James Huttson and Deep time
He was a scottish geologist. He is credited for being the originator of uniformitarianism. One of the big principles in geology. Uniformitarianism explains the features of the earths crust. He was born in 1726 and died in 1797 at the age of 71.
He found granite penetrating metamorphic rocks in the Scotland in a way that showed that the granite had been molten at the time showing that granite is formed from cooling molten rock.He went on to find a similar penetration of volcanic rock through sedimentary rock near Edinburgh.
What it meant
It showed that volcanic rock melted and rose to the top cooling and forming more rock such as granite. He said that this showed how old the earth was as he described the different layers of rock as time. He was able to determine how old the earth was by the different layers but of course it was just an approximation.
How old the earth is
The earth is approximately 4.5 billion years old and scientists know this by the different layers of the earth, simulations and uniformitarianism ( the features of the earth's crust. Scientists know this as we can estimate the age by the time it takes for a certain length of rock to have formed like it has.
Why scientists need to use imagination with his theory
They need to use their imaginations as if you take the age of the layers of rock that we can look at then we can estimate how far down it is and how long it would be for the rock layers to have formed to make it the earth we know of today.