Sedimentary rocks form through the deposition of sediments or fragments by processes like erosion, transportation, and deposition. Sedimentary structures are classified based on how the sediments were deposited and include stratification, graded bedding, cross-bedding, ripple marks, mud cracks, rain drop marks, casts and molds, tool marks, tracks and trails, and burrow marks. Sedimentary rocks also include chemical rocks like limestone and dolomite formed from mineral precipitation, and biochemical rocks like coal and fossil-bearing limestone formed from organic materials.

1. STRUCTURES OFSTRUCTURES OF
SEDIMENTARY ROCKSSEDIMENTARY ROCKS
M.RAJASEKHAR
ASST. PROFESSOR
KUPPAM ENGINEERING COLLGE

2. Structures ofStructures of sedimentary rocks formed by the deposition of sediments orsedimentary rocks formed by the deposition of sediments or
fragments by the process of ETDfragments by the process of ETD
Sedimentary structures are classified into different types based upon theSedimentary structures are classified into different types based upon the
deposition of sediments they aredeposition of sediments they are
1. Stratification
2. Graded bedding
3. Cross bedding
4. Ripple marks
5. Mud cracks
6. Rain drop marks
7. Cast and mould
8. Tool marks
9. Track and Trails
10. Burrow marks

3. StratificationStratification
Stratum- bed Strata- Series of beds
Stratification is defined as the deposition of sediments or fragments in
the series of beds.
These beds having different in mineralogy, clast size, degree of
sorting and color of the different layers.
Thickness of beds are very less is called “Lamination”

5. Graded BeddingGraded Bedding
The velocity of the transporting agent decrease the larger or more dense
particles are deposited first, followed by similar particles
The bedding showing a decrease in grain size from the bottom of the
bed to the top of the bed.

9. Cross BeddingCross Bedding
Consists of set of beds that are inclined relative to one another. The beds
are inclined in the direction that the wind or water was moving at the time of
deposition.
Crass bedding very common in beach deposits, sand dunes, river deposits.

12. SEDIMENTSEDIMENT
 TransportationTransportation
 AbrasionAbrasion
 RoundingRounding
 SortingSorting
 DepositionDeposition
 Environment of deposition- specificEnvironment of deposition- specific
 PreservationPreservation

15. Ripple marksRipple marks
Caused by waves or winds moves up the sediment into long ridges.
→Ripple marks are shallow water deposition
→Asymmetrical ripple marks can give an indication of current direction
→Symmetrical ripple marks form when the waves moves back and forth

17. Mud CracksMud Cracks
Cracks on the sediment are developed due to the shrinkage of the sediment
as it dries.
OR
Formed as muddy sediment dries and contracts.Formed as muddy sediment dries and contracts. Crack formation alsoCrack formation also
occurs in clayey soils as a result of a reduction in water content. occurs in clayey soils as a result of a reduction in water content.

19. Cast and MoldsCast and Molds
Any depression formed on the bottom of a body of water may become a
mold, later get deposited into the depression and will acquire the shape of
that depression called cast.
The body of sediment that gets the shape of the mold is cast.

21. Tool Marks
Scratch marks on the bottom of the water resulting due to any object carried
along by currents are called tool marks.

23. Rain prints or rain drop points
Pits created by falling rain

25. Tracks and Trails
These features are formed when organisms move across the
sediment as they walk, crawl or drag their body parts through the
sediment.

27. Burrow marksBurrow marks
Formed by any organism that burrows into sediment.

31. CHEMICAL SEDIMENTARYCHEMICAL SEDIMENTARY
ROCKSROCKS
 Carbonate RocksCarbonate Rocks
 Limestone- made of calciteLimestone- made of calcite
 Inorganic varietiesInorganic varieties
 micrite, oolites, travertinemicrite, oolites, travertine
 DolomiteDolomite
 RecrystallizationRecrystallization
 Chert- silicaChert- silica
 EvaporitesEvaporites
 Rock gypsumRock gypsum
 Rock saltRock salt

34. BIOCHEMICALBIOCHEMICAL
SEDIMENTARY ROCKSSEDIMENTARY ROCKS
 CoalCoal
 Develops from peatDevelops from peat
 plant fragmentsplant fragments
 LigniteLignite
 Bituminous CoalBituminous Coal
 Carbonate RocksCarbonate Rocks
 Limestone- made of calciteLimestone- made of calcite
 organic varietiesorganic varieties
 CoquinaCoquina
 Fossiliferous LimestoneFossiliferous Limestone
 ChalkChalk

36. BIOCHEMICALBIOCHEMICAL
SEDIMENTARY ROCKSSEDIMENTARY ROCKS
 CoalCoal
 Develops from peatDevelops from peat
 plant fragmentsplant fragments
 LigniteLignite
 Bituminous CoalBituminous Coal
 Carbonate RocksCarbonate Rocks
 Limestone- made of calciteLimestone- made of calcite
 organic varietiesorganic varieties
 CoquinaCoquina
 Fossiliferous LimestoneFossiliferous Limestone
 ChalkChalk

40. SEDIMENTARYSEDIMENTARY
STRUCTURESSTRUCTURES
 BEDDING-BEDDING-
 Principle of Original HorizontalityPrinciple of Original Horizontality
 Bedding planeBedding plane
 Cross-beddingCross-bedding
 Graded bedGraded bed
 Mud cracksMud cracks
 Ripple marksRipple marks
 FossilsFossils

43. SEDIMENTARYSEDIMENTARY
STRUCTURESSTRUCTURES
 BEDDING-BEDDING-
 Principle of Original HorizontalityPrinciple of Original Horizontality
 Bedding planeBedding plane
 Cross-beddingCross-bedding
 Graded bedGraded bed
 Mud cracksMud cracks
 Ripple marksRipple marks
 FossilsFossils

44. DUNESDUNES

47. SEDIMENTARYSEDIMENTARY
STRUCTURESSTRUCTURES
 BEDDING-BEDDING-
 Principle of Original HorizontalityPrinciple of Original Horizontality
 Bedding planeBedding plane
 Cross-beddingCross-bedding
 Graded bedGraded bed
 Mud cracksMud cracks
 Ripple marksRipple marks
 FossilsFossils

50. SEDIMENTARYSEDIMENTARY
STRUCTURESSTRUCTURES
 BEDDING-BEDDING-
 Principle of Original HorizontalityPrinciple of Original Horizontality
 Bedding planeBedding plane
 Cross-beddingCross-bedding
 Graded bedGraded bed
 Mud cracksMud cracks
 Ripple marksRipple marks
 FossilsFossils

51. MudcracksMudcracks

55. SEDIMENTARYSEDIMENTARY
STRUCTURESSTRUCTURES
 BEDDING-BEDDING-
 Principle of Original HorizontalityPrinciple of Original Horizontality
 Bedding planeBedding plane
 Cross-beddingCross-bedding
 Graded bedGraded bed
 Mud cracksMud cracks
 Ripple marksRipple marks
 FossilsFossils
 Body FossilsBody Fossils
 Trace FossilsTrace Fossils

61. Glacial Environment & TillGlacial Environment & Till

64. CALCAREOUS