modeling short-term hydrosedimentary processes and the preservation of river dune deposits suzanne...

Modeling short-term hydrosedimentary processes and the preservation of river dune deposits

Suzanne LeclairMontréal, QC, CANADA

suzanneleclair@sympatico.ca

Theory Experiment

Modeled distributions of dune height and trough elevation based on observed dune migrating behaviour

(without sediment vertical sorting—and hence no constraint on dune scouring)

From Leclair , Sedimentology 2002)

Observations Results vs Simulation model

From Leclair, 2006, GEOLOGY

Inverse modeling:Interpretation of sedimentary record

-15

-10

-5

0

5

10

15

20

25

0 10000 20000 30000 40000

Distance (m)

Ele

vati

on

rel

ativ

e to

dat

um

(m

)Modeling the thickness of

preserved deposit from various hydrographical events at the

channel scale

Observed alongstream dune-bed elevations in the Mississippi River

Quaternary Loire

?

(Research program while at Tulane University– supported by the Board of Regents of Louisiana)

18 m

5 km

Predicting mean thickness of channel deposit --or erosion

bed elevation below 0, m02468

Fra

ctio

n o

f d

istr

ibu

tion

0.5

0.6

0.7

0.8

0.9

1.01st peak rising

2nd peak

falling

3.1 m

(1.3m)

1.5 m1 m(0.8 m)(0.9 m)

Preserved after 1 year

?