THE NAMURIAN OF THE NORTH-WEST QUARTER OF THE ASKRIGG BLOCK

Abstract
Summary: The beds considered range from the Main Limestone at the base of E 1 to the Shunner Fell Grit high in E 2 . The Arnsbergian age of the Shunner Fell Marine Beds is confirmed by the discovery of Tylonautilus nodiferus (Armstrong). Early mutations of this species have also been found from the Faraday House Marine Band and Mirk Fell Ironstones. A widespread minor unconformity at the base of the Mirk Fell Ganister increases southwards and cuts out the Stonesdale and Crow Limestones. The Yoredale Mirk Fell Ganister passes southwards into the Lower Howgate Edge Grit of Millstone Grit facies. The majority of the E 1 non-calcareous beds accumulated in a delta front or interdistributory trough, though bar-finger and marsh deposits can also be recognized. Minor hinge lines existed along the northern and western margins of the Askrigg Block during E 1 times. The block is divided into two dissimilar parts by the Stockdale Vein trending WNW. The northern part is characterized by faults with a similar trend, parallel with the northern margin of the block, whilst the southern section has a more nearly north-south fault pattern, the individual faults being impersistent and with a small throw. In the west of the area the beds are gently folded along axes nearly parallel with the western margin of the block, but the folds are deflected to a more north-easterly direction near the northern edge.

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