Archaeologists are to dig out a portal tomb in Northern Ireland for the first time in 50 years. The partial collapse of Tirnony Dolmen near Maghera has produced a rare opportunity to discover what lies beneath - and exactly how old it is. After the massive capstone of this portal tomb fell to the ground earlier this year, archaeologists will be able to uncover the secrets it has held for millennia before repairs are carried out.
     "After standing in Northern Ireland weather for over 5,000 years some of the tomb's structural stones have begun to crack, causing the capstone to slip," Northern Ireland Environment Agency (NIIEA) archaeologist Paul Logue said. "Before we start to repair the tomb we will excavate it to ensure that the archaeological material associated with it is recorded ahead of restoration work. We hope to find out more about how this tomb was built, when it was built and how it was used."
     The dolmen is remarkable for the free-standing orthostat, 1.8m high, which is beside one of the portal-stones. Behind the tilted capstone is a well-defined square chamber. Archaeologists are hoping to carbon date any items they find which have fallen among the packed stones, giving an accurate date for the building o the tomb. "We have to work out when these portal tombs appeared in Ireland. We haven't done a dig on one of these for almost 50 years - it's only on very very rare occasions that we decide to excavate because for something that important our job is to preserve rather than to excavate," Mr Logue said. "Because this one has been damaged, we can maybe answer a lot of questions."
     The dig will look for surviving traces of the tomb's cairn - a mount of earth or small stones which covered the tomb - and try to determine its original shape.  The excavations should also settle if there is (or isn't) a sort of forecourt area at the tomb, which is implied by an exceptional free standing stone near to one of its portal stones.  If so, the Tirnony Dolmen is not "a typical portal tomb, but rather a progression from the larger 'court tombs'".
     The excavation is being conducted by the Centre for Archaeological Fieldwork at QUB with NIEA. The general public can visit on Fridays (2pm-4pm) or follow progress via the archaeologist's blog on www.ni-environment.gov.uk. Friday opening times may change, so it is advised to check the excavation blog before you travel.

Edited from Belfast Telegraph (15 October 2010), Heritage Key (18 October 2010)