Turbidites from the Clew Bay Complex, Ireland: provenance based on petrography, geochemistry and crustal residence values

Harkin, J.; Williams, David M.; Menuge, Julian F.; Daly, J. Stephen

doi:10.1002/(sici)1099-1034(199612)31:4<379::aid-gj719>3.0.co;2-x

Cited by 13 publications

(6 citation statements)

References 22 publications

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“…T DM ages for the Argyll Group range from 1.65-2.39 Ga (mean = 1.99 Ga, n = 5: Daly & Menuge, 1989), while T DM ages for the Southern Highland Group are virtually identical and range from 1.79-2.36 Ga (mean = 2.03, n = 5: Daly & Menuge, 1989). 1b) are significantly older, ranging from 2.21-2.65 Ga (mean = 2.38 Ga, n = 8: Harkin et al 1996). 1b) are significantly older, ranging from 2.21-2.65 Ga (mean = 2.38 Ga, n = 8: Harkin et al 1996).…”

Section: B Sm-nd Model Age Data From the South Achill Beg Formationmentioning

confidence: 95%

Structural and stratigraphic relationships across the continuation of the Highland Boundary Fault in western Ireland

Chew

2003

Geol. Mag.

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The relationship between the Dalradian Supergroup and the Highland Border Complex in Scotland has remained contentious for over a century. In western Ireland, the contact between the Dalradian Supergroup and the Clew Bay Complex (a correlative of the Highland Border Complex) is superbly exposed on the island of Achill Beg on the North Mayo coast. The unfossiliferous South Achill Beg succession has been traditionally assigned to the Clew Bay Complex, and this interpretation is supported by a combination of Sm-Nd model age data, heavy mineral analysis and lithostratigraphic correlation. T DM ages range from 1.99-2.66 Ga (mean = 2.28 Ga, n = 6). Detailed structural mapping shows that both the Dalradian and the Clew Bay Complex share the same structural history. A D1 high strain event is common to both units, and is associated with the development of tectonic slides. The D2 event is responsible for the formation of crustal-scale nappes. In both units, beds are consistently downward facing on the S2 foliation. Later dextral shearing (D3) resulted in the tilting of the originally recumbent, S-facing D2 nappes into this downward-facing orientation. Rb-Sr and 40 Ar-39 Ar radiometric dating of muscovite confirms that both units were deformed contemporaneously as the S2 nappe fabric in each is dated at c. 460 Ma. This Middle Ordovician age for deformation of the Clew Bay Complex is highly significant, not least because published microfossil data suggest a Silurian age.

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Section: B Sm-nd Model Age Data From the South Achill Beg Formationmentioning

confidence: 95%

Structural and stratigraphic relationships across the continuation of the Highland Boundary Fault in western Ireland

Chew

2003

Geol. Mag.

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“…Dublin, 2001). This low-grade metasedimentary mélange is composed of fine-grained marine sediments including deep-water turbidites, with fragments of amphibolites and mafic igneous rocks (Williams et al 1994;Harkin et al 1996). The Clew Bay Complex was once believed to contain Silurian microfossils (Williams, Harkin & Higgs, 1996), but this finding was refuted when these rocks were shown to have shared a Grampian deformation history with Dalradian units to the north (D. M. Chew, unpub.…”

Section: A the Problem Of Continental Crust Generationmentioning

confidence: 99%

“…Clew Bay Complex samples are in general slightly more negative than the Dalradian averages, with a range from ∼ − 13 to − 24 and median and mean values between − 15.9 and − 19.4 (Table 2; Harkin et al 1996;Chew, 2003). Because samples from the South Mayo Trough have yielded ε Nd(t) values below − 14, the maximum average ε Nd(t) value of the continental crust involved in petrogenesis must be lower than this.…”

Section: In the Clew Baymentioning

confidence: 99%

“…We assume that Nd is approximately seven times more concentrated in Laurentian crust than in the primitive arc melt. This assumption is based upon REE analyses from North Mayo Dalradian and Clew Bay Complex samples (Menuge & Daly, 1990;Harkin et al 1996;Chew, 2003) and from 21 analyses of the Bohaun Volcanic Group, a combination of the two analysed for this study and 19 presented by Clift & Ryan (1994). The ε Nd(t) value that would result from mixing melt of these two compositions is calculated using the relationship:…”

Section: C Recycling Of Laurentian Continental Materials In Arc Magmentioning

confidence: 99%

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Laurentian crustal recycling in the Ordovician Grampian Orogeny: Nd isotopic evidence from western Ireland

et al. 2004

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-Because magmatism associated with subduction is thought to be the principal source for continental crust generation, assessing the relative contribution of pre-existing (subducted and assimilated) continental material to arc magmatism in accreted arcs is important to understanding the origin of continental crust. We present a detailed Nd isotopic stratigraphy for volcanic and volcaniclastic formations from the South Mayo Trough, an accreted oceanic arc exposed in the western Irish Caledonides. These units span an arc-continent collision event, the Grampian (Taconic) Orogeny, in which an intra-oceanic island arc was accreted onto the passive continental margin of Laurentia starting at ∼ 475 Ma (Arenig). The stratigraphy corresponding to pre-, syn-and postcollisional volcanism reveals a progression of ε Nd(t) from strongly positive values, consistent with melt derivation almost exclusively from oceanic mantle beneath the arc, to strongly negative values, indicating incorporation of continental material into the melt. Using ε Nd(t) values of meta-sediments that represent the Laurentian passive margin and accretionary prism, we are able to quantify the relative proportions of continent-derived melt at various stages of arc formation and accretion. Mass balance calculations show that mantle-derived magmatism contributes substantially to melt production during all stages of arc-continent collision, never accounting for less than 21 % of the total. This implies that a significant addition of new, rather than recycled, continental crust can accompany arc-continent collision and continental arc magmatism.

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“…Provenance indicators may be derived from petrography and geochemistry (Bahlburg, 1998;Harkin et al, 1996;Pantopoulos and Zelilidis, 2012) and this kind of information is of high value as it deals with data on the actual reservoir sandstones.…”

Section: Introductionmentioning

confidence: 99%

Provenance of gravity-flow sandstones from the Upper Jurassic–Lower Cretaceous Farsund Formation, Danish Central Graben, North Sea

Nielsen

Weibel

Friis

2015

Marine and Petroleum Geology

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Turbidites from the Clew Bay Complex, Ireland: provenance based on petrography, geochemistry and crustal residence values

Cited by 13 publications

References 22 publications

Structural and stratigraphic relationships across the continuation of the Highland Boundary Fault in western Ireland

Structural and stratigraphic relationships across the continuation of the Highland Boundary Fault in western Ireland

Laurentian crustal recycling in the Ordovician Grampian Orogeny: Nd isotopic evidence from western Ireland

Provenance of gravity-flow sandstones from the Upper Jurassic–Lower Cretaceous Farsund Formation, Danish Central Graben, North Sea

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