Energy resources: Coal
Energy resources: Coal

This free course is available to start right now. Review the full course description and key learning outcomes and create an account and enrol if you want a free statement of participation.

Free course

Energy resources: Coal

1.7.1 Carboniferous mires

During the late Carboniferous, mires developed over vast areas of the UK. Much of today's land area was an extensive, low-lying plain bordering a sea to the south (a sea that was soon to be the site of a mountain-building episode). Any mountains that existed lay hundreds of kilometres to the north. Large river systems meandered southwards across these plains.

At that time, the UK lay in tropical latitudes, almost on the Equator (see Figure 33). The low plains were covered by extensive forests: the Carboniferous equivalent of the present-day tropical rainforests (see Figure 2c). However, most of the 'trees' were hollow, not solid, and more closely resembled modern horsetails than modern trees. No flowers or birds existed, but insect and reptile life was abundant in the forests.

Tropical storms were probably as common then as they are today. Such storms would devastate vast areas of forest, reducing trees and plants to jumbled leaves, branches and crushed hollow logs. The same storms would also have caused extensive flooding. After this devastation, the forest would quickly reestablish itself, only to be devastated again by subsequent storms. The forest floor was probably often metres deep in rotting vegetation destined to become peat and, much later, coal.

In the late Carboniferous, cycles of global sea-level rise and fall resulted from the melting and re-growth of continental ice sheets in the Southern Hemisphere. Consequently, numerous mire-flooding-sediment infill-mire episodes occurred on low-lying coastal plains, which led to thick sedimentary successions with numerous coal seams.

Question 3

Use Figures 2a and 5 to help you match the following sediments in a coal-bearing sequence A-E with their likely environment of deposition (a)-(e).

  • A.Mudstone with freshwater shells

  • B.Siltstone

  • C.Coarse sandstone

  • D.Seatearth

  • E.Coal

  • a.Peat accumulations on the swampy areas of a delta plain

  • b.Distributary stream channels cutting through the delta plain

  • c.Fossil soil beneath the mire

  • d.Deposits laid on delta plain in times of flooding

  • e.Shallow lakes and lagoons on the delta plain


A (e); B (d); C (b); D (c); E (a).


Take your learning further

Making the decision to study can be a big step, which is why you'll want a trusted University. The Open University has 50 years’ experience delivering flexible learning and 170,000 students are studying with us right now. Take a look at all Open University courses.

If you are new to university level study, find out more about the types of qualifications we offer, including our entry level Access courses and Certificates.

Not ready for University study then browse over 900 free courses on OpenLearn and sign up to our newsletter to hear about new free courses as they are released.

Every year, thousands of students decide to study with The Open University. With over 120 qualifications, we’ve got the right course for you.

Request an Open University prospectus