Bellewstown volcanics (and graptolite-bearing shales!), Co Meath

Saturday 31st March 2012

Leader: Dr. Matthew Parkes (National Museum of Ireland)

The fieldtrip will examine the Ordovician stratigraphy of the Bellewstown inlier near Duleek in County Meath, south of Drogheda. In a fairly compact ridge of higher ground there are three (or 4) formations comprising a mix of sedimentary and volcanic rocks, with Silurian rocks, surrounded by Carboniferous. It was believed to have been an island in the Ordovician Iapetus Ocean, with some distinct faunas from adjacent terranes. Fossils are recorded from many places but are not that easy to find. I can almost guarantee that you will be able to collect some graptolite fossils though in fresh quarry surfaces.

Meeting Place: 

Meet at entrance to Bellewstown Quarry (also known as Mullagh Quarry) at 10.30 on Saturday morning Ordnance Survey Discovery Series Sheet 43 National Grid Reference: O 080 675 Map:  Bellewstown Quarry is not listed on Google Maps. It is just south of the pinpoint on the map below at Hilltown Little. View Hilltown Little in a larger map

Itinerary:

10.30     Meet at Bellewstown quarry gates and pool cars if possible, to drive on towards Duleek 10.45     Stop 1 Prioryland Formation mudstone breccia, near Duleek 11.15       Stop 2a Prioryland Formation mudstone, near Duleek                  Stop 2b Diorite intrusion on formation boundary, near Duleek 11.50      Stop 3  lowest Hilltown Formation – field outcrop, freshly bulldozed 12.20     Stop 4 Carnes Formation – Bellewstown Limestone at new water treatment ponds 12.45     Stop 5 Carnes Formation – Large spoil heaps and fresh faces by cattle sheds at Carnes (with good potential for finding fossils of trilobites, brachiopods etc) 13.30     Lunch (bring sandwiches, flask etc and eat out) 14.00     Meet inside Bellewstown Mullagh Quarry and look at the range of rocks, particularly the thick Hilltown Formation, and the exciting stratigraphical questions raised by new radiometric dating evidence by Brian McConnell and Quentin Crowley. End with graptolite fossil collecting within black shale horizons, for as long as people want to carry on, up till about 4pm. Stop 6  On way back to Dublin (for some who travel in that direction) on shoulder of hill with great views over the coast, and small pits/natural exposures.  

For registration please contact excursions secretary Dan O’Shea by email, excursions@geology.ie.

For any enquiries regarding this field trip specifically, you can contact Matthew Parkes on 0871221967 or by e-mail at mparkes@museum.ie

We are able to visit the Bellewstown Quarry by the courtesy of Fergus Gallagher, Kilsaran International Ltd.