Geology and ground models - Practical Engineering Geology - page 48

Skye

SCOTLAND

Rum

Ardnamurchan

Mull

Staffa

Giant's Causeway

Arran

IRELAND
Slieve Gullion

ENGLAND
Intrusive complexes
Dykes & dyke swarms

Mourne

Carlingford

Figure 3.7 Simpli ed map showing Tertiary dyke swarms and igneous intrusion complexes

across northern Britain. Lava flows, from the volcanoes above the igneous complexes that are

now exposed (e.g. Figure 3.26) included the extensive flood basalt sheets of which the Giant ' s

Causeway and the Isle of Staffa are part (see Figures 3.36 to 3.38). Data are from Holmes
(1965) and Richey (1948).

remnant boulders and tors

metamorphic aureole due to
heat from granite

later dyke cutting granite
and country rock

weathered zone with
corestones

granite batholith

joint frequency decreasing
with depth

limestone changed to
marble due to
contact
metamorphism

ore body from minerals concentrated in
late stage cooling fluids from granite,
travelled along fault and replacing
limestone

hydrothermal alteration of
granite from late stage fluids
along fault

Figure 3.8 Schematic representation of igneous rock associations.