Lecture Note
The Volcanoes that Shaped Edinburgh
-
University:
University of Edinburgh -
Course:
EASC08030 | Geology and Landscapes Academic year:
2022
-
Views:
44
Pages:
38
Author:
bratsj1xi4
Edinburgh: shaped by volcanoes Volcano anatomy
Lava flows and ash layers
Plug
Intrusion Types of volcano
Grey volcanoes with silica-rich magma that tends to
have high viscosity and lots of gas; results in
explosive eruptions and steep-sided stratovolcanoes.
Typical rock: andesite.
Montserrat, Eastern
Caribbean
Red volcanoes with silica-poor magma with low
viscosity that flows easily and allows gas to escape.
Usually forms lava flows and flat ‘shield’ volcanoes.
Typical rock: basalt.
Krafla,
Iceland Plate tectonics controls volcano type Plate tectonics controls volcano type Edinburgh’s volcanoes: two episodes
Carboniferous Period
360-300 million years ago
Continental rift in Midland Valley
of Scotland. Surface volcanic
activity across the area and
magma intrusions.
Early Devonian Period
420-400 million years ago
Subduction-related volcanic
activity across Scotland,
including granite formation and
surface volcanoes at Glen Coe,
Ben Nevis, Lorne, Ochil and
Pentland Hills. Episode 1: subduction
Map of the world 450 million years ago
Laurentia
Baltica
Avalonia
Landscape fashioned by geology
series, published by SNH/BGS
www.scotese.com
The Caledonian Orogeny
Continental collision
420 million years ago Episode 1: subduction
Igneous rocks formed at the end of the
Caledonian Orogeny
420 to 400 million years ago
Including most of the granite in the
Highlands, Shetland and southern Scotland
And the volcanic rocks of the Ochil, Sidlaw
and Pentland Hills
Image from Con Gillen, Geology and
Landscapes of Scotland (2nd edition), 2013, Dunedin Pentland Hills: varied volcanic rocks
Pentland Rocks is one of
25 leaflets published by
Lothian and Borders
GeoConservation, and
available as free
downloads from the
Edinburgh Geological
Society website. Pentland Hills Contrasting lava flows
Warklaw Hill basalt
Torduff Hill trachyte Black Hill, Pentlands Modern example: Montserrat Growth of lava dome
November 1995
March 1996 Devastating pyroclastic flows Blackford Hill Andesite on Blackford Hill Evidence of pyroclastic flows?
Andesite
Tuff (lithified volcanic ash) Edinburgh’s volcanoes: two episodes
Carboniferous Period
360-300 million years ago
Continental rift in Midland Valley
of Scotland. Surface volcanic
activity across the area and
magma intrusions.
Early Devonian Period
420-400 million years ago
Subduction-related volcanic
activity across Scotland,
including granite formation and
surface volcanoes at Glen Coe,
Ben Nevis, Lorne, Ochil and
Pentland Hills. World map 340 million years ago – the Carboniferous Period
Britain near the Equator,
drifting north, close to
the southern edge of a
large, stable continent. Episode 2: rifting
Second episode of volcanic
activity, 360-330 million years
ago.
In Edinburgh, this includes the
basalt rock of Craiglockhart Hill,
Arthur’s Seat and also magma
intrusions to form sills. Craiglockhart Hill
Salisbury Crags & Arthur’s Seat ## Castle Rock City centre volcanoes Arthur’s Seat volcano Holyrood Park rock types
Tuff (volcanic ash)
Basalt (lava flow)
Agglomerate (crater fill)
Dolerite (magma intrusion) Whinny Hill lava flows Agglomerate, central vent Modern example: Japan
Oshima volcano, Japan
Active basalt volcano close to Tokyo.
Fissure eruption in crater area, 21 Nov 1986.
During the evening more than 10,000 people
were evacuated safely, with no injuries.
1km 1986 lava flows James Hutton, Edinburgh genius
But the man of scientific
observation, who looks into the
chain of physical events connected
with the present state of things,
sees great changes that have been
made, and foresees a different state
that must follow in time, from the
continued operation of that which
actually is in nature.
James Hutton, 1726-1797 Hutton on Salisbury Crags
“We have a good example of this in the little mountain of
Arthur's Seat, by this town of Edinburgh. This is a peaked hill
of an irregular erupted mass …
on the north side we find remarkable masses
of whin-stone in that regular form among the
strata, and lying parallel with them. The most
conspicuous of these basaltic beds forms the
summit of the hill which is called Salisbury
Craig. Here the bed of whin-stone, more than
60 or 80 feet thick, rises to the west at an angle
of about 40 degrees; it forms the precipicious
summit which looks to the west; and this is an
appearance which is distinguishable upon a
hundred other occasions in the hills and
mountains of this country. t.andl sU'li'faM now
'vfil'v'v.
v'1 v-v
-.-, 'ч 'v
'
;'!' Shaped by volcanoes Shaped by ice The Volcanoes that Shaped Edinburgh
Devonian Period: silica-rich volcanoes
Blackford, Braid & the
Pentland Hills:
410 million years old
Carboniferous Period: silica-poor volcanoes
Arthur’s Seat, Castle Rock &
Craiglockhart Hills
340 million years old
Salisbury Crags &
Corstorphine Hill
320 million years old
The Volcanoes that Shaped Edinburgh
of 38
Report
Tell us what’s wrong with it:
Thanks, got it!
We will moderate it soon!
Struggling with your assignment and deadlines?
Let EduBirdie's experts assist you 24/7! Simply submit a form and tell us what you need help with.
Free up your schedule!
Our EduBirdie Experts Are Here for You 24/7! Just fill out a form and let us know how we can assist you.
Take 5 seconds to unlock
Enter your email below and get instant access to your document