Big Goals for Geologic Time/Stratigraphy

Scale/Magnitude/Hierarchy of Geologic Time

• Earth is 4.5 billion years old- what does this mean
• Resolution of geologic time—how accurately do we know time in different parts of the past; Our view of time is telescoped with a finer units closer to the present
• How do we know/measure geologic time-methods
• Absolute/Radiometric Dating
• Relative Dating/stratigraphic principles
• Cyclostratigraphy
• Biostratigraphy
• Magnetostratigraphy
• Chemostratigraphy
• Thresholds/benchmarks in geologic history; big natural changes/ what makes the major divisions in the geologic time scale

Earth has a history and is always changing- How do we know?

• Reading the rock record
• Proxies
• Nature of rock record- composite nature of rock record (space for time)

How do geoscientists test theories and draw conclusions: what constitutes robustness?

• Geoscientific method brings together multiple lines of evidence.
• Critical evaluation of data.

Rates and processes in the Earth system

• Gradual change vs abrupt events
• External vs internal forcing
• How do measure/know?
• Cyclicity/cycles
• Transgression/regression

Evolution of life

• Relationship to human activity
• What is evolution? What is evidence? Perception
• Missing links/incomplete nature of rock record
• Biotic response to global change