Download - What’s so remarkable about Hutton’s Ideas?
What’s so remarkable about Hutton’s Ideas?
• Contrary to prevailing views of the time• Based on observation – what he saw• Hutton drew inferences from his observations• Inferences are hypotheses• Hypotheses are testable• This is an application of the scientific method
to study of the Earth
Founders of Historical GeologyWilliam Smith 1769-1839
English surveyor and mining engineer
Created the first geologic map
Understood sequences of rock, applied soils,lithology, and fossils
First to recognize that rocks could beidentified by their fossil assemblages
First to “correlate” rocks of the same agebut different lithology
Founders of Historical GeologyWilliam Smith 1769-1839
Correlation led to Principle of Faunal Succession
If we know the position of each rock layer in a sequence, we know their relative age.
Then, if we look a the fossils in the layers, we candetermine the relative ages of them.
This sequence will occur again and again in the geologic record on a widespread geographic scale.
Can then be used to provide relative age of the rocks.
Smith determined that the life forms of each age in Earth history were unique for given intervals
Fossils could then be used to determine the chronology of the rocks
Smith saw it, knew it was right, but didn’t know WHY
Founders of Historical GeologyGeorges Cuvier 1769-1832Alexandre Brongniart 1770-1847
Cuvier was a vertebrate paleontologist (left)Brongniart was a naturalist
Founders of Historical GeologyGeorges Cuvier 1769-1832Alexandre Brongniart 1770-1847
Also recognized the utility of fossils for correlationValidated Smith’s findings
Found that groups of fossils were separated byerosional surfaces (unconformities)
Believed that these changes in life forms on Earthwere caused by catastrophic events(catastrophe, extinction, creation of new life)
Founders of Historical Geology
Georges Cuvier 1769-1832Alexandre Brongniart 1770-1847
This was contrary to Hutton’s uniform, gradual change on Earth over long periods of time.
Led to a new school of thought: Catastrophism
Scientists argued Catastrophism vs Uniformitarianism
Which is right?
Founders of Historical GeologyGeorges Cuvier 1769-1832Alexandre Brongniart 1770-1847
What caused the abrupt changes observed at unconformities?
Ancestors are observed in underlying strata.
Uniformitarianism held sway.
Catastrophic events do happenvolcanism, earthquakes, climate change,meteorite impacts
Founders of Historical GeologyCharles Lyell 1797-1875
Published Principles of Geology(5 volumes - 1830)
First textbook on Geology
Founders of Historical GeologyCharles Lyell 1797-1875
Principles of GeologyFirst to explain and synthesize geologic observations
Added two more rules for interpreting geology.
Founders of Historical GeologyCharles Lyell 1797-1875
Principle of Cross-Cutting Relationships
Founders of Historical GeologyCharles Lyell 1797-1875
Principle of Inclusions
A AqueousB VolcanicC MetamorphicD Plutonic
Founders of Historical GeologyCharles Lyell 1797-1875
Andrew Ramsey stated:
“We collect the data and Lyell teachesus the meaning of them”.
Founders of Historical GeologyCharles Darwin 1809-1882
Added to the understanding of Fossil Succession
Founders of Historical GeologyCharles Darwin 1809-1882
Clarified why the general progression of fossils worked
Evolution - organisms changed through time
Provided the mechanism for Fossil Succession