Pioneers of Geology: Innovative Thinkers and Founders of Historical Geology

1. 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

2. Founders of Historical Geology William 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 be identified by their fossil assemblages First to “correlate” rocks of the same age but different lithology

4. Founders of Historical Geology William 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 can determine 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.

5. 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

6. Founders of Historical Geology Georges Cuvier 1769-1832 Alexandre Brongniart 1770-1847 Cuvier was a vertebrate paleontologist (left) Brongniart was a naturalist

7. Founders of Historical Geology Georges Cuvier 1769-1832 Alexandre Brongniart 1770-1847 Also recognized the utility of fossils for correlation Validated Smith’s findings Found that groups of fossils were separated by erosional surfaces (unconformities) Believed that these changes in life forms on Earth were caused by catastrophic events (catastrophe, extinction, creation of new life)

8. Founders of Historical Geology Georges Cuvier 1769-1832 Alexandre 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?

9. Founders of Historical Geology Georges Cuvier 1769-1832 Alexandre Brongniart 1770-1847 What caused the abrupt changes observed at unconformities? Ancestors are observed in underlying strata. Uniformitarianism held sway. Catastrophic events do happen volcanism, earthquakes, climate change, meteorite impacts

10. Founders of Historical Geology Charles Lyell 1797-1875 Published Principles of Geology (5 volumes - 1830) First textbook on Geology

11. Founders of Historical Geology Charles Lyell 1797-1875 Principles of Geology First to explain and synthesize geologic observations Added two more rules for interpreting geology.

12. Founders of Historical Geology Charles Lyell 1797-1875 Principle of Cross-Cutting Relationships

13. Founders of Historical Geology Charles Lyell 1797-1875 Principle of Inclusions

14. A Aqueous B Volcanic C Metamorphic D Plutonic

15. Founders of Historical Geology Charles Lyell 1797-1875 Andrew Ramsey stated: “We collect the data and Lyell teaches us the meaning of them”.

16. Founders of Historical Geology Charles Darwin 1809-1882 Added to the understanding of Fossil Succession

17. Founders of Historical Geology Charles Darwin 1809-1882 Clarified why the general progression of fossils worked Evolution - organisms changed through time Provided the mechanism for Fossil Succession