relative dating what is it ?. who dunit ? james hutton holyrood park edinburgh castle lets start...
TRANSCRIPT
RELATIVE DATINGRELATIVE DATING
What is it ?
Who Dunit ?Who Dunit ?
James HuttonJames Hutton
Holyrood ParkHolyrood ParkEdinburgh CastleEdinburgh Castle
Let’s start with the story of James Hutton, a wealthy farmer born in 1726. As a farmer, it brought him
into close contact with the land
James Hutton’s James Hutton’s RevelationRevelation
He was the first person to realise
that the Earth must have been very much older than the 6,000
years believed at that time
Hutton’s ImaginationHutton’s Imagination
Hutton was convinced that the lowlands of Scotland had been
made at a later time than the uplands, but he did not have any
proofUNTIL …
Siccar Point, Nr Siccar Point, Nr EdinburghEdinburgh
Whilst walking along the beach at Siccar
Point, he noticed that the pebbles had come
from the cliff – he now understood that the beach sand was
made from the eroding cliffs – that was a big leap of
imagination for its time
Hutton’s Story of Siccar Hutton’s Story of Siccar PointPoint
He then noticed around the corner from the beach that some gently dipping red sandstones were lying
on top of some grey-coloured upright layers
From his observations, he began to unravel the story of what had happened to these
rocks
RELATIVE DATING RELATIVE DATING PRACTICALPRACTICAL
So, what is Hutton’s So, what is Hutton’s Story ? Story ?
The grey-coloured beds (A) were laid down as horizontal
layers of soft muds in the sea.
AThese were
hardened into rock deep in the Earth and then buckled
into folds by immense stresses.
So, what is Hutton’s So, what is Hutton’s Story ? Story ?
These stresses also thrust the rocks up to the surface as great mountains, which were then
eroded.
A These mountains were likewise worn down, and formed the horizontal red beds (B) on top of the vertical grey
rocks.
B
So, what is Hutton’s Story ? So, what is Hutton’s Story ? What is his evidence?
Fragments of the folded grey rock (A) are found in the red beds above it (B) –
so the red beds must be younger.
B
A
A
A
A
A
He didn’t even need fossils to date his beds !
Fold ShapeFold ShapeANTICLINE
younger
older
SYNCLINE
younger
older
What do you What do you think produces think produces
folds ?folds ?