1. Intro to Graphic Correlation
Fossils and Evolution 870:125

2. Loc. A
100 miles
Loc. B 6 5 4 3 2 1 1 2 3 4 5

3. Loc. A Loc. B 100 miles 5 4 6 5 3 4 2 3 1 2 1 Top 4 Base 4 Base 3

4. 6 5 4 3 2 1 1 2 3 4 5

5. 5 + 5 4
top of #4 + 4 6 5 3
base of #4 + 3 4 2 + 2 3 2 1 + 1 1 5 4 3 2 1

6. Selecting Line of Correlation
Select line so that:
It goes through at least some points (ideally bases or tops that are known to have biostratigraphic integrity)
Bases not on line are to the left
Tops not on line are to the right
Assumption: Standard Reference Section is depositionally continuous and fossil ranges are relatively complete

7. Graphic Correlation + + + Loc. A + Line of correlation +5 + 4 6 5 + 3 4
Loc. A + 2
Line of correlation 3 2 + 1 1
Standard Reference Section

8. Significance of LOC + + Section 2 + + + Standard Reference Section5 + 4
Slope of LOC is the
average relationship
between rate of
deposition in the two
sections being correlated
If LOC is correct, any point
in one section can be
correlated to its precise
equivalent in the other
section 6 5 + 3 4
Section 2 + 2 3 2 + 1 1
Standard Reference Section

9. Significance of LOC
LOC may be a straight line if two sections being correlated are both depositionally continuous and if there is a constant relationship between rates of deposition in each
LOC may change slope if rate of deposition changed in one section relative to the other
Horizontal terrace in LOC indicates an unconformity (depositional hiatus or erosion) in one section

10. Significance of LOC SRS SRS hiatus or erosion at other section
while deposition
continued at SRS
increase in rate
of deposition at
SRS relative to
other section
SRS
SRS

11. Compositing and updating the SRS+ 5
add top
of #6 + 4 5 + 3 4
Section 2 6 2
raise
top +
lower
base
add base
of #6 2 3 + 1 1
Standard Reference Section

12. Compositing and updating the SRS
Once range adjustments and range additions have been completed, the SRS becomes a Composite Standard Reference Section

13. PAST data file for Loc A vs. Loc B