LISPB DELTA, a lithospheric seismic profile in Britain: analysis and interpretation of the Wales and southern England section

Maguire, P. K. H.; England, Richard; Hardwick, Anthony

doi:10.1144/0016-76492010-030

Cited by 13 publications

(12 citation statements)

References 59 publications

(102 reference statements)

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“…To the west, the LISPB (Lithospheric Seismic Profile in Britain) profiles (e.g., Barton, 1992;Maguire et al, 2011) transect Avalonia from the Iapetus suture zone to the Rheic suture (see Fig. DR1 for location).…”

Section: Crustal Architecture Of Tsz and Adjacent Avalonia And Balticmentioning

confidence: 99%

The Thor suture zone: From subduction to intraplate basin setting

Smit

Wees

Cloetingh

2016

Geology

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The crustal seismic velocity structure of northwestern Europe shows a low P-wave velocity zone (LVZ) in the lower crust along the Caledonian Thor suture zone (TSZ) that cannot be easily attributed to Avalonia or Baltica plates abutting the TSZ. The LVZ appears to correspond to a hitherto unrecognized crustal segment (accretionary complex) that separates Avalonia from Baltica, explaining well the absence of Avalonia further east. Consequently, the northern boundary of Avalonia is shifted ~150 km southward. Our interpretation, based on analysis of deep seismic profiles, places the LVZ in a consistent crustal domain interpretation. A comparison with present-day examples of the Kuril and Cascadia subduction zones suggests that the LVZ separating Avalonia from Baltica is composed of remnants of the Caledonian accretionary complex. If so, the present-day geometry probably originates from pre-Variscan extension and eduction during Devonian-Carboniferous backarc extension. The reinterpretation of deep crustal zonation provides a crustal framework in which the northern limit of Avalonia corresponds to the southern limit of the deep North German Basin and the northern limit of prolific gas reservoirs and late Mesozoic inversion structures.

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Section: Crustal Architecture Of Tsz and Adjacent Avalonia And Balticmentioning

confidence: 99%

The Thor suture zone: From subduction to intraplate basin setting

Smit

Wees

Cloetingh

2016

Geology

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“…The updates consist of the LISPB-Delta data, which runs NNW-SSE across Wales and SW England and fills an important gap in observations of the crustal structure (Maguire et al 2011). Furthermore, new data is added in southern Scandinavia from the MAGNUS REX profiles (Stratford et al 2009;DeGiorgio 2012).…”

Section: Regional V P Model (Model C)mentioning

confidence: 99%

Comparing gravity-based to seismic-derived lithosphere densities: a case study of the British Isles and surrounding areas

et al. 2016

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S U M M A R YLithospheric density structure can be constructed from seismic tomography, gravity modelling, or using both data sets. The different approaches have their own uncertainties and limitations. This study aims to characterize and quantify some of the uncertainties in gravity modelling of lithosphere densities. To evaluate the gravity modelling we compare gravity-based and seismic velocity-based approaches to estimating lithosphere densities. In this study, we use a crustal model together with lithospheric isostasy and gravity field observations to estimate lithosphere densities. To quantify the effect of uncertainty in the crustal model, three models are implemented in this study: CRUST1.0, EuCrust-07 and a high-resolution P-wave velocity model of the British Isles and surrounding areas. Different P-wave velocity-to-density conversions are used to study the uncertainty in these conversion methods. The crustal density models are forward modelled into gravity field quantities using a method that is able to produce spherical harmonic coefficients. Deep mantle signal is assumed to be removed by removing spherical harmonic coefficients of degree 0-10 in the observed gravity field. The uncertainty in the resulting lithosphere densities due to the different crustal models is ±110 kg m −3 , which is the largest uncertainty in gravity modelling. Other sources of uncertainty, such as the V P to density conversion (±10 kg m −3 ), long-wavelength truncation (±5 kg m −3 ), choice of reference model (<±20 kg m −3 ) and Lithosphere Asthenosphere Boundary uncertainty (±30 kg m −3 ), proved to be of lesser importance. The resulting lithosphere density solutions are compared to density models based on a shear wave velocity model. The comparison shows that the gravity-based models have an increased lateral resolution compared to the tomographic solutions. However, the density anomalies of the gravity-based models are three times higher. This is mainly due to the high resolution in the gravity field. To account for this, the gravity-based density models are filtered with a spatial Gaussian filter with 200 km half-width, which results in similar density estimates (±35 kg m −3 ) with the tomographic approach. Lastly, the gravity-based density is used to estimate laterally varying conversion factors, which correlate with major tectonic regions. The independent gravity-based solutions could help in identifying different compositional domains in the lithosphere, when compared to the tomographic solutions.

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“…8, which show the north–south and east–west crustal structure of the British Isles. We chose these specific traverses because they coincide with three important controlled‐source experiments which were recently remodelled using modern ray tracing methods: CSSP/ICSSP (Al‐Kindi et al 2003); LISPB (Barton 1992); and LISPB‐DELTA (Maguire et al 2011). In each case, the primary velocity interfaces obtained from these wide‐angle experiments coincide with velocity boundaries on our crustal traverses.…”

Section: Modelling Of Receiver Functionsmentioning

confidence: 99%

Crustal structure of the British Isles and its epeirogenic consequences

Davis

White

Baptie

et al. 2012

Geophysical Journal International

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S U M M A R YCrustal receiver functions have been calculated for a network of 51 three-component broadband seismometers distributed across the British Isles and NW Europe. Over 3200 receiver functions were assembled for 1055 events. For each station, preliminary estimates of crustal thickness and V p /V s ratio were obtained from H − κ plots. Stacked receiver functions were then inverted to determine shear wave velocity as a function of depth. Each result was checked by guided forward modelling and by Monte Carlo error analysis. In this way, the robustness of our final calculated velocity profiles was carefully tested. A set of depth migrated profiles was also constructed using an average of 50 events for each station over a range of backazimuths. These profiles agree well with legacy wide-angle crustal models. Our results show that crustal thickness varies between 24 and 36 km across the British Isles. Thicker crust is found beneath north Wales and beneath central Scotland. Thinner crust occurs beneath northwest Scotland and northwest Ireland. By combining our database with the results of controlled source, wideangle experiments and with depth-converted reflection profiles, we have produced a detailed crustal thickness map for a region encompassing the British Isles. Our synthesis of crustal thickness and structure has important implications for the tectonic and magmatic histories of this region. Complex Moho structure with lower crustal P-wave velocities of >7 km s −1 occurs beneath regions of Cenozoic magmatism, which may be consistent with magmatic underplating. Thin crust beneath northern Britain suggests that present-day long wavelength topography is maintained by regional dynamic support, originating beneath the lithospheric plate.

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LISPB DELTA, a lithospheric seismic profile in Britain: analysis and interpretation of the Wales and southern England section

Cited by 13 publications

References 59 publications

The Thor suture zone: From subduction to intraplate basin setting

The Thor suture zone: From subduction to intraplate basin setting

Comparing gravity-based to seismic-derived lithosphere densities: a case study of the British Isles and surrounding areas

Crustal structure of the British Isles and its epeirogenic consequences

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