Where water wells up from the earth: excavations at the findspot of the Late Bronze Age Broadward hoard, Shropshire



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Pollen-stratigraphical analysis


The pollen analysis focused on the upper 80cm of the sedimentary sequence (8cm resolution) with a higher resolution study (4cm intervals) of the uppermost 50cm (~5300 to ~1200 cal yrs BP; ~3350 cal yrs BC to AD ~750), which spans the period of greatest archaeological interest (see fig 11).

Results


Local pollen assemblage zone BH-1 (80–49cm; ~12,252 to ~8960 cal yrs BP; ~10,302 to ~7010 cal yrs BC) spans the Late Devensian Lateglacial and Early Holocene. The pollen record is characterised by high percentage values of herbaceous taxa, notably Sinapis type (48% at 80cm), Cyperaceae (50% at 56cm) and Poaceae (31% at 80cm), as well as Artemisia and Caryophyllaceae. Dominating the tree and shrub pollen taxa are Corylus type (26% at 64cm), Tilia (16% at 64cm) and Alnus (12% in 64cm), as well as Betula, Quercus and Ulmus. Aquatic and spore taxa are poorly represented but include Sparganium type, Dryopteris type and Sphagnum.

Local pollen assemblage zone BH-2 (48–35cm; ~5321 to ~4262 cal yrs BP; ~3371 to ~2312 cal yrs BC) spans part of the Middle Holocene; the abrupt changes in pollen percentages and taxa indicate a major hiatus between zones BH-1 and BH-2, possibly lasting for ~3500 years. The record is characterised by high percentages of tree and shrub taxa, notably Alnus (44% at 44cm), Quercus (14% at 44cm) and Corylus type (15% at 40cm), as well as Tilia and Calluna. Poaceae (22% at 36cm), Apiaceae (7% at 40cm) and Filipendula (7% at 40cm) dominate the herbaceous taxa. Aquatic and spore taxa include Dryopteris type (22% at 44cm), Pteridium (4% at 36cm) and Sphagnum (7% at 36cm). Microscopic charred particles are present at 44cm (1%).

Local pollen assemblage zone BH-3 (35–15cm; ~4262 to ~2500 cal yrs BP; ~2312 to ~550 cal yrs BC) spans the latter part of the Middle Holocene and the transition to the Late Holocene. The record indicates a reduction in tree pollen percentages by comparison to LPAZ BH-2, and a modest rise in shrub taxa, notably Alnus (40% at 28cm), Quercus (14% at 21cm), Corylus type (19% at 28cm) and Calluna (4% at 21cm), as well as Betula and Pinus. Herb taxa are dominated by Poaceae (31% at 24cm), Cyperaceae (11% at 16cm), Filipendula (6% at 24cm), Galium type (6% at 24cm), Lactuceae (2% at 24cm), Plantago lanceolata (2% at 32cm), Poaceae >40 microns (2% at 32cm) and Ranunculus type (3% at 24cm). Aquatic and spore taxa include Dryopteris type (19% at 21cm), Pteridium (2% at 28cm) and Sphagnum (6% at 28cm).

Local pollen assemblage zone BH-4 (15–0cm; ~2500 cal yrs BP / ~550 cal yrs BC onwards) is dominated by herbaceous taxa, notably Poaceae (20% at 4cm), Cyperaceae (18% at 8cm), Filipendula (4% at 8cm), Cirsium type (3% at 4cm), Lactuceae (3% at 4cm) and Plantago lanceolata (3% at 8cm), as well as Poaceae >40 microns (1% at 12cm), Potentilla type (2% at 12cm), Rumex (2% at 8cm) and Succisa (3% at 12cm). Tree and shrub taxa include Alnus (24% at 12cm), Quercus (10% at 12cm), Tilia (3% at 12cm), Ulmus (2% at 8cm), Corylus type (13% at 4cm) and Calluna (3% at 12cm). Aquatic and spore taxa include Dryopteris type (15% at 12cm), Pteridium (2% at 4cm) and Sphagnum (11% at 4cm). Microscopic charred particles are present at 12cm (1%) and 4cm (3%).






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