Geological Sites | Leeds
| Bradford | Calderdale
| Kirklees | Wakefield
 STATUS: RIGS
OTHER DESIGNATIONS:
COUNTY: West Yorkshire
DISTRICT: Bradford
OS GRID REF. SE 038 468
OS SHEET 1:50,000 Landranger 104 Leeds and Bradford
OS SHEET: 1:25,000 Outdoor Leisure 21 South Pennines
BGS Sheet 1:50,000 Geological Sheet 60 Bradford (Solid and Drift Edition)
FIRST DESIGNATED by West Yorkshire RIGS Group in 1996
DATE OF MOST RECENT SURVEY
SCIENTIFIC INFORMATION produced by Neil Aitkenhead
SITE DESCRIPTION:
The site runs along the Bracken Hill Gill in a wooded valley, exposing
Upper Carboniferous (Namurian) mudstones, clays and sandstone beds
which give important information about the environment of deposition
of the rocks.
HISTORICAL ASSOCIATIONS:
The site contains the original exposure of the Marchup Marine Beds where
Anthracoceras glabrum and Cravenoceratoides bisati were
collected. Specimens collected from this site in the 1920s enabled
W. S.
Bisat to describe the goniatite succession in the Arnsbergian (E2) Stage
of the Namurian Epoch.
 EDUCATIONAL VALUE:
The data provided above may enable the visiting student to see for themselves
the evidence for a changing
palaeoenvironment from the abandonment of a river delta with consequent
soil development and plant
colonisation and growth followed by marine flooding with mud deposition
containing marine organisms.
A 'K (potassium)-bentonite' clay band provides evidence of distant volcanic
activity and consequent
ashfall into this marine environment.
The site also illustrates how the rapidly evolving ammonoids (formerly
goniatites) found in marine bands are used in the zoning and correlation
of Namurian and Westphalian rock successions.
AESTHETIC CHARACTERISTICS:
ACCESS AND SAFETY:
Although footpaths pass nearby the site is located on private land. This
is an important scientific site and unauthorised collecting is prohibited.
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