1. Sheila Trampush and Liz Hajek
Evaluating the Effect of Autogenic Sedimentation on the Preservation of Climate Proxy Records: Modeling and Examples from the Paleocene Eocene Thermal Maximum
Sheila Trampush and Liz Hajek

2. Global climate vs. local sedimentation
Fluvial
Coastal Shelf
Colorado
Wyoming
New Jersey
Maryland
Foreman et al., 2012
Baczynski et al., 2013
Stassen et al, 2015
Self-Trail et al, 2012

3. Can landscape dynamics be responsible?
Constant sedimentation = best preserved?
High sedimentation =
best preserved?
Manners et al. (2013)

4. Landscape Dynamics High Sedimentation, High variability
High Sedimentation, Low variability
Fluvial
Lacustrine
Low Sedimentation, High variability
Low Sedimentation, Low variability
Coastal Shelf
Deep Marine

5. (Double Pareto distribution)
Stochastic Sedimentation Model
Sedimentation
Bed elevation
Proxy signal
Record 50
350
350
400
Mean sedimentation
High: 30 cm/Kyr
Low: 10 cm/Kyr 40 30
Density [%]
Total Duration: 200 Kyr
300
250
250 20 10
Time [Kyr]
Time [Kyr]
Elevation [m]
200
Recovery: 180 Kyr -2 2
Annual event size [m]
150
150
(Double Pareto distribution)
100 year event:
+/- 16 cm or 5 cm
1,000 year event:
+/- 170 cm or 40 cm
10,000 year event:
+/- 360 cm or 140 cm
100
Onset: 20 Kyr 50 50
Total model time: 350 ky
200
400 -6 -4 -2 2 -6 -4 -2 2
Elevation [m]
δ13C [‰]
δ13C [‰]

6. Example Synthetic Records
Variable Preservation in All Models
Proxy
Example Synthetic Records
120 80
350
400
150
100 60
300
250 80
100
Time [Kyr]
Elevation [m]
200 60 40
150 40 50
100 20 20 50 -6 -4 -2 2 -6 -4 -2 2 -6 -4 -2 2 -6 -4 -2 2 -6 -4 -2 2
δ13C [‰]
δ13C [‰]
δ13C [‰]
δ13C [‰]
δ13C [‰]

7. Variable Preservation in All Models
Trampush & Hajek, in prep

8. Model Summary High Sedimentation, High variability
High Sedimentation, Low variability
Record Preserved: 88% (53%)
Magnitude: -4.6‰ (-5.2 to -2.2‰)
Onset: 15 Kyr (2 to 57 Kyr)
Recovery: 131 Kyr (51 to 215 Kyr)
High probability of modified record
Record Preserved: 100% (89%)
Magnitude: -5.0‰ (-5.2 to -4.5‰)
Onset: 19 Kyr (3 to 46 Kyr)
Recovery: 171 Kyr (116 to 215 Kyr)
Highest probability of a good record
Fluvial
Lacustrine
Low Sedimentation, High variability
Low Sedimentation, Low variability
Record Preserved: 69% (44%)
Magnitude: -4.1‰ (-5.1 to -1.5‰)
Onset: 10 Kyr (2 to 58 Kyr)
Recovery: 117 Kyr (40 to 210 Kyr)
Lowest probability of a good record
Record Preserved: 87% (58%)
Magnitude: -4.7‰ (-5.2 to -2.6‰)
Onset: 16 Kyr (2 to 53 Kyr)
Recovery: 138 Kyr (51 to 224 Kyr)
High probability of a modified record
Coastal Shelf
Deep Marine

9. Ensemble records are more reliable
300
200
Time [Kyr]
100 -6 -4 -2 2 -6 -4 -2 2 -6 -4 -2 2 -6 -4 -2 2 -6 -4 -2 2
δ13C [‰]
δ13C [‰]
δ13C [‰]
δ13C [‰]
δ13C [‰]

10. Can landscape dynamics be responsible?
Fluvial
Coastal Shelf
Colorado
Wyoming
New Jersey
Maryland
Foreman et al., 2012
Baczynski et al., 2013
Stassen et al, 2015
Self-Trail et al, 2012

11. Wide variety of records in fluvial and shelf environments
Trampush & Hajek, in prep

12. Conclusions
Preservation of proxy systems is sensitive to the sedimentation rate and variability
Individual records can be very different from actual event, but averages of large numbers of records can recover the true event rates and durations
The “body” of the PETM could be entirely an artifact of variable sedimentation (but it’s possible that it’s not)

13. Ensemble records are more reliable