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Welcome! Short Courses Online Summer Sessions The Volcanoes that Shaped Edinburgh Angus Miller The session will start at 19:00 BST.

The Volcanoes that Shaped Edinburgh Angus Miller · Grey volcanoes with silica-rich magma that tends to have high viscosity and lots of gas; results in explosive eruptions and steep-sided

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Page 1: The Volcanoes that Shaped Edinburgh Angus Miller · Grey volcanoes with silica-rich magma that tends to have high viscosity and lots of gas; results in explosive eruptions and steep-sided

Welcome!Short Courses Online Summer Sessions

The Volcanoes that Shaped EdinburghAngus Miller

The session will start at 19:00 BST.

Page 2: The Volcanoes that Shaped Edinburgh Angus Miller · Grey volcanoes with silica-rich magma that tends to have high viscosity and lots of gas; results in explosive eruptions and steep-sided

Asking questions

Please feel free to ask questions! During the session, simply type your question in the Chat box.

I will do my best to answer them along the way, or we can pick them up in discussion.

Page 3: The Volcanoes that Shaped Edinburgh Angus Miller · Grey volcanoes with silica-rich magma that tends to have high viscosity and lots of gas; results in explosive eruptions and steep-sided

Audio checkCan you hear me?

If you can’t hear: Check the Audio/Visual settings in

the Collaborate Panel Try signing out and signing back into

the session Make sure the audio is turned up on

your personal device Type into the chatbox and I will try

to assist you as best I can

Page 4: The Volcanoes that Shaped Edinburgh Angus Miller · Grey volcanoes with silica-rich magma that tends to have high viscosity and lots of gas; results in explosive eruptions and steep-sided

RecordingThis session will now be recorded. Any further information that you provide during a session is optional and in doing so you give us consent to process this information.

These sessions will be stored and published online by the University of Edinburgh for one year after the event. Schools or Services may use the recordings for up to a year on relevant websites.

By taking part in a session you give us your consent to process any information you provide during it, including your name in the chatbox if you ask a question.

Page 5: The Volcanoes that Shaped Edinburgh Angus Miller · Grey volcanoes with silica-rich magma that tends to have high viscosity and lots of gas; results in explosive eruptions and steep-sided

Edinburgh: shaped by volcanoes

Page 6: The Volcanoes that Shaped Edinburgh Angus Miller · Grey volcanoes with silica-rich magma that tends to have high viscosity and lots of gas; results in explosive eruptions and steep-sided

Volcano anatomy

Lava flows and ash layers

PlugIntrusion

Page 7: The Volcanoes that Shaped Edinburgh Angus Miller · Grey volcanoes with silica-rich magma that tends to have high viscosity and lots of gas; results in explosive eruptions and steep-sided

Types of volcano

Montserrat, Eastern Caribbean

Krafla, Iceland

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.

Page 8: The Volcanoes that Shaped Edinburgh Angus Miller · Grey volcanoes with silica-rich magma that tends to have high viscosity and lots of gas; results in explosive eruptions and steep-sided

Plate tectonics controls volcano type

Page 9: The Volcanoes that Shaped Edinburgh Angus Miller · Grey volcanoes with silica-rich magma that tends to have high viscosity and lots of gas; results in explosive eruptions and steep-sided

Plate tectonics controls volcano type

Page 10: The Volcanoes that Shaped Edinburgh Angus Miller · Grey volcanoes with silica-rich magma that tends to have high viscosity and lots of gas; results in explosive eruptions and steep-sided

Edinburgh’s volcanoes: two episodes

Early Devonian Period 420-400 million years agoSubduction-related volcanic activity across Scotland, including granite formation and surface volcanoes at Glen Coe, Ben Nevis, Lorne, Ochil and Pentland Hills.

Early Devonian Period 420-400 million years agoSubduction-related volcanic activity across Scotland, including granite formation and surface volcanoes at Glen Coe, Ben Nevis, Lorne, Ochil and Pentland Hills.

Carboniferous Period 360-300 million years agoContinental rift in Midland Valley of Scotland. Surface volcanic activity across the area and magma intrusions.

Page 11: The Volcanoes that Shaped Edinburgh Angus Miller · Grey volcanoes with silica-rich magma that tends to have high viscosity and lots of gas; results in explosive eruptions and steep-sided

Episode 1: subduction

Landscape fashioned by geology series, published by SNH/BGS

Laurentia

Avalonia Baltica

ww

w. s

cote

s e.c

o m

Map of the world 450 million years agoThe Caledonian OrogenyContinental collision 420 million years ago

Page 12: The Volcanoes that Shaped Edinburgh Angus Miller · Grey volcanoes with silica-rich magma that tends to have high viscosity and lots of gas; results in explosive eruptions and steep-sided

Episode 1: subduction

Igneous rocks formed at the end of the Caledonian Orogeny420 to 400 million years agoIncluding most of the granite in the Highlands, Shetland and southern ScotlandAnd the volcanic rocks of the Ochil, Sidlaw and Pentland Hills

Image from Con Gillen, Geology and Landscapes of Scotland (2nd edition), 2013, Dunedin

Page 13: The Volcanoes that Shaped Edinburgh Angus Miller · Grey volcanoes with silica-rich magma that tends to have high viscosity and lots of gas; results in explosive eruptions and steep-sided

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.

Page 14: The Volcanoes that Shaped Edinburgh Angus Miller · Grey volcanoes with silica-rich magma that tends to have high viscosity and lots of gas; results in explosive eruptions and steep-sided

Pentland Hills

Page 15: The Volcanoes that Shaped Edinburgh Angus Miller · Grey volcanoes with silica-rich magma that tends to have high viscosity and lots of gas; results in explosive eruptions and steep-sided

Contrasting lava flows

Torduff Hill - trachyte

Warklaw Hill - basalt

Page 16: The Volcanoes that Shaped Edinburgh Angus Miller · Grey volcanoes with silica-rich magma that tends to have high viscosity and lots of gas; results in explosive eruptions and steep-sided

Black Hill, Pentlands

Page 17: The Volcanoes that Shaped Edinburgh Angus Miller · Grey volcanoes with silica-rich magma that tends to have high viscosity and lots of gas; results in explosive eruptions and steep-sided

Modern example: Montserrat

Page 18: The Volcanoes that Shaped Edinburgh Angus Miller · Grey volcanoes with silica-rich magma that tends to have high viscosity and lots of gas; results in explosive eruptions and steep-sided
Page 19: The Volcanoes that Shaped Edinburgh Angus Miller · Grey volcanoes with silica-rich magma that tends to have high viscosity and lots of gas; results in explosive eruptions and steep-sided

Growth of lava dome

November 1995

March 1996

Page 20: The Volcanoes that Shaped Edinburgh Angus Miller · Grey volcanoes with silica-rich magma that tends to have high viscosity and lots of gas; results in explosive eruptions and steep-sided

Devastating pyroclastic flows

Page 21: The Volcanoes that Shaped Edinburgh Angus Miller · Grey volcanoes with silica-rich magma that tends to have high viscosity and lots of gas; results in explosive eruptions and steep-sided

Blackford Hill

Page 22: The Volcanoes that Shaped Edinburgh Angus Miller · Grey volcanoes with silica-rich magma that tends to have high viscosity and lots of gas; results in explosive eruptions and steep-sided

Andesite on Blackford Hill

Page 23: The Volcanoes that Shaped Edinburgh Angus Miller · Grey volcanoes with silica-rich magma that tends to have high viscosity and lots of gas; results in explosive eruptions and steep-sided

Evidence of pyroclastic flows?

Andesite

Tuff (lithified volcanic ash)

Page 24: The Volcanoes that Shaped Edinburgh Angus Miller · Grey volcanoes with silica-rich magma that tends to have high viscosity and lots of gas; results in explosive eruptions and steep-sided

Short break – 3 minutes Any questions?Please type your question

in the Chat box.

Page 25: The Volcanoes that Shaped Edinburgh Angus Miller · Grey volcanoes with silica-rich magma that tends to have high viscosity and lots of gas; results in explosive eruptions and steep-sided

Edinburgh’s volcanoes: two episodes

Early Devonian Period 420-400 million years agoSubduction-related volcanic activity across Scotland, including granite formation and surface volcanoes at Glen Coe, Ben Nevis, Lorne, Ochil and Pentland Hills.

Early Devonian Period 420-400 million years agoSubduction-related volcanic activity across Scotland, including granite formation and surface volcanoes at Glen Coe, Ben Nevis, Lorne, Ochil and Pentland Hills.

Carboniferous Period 360-300 million years agoContinental rift in Midland Valley of Scotland. Surface volcanic activity across the area and magma intrusions.

Page 26: The Volcanoes that Shaped Edinburgh Angus Miller · Grey volcanoes with silica-rich magma that tends to have high viscosity and lots of gas; results in explosive eruptions and steep-sided

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.

Page 27: The Volcanoes that Shaped Edinburgh Angus Miller · Grey volcanoes with silica-rich magma that tends to have high viscosity and lots of gas; results in explosive eruptions and steep-sided

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.

Image by Alison Tymon, for Edinburgh Geological Society school poster

www.edinburghgeolsoc.org/learning/

Page 28: The Volcanoes that Shaped Edinburgh Angus Miller · Grey volcanoes with silica-rich magma that tends to have high viscosity and lots of gas; results in explosive eruptions and steep-sided

Craiglockhart Hill

Salisbury Crags & Arthur’s Seat

Page 29: The Volcanoes that Shaped Edinburgh Angus Miller · Grey volcanoes with silica-rich magma that tends to have high viscosity and lots of gas; results in explosive eruptions and steep-sided

##

Page 30: The Volcanoes that Shaped Edinburgh Angus Miller · Grey volcanoes with silica-rich magma that tends to have high viscosity and lots of gas; results in explosive eruptions and steep-sided

Castle Rock

Page 31: The Volcanoes that Shaped Edinburgh Angus Miller · Grey volcanoes with silica-rich magma that tends to have high viscosity and lots of gas; results in explosive eruptions and steep-sided

City centre volcanoes

Page 32: The Volcanoes that Shaped Edinburgh Angus Miller · Grey volcanoes with silica-rich magma that tends to have high viscosity and lots of gas; results in explosive eruptions and steep-sided

Arthur’s Seat volcano

Page 33: The Volcanoes that Shaped Edinburgh Angus Miller · Grey volcanoes with silica-rich magma that tends to have high viscosity and lots of gas; results in explosive eruptions and steep-sided

Holyrood Park rock types

Agglomerate (crater fill)

Basalt (lava flow)

Dolerite (magma intrusion)

Tuff (volcanic ash)

Page 34: The Volcanoes that Shaped Edinburgh Angus Miller · Grey volcanoes with silica-rich magma that tends to have high viscosity and lots of gas; results in explosive eruptions and steep-sided

Whinny Hill lava flows

Page 35: The Volcanoes that Shaped Edinburgh Angus Miller · Grey volcanoes with silica-rich magma that tends to have high viscosity and lots of gas; results in explosive eruptions and steep-sided

Agglomerate, central vent

Page 36: The Volcanoes that Shaped Edinburgh Angus Miller · Grey volcanoes with silica-rich magma that tends to have high viscosity and lots of gas; results in explosive eruptions and steep-sided

1km

Oshima volcano, JapanActive 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.

Modern example: Japan

Page 37: The Volcanoes that Shaped Edinburgh Angus Miller · Grey volcanoes with silica-rich magma that tends to have high viscosity and lots of gas; results in explosive eruptions and steep-sided

1986 lava flows

Page 38: The Volcanoes that Shaped Edinburgh Angus Miller · Grey volcanoes with silica-rich magma that tends to have high viscosity and lots of gas; results in explosive eruptions and steep-sided

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

Page 39: The Volcanoes that Shaped Edinburgh Angus Miller · Grey volcanoes with silica-rich magma that tends to have high viscosity and lots of gas; results in explosive eruptions and steep-sided

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.

Page 40: The Volcanoes that Shaped Edinburgh Angus Miller · Grey volcanoes with silica-rich magma that tends to have high viscosity and lots of gas; results in explosive eruptions and steep-sided
Page 41: The Volcanoes that Shaped Edinburgh Angus Miller · Grey volcanoes with silica-rich magma that tends to have high viscosity and lots of gas; results in explosive eruptions and steep-sided

Shaped by volcanoes

Page 42: The Volcanoes that Shaped Edinburgh Angus Miller · Grey volcanoes with silica-rich magma that tends to have high viscosity and lots of gas; results in explosive eruptions and steep-sided

Shaped by ice

Page 43: The Volcanoes that Shaped Edinburgh Angus Miller · Grey volcanoes with silica-rich magma that tends to have high viscosity and lots of gas; results in explosive eruptions and steep-sided
Page 44: The Volcanoes that Shaped Edinburgh Angus Miller · Grey volcanoes with silica-rich magma that tends to have high viscosity and lots of gas; results in explosive eruptions and steep-sided

The Volcanoes that Shaped Edinburgh

Blackford, Braid & the Pentland Hills:

410 million years old

Arthur’s Seat, Castle Rock & Craiglockhart Hills

340 million years old

Salisbury Crags & Corstorphine Hill

320 million years old

Devonian Period: silica-rich volcanoes Carboniferous Period: silica-poor volcanoes

Page 45: The Volcanoes that Shaped Edinburgh Angus Miller · Grey volcanoes with silica-rich magma that tends to have high viscosity and lots of gas; results in explosive eruptions and steep-sided

THANK YOU!We hope you enjoyed this Short Courses Online Summer Session.

Our 2020/21 Short Courses opened for booking on Monday 3 AugustPlease visit our website for more information.

www.ed.ac.uk/short-courses

Any questions?