Local Rocks
Within easy reach of Glasgow there lies a rich variety of igneous, sedimentary and metamorphic rocks. These rocks were laid down during a period of over 500 million years, starting in the Neoproterozoic period (1000 to 541 Ma) and finishing in the Triassic period (252 Ma to 201 Ma). (A chronostratigraphic chart describing the internationally agreed geological time scale can be found here.)
The map below shows the rock types that are found in the extended Glasgow area, and the key to the right describes the symbols used in the map. Below the map are two panels. The left panel contains links to pages describing the rock cycle, the three different rock types (igneous, sedimentary and metamorphic) and rock-forming minerals. The right panel contains links to pages describing twelve sites in the extended Glasgow area. These links can also be accessed by moving the mouse pointer over the pins on the map. When the pointer is above a pin, a hint with the site name is shown, and the page describing the site can be opened by clicking the mouse button.
Key
Sedimentary Rocks |
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Mudstone, sandstone, limestone Middle-Upper Triassic |
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Stewartry Group, sandstone, breccia, conglomerate Lower Permian |
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Coal Measures Group, mudstone, sandstone, coal Upper Carboniferous |
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Clackmannan Group, sedimentary cycles Lower-Upper Carboniferous |
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Strathclyde Group, sedimentary cycles Lower-Upper Carboniferous |
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Inverclyde Group, sandstone, siltstone, mudstone Lower Carboniferous |
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Stratheden Group, sandstone, conglomerate Upper Devonian |
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Strathmore Groups, sandstone, conglomerate, mudstone Lower Devonian |
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Arbuthnott- Garvock Group, sandstone, conglomerate Lower Devonian |
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Lanark Group, sandstone, conglomerate Silurian-Devonian |
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mudstone, siltstone, sandstone Middle Silurian |
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Hawick Group, wacke Lower-Middle Silurian |
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Gala Group, wacke Lower Silurian |
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Shinnel and Glenlee Formations, wacke Middle-Upper Ordovician |
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Leadhills Supergroup, wacke Middle-Upper Ordovician |
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Portpatrick and Glenwhargen Formation, wacke Middle Ordovician |
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Kirkcolm Formation, wacke Middle Ordovician |
Igneous Rocks |
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Felsic igneous intrusives Palaeogene |
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Dolerite and tholeiitic basalt Carboniferous-Permian |
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Midland Valley Sill Complex, quartz- dolerite Upper Carboniferous |
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Strathclyde Group, mafic lava and tuff Lower Carboniferous |
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Felsic intrusion Upper Silurian-Devonian |
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Mafic lava and tuff Silurian-Devonian |
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Ballantrae Ophiolite Complex- serpentenite Lower Ordovician |
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Balcreuchan Group basaltic lava, agglomerates Lower Ordovician |
Metamorphic Rocks Dalradian Supergroup |
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Southern Highland Group, psammite, pelite Neoproterozoic-Cambrian |
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Metamorphosed lava and tuff Neoproterozoic |
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Argyll Group, psammite, semi- pelite, pelite Neoproterozoic |