Geologic Time and Stratigraphy
Stratigraphy is arranging rocks in some sort of logical sequence in terms of their age
Strata simple means layer
Ancient Greeks recognized fossils embedded in rocks now on top of mountains.
Cor relating the rocks seen in one location with rocks seen in another one, can be within a few
kilometres or fur ther apart. The idea is to find the contemporary environment in Canada
Dilvui m (meaning 'of a f lood') Strict biblical interpretations of Earth's histor y (rocks and
landscapes result from Noah's f lood) More than one f lood recognized (new life created each
time so each layer contains different for ms)
Archbishop Ussher 1581-1656: declared in 1625 that “earth formed at 9 am on October 26
4004 B.C” He based this on counting generations in the bible.
Georgius Agricola 1494-1555 was the father of mining geology. Recognized that fossils are
remains of marine organisms in 1531. De Re Metallica was published after his death in 1556.
Nicholas Steno 1631-1686 stated that mountains can be raised and lowered, land can be
conveyed from one place to another.
“The Scottish Enlightenment” c.1730-1830: Joseph Black (a pioneer of chemistry) James Hutton
(a farmer who was interesting in soil and became interesting in how soil formed. Regarded as
the father of modern day geology), Adam Smith (founder of modern day economics, wealth of
nations), James Watt (Name used as an index of energy, invented the steam engine), Walter
Scott (A writer, who wrote about Scotland). An english visitor to Edinsburg remarked: “Here I
stand at what is called the Cross of Edinsburgh and can in a few minutes take 50 men of genius
and learning by t he land”
James Hutton 1726-1797: Recognized “unconformities”(are the gaps in the geologic records)
within layers of rocks and the igneous origin of granite. Proposed the concept of
“unifor mitarianism” (the present is the key to the past) Came into conf lict with Abram Werner
and 'diluvialism' and 'catastrophism'
Arthur's Seat: has a very distinctive shape. It or iginated from eros ion down. It is a sill. Was the
first place Hutton noticed igneous rocks .
John Playfair (geologist) 1747-1819 developed the concept of “deep time” wrote a book that
summarized Hutton's idea, and made it understandable.
There are fossils in the secondary strata but not the pr imary strata
The grat unconformity is in Marmora ontario. Precambrian 1 Gs rocks are located at the bottom
An angular unconfor mity near kingston. 500 million missing years. 1 billion year old rocks at
the bottom and 500 million year rocks on the top. Is angular because there is f lat lying rocks and
steep dipping rocks
The Taconic unconfor mity located in New York State about 440 Ma
Charlies Lyell's wrote the geology textbook 'Principles of Geology' in 1830. Lyell's had a very
logical way of thinking.
Louis Agassiz 1807-1873: Catastiophism and Creationism VS Charles Darwin 1809-1882
Unifor mitarianism and Evolution. The big debate of the 19
1830's discovery of the or igin of coal by William Logan: Formed in Situ from plant debris
growing in swamps. Confirmed by discovery of in Situ lithified tree trunks in coal seams