the value of 9.2kms-' determined in previous interpretations (Miller et al 1979(Miller et al , 1982. However, except for a velocity estimate of 8.8 km s-' at 94 km depth beneath the Arabian Shield (Prodehl 1985), the velocity derived here is at least 0.1-0.2 km s-l greater than those velocities which are usually determined to exist at 90-100 km depth (Prodehl 1984).…”

Section: Discussion a N D Conclusioncontrasting

confidence: 80%

“…In contrast, in the two V-Z functions shown by Miller et al (1977Miller et al ( , 1978Miller et al ( , 1982 for the region between shot-points B and E , velocities of at least 6.5 km s-' firstly occur at depths of about 23 km in the case of shot-point BE and 36 km in the case of shot-point DE. A second difference is that in the present model a low velocity layer occurs beneath the whole of the main line in the upper crust (Fig.…”

Section: Discussion a N D Conclusionmentioning

confidence: 66%

“…8) and previous models is the crustal thickening beneath the central region of the Alps (Alpine Explosion Seismology Group 1976;Miller et al 1977Miller et al , 1978Miller et al , 1982Egloff 1979). However, in the present two-dimensional model the shape of the crust-mantle boundary, especially in the transition between the thin and thick crusts, has been determined in more detail than previously.…”

Section: Discussion a N D Conclusionmentioning

confidence: 96%

See 2 more Smart Citations

A fine structural section through the crust and lower lithosphere along the axial region of the Alps

Yan¹,

Mechie²

1989

Geophysical Journal International

View full text Add to dashboard Cite

SUMMARY A unified two‐dimensional lithospheric model has been derived for the P‐wave velocity structure beneath the Alpine Longitudinal Profile (ALP'75) main line by making new phase correlations and using ray‐tracing and ray‐theoretical seismogram calculations in laterally inhomogeneous media. Due essentially to an increase in thickness of the lower crust, the total crustal thickness increases from 30–40 km in the peripheral regions to about 50 km in the central region of the Alps. The thickness change is more abrupt at the eastern end than at the western end of the line. The boundary between the upper and lower crust occurs at 18–20 km depth except in the peripheral region at the eastern end of the line where it occurs at 14–16 km depth. Along the whole line the seismic basement has velocities averaged over some tens of kilometres of 5.85‐6.15 km s‐1 with individual values having uncertainties of ±0.05‐0.1 km s‐1 at least east of shot‐point B. The lower part of the upper crust has been modelled as a low velocity layer, which is most pronounced beneath the peripheral regions, and which is generally underlain by a transition zone at the base of which the top of the lower crust occurs. The top of the lower crust has been modelled with velocities ranging from 6.25‐6.5 km s‐1 beneath the peripheral regions to 6.5‐6.65 km s‐1 beneath the central Alps. Velocity uncertainties at the top of the lower crust are estimated to be around ±0.2 km s‐1. Beneath the central Alps a low velocity layer has also been modelled in the lower crust. The top 6 km of the mantle has been modelled with velocities of 8.0–8.2 km s‐1 with individual estimates having uncertainties of ±0.15 km s‐1. Below this, the upper mantle down to almost 100 km depth has been modelled as a series of high velocity layers embedded in material with lower velocities of 8.0–8.2 km s‐1. The combined effects of tectonic overthrusting and uplift and erosion have probably led to the lower crust being apparently thicker than the upper crust in the central Alps at the present day.

show abstract

Section: Discussion a N D Conclusioncontrasting

confidence: 80%

Section: Discussion a N D Conclusionmentioning

confidence: 66%

Section: Discussion a N D Conclusionmentioning

confidence: 96%

See 1 more Smart Citation

A fine structural section through the crust and lower lithosphere along the axial region of the Alps

Yan¹,

Mechie²

1989

Geophysical Journal International

View full text Add to dashboard Cite

show abstract

“…Evidence plates defined by the seismic reflection data alone are for extensional deformation prior to collision is preserved sufficient enough to lead us to an interpretation. adjacent to the Alpine root zone in the lowermost crust of Alps than in the central Alps (Miller, Mueller & Perrier 1982).…”

Section: Comparison To the Ecors-crop Western Alps Profilementioning

confidence: 99%

Results of NFP 20 seismic reflection profiling along the Alpine section of the European Geotraverse (EGT)

Valasek

Mueller

Frei³

et al. 1991

Geophysical Journal International

View full text Add to dashboard Cite

SUMMARY Recent deep‐crustal seismic reflection profiling across the central Alps of eastern and southern Switzerland has provided a detailed image of this continental collision zone. As part of the Swiss National Science project NFP 20, a series of reflection profiles was recorded during two phases along N‐S transects crossing the Alpine edifice. The eastern and southern profiles coincide with the Alpine segment of the European Geotraverse (EGT) and in part with the earlier Swiss Geotraverse. These data together with other geophysical and extensive geologic information form a unique and comprehensive volume of crustal information for this region of the Alps. On a larger scale, the new reflection data also add to a growing set of profiles crossing the Alpine fold belt which includes an additional traverse carried out by NFP 20 across the western Swiss Alps and the ECORS‐CROP profile across the western Alps. The initial results of the reflection data across the central Alps outline a crustal framework involving northward indentation of the Adriatic hinterland into the subducting European foreland. This occurs beneath the collapsed oceanic basins of the Penninic allochthon which is defined by its highly reflective crystalline nappes. The present crustal thickness within the Alpine collision zone has doubled to about 60 km by both vertical and horizontal displacements along an inferred complex detachment system controlled by the Adriatic wedge. The south‐plunging European foreland implies that portions of the thickened crust have been subducted into the upper mantle. This general framework of flake tectonics is laterally consistent with the ECORS‐CROP results, from the western Alps. However, the western Alps show a higher degree of crustal imbrication which may be related to the presence of the rigid Ivrea body and an overall greater amount of crustal shortening compared to the central Alps.

show abstract

“…The imprint of contemporary regional metamorphism may perhaps be seen as seismic low velocity channels in the middle and lower crust of active orogenic belts, owing to the elevation of pore pressure (e.g. present day European Alps ;Miller et al 1982). Such an interpretation requires to be supported by a much more comprehensive database of experimental seismic P and S wave velocity measurements at high temperatures with pore pressures than is presently available.…”

Section: Concluding Discussionmentioning

confidence: 99%

Mechanistic interactions between deformation and metamorphism

Rutter

Brodie

1995

Geological Journal

View full text Add to dashboard Cite

The deformability of rocks, i.e. the resistance to deformation and the mode of failure, may be strongly influenced by syn-tectonic metamorphic reactions. Such mechanistic interactions can often be inferred from studies on naturally deformed tectonites or from suitably designed experiments. The localized nature of retrograde reactions sometimes means that the particular interaction can be inferred as a result of the preservation of both the deformed rock and its protolith, but in prograde situations recrystallization at the metamorphic peak tends to destroy microstructural evidence of the deformation mechanism.Syn-metamorphic mechanistic interaction can be classified according to the effects of: (a) elevated fluid pressure produced during dehydration or decarbonation reactions; (b) transient grain size changes with a possible transition to grain size sensitive flow; (c) effects of changes in pore fluid chemistry and recrystallization on the resistance to plastic flow of silicates (e.g. quartz); (d) enhancement of chemical potential gradients driving diffusive creep; and (e) enhancement of plasticity through the effects of solid phase volume changes. The first three of these effects are expected to be the most important. A soil mechanics approach to the description of the flow of porous rocks provides a basis for understanding deformation during regional prograde reactions, but simple, steady-state constitutive laws of the type used to describe plastic flow of monomineralic rocks are unlikely to be able to be applied to syn-metamorphic deformation.

show abstract

Structure and dynamics of the Alps: A geophysical inventory

Cited by 27 publications

References 21 publications

A fine structural section through the crust and lower lithosphere along the axial region of the Alps

A fine structural section through the crust and lower lithosphere along the axial region of the Alps

Results of NFP 20 seismic reflection profiling along the Alpine section of the European Geotraverse (EGT)

Mechanistic interactions between deformation and metamorphism

Contact Info

Product

Resources

About