Harlech Dome

{{Short description|Geological dome in Wales}}

{{Use dmy dates|date=April 2022}}

File:Harlech dome.png

The Harlech Dome is a geological dome in southern Snowdonia in north Wales. It extends approximately from Blaenau Ffestiniog in the north to Tywyn in the south, and includes Harlech, The Rhinogydd,{{cite web|url=http://www.thesnowdonian.com/regions/rhinogydd|title=Rhinogydd|work=The Snowdonial|accessdate=16 November 2014|url-status=dead|archiveurl=https://web.archive.org/web/20141129014708/http://www.thesnowdonian.com/regions/rhinogydd|archivedate=29 November 2014}} Barmouth and Cadair Idris.

The geological layer structure comprises Cambrian sedimentary, volcanic and intrusive rocks from the lower Paleozoic age approximately 4.5 km thick.{{cite web|url=http://www.ccgc.gov.uk/landscape--wildlife/geological-gems/wales-journey-through-time/cambrian/cambrian-rocks-in-wales.aspx|title=Cambrian rocks in Wales|work=Countryside Council for Wales|accessdate=14 November 2014|url-status=dead|archiveurl=https://web.archive.org/web/20141129084404/http://www.ccw.gov.uk/landscape--wildlife/geological-gems/wales-journey-through-time/cambrian/cambrian-rocks-in-wales.aspx?lang=en|archivedate=29 November 2014}}

The geology contains the Harlech Grits Group, Mawddach Group, Rhobell Volcanic Group and Aran Volcanic Group.

The area contains a wide range of metallic minerals and has been mined for (copper,{{cite web|url=http://nora.nerc.ac.uk/11869/|title=Mineral exploration in the Harlech Dome, North Wales|work=NERC Open Resesarch Archive|accessdate=16 November 2014}} silver, zinc, manganese,{{cite web|url=http://davel.f2s.com/hendrecoed/Merioneth-Manganese/geology/|title=Geology - Harlech Dome|work=Merioneth Manganese|accessdate=16 November 2014}} gold{{cite web|url=http://www.bernardoconnor.org.uk/Publications/Arthog%27s%20geology.htm|title=The Geology of the Barmouth and Arthog area|work=Bernard O’Connor |accessdate=16 November 2014}}{{cite web|url=http://www.geologywales.co.uk/storms/spring13a.htm|title=Chasing ancient microcontinents in North Wales - the Megumia project|work=Geology Wales|accessdate=16 November 2014}}) in the past.{{cite web|url=https://www.bgs.ac.uk/downloads/start.cfm?id=1743 |title=Mineral Reconnaissance Programme Report No 74 - "A reconnaissance geochemical drainage survey of the Harlech Dome, North Wales" (1985 PDF - mineralogical report, 113pp)]|work=British Geological Survey, Natural Environment Research Council |accessdate=14 November 2014}}