Evidence for Cenozoic tectonic deformation in SE Ireland and near offshore
OPEN ACCESS
Loading...
Author / Producer
Date
2004-11
Publication Type
Journal Article
ETH Bibliography
yes
OPEN ACCESS
Data
Rights / License
Abstract
An integrated study of topography, bathymetry, high-resolution aeromagnetic data, and structural observations demonstrates significant Cenozoic fault activity in SE Ireland. Tectonically generated knickpoints and reddened fault breccias along topographic escarpments that are underlain by greywacke bedrock and trend oblique to the regional Caledonian strike provide evidence for fault displacement. Near-offshore faults with similar geometry produce present-day bathymetric scarps and localized tectonic topography in the inverted Kish Bank Basin. The integration of offshore high resolution aeromagnetic data and structural interpretation of the Kish Bank Basin provides evidence for dextral transtension on NNW trending faults and sinistral transpression on ENE trending faults bounding a lower Paleozoic to Carboniferous basement block. These faults correlate onshore with previously recognized Caledonian faults producing topographic offsets and surface uplift. To the north, offshore structures can be traced onshore and cut exposures of the Caledonian Leinster Granite. Structural analysis of these outcrops indicates post-Variscan deformation. A major fault on the NW margin of the batholith cuts a major erosion surface developed on Carboniferous carbonate rocks, and nonmarine Miocene deposits are preserved above this surface. Fault kinematics provide evidence of two paleostress systems: (1) NW-SE σ₁, subvertical σ₂ and NE-SW σ₃ followed by (2) a clockwise swing of σ₁ to NNW-SSE. Timing of deformation in both stress systems is probably post-Oligocene age. The mechanism driving this deformation is likely ridge-push. Much is already known about Cenozoic tectonics and exhumation from offshore basins. This study shows that onshore Ireland has also been affected by significant tectonic activity and exhumation during the Cenozoic.
Permanent link
Publication status
published
External links
Editor
Book title
Journal / series
Volume
23 (6)
Pages / Article No.
Publisher
American Geophysical Union
Event
Edition / version
Methods
Software
Geographic location
Date collected
Date created
Subject
Ireland; Cenozoic; reactivation; knickpoints; Uplift