continental-margin sedimentation during high sea level fluvial and glacial valleys flooded sediments...

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Continental-Margin Sedimentation during High Sea Level Fluvial and glacial valleys flooded Sediments trapped in river-mouth estuaries and fjords If much sediment supplied, estuaries and fjords are filled deltas formed Sediment can escape to continental shelf mud winnowed by waves leaving sand nearshore mud transported to middle shelf On collision margins (narrow, steep shelf) sediment can escape to continental

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Page 1: Continental-Margin Sedimentation during High Sea Level Fluvial and glacial valleys flooded Sediments trapped in river-mouth estuaries and fjords If much

Continental-Margin Sedimentation during High

Sea Level

Fluvial and glacial valleys flooded

Sediments trapped in river-mouth estuaries and fjords

If much sediment supplied, estuaries and fjords are filled

deltas formed

Sediment can escape to continental shelfmud winnowed by wavesleaving sand nearshoremud transported to middle shelf

On collision margins (narrow, steep shelf)sediment can escape to continental slope

Page 2: Continental-Margin Sedimentation during High Sea Level Fluvial and glacial valleys flooded Sediments trapped in river-mouth estuaries and fjords If much

Holocene deposits (<20,000 y) on continental shelves

Note: boundary between modern inner-shelf sand and modern mid-shelf mud depends on waves

Page 3: Continental-Margin Sedimentation during High Sea Level Fluvial and glacial valleys flooded Sediments trapped in river-mouth estuaries and fjords If much

Washington continental shelf

Page 4: Continental-Margin Sedimentation during High Sea Level Fluvial and glacial valleys flooded Sediments trapped in river-mouth estuaries and fjords If much
Page 5: Continental-Margin Sedimentation during High Sea Level Fluvial and glacial valleys flooded Sediments trapped in river-mouth estuaries and fjords If much

Continental-Margin Sedimentation during High

Sea Level

Fluvial and glacial valleys flooded

Sediments trapped in river-mouth estuaries and fjords

If much sediment supplied, estuaries and fjords are filled

deltas formed

Sediment can escape to continental shelfmud winnowed by wavesleaving sand nearshoremud transported to middle shelf

On collision margins (narrow, steep shelf)sediment can escape to continental slope

Page 6: Continental-Margin Sedimentation during High Sea Level Fluvial and glacial valleys flooded Sediments trapped in river-mouth estuaries and fjords If much

41o00’

40o50’

40o40’

124o40’ 124o30’

700

600

500

400

350

300

250 20

015

0 100

9080

7060

5040

302 0

10

Eel River Drainage BasinEel River Drainage Basin

Eel River Drainage Basin~9000 km2

Study Area

0 m

350

1400

Elevation

CaliforniaEel margin

Page 7: Continental-Margin Sedimentation during High Sea Level Fluvial and glacial valleys flooded Sediments trapped in river-mouth estuaries and fjords If much

Eel Canyon, northern California

Multiple entrants that are presently receiving sediment and experience many turbidity currents each year

Page 8: Continental-Margin Sedimentation during High Sea Level Fluvial and glacial valleys flooded Sediments trapped in river-mouth estuaries and fjords If much
Page 9: Continental-Margin Sedimentation during High Sea Level Fluvial and glacial valleys flooded Sediments trapped in river-mouth estuaries and fjords If much
Page 10: Continental-Margin Sedimentation during High Sea Level Fluvial and glacial valleys flooded Sediments trapped in river-mouth estuaries and fjords If much
Page 11: Continental-Margin Sedimentation during High Sea Level Fluvial and glacial valleys flooded Sediments trapped in river-mouth estuaries and fjords If much

Core

Dep

th0

5

10

15

20

25

30

Core

Dep

th

30

35

40

45

50

55

60L1C12

DUPLICATE DUPLICATE CORESCORES

L1C13L1C13 L1C12

LarryChannelThalweg

= 137 m