Prehistoric gold markers and environmental change: A two-age system for standing stones in western Ireland

Abstract

The Murrisk Peninsula in southwest County Mayo is a major target for gold exploration in Ireland. The most productive areas include the Cregganbaun Shear Zone and Cregganbaun Quartzite Belt on Croagh Patrick, both geologically related to Iapetus closure, and gold is concentrated in alluvial deposits of river systems draining these areas. A comparison of gold occurrences with the location of prehistoric stone monuments reveals that simple standing-stone monuments, though isolated from other monument types, correlate with alluvial gold. South of the Murrisk Peninsula in Connemara, isolated standing stones are associated with a wide range of mineral resources and with other monuments. Dating of the stones relative to blanket-bog expansion and coastal landform changes indicates that standing stones were raised as markers of gold placer deposits before a climatic deterioration at 1200 B.C. Late Bronze Age monuments with a ceremonial purpose are more complex and include stone alignments.

The role of geoarchaeology in extending our perspective

“…A quick glance through some recent papers reveals work being done, for instance, on how changing lake levels relate to the distribution of archaeological sites in Maine, USA (Pelletier et al 2007) and around the Aral Sea (Boroffka et al 2006). Past changes to sea level have been shown to have had an impact on the disappearance of the Lapita culture in New Caledonia (Carson 2008), on the distribution of Italian Neolithic sites (Lorusso 2007) and prehistoric American sites (Leach & Belknap 2007), on Chinese civilizations (Zhang et al 2005), and on the use of alluvial gold deposits in prehistoric Ireland (Moore 2006). Problems of increasing aridity have received attention in many parts of the world, including North America (French 2007;Huckleberry & Duff 2008), South America (Neme & Gil 2009;Sampietro & Neder), and Europe and the Middle East (Brooks 2006;French 2007;Gillmore et al 2007;Gillmore et al).…”