features in sedimentary rocks that reflect depositional or … · 2015-03-20 · sedimentary...
TRANSCRIPT
![Page 1: Features in sedimentary rocks that reflect depositional or … · 2015-03-20 · Sedimentary Structures:! • Features in sedimentary rocks that reflect depositional or diagenetic](https://reader030.vdocuments.mx/reader030/viewer/2022040601/5e8ef6faf673833f365e9660/html5/thumbnails/1.jpg)
Sedimentary Structures: • Features in sedimentary rocks that reflect
depositional or diagenetic processes. – Diagenesis:
• physical and/or chemical changes to sediments following deposition and up to metamorphism.
![Page 2: Features in sedimentary rocks that reflect depositional or … · 2015-03-20 · Sedimentary Structures:! • Features in sedimentary rocks that reflect depositional or diagenetic](https://reader030.vdocuments.mx/reader030/viewer/2022040601/5e8ef6faf673833f365e9660/html5/thumbnails/2.jpg)
Sedimentary Structures: • Sedimentary structures can sometimes yield
information on: – paleocurrent direction, and – stratigraphic “up” direction
• Latter is useful if working in folded and potentially overturned rocks.
![Page 3: Features in sedimentary rocks that reflect depositional or … · 2015-03-20 · Sedimentary Structures:! • Features in sedimentary rocks that reflect depositional or diagenetic](https://reader030.vdocuments.mx/reader030/viewer/2022040601/5e8ef6faf673833f365e9660/html5/thumbnails/3.jpg)
Sedimentary Structures: • 1) bedding:
– sediments deposited in layers (most commonly parallel to Earth’s surface)
a bed
If layers are thinner than 1 cm, typically termed “laminations”!
![Page 4: Features in sedimentary rocks that reflect depositional or … · 2015-03-20 · Sedimentary Structures:! • Features in sedimentary rocks that reflect depositional or diagenetic](https://reader030.vdocuments.mx/reader030/viewer/2022040601/5e8ef6faf673833f365e9660/html5/thumbnails/4.jpg)
Sedimentary Structures: • 2) graded bedding:
– coarser sediments on bottom
Deposition from a waning current
![Page 5: Features in sedimentary rocks that reflect depositional or … · 2015-03-20 · Sedimentary Structures:! • Features in sedimentary rocks that reflect depositional or diagenetic](https://reader030.vdocuments.mx/reader030/viewer/2022040601/5e8ef6faf673833f365e9660/html5/thumbnails/5.jpg)
Sedimentary Structures: • 2) graded bedding:
![Page 6: Features in sedimentary rocks that reflect depositional or … · 2015-03-20 · Sedimentary Structures:! • Features in sedimentary rocks that reflect depositional or diagenetic](https://reader030.vdocuments.mx/reader030/viewer/2022040601/5e8ef6faf673833f365e9660/html5/thumbnails/6.jpg)
Sedimentary Structures: • 2) graded bedding:
![Page 7: Features in sedimentary rocks that reflect depositional or … · 2015-03-20 · Sedimentary Structures:! • Features in sedimentary rocks that reflect depositional or diagenetic](https://reader030.vdocuments.mx/reader030/viewer/2022040601/5e8ef6faf673833f365e9660/html5/thumbnails/7.jpg)
Sedimentary Structures: • 2) graded bedding:
![Page 8: Features in sedimentary rocks that reflect depositional or … · 2015-03-20 · Sedimentary Structures:! • Features in sedimentary rocks that reflect depositional or diagenetic](https://reader030.vdocuments.mx/reader030/viewer/2022040601/5e8ef6faf673833f365e9660/html5/thumbnails/8.jpg)
Sedimentary Structures: • 3) imbricated clasts:
– flattened clasts imbricated in stream bottom:
current direction
Can’t be used for stratigraphic “up”
![Page 9: Features in sedimentary rocks that reflect depositional or … · 2015-03-20 · Sedimentary Structures:! • Features in sedimentary rocks that reflect depositional or diagenetic](https://reader030.vdocuments.mx/reader030/viewer/2022040601/5e8ef6faf673833f365e9660/html5/thumbnails/9.jpg)
Sedimentary Structures: • 3) imbricated clasts:
![Page 10: Features in sedimentary rocks that reflect depositional or … · 2015-03-20 · Sedimentary Structures:! • Features in sedimentary rocks that reflect depositional or diagenetic](https://reader030.vdocuments.mx/reader030/viewer/2022040601/5e8ef6faf673833f365e9660/html5/thumbnails/10.jpg)
Sedimentary Structures: • 3) imbricated clasts:
![Page 11: Features in sedimentary rocks that reflect depositional or … · 2015-03-20 · Sedimentary Structures:! • Features in sedimentary rocks that reflect depositional or diagenetic](https://reader030.vdocuments.mx/reader030/viewer/2022040601/5e8ef6faf673833f365e9660/html5/thumbnails/11.jpg)
Sedimentary Structures: • 4) Sole Marks & Casts:
– Sedimentary structures preserved on the underside of a bed
– Typically an infilling (cast) of a depression in the underlying bed
Original structure!(e.g., groove)!
Cast of original structure!(e.g., groove cast)!
![Page 12: Features in sedimentary rocks that reflect depositional or … · 2015-03-20 · Sedimentary Structures:! • Features in sedimentary rocks that reflect depositional or diagenetic](https://reader030.vdocuments.mx/reader030/viewer/2022040601/5e8ef6faf673833f365e9660/html5/thumbnails/12.jpg)
Sedimentary Structures: • 4) Sole Marks I; flute casts
– Scoured out depressions in mud (usually associated with turbidity currents).
mud
sand mud
sand
paleocurrent
up
Steep side faces current!
![Page 13: Features in sedimentary rocks that reflect depositional or … · 2015-03-20 · Sedimentary Structures:! • Features in sedimentary rocks that reflect depositional or diagenetic](https://reader030.vdocuments.mx/reader030/viewer/2022040601/5e8ef6faf673833f365e9660/html5/thumbnails/13.jpg)
Sedimentary Structures: • 4) flute casts:
![Page 14: Features in sedimentary rocks that reflect depositional or … · 2015-03-20 · Sedimentary Structures:! • Features in sedimentary rocks that reflect depositional or diagenetic](https://reader030.vdocuments.mx/reader030/viewer/2022040601/5e8ef6faf673833f365e9660/html5/thumbnails/14.jpg)
Sedimentary Structures: • 4) flute casts:
![Page 15: Features in sedimentary rocks that reflect depositional or … · 2015-03-20 · Sedimentary Structures:! • Features in sedimentary rocks that reflect depositional or diagenetic](https://reader030.vdocuments.mx/reader030/viewer/2022040601/5e8ef6faf673833f365e9660/html5/thumbnails/15.jpg)
Sedimentary Structures: • 4) flute casts:
![Page 16: Features in sedimentary rocks that reflect depositional or … · 2015-03-20 · Sedimentary Structures:! • Features in sedimentary rocks that reflect depositional or diagenetic](https://reader030.vdocuments.mx/reader030/viewer/2022040601/5e8ef6faf673833f365e9660/html5/thumbnails/16.jpg)
Sedimentary Structures: • 4) Sole Marks II: groove casts
![Page 17: Features in sedimentary rocks that reflect depositional or … · 2015-03-20 · Sedimentary Structures:! • Features in sedimentary rocks that reflect depositional or diagenetic](https://reader030.vdocuments.mx/reader030/viewer/2022040601/5e8ef6faf673833f365e9660/html5/thumbnails/17.jpg)
Sedimentary Structures: • 5) current ripple marks:
Current ripples are asymmetric…
not equal
erosion deposition current
![Page 18: Features in sedimentary rocks that reflect depositional or … · 2015-03-20 · Sedimentary Structures:! • Features in sedimentary rocks that reflect depositional or diagenetic](https://reader030.vdocuments.mx/reader030/viewer/2022040601/5e8ef6faf673833f365e9660/html5/thumbnails/18.jpg)
Sedimentary Structures: • 5) current ripple marks:
![Page 19: Features in sedimentary rocks that reflect depositional or … · 2015-03-20 · Sedimentary Structures:! • Features in sedimentary rocks that reflect depositional or diagenetic](https://reader030.vdocuments.mx/reader030/viewer/2022040601/5e8ef6faf673833f365e9660/html5/thumbnails/19.jpg)
Sedimentary Structures: • 5) current ripple marks:
Three-dimensional ripples
trough cross-bedding
![Page 20: Features in sedimentary rocks that reflect depositional or … · 2015-03-20 · Sedimentary Structures:! • Features in sedimentary rocks that reflect depositional or diagenetic](https://reader030.vdocuments.mx/reader030/viewer/2022040601/5e8ef6faf673833f365e9660/html5/thumbnails/20.jpg)
Sedimentary Structures: • 6) oscillation ripple marks:
oscillation ripples are symmetric…
current
up
![Page 21: Features in sedimentary rocks that reflect depositional or … · 2015-03-20 · Sedimentary Structures:! • Features in sedimentary rocks that reflect depositional or diagenetic](https://reader030.vdocuments.mx/reader030/viewer/2022040601/5e8ef6faf673833f365e9660/html5/thumbnails/21.jpg)
Sedimentary Structures: • 6) oscillation ripple marks :
![Page 22: Features in sedimentary rocks that reflect depositional or … · 2015-03-20 · Sedimentary Structures:! • Features in sedimentary rocks that reflect depositional or diagenetic](https://reader030.vdocuments.mx/reader030/viewer/2022040601/5e8ef6faf673833f365e9660/html5/thumbnails/22.jpg)
Sedimentary Structures: • 7) cross beds :
– Internal structure of ripples or dunes
Note: beds are truncated on their tops
up
current
![Page 23: Features in sedimentary rocks that reflect depositional or … · 2015-03-20 · Sedimentary Structures:! • Features in sedimentary rocks that reflect depositional or diagenetic](https://reader030.vdocuments.mx/reader030/viewer/2022040601/5e8ef6faf673833f365e9660/html5/thumbnails/23.jpg)
Sedimentary Structures: • 7) cross beds :
![Page 24: Features in sedimentary rocks that reflect depositional or … · 2015-03-20 · Sedimentary Structures:! • Features in sedimentary rocks that reflect depositional or diagenetic](https://reader030.vdocuments.mx/reader030/viewer/2022040601/5e8ef6faf673833f365e9660/html5/thumbnails/24.jpg)
Sedimentary Structures: • 7) cross beds :
![Page 25: Features in sedimentary rocks that reflect depositional or … · 2015-03-20 · Sedimentary Structures:! • Features in sedimentary rocks that reflect depositional or diagenetic](https://reader030.vdocuments.mx/reader030/viewer/2022040601/5e8ef6faf673833f365e9660/html5/thumbnails/25.jpg)
Sedimentary Structures: • 7) cross beds :
![Page 26: Features in sedimentary rocks that reflect depositional or … · 2015-03-20 · Sedimentary Structures:! • Features in sedimentary rocks that reflect depositional or diagenetic](https://reader030.vdocuments.mx/reader030/viewer/2022040601/5e8ef6faf673833f365e9660/html5/thumbnails/26.jpg)
Sedimentary Structures: • 8) herringbone cross beds:
Common in areas with tidal influence…
![Page 27: Features in sedimentary rocks that reflect depositional or … · 2015-03-20 · Sedimentary Structures:! • Features in sedimentary rocks that reflect depositional or diagenetic](https://reader030.vdocuments.mx/reader030/viewer/2022040601/5e8ef6faf673833f365e9660/html5/thumbnails/27.jpg)
Sedimentary Structures: • 8) herringbone cross beds:
![Page 28: Features in sedimentary rocks that reflect depositional or … · 2015-03-20 · Sedimentary Structures:! • Features in sedimentary rocks that reflect depositional or diagenetic](https://reader030.vdocuments.mx/reader030/viewer/2022040601/5e8ef6faf673833f365e9660/html5/thumbnails/28.jpg)
Sedimentary Structures: • 9) mudcracks :
– Formed in drying mud.
mud
contracts on top first
up
![Page 29: Features in sedimentary rocks that reflect depositional or … · 2015-03-20 · Sedimentary Structures:! • Features in sedimentary rocks that reflect depositional or diagenetic](https://reader030.vdocuments.mx/reader030/viewer/2022040601/5e8ef6faf673833f365e9660/html5/thumbnails/29.jpg)
Sedimentary Structures: • 9) mudcracks:
![Page 30: Features in sedimentary rocks that reflect depositional or … · 2015-03-20 · Sedimentary Structures:! • Features in sedimentary rocks that reflect depositional or diagenetic](https://reader030.vdocuments.mx/reader030/viewer/2022040601/5e8ef6faf673833f365e9660/html5/thumbnails/30.jpg)
Sedimentary Structures: • 9) mudcracks in rocks: