gy 402: sedimentary petrology

GY 402: Sedimentary Petrology

Lecture 6: Primary and Diagnostic Sedimentary

Structures

Instructor: Dr. Douglas W. Haywick

UNIVERSITY OF SOUTH ALABAMA

1. Models of traction structures

2. Sediment transport versus aggregation

3. Wave ripples

4. Erosional features

5. Surface features

6. Intrusive (dewatering & loading) structures

7. Really diagnostic structures (just a couple!)

Today’s Lecture

Models of Traction Structures

1) Small current ripples

From Reineck, H.-E. and Singh, I.B. 1980. Depositional Sedimentary Environments. Springer-Verlag, Berlin. 549p.

30 cm

From Reineck, H.-E. and Singh, I.B. 1980. Depositional Sedimentary Environments. Springer-Verlag, Berlin. 549p.

50 cm

Models of Traction Structures

From Reineck, H.-E. and Singh, I.B. 1980. Depositional Sedimentary Environments. Springer-Verlag, Berlin. 549p.

Models of Traction Structures

1) Small current ripples

current

Harms, J.C., Southard, J.B., Spearing, D.R. and Walker, R.G., 1975. Depositional Environments as Interpreted from Primary Sedimentary Structures and Stratigraphic Sequences. SEPM Short Course 2.

15 cm

Models of Traction Structures

1) Small current ripples (Linguoidal)

From Reineck, H.-E. and Singh, I.B. 1980. Depositional Sedimentary Environments. Springer-Verlag, Berlin. 549p.

10 cm

Models of Traction Structures

1) Small current ripples (lunate)

From Reineck, H.-E. and Singh, I.B. 1980. Depositional Sedimentary Environments. Springer-Verlag, Berlin. 549p.

30 cm

100 cm

Models of Traction Structures

2) Large current ripples

From Reineck, H.-E. and Singh, I.B. 1980. Depositional Sedimentary Environments. Springer-Verlag, Berlin. 549p.

From: Harms, J.C., Southard, J.B., Spearing, D.R. and Walker, R.G., 1975. Depositional Environments as Interpreted from Primary Sedimentary Structures and Stratigraphic Sequences. SEPM Short Course 2.

50 cm

100 cm

Models of Traction Structures

Computer animation of

ripple migration

Source: USGS Coastal & Marine Geology Web page (http://walrus.wr.usgs.gov/seds/).

Large Current Ripple Aggregation/Erosion

Sorry: This image will not play in on line

videos

75 cm

30 cm

From: Harms, J.C., Southard, J.B., Spearing, D.R. and Walker, R.G., 1975. Depositional Environments as Interpreted from Primary Sedimentary Structures and Stratigraphic Sequences. SEPM Short Course 2.

Erosion removes bed form topography

Models of Traction Structures

Trough-cross stratification

migration aggr

egat

ion

current

Migration versus aggregation

Transport versus aggregation

30 cm

From Reineck, H.-E. and Singh, I.B. 1980. Depositional Sedimentary Environments. Springer-Verlag, Berlin. 549p.

Climbing Ripples

Transport versus aggregation

Transport versus aggregation

Transport versus aggregation

Climb angle

Form through the action of “orbicular flow”

Wave ripples

From Reineck, H.-E. and Singh, I.B. 1980. Depositional Sedimentary Environments. Springer-Verlag, Berlin. 549p.

Wave ripples

Wave ripples

From Reineck, H.-E. and Singh, I.B. 1980. Depositional Sedimentary Environments. Springer-Verlag, Berlin. 549p.

Cross- stratification records aggregation versus transport

Rip up clasts

Erosional structures

Rip up clasts

Scours

Erosional structures

Rip up clasts

Scours

Channels

Erosional structures

Rip up clasts

Scours

Channels

Flute marks

Surface view

Bot

h fr

om R

eine

ck, H

.-E. a

nd S

ingh

, I.B

. 198

0. D

epos

ition

al S

edim

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ry

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ents

. Spr

inge

r-Ver

lag,

Ber

lin. 5

49p.

Erosional structures

Rip up clasts

Scours

Channels

Flute marks

Under bed view

From Reineck, H.-E. and Singh, I.B. 1980. Depositional Sedimentary Environments. Springer-Verlag, Berlin. 549p.

Erosional structures

Rip up clasts

Scours

Channels

Flute marks

Tool marks

From Lucchi, F.R.,1995. Sedimentographica. Second Edition. Columbia University Press. 255p.

Erosional structures

Rain drop imprints

Mudcracks

75 cm

http://www.bedford.k12.ny.us/flhs/science/geoscience/images/mudcrackssample.jpg

Surface features

Ancient (Triassic)

Modern

Rain drop imprints

Mudcracks

Beastie trails

40 cm

http://www.fossilmall.com/Stonerelic/trace%20fossils/DD39/DD39c.jpg

Surface features

Ancient (Silurian)

Modern

Rain drop imprints

Mudcracks

Beastie trails

Parting lineations

75 cm

http://ic.ucsc.edu/~casey/eart150/Lectures/Foliations&Lineations/PartingLinParrsbourghNS.jpg

Surface features

Ancient (Permian)

Modern

Loads

From

Luc

chi,

F.R

.,199

5. S

edim

ento

grap

hica

. Sec

ond

Editi

on. C

olum

bia

Uni

vers

ity

Pres

s. 25

5p.

Intrusive structures

Loads

Ball and pillows

From

Rei

neck

, H.-E

. and

Sin

gh, I

.B. 1

980.

Dep

ositi

onal

Sed

imen

tary

En

viro

nmen

ts. S

prin

ger-V

erla

g, B

erlin

. 549

p.

Intrusive structures

Loads

Ball and pillows

Sand dykes (dewatering)

Intrusive structures

Loads

Ball and pillows

Sand dykes

Mud volcanoes

Both from Reineck, H.-E. and Singh, I.B. 1980. Depositional Sedimentary Environments. Springer-Verlag, Berlin. 549p.

20 cm

3 m

Intrusive structures

Loads

Ball and pillows

Sand dykes

Mud volcanoes

Monroes

20 cm

From Reineck, H.-E. and Singh, I.B. 1980. Depositional Sedimentary Environments. Springer-Verlag, Berlin. 549p.

Intrusive structures

1) Beach environments Low angle cross-stratification

Both from: Harms, J.C., Southard, J.B., Spearing, D.R. and Walker, R.G., 1975. Depositional Environments as Interpreted from Primary Sedimentary Structures and Stratigraphic Sequences. SEPM Short Course 2.

Really diagnostic sedimentary structures

2) Muddy tidal environments

flaser bedding wavy bedding lenticular bedding

All from Reineck, H.-E. and Singh, I.B. 1980. Depositional Sedimentary Environments. Springer-Verlag, Berlin. 549p.

Really diagnostic sedimentary structures

3) Sandy tidal environments

From

Rei

neck

, H.-E

. and

Sin

gh, I

.B. 1

980.

Dep

ositi

onal

Se

dim

enta

ry E

nviro

nmen

ts. S

prin

ger-V

erla

g, B

erlin

. 549

p.

Herringbone cross-

stratification

Really diagnostic sedimentary structures

4) Deep marine environments

(density currents) Turbidites

From

Luc

chi,

F.R

.,199

5. S

edim

ento

grap

hica

. Sec

ond

Editi

on.

Col

umbi

a U

nive

rsity

Pre

ss. 2

55p.

Really diagnostic sedimentary structures

Graded bedding

HCS (hummocky cross-stratification)

From: Harms, J.C., Southard, J.B., Spearing, D.R. and Walker, R.G., 1975. Depositional Environments as Interpreted from Primary Sedimentary Structures and Stratigraphic Sequences. SEPM Short Course 2.

4) Deep marine environments (density currents)

Really diagnostic sedimentary structures

GY 402: Sedimentary Petrology

Lecture 6: Sedimentary Structures

Instructor: Dr. Doug Haywick dhaywick@southalabama.edu

This is a free open access lecture, but not for commercial purposes. For personal use only.