Nigeria's free digital learning hub. Videos, lecture notes, practice questions and leaderboards aligned with CCMAS, NBTE, NCCE, WAEC, NECO, IJMB and JAMB curricula.
Loading
Nigeria's free digital learning hub. Videos, lecture notes, practice questions and leaderboards aligned with CCMAS, NBTE, NCCE, WAEC, NECO, IJMB and JAMB curricula.
Geology · 100 Level
This is the complete lecture note for GEY 212 Field measurement and mapping techniques, prepared for Geology students at 100 Level. You can read it online below, open it in the full viewer, or download the PDF for offline study. It pairs with the course's video lectures, so you can read and watch together.
LA-NET | ONLINE LEARNING VIDEO PLATFORM FOR POST-SECONDARY & HIGHER INSTITUTION STUDENTS
LA-NET | ONLINE LEARNING VIDEO PLATFORM FOR POST-SECONDARY & HIGHER INSTITUTION STUDENTS GEY 212: Introduction to Geological Field Mapping (2 Units C: PH 90) Course Code: GEY 212 Course Title: Introduction to Geological Field Mapping Course Unit: 2 Units C Series 1 Introduction to Geological Field Equipment Series 2 Field Measurement and Mapping Techniques Series 3 Topographic and Geological Map Interpretation Series 4 Observation and Recording of Rock and Structural Features Series 5 Field Data Management and Geological Report Writing Series 1 Introduction to Geological Field Equipment Part 1: Basic Geological Field Instruments • 1.1 Compass-clinometer • 1.2 Measuring tapes and range finders • 1.3 Sample collection tools Part 2: Principles of Instrument Usage • 2.1 Handling and calibration of instruments • 2.2 Recording accurate field measurements Part 3: Safety and Care of Equipment • 3.1 Safe handling practices in the field • 3.2 Maintenance and storage of instruments
LA-NET | ONLINE LEARNING VIDEO PLATFORM FOR POST-SECONDARY & HIGHER INSTITUTION STUDENTS Introduction Geological fieldwork depends on the effective use of specialised instruments. These tools enable geologists to measure, record, and interpret features of rocks and structures directly in their natural environment. As you begin your study of geological mapping, it is essential to become familiar with the basic equipment used in the field and to understand how to operate them correctly. The aim of this Series is to introduce you to the fundamental geological field instruments, explain their principles of usage, and highlight the importance of safety and care in handling them. We shall commence this Series by examining the basic geological field instruments, beginning with the compass-clinometer, measuring tapes, and sample collection tools. Next, we will explore the principles of instrument usage, focusing on handling, calibration, and accurate recording of field measurements. Finally, we will conclude by considering safety practices and the proper care and maintenance of equipment, ensuring that you are well prepared for practical fieldwork. Series Learning Outcomes Upon completing this Series, you should be able to: • SLO 1.1 define the functions of basic geological field instruments such as the compass-clinometer, measuring tapes, and sample collection tools, • SLO 1.2 demonstrate how to handle and calibrate geological instruments for accurate field measurements, • SLO 1.3 apply correct procedures for recording field data using appropriate equipment, and • SLO 1.4 evaluate safe handling practices and maintenance techniques for geological instruments. 1.1 Basic Geological Field Instruments 1.1.1 Compass-clinometer The compass-clinometer is a combined instrument used to measure both the orientation and inclination of geological features. A compass measures bearing, which is the horizontal angle between a direction and a reference meridian, while a clinometer measures dip, which is the angle of inclination of a rock layer or structure relative to the horizontal. This instrument is essential for recording the strike and dip of rock formations in the field.
LA-NET | ONLINE LEARNING VIDEO PLATFORM FOR POST-SECONDARY & HIGHER INSTITUTION STUDENTS Figure 1.1 Compass-clinometer with labelled components Fill in the blank: The angle of inclination of a rock layer relative to the horizontal is called ______. 1.1.2 Measuring tapes and range finders Measuring tapes are flexible tools used to determine linear distances in the field. They are often made of steel or fibreglass to withstand rugged conditions. Range finders are optical or electronic devices that measure distances without direct contact, useful in terrains where tapes cannot be stretched. Accurate measurement of distance is fundamental for plotting geological features on maps.
LA-NET | ONLINE LEARNING VIDEO PLATFORM FOR POST-SECONDARY & HIGHER INSTITUTION STUDENTS Plate 1.2 Measuring tape in geological fieldwork Fill in the blank: A device that measures distance without direct contact is called a ______. 1.1.3 Sample collection tools Sample collection tools include hammers, chisels, and sample bags. A geological hammer is used to break rock samples, while chisels assist in extracting specimens from hard surfaces. Samples are stored in labelled bags to ensure proper identification. Correct sampling is vital for laboratory analysis and for linking field observations with mineralogical and structural studies.
LA-NET | ONLINE LEARNING VIDEO PLATFORM FOR POST-SECONDARY & HIGHER INSTITUTION STUDENTS Plate 1.3 Rock sampling using a geological hammer Fill in the blank: Rock specimens collected in the field should always be stored in ______ bags. Pilot questions 1.1 1. Which instrument is used to measure both strike and dip of rock layers? 2. What is the main advantage of a range finder compared to a measuring tape? 3. Name two tools commonly used for collecting rock samples. 4. What is the purpose of labelling sample bags in geological fieldwork? 5. Define the term “bearing” in geological mapping. 2.1 Principles Of Instrument Usage 2.1.1 Handling and calibration of instruments Proper handling of geological instruments ensures accuracy and durability. Handling refers to the way an instrument is held, positioned, and used during fieldwork. For example, a compass-clinometer must be held level to avoid errors in measuring strike and dip. Calibration is the process of adjusting an instrument so that its readings are accurate. A compass may need to be checked against a known direction, while a clinometer should be tested against a horizontal surface. Calibration is essential before beginning fieldwork, as even small errors can lead to incorrect geological interpretations.
LA-NET | ONLINE LEARNING VIDEO PLATFORM FOR POST-SECONDARY & HIGHER INSTITUTION STUDENTS Figure 2.1 Calibration of a compass-clinometer Fill in the blank: Adjusting an instrument to ensure its readings are accurate is called ______. 2.1.2 Recording accurate field measurements Accurate field measurements are the foundation of geological mapping. Measurements of strike, dip, and distance must be recorded carefully in field notebooks. A strike is the direction of a horizontal line on a rock surface, while a dip is the angle at which the rock surface inclines from the horizontal. To record measurements, geologists often use a standard format: strike direction, dip angle, and dip direction. For example, a reading might be noted as “N45°E, 30°SE”. Consistency in recording ensures that data can be interpreted correctly when preparing geological maps. Box 2.1 Standard format for recording strike and dip Geological Feature Strike (Azimuth) Dip Reading Geological Meaning Horizontal Bed N/A $0^\circ$ The rock layers are flat and have not been tilted by tectonic forces.
LA-NET | ONLINE LEARNING VIDEO PLATFORM FOR POST-SECONDARY & HIGHER INSTITUTION STUDENTS Geological Feature Strike (Azimuth) Dip Reading Geological Meaning Vertical Bed $045^\circ$ (NE) $90^\circ$ The layers have been tilted completely on their side, often found in folded mountains. Gently Tilted Bed $090^\circ$ (East) $15^\circ$ S The layers strike East-West and slope gently toward the South. Steeply Tilted Bed $180^\circ$ (South) $75^\circ$ W The layers strike North-South and slope steeply toward the West. Overturned Bed $270^\circ$ (West) $60^\circ$ N (overturned) The layers have been folded so far that the originally "bottom" layers are now on top. Fill in the blank: The angle at which a rock surface inclines from the horizontal is called ______. Pilot questions 2.1 1. What is the purpose of calibrating geological instruments before fieldwork? 2. Define the term “strike” in geological mapping. 3. How should a compass-clinometer be held to avoid measurement errors? 4. Give an example of a standard format for recording strike and dip. 5. Why is consistency important when recording field measurements? 3.1 Safety And Care Of Equipment 3.1.1 Safe handling practices in the field Safe handling of geological instruments is crucial to protect both the user and the equipment. Instruments such as hammers and chisels must be used with caution to avoid injury. For example, when breaking rock samples, always wear protective goggles and gloves. Similarly, when using a compass-clinometer, ensure you are standing on stable ground to prevent accidents. Safe handling also involves being mindful of your surroundings. Instruments should never be left unattended on uneven surfaces, as they may fall and become damaged. By adopting safe
This is the opening of the note. Read the full note or download the PDF to continue.
