End-Silurian modifications of Ordovician terranes in western Ireland

Williams, David M.; Harper, David A. T.

doi:10.1144/gsjgs.148.1.0165

Cited by 38 publications

(12 citation statements)

References 45 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This distribution demonstrates an asymmetric pattern of channel migration that may have been controlled by a relative dextral shift of the source area. In western Ireland several authors have demonstrated a pervasive sinistral component of translation during the Lower Palaeozoic period (Williams & Harper, 1991;Hutton & Dewey, 1986). Within a broadly sinistrally controlled basin, however, dextral faults may exist that, under transtension, would be aligned at a high angle to the major bounding faults (Sanderson & Marchini, 1984).…”

Section: Discussionmentioning

confidence: 99%

Tectonic control on sedimentation during transgression: a case study from Silurian successions in Ireland and Scotland

O'connor

Williams

1999

Geol. Mag.

Self Cite

View full text Add to dashboard Cite

The Silurian succession of North Galway is relatively well constrained in terms of environmental analysis and, in its lower half, palaeontologically. The initiation of a late Llandovery marine transgression can be demonstrated over fluviatile red sandstones. The deposition of shallow-water conglomerates at the base of a turbidite sequence within the succession indicates the long-lived presence of a channel system that was probably fault controlled. The back-stripping method allows a subsidence curve to be constructed for this succession. It demonstrates an initial period of rapid rift-related subsidence followed by a short-lived hiatus that may be due to the cessation of subduction in this part of the Caledonides. A comparison of the Galway subsidence curve with that of the Silurian succession at Girvan in Scotland shows strong, but diachronous, similarities. This tends to support an earlier suggestion that they formed part of a single but partitioned basin throughout most of the Silurian period. Although the eustatic fall in sea level at the Llandovery–Wenlock boundary can be recognized, the influence of tectonic regime and sedimentation rates were the controlling factors in determining relative sea levels.

show abstract

Section: Discussionmentioning

confidence: 99%

Tectonic control on sedimentation during transgression: a case study from Silurian successions in Ireland and Scotland

O'connor

Williams

1999

Geol. Mag.

Self Cite

View full text Add to dashboard Cite

show abstract

“…They straddle significant Lower Palaeozoic terrane boundaries (Murphy et al 1990;Ryan & Dewey, 1991;Williams & Harper, 1991). They straddle significant Lower Palaeozoic terrane boundaries (Murphy et al 1990;Ryan & Dewey, 1991;Williams & Harper, 1991).…”

Section: Introductionmentioning

confidence: 99%

Terrane amalgamation in the Clew Bay region, west of Ireland

Johnston

Phillips

1995

Geol. Mag.

View full text Add to dashboard Cite

The Caledonides of the west of Ireland provide a well-exposed and well-mapped example of an oblique collision zone. The east-northeast trending Deer Park and Achill Beg Fault system is a crustal scale ductile sinistral strike-slip duplex of late Ordovician age, imbricating late Precambrian granulite facies lower crustal rocks, near eclogite facies supracrustal rocks, up to amphibolite facies Dalradian metasedimentary rocks and greenschist facies Cambro-Ordovician rocks. This fault system is correlated with a pre-

show abstract

“…(e.g. Williams and Harper, 1991). A likely sequence of events involves the Ordovician fore-arc and arc assemblage of South Mayo colliding in dextral regime with the Laurentian margin in the Early Ordovician.…”

Section: Introductionmentioning

confidence: 99%

Oroclinal bending in the Caledonides of western Ireland: a mid-Palaeozoic feature controlled by a pre-existing structural grain

1998

View full text Add to dashboard Cite

The Caledonides of the west of Ireland mark a segment of the Caledonian-Appalachian orogen where the structural grain swings from the NE-SW trend that typifies the Caledonides of northern Britain to an E-W orientation. The origin of this arcuate structure has previously been proposed to be either primary, reflecting the original geometry of promontories and embayments in the Laurentian margin in this sector of the orogen, or secondary, as evidenced by palaeomagnetically determined clockwise rotations in Silurian rocks in the region. We report the results of a palaeomagnetic investigation of the Early to middle Ordovician Mweelrea Ignimbrites (Llanvirn), from an accreted Taconic arc (the South Mayo Trough) in that part of the western Irish Caledonides that has an E-W trend. After removal of a low-temperature component of magnetisation, (L), interpreted to represent a viscous component of the earth's present field, a high-temperature component of magnetisation, (H), was isolated at fifteen sites in four ignimbrite flows. H passes a palaeomagnetic fold test yielding a tilt-corrected mean remanence direction D D 132:6º, I D 29:1º, Þ 95 D 17:9º which corresponds to a palaeopole at 36.4ºE, 9.9ºS. The pole is in reasonable agreement with established Early to middle Ordovician reference poles for Laurentia and indicates that no significant rotation occurred between the E-W South Mayo Trough and the Laurentian margin after accretion, and therefore that the curvature of this segment of the orogen is likely to be primary. This contrasts with other results from Silurian sequences to the south, which record significant post-Silurian clockwise rotations. Examination of all reliable palaeomagnetic data from the region indicates that the clockwise rotations are restricted to the rocks south of the South Mayo Trough. We propose that the rotations in the south are linked with the superposition of the pre-existing structural grain on the younger rock units during Late Silurian and Early Devonian sinistral transpression.

show abstract

End-Silurian modifications of Ordovician terranes in western Ireland

Cited by 38 publications

References 45 publications

Tectonic control on sedimentation during transgression: a case study from Silurian successions in Ireland and Scotland

Tectonic control on sedimentation during transgression: a case study from Silurian successions in Ireland and Scotland

Terrane amalgamation in the Clew Bay region, west of Ireland

Oroclinal bending in the Caledonides of western Ireland: a mid-Palaeozoic feature controlled by a pre-existing structural grain

Contact Info

Product

Resources

About