Paper Published by Ussher Society
JGP have recently had a paper accepted by The Ussher Society. The paper will be included in their Proceedings of the Ussher Society publication, Geoscience in South-West England, 14, 192–200.
Titled: ‘Evidence’ for transition between Authigenic and Allogenic Aquifer functioning related to Regional Uplift and Sea Level Change in the Plymouth Coastal Karst Aquifer. The paper was written by Chris Easterbrook and Rod Smith.
The Plymouth Coastal Karst Aquifer comprises Middle to Late Devonian limestones and underlies much of the early urban centres of Plymouth and Stonehouse. Whilst once important as a source of water the aquifer is now only used to supply limited water supply to industry, the aquifer becoming contaminated by saline intrusion in the 19th century.
A tentative model for the development of the aquifer and the major limestone gorge complex which dissects it over the Middle and Late Pleistocene is presented. This model is based on regional and recessional uplift estimates and recent global eustatic sea level estimates.
Periods when the aquifer may have functioned authigenically are linked to periods of high sea level and haloclinal cave development. Allogenic aquifer phases are linked to the development of vadose engulfment and the downcutting of the Limestone Gorge complex. Two such phases are identified in the western portion of the aquifer associated with the former Sour Pool. A tentative chronology of the phases and the development of the gorge is discussed in relation to the proposed uplift model. The maximum elevation of the aquifer suggests that the aquifer may have developed over the last 400 to 600 kyr. The development of the aquifer is considered in relation to other coastal aquifers in south Devon.
A copy of paper is available from The Ussher Society