2007 Michigan Academy Meeting -The glacial section at Grand

Welcome

to the Geological Sciences section of

the Michigan Academy of Sciences,

Arts, and Letters

2007 Meeting at Ferris State University

The glacial section at Grand

Valley State University: A

Lake Michigan lobe advance

into a glacial lakePatrick M. Colgan

Grand Valley State University

Allendale, Michigan

Michigan

Counties

Ottawa County

10 kilometers N

GVSU

Grand

Rapids

Lake

Plain

Lake

Border

morainesLake Border Advance of the

Lake Michigan Lobe

~14,500-15,500 14C yrs B.P.

1 km

Allendale

Delta

end

moraineGlacial

Lake Chicago

Plain

Allendale

GVSU

Campus

500 meters

N

1

Lake Ontario

Hall

2

Section 1: Silt-rich diamicton with oxidized vertical joints, striated clasts, high density.

Dm

Sr-Sx

Dms

Section 1: Contact between diamicton and sand. Shear zone between.

clast of

diamicton

ripples

In silty

sand

Section 1: Clast of reddish diamicton in silty sand.

Sx-Sr

Sp

Fl

Sx-Sr

Fl

Section 1: planar bedded fine sands, crossbedding, ripples, and fines.

Sp

Fl

Sx-Sr

Section 1: laminated fines

Section 1 – Ravine Apartments

SC Z

0

1

2

3

meters G

erosional

surface

covered

Fl-Fm

Sr

Sx

Fm-Fl

Sx

Fm-Fl

Dm

Sp-Sr

1

2

3

4

5

67a7b8

9

10

11

12

13

sediment

samplessediment

facies

texture

D1

D2

GV-1-2 (diamicton - basal till)

0

10

20

30

40

50

60

70

80

90

100

0.0010 0.0100 0.1000 1.0000 10.0000

diameter (mm)

% c

oars

er

sandsilt grclay

GV-2-1 (sandy silt - glaciolacustrine)

0

10

20

30

40

50

60

70

80

90

100

0.0010 0.0100 0.1000 1.0000 10.0000

diameter (mm)

% c

oars

er

sandsilt grclay

GV-2-13 (clayey silt - glaciolacustrine )

0

10

20

30

40

50

60

70

80

90

100

0.0010 0.0100 0.1000 1.0000 10.0000

diameter (mm)

% c

oars

er

sandsilt grclay

D

Sr

Sr

Sr

Fm-Fl

Fm-Fl

Fm-Fl

S1

S2

S3

S4

S6

S5

clast of Dm

Sp

500 meters

N

1

Lake Ontario

Hall

2

Section 2: Silt-rich diamicton with striated and wedge shaped clasts.

fines

fines

rippled and cross-bedded

fine sands

rippled and cross-bedded

fine sands

rippled and cross-bedded

fine sands

planar bedded fine sands

trough cross-bedded sands

Section 2

Section 2 – planer bedded sand with scour of rippled sand

Section 2 – trough cross bedded sands

Section 2 - Granite clasts and clay rip-up clasts in laminated and deformed clay

2 cm

Section 2 - Thick clay bed in fine sand.

1

2

3

5

6

7

8

9

10

4

covered

Fm-Dm

inclusions of clasts of fines in sand

Fl-Fm

Fl-Fm

Fl-Fm

Dml-Fl

DmmFm-Fl

Fl-Fm

Fl-Fm

St-Sr (A)

St-Sr (A)

St-Sr

St

Sr (A)

St-Sr (A)

St-Sr (A)

St-Sr (A)

St

St

Sr

Sr

Sr

Sr (A)

St-Sr (A)

Sl

Sl

Sl

Samples

7

6

1

18

15

14

12

11

10

16

17

2

3

4

5

9

8

meters

St-Sr (A)

C Z S G D

0

SR2-10 (fine sand)

0

10

20

30

40

50

60

70

80

90

100

0.0010 0.0100 0.1000 1.0000 10.0000

diameter (mm)

% c

oars

er

sandsiltclay gr

SR2-16 (silty clay)

0.0

10.0

20.0

30.0

40.0

50.0

60.0

70.0

80.0

90.0

100.0

0.0010 0.0100 0.1000 1.0000 10.0000

diameter (mm)

% c

oars

er

grsandsiltclay

Section 3 – South Ravine

1 km

1

Lake Ontario

Hall

2

N

193 (479)

194 (479)

141 (523)

147 (518)

190 (510)

208 (520)

fine silty sand (lacustrine)

diamicton

(basal till)

Marshall Sandstone

~ 480-510 feet

clay, silt and fine sand (lacustrine)

Section 2

South Ravine

Ravine

Apartments

ele

vati

on

(ft

)

distance (meters)S N

Lake

Ontario

Hall

vertical exaggeration ~16:1

North to South Cross Section across GVSU Campus

diamicton (basal till)?

Interpretations

• Upper diamicton is basal till deposited during Lake Border advance.

• Lower sequence is interpreted as numerous underflows (turbidites) of fine silty sand overlain by thin rainout deposits of clay and silt.

• Till was deposited directly on lake sediments and inclusions of till suggest that the advance occurred as sediment was deposited into a proglacial lake.

• Minor debris flows and rainout layers are present.

Adapted from Benn and Evans (1998) after Powell and Domack (1995)

rain out of fine

silt and clay

underflows

of sand

(Sx-Sp-Sr)

deposition

of basal till (Dm)debris

flows (Dml)clay and silt

(Fm-Fl)

Morainal bank sedimentation model

Future Work

• Collect vibracores in areas of poor

exposure to see how extensive the

lacustrine sediments are.

• Compare diamicton clasts in upper sand to

basal till with grain size and clay

mineralogy.

• Collect vibracores to see what is below the

measured sections.

Acknowledgements

• Thanks to the GVSU geomorphology

students who have worked on the ravine

sediments in projects with me and other

faculty at GVSU.