GR [6284 5188] & [6266 5185]
Sykes in Bowland is not far from Dunsop Bridge. It is also a very picturesque valley as can been seen by the photograph.
Sykes Anticline is fully exposed in Rams Clough. Permission is needed to enter the clough. The core of the anticline (Hetton Beck Limestone) can be seen in easy to access roadside quarries. The limestone belongs to that part of the stratigraphy desribed as the Hodder Mudstone Formation (late Chadian - Holkerian). This formation was first proposed by Riley (1990b) and corresponds closley with the Worston Shale Series of Parkinson (1926), the Worston Shales of Earp et al (1961) and the Salthill Cap Beds and Cephalopod Shales of Miller & Grayson (1972). One of the two roadside quarries can just be made out on the right-hand side of the road as it disappears in the distance.
Having explored the limestone and associated mineralisation, it is instructive move to car park shown. This gives you easy access to roadside outcrops at Trough Scar in the Upper Bowland Shale Formation.
Hetton Beck Limestone
Members of CPGS are exploring one of the roadside quarries in the Hetton Beck Limestone which forms the core of Sykes Anticline. The Hetton Beck Limestone Member (an integral part of the Hodder Mudstone Formation) is of late Chadian age consisting of argillaceous, fine to coarse grained packstones and thin shaly mudstone interbeds. Fossils abound throughout the limestone and much of the bedding has been obliterated by bioturbation. Some beds appear
to contain intraformational lithoclasts - an indicator of reworking of the sediment. Soft sediment slumping can be seen in the upper part of the sequence. The lower photograph is a particularly conspicuous large channel filled with slumped graded packstone beds.
In the higher parts of the quarry cherts appear as discrete units. The silicification may probably be related to the mineralisation.
Syringopora: a coral
Corals are particularly abundant in the quarries with large Syringopora colonies being the most conspicuous. Syringopora is a tabulate coral. They are characterised by having closely spaced tabulae with septa and dissepiments being absent or very weakly developed. The coral is preserved as a cluster of long slender tubes (corallites).
Corals are animals that live in the sea. They comprise a soft bodied animal (polyp) that lives in a calcareous skeleton (corallum). The polyp takes calcium carbonate from sea water to create the skeleton of calcite or aragonite. The cup (corallite) where the polyp lives is strengthened by septa (radiating plates), tabulae (corallite floors which build up on one another) and sometimes dissepiments (small concentrically arranged plates between the septa). Corals either live alone or in a group. Single corals are commonly called solitary corals whilst grouped corals are commonly called colonial or compound.
Notice how through weathering the coral colony shown in the photograph is neatly etched out of the limestone.
There is a rich history of metalliferous ore mining in the area. Galena and sphalerite have been intermittently mined from the limestones in the core of Sykes Anticline since the sixteenth century. Also extracted (though in smaller quantities): chalcopyrite, malachite, silver, fluorite and baryte.
The two limestone quarries at Sykes are separated by the road and Losterdale Brook. If you examine the area around the brook you will find evidence of addits. Also, just south of the quarry is an old house (Smelt Mill Cottage) at the foot of Smelt Mill Clough.
The main ore body appears to have been an ENE trending vein, with some irregular off-shoots tracing a minor fault plane on either side of the valley and lying sub-parallel to the major axial trend of the anticline. If you look carefully at the photograph, especially near the top, you should be able to make out some mineralisation and perhaps an addit or two.
Trough Scar: Upper Bowland Shale
The roadside exposures are predominantly interbedded shales, mudstones, calcareous mudstones and siltstones. Siderite concretions are present a few horizons. These early Pendleian sediments were laid down largely from suspension in relatively deep, poorly oxygenated waters. A smattering of bivalves and fish faunas indicate a restricted marine or non-marine environment.
The discovery of beds of abundant thick-shelled ammonoids (goniatites) indicate fully marine conditions. Eustatic sea-level changes are thought to be responsible for these sea-level highstand of minor trangressive cycles.
There are three minor cycles recognised at Trough Scar, two of which are marine bands and one influx of sand deposited as turbidity currents in a few localised channels on the sea floor. The cycles are as follows:
|Cravenoceras malhamense marine band
||Grid Ref. 6249 5284
|Hind Sandstone Member
||Grid Ref. 6252 5285
|Eumorphoceras pseudobilingue marine band
||Grid Ref. 6253 5282
At the top of the sequence the Cravenoceras malhamense marine band is about 2.4 metres thick with a base 14 metres below the base of the Pendle Grit Formation. The Hind Sandstone (named after Hind Clough in the Brennand Valley) is a coarse-grained feldspathic, massive sandstone. Plant debris and crinoid ossicles have been found in the sandstone. The Eumorphoceras pseudobilingue marine band is expposed on the western bank of the stream, 42 metres below the base of the Pendle Grit Formation.