1. EBS101 ENGINEERING GEOLOGY DR HAREYANI ZABIDI
GEOLOGICAL MAPS
EBS101 ENGINEERING GEOLOGY
DR HAREYANI ZABIDI

2. OBJECTIVES To read and interpret geologic maps
To learn the rule of V’s and understand the relationships between contacts and contour lines
To locate and identify the 3 major fault types on maps and cross sections
To recognize unconformities and intrusions on maps
To interpret geologic history from a geologic map

3. Frequently-used maps
Solid and Drift map – shows the distribution of the various rocks and soils that occur close to the surface of the ground
Useful for civil engineering work
Subsurface maps – show the thickness and underground distribution of rock and soil
Useful for mining engineers and others whose engineering work is located at depth

4. Solid and drift maps
Drift edition – a map of surface geology, shows the position, and the general character of all geological materials that occur at ground level
Harder rocks and all other materials, such as alluvium, glacial drift, mud flows, sand dunes, etc.
All these have been transported or drifted, to their original position; called a drift edition

5. Solid and drift maps
Solid editions – not all drift at ground level is thick, much can be thin
Often to construct a map beneath the drift; when no drift is shown on a map, only the solid geology; called a solid edition
Thus the geology of an area can be studied using two maps,
Showing the drift and the solid geology; between areas of drift
Showing only the solid geology beneath the drift areas

6. What is a geological map ?
Gives information on the superficial layers of the earth’s crust
The geological information are listed according to their composition (lithology), their age (stratigraphy) and their structural position (tectonic)
Placed on a topographic base (map) using different graphic elements (symbols, figurative and color)
The choice of scale depends on the geological content and the intended objective of the map.

7. A geologic map is an illustration of a huge volume of geologic information.
Using a geological map, a geologist can show the distribution of rock bodies at the surface of the Earth and geologic structures which have deformed those rocks.
Geological maps show the occurrence, nature, extent and stratigraphic age of rock strata in a district

8. How are geological maps made ?
The essential condition for establishing a geological detail map is a precise field survey, based on numerous measurements and observations.
The topographic base is generally taken from maps at a scale of 1:10'000, such as those of the comprehensive cadastral plans.

9. The field geologist determines the rock type according to various criteria and measures its orientation.
All data are transcribed onto the map and in a field notebook.
Besides the natural or artificial outcrops, data from bore holes or important test holes are taken in consideration.

10. In the case of a doubtful rock identification, complementary investigations are carried out in the laboratory on samples of these rocks.
At the end of the field survey, the geologist establishes an original draft at a scale of 1:25'000 and constructs some geological sections across the studied sector.
He also writes an explanatory note that generally contains numerous illustrations.

11. The geological cartography section assures the direction of the project, carries out the editing of the map, establishes the final legend of the map and provides indispensable data for the cartographers.

12. GEOLOGICAL MAP OF KUALA LUMPUR (GOBBETT, 1964)

13. Modern karst
Aureole zone
Paleokarst
Quartzite and phyllite
----- ANGULAR
UNCONFORMITY -----
Calcitic marble
Fine grained - black
graphitic schist
Fine grained - quartz-
mica schist
Graf/ diagram to prove the chemical observation
Series of vertical faulting – cut both granite and sediment formations
Younger than quartz veins

14. Structure and Cross Section
Sheet 94
Kuala Lumpur
SELANGOR
4 cross section:
1 cross section – aligned with SMART project
3 cross sections – cross the alignment of SMART project
Details of solid geology and structural geology
Potential of karst formation
Graf/ diagram to prove the chemical observation
Schematic diagram showing direction of cross sections in Kuala Lumpur

15. Cross Section 1 Aligned with SMART project location
Geological profile parallel with SMART project
Development of karst:
Unconformity boundary – Kuala Lumpur Limestone Formation and Kenny Hill Formation
Contact zone – Kuala Lumpur Limestone Formation and granitic rock
Graf/ diagram to prove the chemical observation

16. Cross Section 2 Northern part of SMART project
Opposite direction of SMART project
Development of karst:
Contact zone – Kuala Lumpur Limestone Formation and granitic rock
Fold – Hawthornden Formation

17. Cross Section 3 Crossed SMART project alignment
Crossing folded Kuala Lumpur Limestone Formation
Development of karst:
Contact zone – Kenny Hill Formation
– Granitic rock

18. Cross Section 4 Southern part of SMART project Development of karst:
Contact zone with Kenny Hill Formation
Fault in Kuala Lumpur Limestone Formation
Klang River

19. A GEOLOGICAL MAP, GEOLOGICAL CROSS-SECTION AND 3D STRUCTURE

21. MAP INTERPRETATION

22. OUTCROP PATTERNS
Horizontal beds – outcrops follow the contours; constant altitude
Vertical beds – straight outcrops ignore the contours (dyke on the Tan Vale map)
Dipping beds – curved outcrops; cut across and respond to the contours (erosion) – sandstone
Dip direction – V in Valley Rule; an outcrop of a dipping rocks bends around a V shape where it crosses a valley, and the V of the outcrop points in the direction of dip

23. 5. Succession – younger rocks coming to outcrop in the direction of dip.
6. Width of outcrop – greater on thicker beds and at lower dips

24. STAGES OF MAP INTERPRETATION
Identify faults and unconformities (structural breaks)
Identify dips by V in Valley Rule
Determine succession
Identify fold axes (dip and outcrop bends)
Draw stratum contours
Draw cross-section to show sub-surface structure

32. Transformation from
locality to a map

36. Tutorial 1