Upper Trap
Silurian (Telychian)
PERIOD |
GROUP |
FORMATION |
Silurian |
- |
Upper Trap |
Lithology
Basalt. Contaminated enstatite-bearing basalts, with or without olivine. May be strongly amygdaloidal and are much altered with with plagioclase completely or partially albitised, enstatite replaced by bastite and olivine altered to chlorite and opaque oxides. Can be distinguished from the Lower Trap by the presence of quartz xenocrysts, visible with a hand lens.
Upper Boundary
Abrupt trnsition to mudstone and sandstone of the Tortworth Beds.
Lower Boundary
Abrupt change to mudstone and sandstone of the Damery Beds.
Representative Sites
No Accessible Exposure
Information on lithology and boundaries taken from the British Geological Survey Lexicon of Named Rock Units
and BGS Memoirs.
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