Provenance of late Ashgill (Hirnantian) fine‐grained sediments and pebbles in the Welsh Basin: A ND and SR isotope study

Leng, Melanie J.; Evans, Jane

doi:10.1002/gj.3350290102

Cited by 4 publications

(1 citation statement)

References 12 publications

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“…(4) Hirnantian sediments in Wales have isotopic signatures with both Avalonian and Gondwanan components (Leng & Evans, 1994). They include both first- and second-cycle sand-grade material (James, 1971) and their petrography is fully consistent with a palaeolatitude of 30°S, which implies extremes of neither mechanical weathering at the source (cold, dry climate) nor chemical weathering (humid, tropical climate) (see van de Kamp, 2010).…”

Section: The Welsh Basinmentioning

confidence: 99%

Assessment of Hirnantian synglacial eustacy and palaeogeography in a tectonically active setting: the Welsh Basin (UK)

James

2013

Geol. Mag.

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The Hirnantian stratigraphy of Wales is critically assessed against the global evidence for two major Hirnantian synglacial eustatic lowstands. The evidence for two separate lowstands of relative sea level is locally suggestive in shelf sequences but generally only permissive in the basin. Nowhere can the possible candidate lowstands be separated biostratigraphically and thus basinwide correlation that might rule out local tectonic control is impossible to prove. Consistent with palaeolatitude evidence and a situation far removed from the Gondwana margin, there is no facies evidence (e.g. dropstones) for local glacial conditions and the diamictites are of mass-flow origin. Sequence stratigraphic reasoning proves helpful in the correlation of the basinal succession in Central Wales with the shelf sequences along the Tywi Lineament and the Variscan Front, and suggests that the first appearance of Normalograptus persculptus in Wales does not correspond with the base of the persculptus Biozone. Extensive new palaeocurrent data and sedimentological restudy is combined with review of earlier knowledge to argue for significant revisions to previous palaeogeographic maps for 'generalized lowstand conditions', notably along the Bala Lineament, the Variscan Front and the Central Wales Inliers.

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Section: The Welsh Basinmentioning

confidence: 99%

Assessment of Hirnantian synglacial eustacy and palaeogeography in a tectonically active setting: the Welsh Basin (UK)

James

2013

Geol. Mag.

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Recognising different sediment provenances within a passive margin setting: Towards characterising a sediment source to the west of the British late Carboniferous sedimentary basins

et al. 2011

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A second major fluvial sourceland for the Silesian Pennine Basin of northern England

Glover

Leng²,

Chisholm

1996

JGS

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New Nd and Sr data indicate that two isotopically distinct terrains supplied sediment to the Silesian Pennine Basin. The sources consisted of a northerly-derived fluvial system, which was responsible for much of the detritus during Namurian times, and a second major system which entered at the west and south sides of the basin. This second source, which provided material derived from the former Avalonian/Armorican and Gondwanan terranes, became more influential through the Silesian, so that by Westphalian B/C times, the central parts of the basin were being fed by systems derived from the west and south of the basin. Although the inferred source rocks are petrographically diverse their Nd-Sr signatures are remarkably similar, perhaps due to multicyclic sediment homogenization. The change in provenance may reflect early Variscan tectonic activity to the west of the Pennine Basin.

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Provenance of late Ashgill (Hirnantian) fine‐grained sediments and pebbles in the Welsh Basin: A ND and SR isotope study

Cited by 4 publications

References 12 publications

Assessment of Hirnantian synglacial eustacy and palaeogeography in a tectonically active setting: the Welsh Basin (UK)

Assessment of Hirnantian synglacial eustacy and palaeogeography in a tectonically active setting: the Welsh Basin (UK)

Recognising different sediment provenances within a passive margin setting: Towards characterising a sediment source to the west of the British late Carboniferous sedimentary basins

A second major fluvial sourceland for the Silesian Pennine Basin of northern England

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