![]() panels with co-cured or adhesively bonded frames and stiffeners. Many composite components in aerospace structures are made of flat or curved. Results were compared to fatigue tests on stringer flange/skin specimens to verify the approach. Read moreĪ methodology is presented for determining the fatigue life of bonded composite skin/stringer structures based on delamination fatigue characterization data and geometric nonlinear finite element analyses. The ability of the lower crust to preserve brittle structures is poor, with demonstrable structural linkage between the middle and lower crust associated only with major geological features such as crustal terrane boundaries or suture zones. The lower crust is considered to be a relatively recent, probably Tertiary, feature that has behaved in a highly ductile fashion. A number of major Variscan thrusts terminate at this layer offshore to the south of Ireland. 22km depth, coincides with the top of the reflective lower crust and is interpreted as the crustal brittle-ductile transition. ![]() This suggests that only a moderate change in ductility occurs at the 11-14km décollement. Caledonian, Variscan and Mesozoic-Tertiary structure is preserved in the middle crust, and widespread structural linkage with the upper crust can be demonstrated. A number of major Variscan and pre-Variscan faults flatten into this layer, before continuing into middle crust that deformed in a more ductile fashion. depth, separates brittle upper crust from middle crust. These influenced the style of Devono-Carboniferous extension, Variscan deformation and the development of the Mesozoic-Tertiary Celtic Sea basins. ![]() Interpretation of deep-crustal seismic data across the Variscan fold belt in southern Ireland and the Celtic Sea suggests the presence of two intra-crustal ductility boundaries, characterised by subhorizontal detachments. The final locally updated plate model supports the hypothesis of compartmentalization of the continental region of the Goban Spur margin, highlights the significant role of inherited structures, and renews linkages between the Goban Spur and its potential conjugates during oblique rifting. The present-day crustal thicknesses on the Goban Spur from the locally updated plate model agree with those derived from gravity inversion, providing a possible remedy for the crustal thickness discrepancy generated by existing models. In addition, the seismic reflection data are used to assist in adjusting the geometry of the modelled zone of deformation on the Goban Spur. ![]() More importantly, the seismic reflection data show zones of focused faulting, which are incorporated into the plate model as inherited weakness zones. The new long-offset seismic reflection data reveal the complex architecture of the Goban Spur basins, which are filled with highly variable sediment thicknesses, suggestive of a protracted and polyphased rifting history. This study seeks to resolve this discrepancy by locally updating an existing plate model of the southern North Atlantic by incorporating constraints from four newly-presented seismic reflection profiles. Specifically, crustal thicknesses calculated for the Goban Spur from existing plate models show a discrepancy with those derived from independent geophysical methods like gravity inversion and seismic refraction modelling. To date, kinematic plate reconstruction models have struggled to restore the tectonic evolution of the Goban Spur, offshore Ireland. The main evidences involve the asymmetry degree of the basins, timing of the volcanism, a delaminated crust observed in the Goban Spur sector and a hyper-extended crust in the Porcupine area. The most interesting aspect about the structural style concerns the passive mode of opening of this rift complex. Furthermore, comparing our results with rifting models proposed by other authors, we obtained a consistent scenario of rift development. Our approach consists of the interpretation of seismic data, a detailed geometrical and geological description of the tectonic structures, section construction and balancing. The main objective is to improve the understanding of the style of the continental rifting developed in the N sector of the Atlantic margin. They represent a N trending Mesozoic rift complex related to the Atlantic opening. In this work we present a structural analysis of two geological cross-sections across the Porcupine and Goban Spur basins located in the offshore of western Ireland.
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