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Coal formation:
when:
North European principle coalfields:-
era - Upper Palaeozoic dates:
how:
first by peat formation
formed in vast coastal swamps containing jungle-like vegetation modern analagous locations eg Florida Everglades - ancient swamps dominated by large scaly-barked trees (lycopsids)
- club-mosses and horsetails 45 - 60 ft (15 -20m)
dead vegetation protected from total decay by submergence in water
compression from overlying material forms peat aerobic bacterial activity near surface anaerobic bacterial activity raises acidity of water deepest layers of peat transformed into gytta requires large quantities of vegetation to form thick seams but does not require large thickness of peat
subsequent burial by sediments protects from erosion
then by coalification
bituminisation
deeper burial + geothermal gradient starts bituminisation gradual escape of more volatile hydrocarbon compounds increased burial and compaction produces higher rank of coal
lignite / brown coal sub-bituminous bituminous
metamorphism
where:
the palaeoenvironment:
the palaeoclimate:
the palaeogeography:
palaeomagnetic data shows North-European land mass near equator part of a much larger land mass (Laurasia) Lower Carboniferous (Dinantian)
NW Europe: in UK Pennine area:
localised stable blocks - & subsiding basins - limestone formation on stable blocks repeated sandstone - shale formations in basins
Early Upper Carboniferous (Namurian) Later Upper Carboniferous (Silesian)
in UK Pennine area:
deltas are extensive and established large areas flat & low-lying coastal swamps recurrent / rhythmic subsidence
End Carboniferous
NW Europe: in UK Pennine area:
folding, faulting uplift & erosion
the palaeotectonic activity:
what happened next:
Permian
what happened later
the Mesozoic:
Triassic Jurasic Cretacious
the Cenozoic:
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