1. Sedimentary Structures
Features of sed rocks recording processes occurring during deposition or between deposition and lithification.
Important for interpreting depositional processes, and reconstructing depositional environments and geological history

2. Importance of Sedimentary Structures
Geopetal structures: indicators of top-bottom
Directional structures: indicators of current direction & transport agent

3. Types of Sed Structures
Primary sedimentary structures: occur in clastic sediments & generated by same processes (currents, etc.) that caused deposition.
Secondary sedimentary structures: caused by post-depositional processes, including biogenic, chemical, and mechanical disruption of sediment.

4. Depositional Sed Structures
Most fundamental sed structures are beds and laminae
Usually formed by
Suspension sedimentation
Accumulation of bed load
Beds identified through changes in
grain size,
composition
Bedding planes result from period on non-deposition or from erosion
Beds form within hrs/days
Laminations form almost instantaneously or over years
Schulumberger

5. b
Sedimentary beds near Del Rio, TX

6. Laminations, Moenkopi Fm, Lake Mead newterra. chemeketa. edu/
Laminations, Moenkopi Fm, Lake Mead newterra.chemeketa.edu/.../sedrocktype.htm  

7. Laminations, Monterey Formation
Kurt A. Grimm (1), Daniel L. Orange Journal of Sedimentary Research Volume 67 (1997)

8. Laminations composed of lighter sand and darker heavier minerals, Chinnai, India, New World Encylopedia

9. Wedge bedding. Successive stack of erosive-based channels creates wedge-shape bedding cross-sections. higuai Formation, Inner Mongolia, China.

10.
Graded bedding. Graded bedding results from a rapid decrease in flow velocity that causes sediment to drop out of suspension. Larger particles settle fastest, therefore they accumulate at the bottom of the bed. Houcheng Formation, Jurassic, Hebei Province, China

11. Tabular cross-bedding
Tabular cross-bedding. These steep foresets are typical of eolian deposition. Late Jurassic, Liaoning Province, China.

12. Ripple Morphology

13. Bed Response to Steady-state, Unidirectional, Water Flow
FLOW REGIME CONCEPT
Consider variation in: Flow Velocity only
Flume Experiments (med sand & 20 cm flow depth)
A particular flow velocity (after critical velocity of entrainment) produces
a particular bed configuration (Bed form) which in turn
produces a particular internal sedimentary structure.
Cross bed formation
USGS
Heller—U. Wyoming

14. Bed Response to Steady-state, Unidirectional, Water Flow
Consider Variation in Grain Size & Increasing Flow Velocity
for sand <~0.2mm: No Large Ripples/Dunes
for sand ~0.2 to 0.8mm Idealized Flow Regime Sequence of Bed forms
for sand > 0.8: No ripples, Have Lower Plane Bed bed

15. Toroweap Formation. The cross beds are sedimentary structures that represent the slip faces of ancient sand dunes. Thus, this specific layer in the Toroweap likely represents a sand dune. The Toroweap underlies the Kaibab Formation and is also late Early Permian in age (roughly 275 to 270 Ma).

16. Wave Ripples. Cross-sectional view of ripple cross-laminated sandstone, showing bi-directional cross laminae indicative of a wave origin. Entrada Formation, Jurassic, San Rafael Swell, Utah

17. Ripple Marks. A pile of eroded, rippled beds that all contain gorgeous ripple marks. If you click on nothing else, click to enlarge this one! Carmel Formation, Utah.

18. Ripple Marks. Casts of wave ripples on the base of a sandstone bed
Ripple Marks. Casts of wave ripples on the base of a sandstone bed. Cretaceous, Hebei Province, China

19. Linguloid Ripples. These mud-draped ripples are linguloid in form, indicating shallow, rapid flow within the ripple stability field. Permian, Inner Mongolia, China

20. Herrigbone cross-stratification
Herrigbone cross-stratification. Bi-directional cross beds such as these are indicative of a tidal origin. Curtis Formation, Jurassic, Utah

21. Climbing current ripples
Climbing current ripples. Ripple foresets that "climb" on the backs of their predecessors are indicative of waning flow conditions and rapid sediment fallout, such that sediment drops out of suspension as fast as it can be molded into a bedform. Entrada Formation, Jurassic, Utah.

22. Soft Sediment Deformation

23. Climbing current ripples and convolute lamination
Climbing current ripples and convolute lamination. The result of rapid sediment fallout is often instability due to liquefaction, leading to disruption of laminae by water escape. Such disruption is termed convolute lamination. Modern Colorado River, Utah.

24.
beds, flame structures. Rapid sediment fallout from suspension often loads underlying fine-grained sediment to the point of failure, causing foundering of the overlying sediment and formation of structures termed flames (for obvious reasons!). Permian, Inyo County, California.

25. Sole/Bedding Plane Markings

26. Flute casts. Flutes are caused by erosional eddies at the base of a turbulent flow. The deepest scour is on the upstream end of the flute, and the scours widen and become shallower downflow. Shiguai Formation, Inner Mongolia, China.

27. Flute casts in Austin Glen turbidites, near Hannacroix, NY

28. Groove Casts, base of a turbidite sandstone, Laga Basin, Italy

29. Mudcracks
Dessication cracks. Mudcracks can become very large, which may make them difficult to recognize in small outcrops. Person for scale. Jixian Formation, Proterozoic, China.

30. Erosioanl Structure --Scours
Pigeon Point Formation: An Upper Cretaceous Shoreline Succession, Central California Coast John H. Tyler Journal of Sedimentary ResearchVolume 42 (1972)

31. Channel & Fill
Miocene sedimentary rocks, Tierra del Fuego coast (© 2010 clasticdetritus.com)

32. Biogenic Structures http://www.earthscienceworld.org/images/index.html
Feeding trails and burrows as trace fossils in rock.
Copyright © Bruce Molnia, Terra Photographics
Crossbedded and rippled sandstone with burrows at Point Lobos, California.
Copyright © Bruce Molnia, Terra Photographics

33. Tubidite Sequence
faculty.gg.uwyo.edu/

34. Coarser Turbidite units dissappear with greater distance downflow

35. http://faculty. gg. uwyo

36. Turbidites http://www.earthscienceworld.org/images/index.html
Bouma sequence in Santa Paula. A Bouma Sequence is a succession consisting of five intervals, each characterized by a particluar sedimentary structure, which forms a turbidite. Copyright © Dr. Roger Slatt, University of Oklahoma

37. More Turbidites. Identify Sequence and Flow Regime http://sepmstrata
BOUMA-SEQUENCE (SCHLUMBERGER)
bouma-© 1998 by Hugo Ortner.jpg

38. Video Sources Sediment entrainment
Turbulent flow
Turbulent flow 2
Debris Flow
Debris flow

39. Turbidity Currents 
Photos
Tubidites
© 1998 by Hugo Ortner
Inverse grading 
Crossbeds