Presentation is loading. Please wait.

Presentation is loading. Please wait.

Relative susceptibility To weathering

Similar presentations

Presentation on theme: "Relative susceptibility To weathering"— Presentation transcript:

1 Relative susceptibility To weathering

2 Products of Weathering

3 Factors influencing Weathering Rates
Rock structures – chemical/mineral composition, physical features Topography Climate Vegetation Time


5 Sediments and Sedimentary Rocks

6 Sediments - unconsolidated particles created by
1. The weathering of rock 2. The secretions of organisms or decomposition of organic matter 3. Chemical precipitation

7 Sedimentary Rock Formation
Weathering – breakdown both physically (clasts) or chemically Erosion – loosening of weathered products (clasts) and initial transport Transportation – movement of materials via wind, water, or ice; sorting and rounding can occur Deposition – material settles out of the transporting medium Lithification – process of either cementation or compaction of the material

8 W. W. Norton

9 Sedimentary Rocks Composed of lithified sediments
by compaction – weight of overlying sediment compresses sediment, important in fine-grained sediments by cementation – materials carried in solution precipitates minerals - iron oxides, carbonates, silica Two Classifications - clastic -nonclastic

10 Fig. 7.16 W. W. Norton

11 Sedimentary Rocks Clastic Rock – composed of fragments of preexisting rocks. Nonclastic Rock – composed of chemical precipitates or biochemical matter.

12 Daily Question Use a Venn diagram to compare and contrast clastic, chemical nonclastic, and biochemical nonclastic sedimentary rocks. Identify at least five characteristics. Clastic Chemical Biochemical

13 Types of Sediments - Clastic
Broken fragments of rock produced by weathering. Classified according to size. Range in size from largest boulder to smallest clay particle.

14 Clastic Texture Increasing distance from source The size, shape, and distribution of particles that collectively make up a rock Increasing distance from source

15 Which sample is closer to the source of sediment?

16 Sorting - a function of transport mechanism
1. Water 2. Wind 3. Glaciers

17 Sorting by Wind

18 Fig. 7.26a Stephen Marshak

19 Graded Beds Fining up

20 Texture and Transport Distance
In general, as transport distance increases, rounding and sorting increase. Examples: Breccia – cemented close to source Conglomerate – transported then cemented

21 Types of Sediments - Biogenic
Terrestrial sediments - mainly plant matter ex. Coal Marine sediments - mainly carbonates Corals - large components of reefs. Bivalves, gastropods, foraminifers - whole or partial skeletons form sand and gravels. Algae, crinoids, echinoderms, bryozoans - disintegrate to form some sand particles and lime mud. Diatoms, Radiolaria – bedded chert sio2

22 Coral (carbonate)

23 Foramanifera

24 Diatoms

25 Types of Sediments - Chemical
Inorganic process, no biological activity involved. Formed by minerals precipitating from solution. i.e. – Ca2+ + CO32- = CaCO3 Na+ + Cl- = NaCl

26 Chemical Sediments Terrestrial - Evaporites: Gypsum - CaSO4 . H2O
Anhydrite -CaSO4 Halite - NaCl


28 Chemical Sediments 2. Marine Carbonates - CaCO3 (limestone)
Chert (Quartz) – SiO2

29 Bedding – Layering or stratification in sedimentary rock

30 Fig. 7.25abc W. W. Norton

31 Cross Bedding – water or wind



34 Ripple Marks


36 Sedimentary Environments

37 Sedimentary Systems and Plate Tectonics

Download ppt "Relative susceptibility To weathering"

Similar presentations

Ads by Google