Welsh Basin Stratigraphy field course

Module number: GL3114

Module co-ordinator: Professor Mark Williams 

Visit the magnificent and ancient landscape of Wales and decipher its 600 million year old history. From its volcanic origins in the Precambrian, Wales gave birth to a marine basin in the Cambrian Period some 520 million years ago and this was long-lived for 100 million years. In Welsh strata are preserved the story of Earth’s first complex marine ecosystems - the story of bizarre ecosystems that inhabited the deep marine seabed hundreds of millions of years ago, and of the amazing graptolites, Earth’s first globally distributed zooplankton.

Here too, visit some of the first rivers to flow in a meandering pattern on Earth, now fossilised in the Devonian rocks at Freshwater West, and the animals that burrowed into the ancient riverbanks. A story as great as any from the Welsh bards, on this course you will understand how geologists piece together precise pictures of Earth’s landscape and biosphere evolution over immense periods of time. And also understand why Dylan Thomas loved New Quay.

(Image: The birth of an ocean. Students study the beginnings of the Iapetus Ocean in the half billion-year old rocks at the Wrekin, Shropshire [credit: Vincent Perrier].)

Topics covered

  • Geology, plate tectonic setting and palaeoenvironmental evolution of the Welsh basin
  • Use of field data to critically test hypotheses about the evolution of a particular rock succession
  • How to classify and characterise major types of lithofacies and biofacies and understand their relationship to palaeogeography
  • How to understand a sedimentary succession in terms of climate and oceanographic change
  • Relationship between biostratigraphy, chronostratigraphy and lithostratigraphy


  • Field course including evening lectures on the trip


  • Notebook documenting field exercises