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



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Interpretation


During LPAZ BH-1 (~12,252 to ~8960 cal yrs BP; ~10,302 to ~7010 cal yrs BC), the pollen record indicates that the local wetland comprised vegetation typical of a fen with Cyperaceae (sedge family), Poaceae (grass family), Sparganium (bur-reed) and Sphagnum moss, together with Alnus (alder) and Salix (willow) carr woodland. The dryland vegetation was initially dominated by herbaceous taxa, notably Sinapis (Brassicaceae / mustard family) and Artemisia (eg glacier wormwood), indicating the presence of short turf grassland and tall herb plant communities. These are consistent with the Late Devensian Lateglacial age for the lower part of the sedimentary sequence (~137–69cm; ~15,000 to 11,500 cal yrs BP), and the presence of cold, harsh climatic conditions (eg tundra and semi-desert). This record is also consistent with pollen data from the UK spanning the Late Devensian Lateglacial including nearby Crose Mere.51

Mixed deciduous woodland and shrubland comprising Corylus (hazel) and Tilia (lime) with lesser amounts of Quercus (oak), Ulmus (elm) and Betula (birch), succeeded the herb dominated plant communities, which is broadly consistent with other pollen records for the Early Holocene in Shropshire.52 The possible dominance of Tilia within the woodland cover during the Early Holocene has been suggested by several of these studies despite the low percentages often recorded due to its poor pollen dispersal.53

The transition to LPAZ BH-2 (~5321 to ~4262 cal yrs BP; ~3371 to ~2312 cal yrs BC) was marked by a major hiatus in the sedimentary sequence, possibly lasting ~3500 years. The renewal of peat formation and presence of Alnus, Polypodium (polypody fern), Sphagnum and a range of herbaceous taxa is consistent with the presence of fen carr woodland. The surrounding dryland comprised mixed deciduous woodland and shrubland dominated by Corylus and Quercus suggesting the presence of open (‘parkland’) rather than closed woodland. Supporting this interpretation is the presence of dwarf shrubland (heathland), grassland and disturbed ground comprising Calluna (heather), Apiaceae (carrot family) and Plantago (eg common plantain). The declining Tilia pollen values are consistent with the age proposed for LPAZ BH-2, and suggests that the evidence from Broadward Hall for a decline in lime woodland may be correlated with the classic ‘Tilia decline’ of north-west Europe during the Late Neolithic and Bronze Age from ~5000 to ~3000 cal yrs BP (~3050 to ~1050 cal yrs BC).54 Supporting this interpretation are the low values of Ulmus pollen indicating that LPAZ BH-2 post-dates the classic ‘Ulmus decline’ of north-west Europe during the Neolithic from ~6347 to ~5281 cal yrs BP (~4397 to ~3331 cal yrs BC).55

From ~4262 to ~2500 cal yrs BP (~2312 to ~550 cal yrs BC), LPAZ BH-3 indicates a local wetland dominated by fen carr woodland but with a slight reduction in the proportion of Alnus, and a corresponding increase in Poaceae, Cyperaceae and especially Sphagnum moss. This suggests an increase in bog surface wetness, which is confirmed by the formation of moss peat from ~4173 to ~3996 cal yrs BP (~2223 to ~2046 cal yrs BC). The reason for this hydrological change remains unclear but given the evidence presented below for localised human activity, the increase in wetness may have been initiated by increased overland flow due to woodland clearance. The dryland vegetation shows a marked reduction in mixed deciduous woodland cover, especially Tilia. This coincides with the first clear evidence for human activity characterised by the presence of cereal pollen (undifferentiated), suggesting localised cultivation. The increase in herbaceous taxa is consistent with this signature for human impact on the environment; especially those taxa associated with disturbance and cultivated ground such as Plantago lanceolata (ribwort plantain). The Late Bronze Age spearheads from Broadward Hall, which have been radiocarbon dated to 2921–2765 cal yrs BP (980–830 BC cal yrs BC; 2740 ± 30 BP) and 2943–2780 cal yrs BP (940–820 BC cal yrs BC; 2760 ± 30 BP), may be correlated with the upper part of LPAZ BH-3 (~21–18cm). Therefore, we can state with increased certainty that the environmental changes recorded during this zone correspond to localised human activities.

Finally, LPAZ BH-4 (~2500 cal yrs BP / ~550 cal yrs BC onwards) indicates a significant increase in herbaceous and spore taxa associated with both dryland and wetland vegetation, and an overall reduction in tree and shrub taxa. The wetland comprised Poaceae, Cyperaceae, Sphagnum moss, Succisa (devil’s bit scabious) and Potentilla (tormentil) but with lesser amounts of Alnus by comparison to previous zones. This suggests a retrogressive development to grass-, sedge- and moss-dominated fen swamp. On the dryland, herbaceous taxa increase in diversity, notably Poaceae, Anthemis (chamomile), Artemisia (mugwort), Cirsium (thistle), Lactuceae (eg dandelion), Plantago lanceolata and Rumex (docks and sorrels). These taxa indicate open conditions and, together with the presence of cereal pollen and microscopic charred particles, provide further evidence for human impact on the local environment characterised by clearance, cultivation and the possibility of deliberate biomass burning. The transition to more open conditions during zones BH-3 and BH-4 (from ~4262 cal yrs BP / ~2312 cal yrs BC onwards) seems to be consistent with pollen data from other Shropshire sites,56 and therefore supports the interpretation from Broadward Hall of increasing human impact from the Bronze Age onwards.




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