1. Chronostratigraphy
Units defined based on time-equivalent stratal surfaces, natural stratigraphic subdivisions
Chronozones vary in space but not time
Correspond to physical boundaries, which can generate reflections
SLIDE 9
When using a lithostratigraphic methodology:
Units defined based on time-equivalent stratal surfaces, natural stratigraphic subdivisions
Chronozones vary in space but not time
Correspond to physical boundaries, which can generate reflections
The diagrammatic cross section shows 3 time-units
- one major episode or pulse of deposition color-coded yellow
- a second episode shown in orange
- a third erisode indicated by white
How do we break the rock record into time units?
- there may be index fossils
- there may be beds that mark time – e.g., a volcanic ash layer
- we can use a method we call sequence stratigraphic analysis – which is beyond the scope of this course
Unit 3
Unit 2
Unit 1
Time Unit 1
Time Unit 2
Time Unit 3
Courtesy of ExxonMobil
L 11 – Stratigraphic Analysis