Pollen analytical investigations at Carrownaglogh prehistoric field system, County Mayo, Ireland

Palaeoecological investigations were carried out at a late Bronze Age site situated at Carrownaglogh, northeast Co. Mayo, with a view to reconstructing environmental conditions prior to and following blanket bog growth, which served to preserve the site.
The main feature of the excavated area consisted of a stone wall enclosure (2.2 ha) sited on a small knoll at 150 m O.D. Well defined cultivation ridges, 14C dated to the 9th century B.C., filled the area within the enclosure. Outside the enclosure, the ground is ridged or levelled and stone cleared.
Soil profile descriptions, chemical and mechanical analyses of fossil soils and pollen analysis of a series of short monoliths, which included mineral soil and overlying peat, were carried out.
To facilitate interpretation of the pollen analytical results surface samples from poorly fertilised arable land, where chemical weed control was minimal, were pollen analytically investigated.
A pollen diagram from the adjoining basin, spanning the period from c. 3600 yr B.P. to recent times, enables results of the above investigations to be placed in the context of the regional vegetational history.
Three distinct phases of extensive woodland clearance associated with arable and pastural farming are identified, dating to 2750, 1950 and 1000 yr B.P. The first of these, which emerges with particular clarity in the concentration pollen diagram, is equated with the farming phase which resulted in the ridge formation on the knoll.

研究团队于梅奥郡（County Mayo）东北部卡洛纳格洛赫（Carrownaglogh）的一处青铜时代晚期遗址开展古生态学（Palaeoecology）调查，旨在重建该遗址被毯状泥炭沼覆盖前后的环境状况——毯状泥炭沼正是该遗址得以完好保存的原因。
发掘区域的核心遗存为一处占地2.2公顷的石墙围场，坐落于海拔150米的小型丘岗之上。围场内遍布轮廓清晰的耕作垄，经碳十四（14C）测年，其年代可追溯至公元前9世纪。围场外侧的地面则被整理为垄状或平整状态，并清理了石块。
研究人员对一系列包含矿质土壤及其上覆泥炭的短柱状土芯开展了土壤剖面描述、古土壤的化学与机械组成分析，以及孢粉分析（pollen analysis）。
为便于阐释孢粉分析结果，研究人员还对施肥量低、化学除草极少的低肥力耕地的地表样品开展了孢粉分析。
取自相邻盆地的孢粉图涵盖了约距今3600年至今的时段，可将上述各项调查结果置于区域植被演化历史的框架中进行解读。
研究识别出三个与农耕及畜牧活动相关的大规模林地开垦阶段，年代分别为距今2750年、1950年及1000年。其中第一个阶段在浓度孢粉图中呈现得尤为清晰，其对应于丘岗上耕作垄形成的农耕活动时期。