|
Regular Article |
1 1Research School of Earth Sciences, The Australian National University, Canberra ACT 0200, Australia
2 2School of Earth Sciences, University of Birmingham, Birmingham B15 2TT, UK (e-mail: aewright@onetel.net.uk)
3 3School for Professional and Continuing Education, University of Birmingham, Birmingham B15 2TT, UK
Abstract: Ages for volcanism in the British Late Precambrian have been inferred from interpretations of SHRIMP zircon ages as follows: 559.3 ± 2.0 Ma for a tuff from the Beacon Hill Formation of the Charnian Supergroup; 566 ± 3 Ma for a tuff at Bardon Hill also in the Charnwood Forest area with abundant inherited grains at 590.5 ± 1.6; 566.6 ± 2.9 Ma and 555.9 ± 3.5 Ma for bentonite and tuff in the Stretton Group of the Longmyndian Supergroup; 604.7 ± 1.6 Ma for an ignimbrite of the Padarn Tuff Formation of the Arfon Group, and 572.5 ± 1.2 Ma for a tuff within the Fachwen Formation of the Arfon Group. These ages confirm that there were two major phases of volcanic activity in the English Midlands and Wales, one about 620–590 Ma and another about 575–550 Ma. This was followed in most of England and Wales by a major phase of tectonism before the Cambrian (Tommotian) transgression across the Midland Platform. Within the depocentre of the Welsh early Palaeozoic basin, however, sedimentation started within the second period of volcanism and may have continued without interruption well into the Cambrian Period. It is probable that the late phases of the Avalonian Orogeny lasted until after the beginning of the Cambrian. These new data show that the terranes of the Avalonian of England and Wales are comparable with those of eastern Canada and New England. The age estimate for the Charnia horizon is broadly similar to those obtained elsewhere in the world on rocks containing the earliest Ediacaran fauna and adds to the building of an extended time-scale for the global Ediacaran.
Key Words: Avalonian • Charnian • Longmyndian • Arfon Group • Ediacaran
This article has been cited by other articles:
 |
|
 |
|
  R. D. Nance, J. B. Murphy, R. A. Strachan, J. D. Keppie, G. Gutierrez-Alonso, J. Fernandez-Suarez, C. Quesada, U. Linnemann, R. D'lemos, and S. A. Pisarevsky Neoproterozoic-early Palaeozoic tectonostratigraphy and palaeogeography of the peri-Gondwanan terranes: Amazonian v. West African connections Geological Society, London, Special Publications, 2008; 297: 345 - 383. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
D. I. Groves, R. M. Vielreicher, R. J. Goldfarb, and K. C. Condie Controls on the heterogeneous distribution of mineral deposits through time Geological Society, London, Special Publications, 2005; 248: 71 - 101. [Abstract] [PDF]
|
|
|
|
 |
|
 H. LORENZ, D. G. GEE, and M. J. WHITEHOUSE New geochronological data on Palaeozoic igneous activity and deformation in the Severnaya Zemlya Archipelago, Russia, and implications for the development of the Eurasian Arctic margin Geological Magazine, 2007; 144: 105 - 125. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
D. MCILROY, T. P. CRIMES, and J. C. PAULEY Fossils and matgrounds from the Neoproterozoic Longmyndian Supergroup, Shropshire, UK Geological Magazine, 2005; 142: 441 - 455. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 K. J. Peterson, M. A. McPeek, and D. A. D. Evans Tempo and mode of early animal evolution: inferences from rocks, Hox, and molecular clocks Paleobiology, 2005; 31: 36 - 55. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 B. Waggoner The Ediacaran Biotas in Space and Time Integr. Comp. Biol., 2003; 43: 104 - 113. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 P. Stone and R.J. Merriman Basin thermal history favours an accretionary origin for the Southern Uplands terrane, Scottish Caledonides Journal of the Geological Society, 2004; 161: 829 - 836. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
ALANS. COLLINS and C. BUCHAN Provenance and age constraints of the South Stack Group, Anglesey, UK: U-Pb SIMS detrital zircon data. Journal of the Geological Society, 2004; 161: 743 - 746. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J.B. Murphy, J. FernAndez-SuArez, TeresaE. Jeffries, and RobinA. Strachan U-Pb (LA-ICP-MS) dating of detrital zircons from Cambrian clastic rocks in Avalonia: erosion of a Neoproterozoic arc along the northern Gondwanan margin Journal of the Geological Society, 2004; 161: 243 - 254. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. Horak, W. Compston, A.E. Wright, and P. Toghill Discussion on dating the Late Precambrian volcanicity of England and Wales Journal of the Geological Society, 2003; 160: 329 - 330. [Full Text] [PDF]
|
|
|
|
|
|
D. Grazhdankin Patterns of distribution in the Ediacaran biotas: facies versus biogeography and evolution Paleobiology, 2004; 30: 203 - 221. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 E.R. Phillips, J.A. Evans, P. Stone, M.S.A. Horstwood, J.D. Floyd, R.A. Smith, M.C. Akhurst, and H.F. Barron Detrital Avalonian zircons in the Laurentian Southern Uplands terrane, Scotland Geology, 2003; 31: 625 - 628. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
K. J. Peterson, B. Waggoner, and J. W. Hagadorn A Fungal Analog for Newfoundland Ediacaran Fossils? Integr. Comp. Biol., 2003; 43: 127 - 136. [Abstract] [Full Text] [PDF]
|
|
