1. The document discusses different zones of the ocean floor and sediments found in each zone. It describes key organisms, depths, and ratios that define each zone. 2. It then summarizes different types of clays found in ocean sediments, including their chemical composition and properties like swelling. Kaolinite, montmorillonite, and illite are discussed in detail. 3. Finally, it outlines different types of sediments found on the ocean floor including biogenous sediments like carbonates and silicates, hydrogenous sediments like manganese nodules, and phosphorites. Conditions required for carbonate deposition are also summarized.

1. OCEAN FLOOR
IMPORTANT POINTS:
1. DIP/ SLOPE Of each Zone
2. Important Organisms Present if any
3. Depth of each Zone
4. What is meant by 1:40, 1:1000 etc

2. OCEAN FLOOR & OCEAN SEDIMENTS
SiO2 and CaCO3 are widely observed in
biogenous deposits.
O, Na, Ca, K abundant in Lithogenous Sediments.
Feldspars and Fe-Mg Minerals alter to Clays and
Oxides of Iron.
Hence, Weathering of Basalts --> Clay, Fe-Oxides.

3. Clays:
Hydrated Alumino Silicates.
Decomposition of Feldspars & Fe-Mg-Minerals.
04-Types:
 Illite:
 Chlorite
 Montmorillonite
 Kaolinite

4. Tetrahedron Octahedron
Si- at Centre;
Silica Sheet
Al ——> Gibbsite
Mg ——> Brucite

5. In Clays:
 Tetrahedron unit Charge: -1
 Octahedron Unit Charge: +1

6. Kaolinite:
G - Si - G - Si – G – Si - G- Si and so on
 Thickness of Single sheet is 7A°
 Sheets connected by H-Bond
 H-Bond is strong and mineral is stable
 No Swelling & Shrinkage of Mineral
Formation:
 Due to weathering of K-Feldspars & Muscovite
 Contain Metallic Ions – K & Al

7. Montmorillonite
 Si- G - Si – G – Si- G …. and so on
 Gibbsite is sandwiched by Silica Sheets.
 Sheets are separated by Structural water
 Thickness of one unit is 10°
 High Swelling and shrinkage
 Black cotton soil-- Bentonite
Si : G = 2:1

8. Illite:
 Si-G-Si - Si-G-Si - Si-G- Si
 K- ions are in between units
 Sheets are held by Vanderwall forces
 Swell more than Kaolinite
 Si: G = 1:2
 No- H Bonds

9. Q1. Choose the correct increasing order of the swelling
of followings minerals:
1. Montmorillonite – Kaolinite – Illite
2. Illite - Montmorillonite – Kaolinite
3. Kaolinite – Illite – Montmorillonite
4.Montmorillonite – Illite – Kaolinite

10. Q2. The Brucite and Gibbsite are the Octahedral Minerals primarily
differing in which pair among the following ions?
1. Al and K 3. K and Mg
2. Mg and Si 4. Al and Mg
Q3. The Montmorillonite has _________ ion in its structure, while
as Illlite has ______ions in between its structural units?
1. H2O and Na- ions 3. H2O and K- ions
2. Na and K- ions 4. K and Al - ions

11. BIOGENOUS SEDIMENTS:
Carbonates and Silicates
Silica: Secreted by Diatoms (Micro- Plants)
And Radiolarians (Micro- Animals)
Carbonates:
Foraminifera: Animals
Pteropods & Coccolithophores (Algae)
Coral & Algae Skelton also Calcareus Sediments

12. Hydrogenous Sediments:
• Manganese Nodules on deep Ocean Floor.
• MnO2 (30%) and Fe2O3(20%) main components.
• Contain Cu, Co, and Ni 2%
Origin of Mn & Fe
• Weathering of Volcanic material – Ocean Floor
• Continental runoff & discharge in sea

13. Phosphorites in Oceans: (1000m)
 P2O5 –As Nodules – Continental Shelf
 Conc. May reach 30% by weight
Origin, Possible reason:
 Upwelling of Cold waters rich in Phosphorous

14. Glauconite in Oceans: (2500m)
 Greenish Colour – Hence, Green muds, Green sand etc.
 Contain ions like: K- Mg – Fe.
 Submarine weathering of Biotite – (Thought to be its
origin)

15. Carbonates:
 Low CO2 favours carbonate deposition
 High pH favours carbonate deposition.
 H2O + CO2 = H2CO3= H+ + HCO3
- = H+ + H+ + CO3
-2
 High pH , Low CO2, High Temp = Carbonate Pptn