Early ideas on stratigraphy
How laters get bent and broken
Relative age of rock
Absolute age of rock
The geolicescale: 4.56 billion today
Ancient Greeks recognized fossils embedded in rocks now on tops of mountains
How did they get there? Strata
"Diluvium"(meaning 'of flood')
• Strict biblical interpretation of earth's history (rocks of landscapes result from
• More than one flood recognized (new life created each time so each layer
contains different life forms)
Archbiship Ussher (1571-1656)
• "Earth formed at 9am on October 26th 4004 B.C"
• Based on counting generations in the bible
Georgius Agrcola 1494-1555
• "Father of mining geology"
• Recognizes that fossils are remains of marine organisms in 1531
Nicolase Steno 1631-86: "Mountains can be raised and lowered, land can be
conveyed from one place to another"
James Hutton 1726-97
1. Recognized "unconformities" within layers of rocks and the igneous
origin of granite
2. Proposed concept of "uniformitarianism" (the present is the key to the
3. Came into conflict with Abram Werner and "diluvialism" and
• Facies: means "appearance of"
• Geologists speak of rock facies
• unconformative gaps- a groups of rocks formed at the same time and went
Hutton's unconformity at siccar point in scotland
1. Deposition of older strata (silurian)
2. Doformation of strata in mountain-building even
3. Erosion to produce surface of unformity
4. Deposition of younger stata (devonian)
5. Uplift, tilting erosion "the mind grows giddy gazing so far back into the abyss of time"
John playfair, geologist (1747-1819): the concept of deep time)
The Great unconformity at Marmora, Ontario
-oldest mining town
-formation of mountin, erosion getting rid of them, formation of limestone on
-over 600million years old: Precambrian: 1Ga
-proterozoic - youngest exo