Earthwatcher's photos with the keyword: tuff

A day on the Langdale Pikes - Photo 15 Harrison Stickle's profile is less familiar when viewed from the path to Pavey Ark. The blobby rocks on the left are part of the Pavey Ark Member (formerly the 'Pavey Ark Breccia'). This is a very coarse tuff with many angular rock fragments, volcanic bombs and andesite lava spatter, possibly resulting from a pyroclastic flow settling into water; and thus indicative of the very violent volcanic history of much of the Lake District's distant past.

These rocks are on Pavey Ark in the Lake District National Park, England, about 350 m ENE of the summit cairn. The grid reference of the camera location is NY 28768 08076, close by the North Rake footpath. The rocks in this photo belong to the uppermost part of the Dungeon Ghyll Member in the Borrowdale Volcanic Group (Ordovician). They are coarse, crudely bedded volcaniclastic pebbly sandstones, probably resulting from ash-fall into water, with accompanying andesite lava spatter; the whole lot subsequently disrupted by slumping and mass movement (Millward et al, 2000). The 'strangeness' is due to the presence of curious, concentric ring-like structures which appear to be secondary (i.e. later) concretions - expanding growths of secondary minerals (epidote?) to form spheroidal masses, which are easily discernible in the main photo (zoom in). The origin of these structures is unclear, and they do not seem to be documented from anywhere else in the district, although I have seen similar but less well developed structures on Side Pike in Great Langdale and near Levers Water in the Coniston Fells. Reference: Millward, D. et al. 2000. Geology of the Ambleside district, British Geological Survey Memoir for 1:50000 Geological Sheet 38, London HMSO.

The rocks in this photo belong to the uppermost part of the Dungeon Ghyll Member in the Borrowdale Volcanic Group (Ordovician). They are coarse, crudely bedded volcaniclastic pebbly sandstones, probably resulting from ash-fall into water, with accompanying andesite lava spatter; the whole lot subsequently disrupted by slumping and mass movement (Millward et al, 2000). The 'strangeness' is due to the presence of curious, concentric ring-like structures which appear to be secondary (i.e. later) concretions - expanding growths of secondary minerals (epidote?) to form spheroidal masses. The origin of these structures is unclear, and they do not seem to be documented from anywhere else in the district, although I have seen similar but less well developed structures on Side Pike in Great Langdale and near Levers Water in the Coniston Fells. Reference: Millward, D. et al. 2000. Geology of the Ambleside district, British Geological Survey Memoir for 1:50000 Geological Sheet 38, London HMSO.

An old level into an abandoned slate mine, adjacent to the active Thrang Quarry, Chapel Stile in the English Lake District. The abandoned mine worked beautifully figured green slate - mostly waterlain volcanic tuff of the Seathwaite Fell Formation in the Borrowdale Volcanic Group (Ordovician).

Near the summit of Pavey Ark, Lake District National Park, England. The rocks in this photo belong to the Pavey Ark Member (formerly the 'Pavey Ark Breccia') in the Borrowdale Volcanic Group (Ordovician). This is a very coarse tuff with many angular rock fragments, volcanic bombs and andesite lava spatter, possibly resulting from a pyroclastic flow settling into water; the whole lot subsequently disrupted by slumping and mass movement (Millward et al, 2000). This is indicative of the very violent volcanic activity which took place here way back in the Ordovician. Reference: Millward, D. et al. 2000. Geology of the Ambleside district, British Geological Survey Memoir for 1:50000 Geological Sheet 38, London HMSO.

The active slate quarry at Chapel Stile, Great Langdale, in the English Lake District. The quarry works beautifully figured green slate - mostly waterlain volcanic tuff of the Seathwaite Fell Formation in the Borrowdale Volcanic Group (Ordovician).

Rusting mining equipment and a slate retaining wall in the side of an old level into an abandoned slate mine, adjacent to the active Thrang Quarry, Chapel Stile in the English Lake District. The abandoned mine worked beautifully figured green slate - mostly waterlain volcanic tuff of the Seathwaite Fell Formation in the Borrowdale Volcanic Group (Ordovician).

An old level into an abandoned slate mine, adjacent to the active Thrang Quarry, Chapel Stile in the English Lake District. The abandoned mine worked beautifully figured green slate - mostly waterlain volcanic tuff of the Seathwaite Fell Formation in the Borrowdale Volcanic Group (Ordovician).

The Great Slab (or Flat Crags) consists almost entirely of a single, tilted bedding plane of water-lain tuff (volcanic 'ash'). Although the main footpath to the top of Bowfell passes close to the Great Slab, many walkers pass by with their noses set on the summit cairn and remain completely unaware of the existence of this amazing feature. Originally posted as a clue to a Guesswhere UK pic. See where this picture was taken. [?]