Lecture 13
Table of Contents
- Tectonics and Surface Relief
- Why study surface relief?
- Why study surface relief?
- Why study surface relief?
- Why study surface relief?
- Why study surface relief?
- Why study surface relief?
- Why study surface relief?
- Why study surface relief?
- Above and Below sea level
- 13.1 Why are continents high and oceans low?
- 13.1 Why are continents high and oceans low?
- 13.1 Why are continents high and oceans low?
- 13.1 Why are continents high and oceans low?
- 13.1 Why are continents high and oceans low?
- 13.1 Why are continents high and oceans low?
- 13.1 Why are continents high and oceans low?
- 13.1 Why are continents high and oceans low?
- 13.2 How do we know ... that mountains have roots?
- 13.2 How do we know ... that mountains have roots?
- 13.2 How do we know ... that mountains have roots?
- 13.2 How do we know ... that mountains have roots?
- 13.3 How does isostasy relate to active geologic processes?
- 13.3 How does isostasy relate to active geologic processes?
- 13.3 How does isostasy relate to active geologic processes?
- 13.3 How does isostasy relate to active geologic processes?
- 13.3 How does isostasy relate to active geologic processes?
- Glacial Isostasy
- 13.3 How does isostasy relate to active geologic processes?
- 13.3 How does isostasy relate to active geologic processes?
- 13.3 How does isostasy relate to active geologic processes?
- 13.3 How does isostasy relate to active geologic processes?
- 13.4 Why does sea level change?
- 13.4 Why does sea level change?
- 13.4 Why does sea level change?
- 13.4 Why does sea level change?
- 13.4 Why does sea level change?
- 13.4 Why does sea level change?
- 13.5 How and where do mountains form?
- 13.5 How and where do mountains form?
- 13.5 How and where do mountains form?
- 13.5 How and where do mountains form?
- 13.5 How and where do mountains form?
- 13.5 How and where do mountains form?
- 13.5 How and where do mountains form?
- 13.6 How does mountain building relate to the growth of continents?
- 13.6 How does mountain building relate to the growth of continents?
- Non-Subductable Crust
- Non-Subductable Crust 2
- 13.6 How does mountain building relate to the growth of continents?
- 13.6 How does mountain building relate to the growth of continents?
- 13.6 How does mountain building relate to the growth of continents?
- Provinces of North America
- 13.6 How does mountain building relate to the growth of continents?
- 13.6 How does mountain building relate to the growth of continents?
- 13.6 How does mountain building relate to the growth of continents?
- Island Arcs
- 13.6 How does mountain building relate to the growth of continents?
Text and Images from Slide
13.3 How does isostasy relate to active geologic processes?
- Problems with Pratt and Airy isostasy
- These models do explain some geologic situations in a general way but lack in detail and fail to explain certain features at all
- The wood block analogy suffers in two ways
- Assumes a very weak crust and also that faults penetrate through the entire crustal thickness. In reality, upper crust is strong, and faults do not penetrate lower crust due to plastic flow.
- The mantle is almost entirely solid rock, not liquid. Even though mantle flows like a high-viscosity liquid, it is very slow. Adjustments of the crust are limited by the slow flow of mantle from one area to another below regions of changing crustal weight.
- So a more precise analogy might be to think of the crust as a single flexible sheet. The entire model then is more akin to a water bed that responds very slowly—flexural isostasy.