|
|
|
N.E.G.S. Field Trip: Wards Hill Quarry, leader; Gordon Liddle. Lordenshaws Hill Fort and Tosson Lime Kiln, leader Derek Teasdale. 23rd. June, 2012 A party of 15 members including the two leaders met at Wards Hill Quarry, NZ078967, about 3 miles southeast of Rothbury in mid Northumberland. The quarry consists of Lower Carboniferous sediments, limestones and shales with a late Carboniferous (294Ma. +or-400Ka.) sill like dolerite intrusion, possibly a leaf (or leaves) from a feeder dyke associated with the Great Whin Sill. At this locality, in the western part of the quarry, the dolerite was proved, under thin section examination, to grade into altered basalt near its margin with the underlying fossiliferous limestone. It was highly fractured and consisted of fresh feldspars and chloritised/serpentinised ferromagnesian minerals within a dark glassy matrix. The limestone did not appear to be metamorphosed and was fossiliferous, containing productids. The leader pointed out several structural features, small scale antiform and synform folding as well as minor faulting, all of which are not thought to be tectonic but the result of the intrusion itself forcing its way through the country rock. In one of the localities part of the sill was shown to have a dyke like transgressive feature. In summary, the party found the locality to be extremely interesting and enigmatic. (cf. photo's). The party then made its way to Lordenshaws Hill Fort, NZ054989 about 2 miles south of Rothbury. From here, the leader, Derek Teasdale, pointed out how the wonderful panoramic views were the result of the underlying geology. In the distance could be seen an impressive range of hills formed by Devonian andesite lavas which were intruded by a large granite mass about 380Ma. Nearby, the less resistant Cementstone Group resulted in the valley through which the meandering River Coquet flows. The high ground in this area, e.g. Simonside, consists predominantly of sandstones belonging to the Fell Sandstone Group which, in this area, has a regional dip to the southeast. Nearby, on a rocky promontory, enigmatic cup and ring marks, believed to date from Neolithic to the early Bronze Age, were pointed out. The party engaged in much speculation and debate as to the purpose and meaning of these marks. The general consensus seemed to be that they had some religious significance. The Iron Age hillfort itself was then visited. It was seen to consist of three or four circular ridges and furrows which enclosed the remains of what appeared to be about three stone circular houses. Ancient trackways were also identified in the area. (cf. photo's).
The final
port of call was Tosson
Lime Kiln, NU027009.
The leader explained how operating lime kilns were once a common
site across Northumberland and how limestone (calcium carbonate) was
calcined to form lime (calcium oxide) which was used to make cement
or improve soil quality. The lime kiln was designed by
architect George Reaval and was built in 1888. It is considered
the best preserved lime kiln in Northumberland. During the 2nd World
War it fell into disuse since the glow from the kiln might have
caught the attention of enemy aircraft flying above. Many of the
bricks had the name "Heddon" moulded on them, perhaps some
clue as to their provenance. |
