Coppedhall Hanger

Site of Special Scientific Interest · 51.0379, -0.4636

Also within

West Sussex County

Condition (Natural England)

Favourable (2)
UnitFeatureConditionArea (ha)Assessed
TQ077276 Favourable 0.24 2012-09-13
TQ078276 Favourable 0.39 2012-09-13

Geology & landscape

Rock Type: Conglomerate

Landscape processes: Fluvial

Description

Description The banks of a stream at this site expose the Okehurst Sand Member BGS Bed 3a, in the lower Weald Clay Group. The site is important for the detailed evidence it yields onpalaeoclimate, depositional environments and origins of the detritus. A 1m thick sequence of intraformational conglomerate, sand and silt overlies a mat of jetified tree twigs and branches. This sequence indicates a fluvial point bar deposited in a meandering channel. ‘Cornstone’ clasts in the conglomerate seams record the erosion of nearby drained soils and suggest a warm alternating wet and dry climate. Tree fragments point to a more distant forest or savannah. Extrabasinal clasts in the sands are predominantly Hercynian on the basis of isotopic dates and are therefore derived from Cornubia clasts include high Kfeldspar, tourmaline, topaz, Li bearing biotite, microcline, garnet and staurolite. Other Information This is a new site and is to be included within a 'Geological Conservation Review'

Plant communities

A9 — Fast flowing river and stream, Marginal and inundation, Pond ditch and canal, Sluggish river and stream

Potamogeton natans community

Schoenoplectus lacustris, Juncus bulbosus, Sparganium angustifolium, Sparganium erectum, Sparganium minimum, Alisma plantago-aquatica, Lobelia dortmanna, Equisetum fluviatile, Myriophyllum alterniflorum, Elodea canadensis, Lemna minor, Lemna trisulca, Nymphaea alba, Callitriche platycarpa, Callitriche stagnalis, Littorella uniflora, Potamogeton natans, Ranunculus trichophyllus, Glyceria fluitans, Chara subspinosa

A14 — Fast flowing river and stream

Myriophyllum alterniflorum community

Isolepis fluitans, Juncus bulbosus, Fontinalis antipyretica, Lobelia dortmanna, Equisetum fluviatile, Myriophyllum alterniflorum, Lemna minor, Callitriche stagnalis, Littorella uniflora, Potamogeton filiformis, Potamogeton gramineus, Potamogeton natans, Ranunculus peltatus, Chara spp., Nitella hyalina

A17 — Chalk river and stream, Fast flowing river and stream

Ranunculus penicillatus ssp. pseudofluitans community

Berula erecta, Nasturtium officinale, Elodea canadensis, Lemna minor, Callitriche stagnalis, Veronica beccabunga, Polygonum amphibium, Polygonum hydropiper, Potamogeton crispus, Potamogeton pectinatus, Ranunculus penicillatus ssp. pseudofluitans

A18 — Fast flowing river and stream

Ranunculus fluitans community

Fontinalis antipyretica, Fontinalis squamosa var. curnowii, Myriophyllum alterniflorum, Myriophyllum spicatum, Elodea canadensis, Mentha aquatica, Lemna gibba, Lemna minor, Potamogeton perfoliatus, Ranunculus fluitans, Glyceria fluitans, Phalaris arundinacea