Ancient volcanoes of Ireland...

dogmatix

Anyone know of a good site or source for information on ancient volcanoes in Ireland? There is very little info on specific sites - i'm particularily interested in Arklow head and Tara hill in Wexford. According to one website "Tara Hill is a volcanic feature that never erupted" whatever that means!

Same with Kildare - apparently the hill of allen is an ancient volcano but it s difficult to find info on its age, how big it would have originally been, what type of volcano it was etc.

slowburner

Here's a screenshot of some of the geology of the area. Not far enough south for Tara hill though because the major volcanic stuff is around Avoca. It's from the GSI site - it's well worth having a poke around there.

The Vale of Avoca and the associated mineralogy is the product of a submarine volcano from 100 million years ago if memory serves. The yellow pyrites around the mines are deposits left from geo-thermal vents on the ancient seabed (forgive my terminology please geographers/geologists ).
I think that Arklow head and Tara hill are more resilient remnants of the same deposits and the softer stuff has been eroded away in between by glacial action and rivers.
Don't think I'd lose much sleep over Tara hill erupting.

NotCarrotRidge

There are probably academic papers on all of the volcanic centres in Ireland, but you'd have to go looking for them and they're probably full of more detail than you're interested in.

Your best bet is probably to look by area, all of the GSI's bedrock mapping sheets have had a booklet accompanying them, they can be ordered from the website or you can actually drop into their public office to read them.

dogmatix

Thanks for the information everyone. The yellow bits around Arklow head seem to indicate Ordovician age. Had to look that up - 400 million years ago or thereabouts. Much older than I thought.

These two links gave some info on Ireland in Ordovician times - not specific to my two areas but interesting none the less:

http://www.geoschol.com/counties/MEATH_GEOLOGY.pdf

http://sepmstrata.org/HookHeadEire/PlatesTecIreland/pages/BlakeyLateOrd.html

LordSutch

I remember well as a child I always wanted the Sugarloaf mountain in Wicklow to be a real volcano,
it even looked like the real thing to me (how exciting)! rivers of lava running down the sides and all )

Subpopulus

Slive Gullion just southwest of Newry is an ancient volcano. There was a very good article in Earth Science 2000 a year or two ago giving a fairly layman's description of the igneous dykes that have been exposed by the building of the M1 round Newry.

Wild Bill

Croghan in County Offaly is an extinct volcano; visible from the M6 (south of)

Silvics

Pallasgreen volcanics in Limerick. Road to Tipp town

JupiterKid

And of course you can't discuss ancient volcanic structures and regions in Ireland without mentioning the Antrim mountains and the Giant's Causeway.

Cryogen

Derk hill, Limerick is an ancient volcano

Carawaystick

JupiterKid wrote: »

And of course you can't discuss ancient volcanic structures and regions in Ireland without mentioning the Antrim mountains and the Giant's Causeway.

There's big Bassalt columns visible on the inside of Arklow Rock quarry, similar to the Organ Pipes at the GC

coolabuaile

Basalt columns in Kerry to, south of lough guitane, killarney.

rightyabe

I was told at National School that Errigal was a ancient volcano..is that true?

dogmatix

Afraid not, Errigal is a quartzite peak which gives it a conical shape that mimics the traditional image of a volcano. The same is true for the sugar loaf in wicklow - also quartzite and often mistaken for a volcano.

An Ri rua

Croghan Hill, Co Offaly was of sufficient interest for a Canadian prospecting company to be doing surveys for diamonds.
I was up there just under 20 years ago and met a geologist from same.

Its a volcanic plug from the Carboniferous Period.

ardmacha

Slive Gullion just southwest of Newry is an ancient volcano

http://www.south-armagh.com/index.cfm/area/information/page/Landscapes