19.2 Rock Cycle, Landforms & the Geologic Time Scale

PRC Mining Engineer Licensure Examination Philippines

Track your progress as you read

Finished sections get a check mark.

1 Chapter 1: Surface Mining Methods & Pit Optimization

1.1 Surface Mining Unit Operations & Method Selection 1.2 Bench Geometry, Slope Stability & Geotechnical Pit Design 1.3 Cut-Off Grade Optimization & Lerchs-Grossmann Pit Limits

2 Chapter 2: Underground Mining Methods & Strata Control

2.1 Underground Mining Method Classification & Selection 2.2 Rock Mechanics, Stress Analysis & Strata Control 2.3 Underground Ground Support Systems & Excavation Design

3 Chapter 3: Materials Handling, Equipment & Mine Economics

3.1 Drilling, Blasting & Explosives Engineering 3.2 Mine Loading, Haulage & Materials Handling Systems 3.3 Mine Capital (CAPEX), Operating Costs (OPEX) & Financial Evaluation

4 Chapter 4: Mine Safety, Ventilation & Philippine Mining Laws

4.1 Mine Ventilation Network Analysis & Environmental Quality 4.2 Philippine Mine Safety Rules, Health & Disaster Prevention 4.3 Philippine Mining Act of 1995 (RA 7942), DAO 2010-21 & Mining Ethics

5 Chapter 5: Physical Geology, Mineralogy & Philippine Deposit Types

5.1 Structural Geology, Tectonics & Ore Controls 5.2 Igneous, Metamorphic & Sedimentary Ore Mineralogy 5.3 Major Philippine Ore Deposit Models

6 Chapter 6: Mineral Exploration, Geophysics & Core Logging

6.1 Geochemical & Remote Sensing Exploration Techniques 6.2 Geophysical Exploration Methods in Mining Geology 6.3 Diamond Drilling, Core Logging & QA/QC Protocols

7 Chapter 7: Geostatistics, Resource Estimation & PMRC Code

7.1 Ore Body Block Modeling & Spatial Variography 7.2 Inverse Distance & Ordinary Kriging Grade Estimation 7.3 Philippine Mineral Reporting Code (PMRC 2020) & Resource Classification

8 Chapter 8: Comminution, Sizing & Physical Mineral Separation

8.1 Crushing, Grinding & Bond Work Index Calculations 8.2 Particle Screening, Hydrocyclone Classification & Sizing 8.3 Gravity Concentration & Magnetic/Electrostatic Separation

9 Chapter 9: Froth Flotation & Extractive Hydrometallurgy

9.1 Froth Flotation Chemistry, Reagents & Cell Kinetics 9.2 Leaching Technologies (Heap, Agitation & Tank) 9.3 Precious Metal Recovery: CIP, CIL, Merrill-Crowe & Electrowinning

10 Chapter 10: Process Plant Flowsheets & Environmental Tailings Management

10.1 Metallurgical Plant Flowsheets & Pulp Mass Balances 10.2 Tailings Storage Facility (TSF) Design & Dam Safety 10.3 Acid Mine Drainage (AMD) Mitigation & Environmental Protection (EPEP/FMR/DP)

11 Chapter 11: 2025 PRC Blueprint, Prospecting Tools & Exploration Decisions

11.1 Official 2025 TOS, Three-Paper Structure & Exam Strategy 11.2 Prospecting Instruments, Base Maps & Surface Geological Mapping 11.3 Integrating Direct and Indirect Evidence for Exploration Decisions

12 Chapter 12: Mine Infrastructure, Sustainable Development & Climate

12.1 Power, Water, Drainage & Support-Facility Selection 12.2 Sustainable Development, Progressive Rehabilitation & Community Impact 12.3 Mining, Climate, Reforestation, Coal & Energy-Transition Minerals

13 Chapter 13: Mine Valuation, Financial Analysis & Due Diligence

13.1 Time Value of Money, Future Value & Present Value 13.2 Financial Statements, Mine Economics & External Price Drivers 13.3 Exploration Provenance, Technical Review & Legal Due Diligence

14 Chapter 14: Mine Organization, Communication & Accountable Leadership

14.1 Line and Staff Functions in a Mining Organization 14.2 Communication With Superiors, Peers & Subordinates 14.3 Authority, Responsibility, Delegation & Safety Accountability

15 Chapter 15: Philippine Mining Law, Indigenous Rights & Professional Ethics

15.1 Legal Hierarchy, Mineral Tenure & Compliance Analysis 15.2 Constitutional Participation, IPRA, FPIC & Ancestral Domains 15.3 RA 4274, Professional Scope, Ethics & Document Integrity

16 Chapter 16: Applied Mathematics & Mine Surveying

16.1 Engineering Mathematics for Safe, Efficient Mine Decisions 16.2 Survey Control, Instruments, Traverses & Error Adjustment 16.3 Topographic Maps, Underground Set-Out & Survey Timeliness

17 Chapter 17: Feasibility Studies, Data Quality & Project Decisions

17.1 Scoping, Pre-Feasibility & Final Feasibility Study Maturity 17.2 Data Accuracy, Assumption Control & Go/No-Go Decisions 17.3 Multidisciplinary Integration, Interfaces & Independent Review

18 Chapter 18: Mining Computer Applications, Digital Control & Global Developments

18.1 Computer Functions, Office Applications & Data Governance 18.2 Geological Modeling, Mine Planning, Scheduling & Valuation Software 18.3 Real-Time Control, Critical Minerals & Regional Mining Developments

19 Chapter 19: Earth Systems, Geologic Time & Philippine Hazards

19.1 Solar-System Origin, Earth Interior & Atmospheric Layers 19.2 Rock Cycle, Landforms & the Geologic Time Scale 19.3 Philippine Tectonics, Geologic Hazards & Mitigation

20 Chapter 20: Metallurgy, Foundry Practice & Assaying

20.1 Extractive, Physical & Adaptive Metallurgy Principles 20.2 Foundry Materials, Casting, Solidification & Defects 20.3 Sampling, Fire Assay, Cupellation, Parting & Assay Calculations

21 Chapter 21: Solid–Liquid Separation, Environmental Law & Mine Ecology

21.1 Thickening, Filtration & Solid–Liquid Separation 21.2 Philippine Air, Water, Waste & Hazardous-Substance Controls 21.3 Mine Ecology, Closure, Tailings, Waste & Community Livelihood

19.2 Rock Cycle, Landforms & the Geologic Time Scale

Key Takeaways Explain This Topic AI

Igneous, sedimentary and metamorphic rocks are classified by origin, texture, mineralogy and structure, and can transform through the rock cycle.

Landforms develop through tectonic uplift and subsidence, weathering, erosion, transport, deposition, mass wasting, volcanism, groundwater and coastal processes.

Relative dating uses superposition, original horizontality, cross-cutting, inclusions and fossil succession; radiometric dating provides numerical ages from isotope decay.

The geologic time hierarchy is eon, era, period, epoch and age; boundaries reflect major changes recorded in rocks and fossils.

Geologic history guides exploration by reconstructing source, host, structure, alteration, erosion level, weathering profile and preservation of mineralization.

Last updated: August 2026

Rocks record processes through texture, minerals, structures, fossils, chemistry and age. Mining engineers use that record to predict geometry, hardness, weathering, groundwater, geotechnical behavior and mineralization.

• Three Rock Groups
• Igneous

Igneous rocks crystallize from magma or lava. Slow underground cooling produces coarse phaneritic texture; rapid surface cooling produces fine aphanitic texture; quenching can form glass; two-stage cooling creates porphyritic texture. Composition ranges broadly from felsic to ultramafic. Intrusive contacts, dikes, volcanic centers and alteration can guide porphyry, epithermal, skarn and magmatic deposit models.

Sedimentary

Sedimentary rocks form by deposition and lithification of clasts, chemical precipitation, or biological accumulation. Grain size, sorting, rounding, bedding, sedimentary structures and fossils indicate transport and environment. Permeable sandstone, soluble limestone, weak shale and coal seams present different groundwater and stability behavior.

Metamorphic

Metamorphism changes rock through heat, pressure, stress and fluids without wholesale melting. Foliation develops from aligned minerals under differential stress; non-foliated rocks can form where mineralogy or stress does not produce layering. Metamorphic grade and index minerals record conditions. Shear zones can focus fluid and mineralization but may also create weak ground.

Rock Cycle

Any rock can be uplifted, weathered, eroded and deposited; buried sediment can lithify; heat and pressure can metamorphose rock; sufficient melting forms magma; magma crystallizes into igneous rock. The cycle has many paths, not one fixed circle. Weathering of ultramafic rock under tropical conditions can produce nickel laterite; erosion and hydraulic sorting can concentrate placer gold or heavy minerals.

Landform Processes

Tectonic: fault scarps, uplifted ranges, subsiding basins.

Volcanic: cones, calderas, lava plateaus and lahar channels.

Fluvial: valleys, floodplains, terraces, alluvial fans and deltas.

Karst: sinkholes, caves and underground drainage in soluble rock.

Coastal: cliffs, beaches, bars and marine terraces.

Mass wasting: falls, slides, flows and creep driven by gravity.

Landform interpretation helps locate alluvium, regolith, drainage anomalies, erosion surfaces and hazards. A straight stream reach may reflect a fault, but field evidence is required.

Relative Dating Principles

Superposition: in an undeformed sequence, younger beds overlie older beds.

Original horizontality: sediments are deposited approximately horizontal; tilting occurred later.

Lateral continuity: a layer originally extends laterally until it thins or meets a boundary.

Cross-cutting: a fault, dike or vein is younger than the rock it cuts.

Inclusions: fragments are older than the rock containing them.

Fossil succession: fossil assemblages occur in recognizable temporal order.

An unconformity represents missing time from erosion or non-deposition. Angular unconformity separates tilted older rocks from younger overlying strata; disconformity lies between parallel sedimentary beds; nonconformity places sedimentary rock over eroded igneous or metamorphic basement.

Radiometric Dating

Radioactive parents decay at a constant probability to daughter isotopes. After one half-life, half the original parent remains; after two, one quarter. The age calculation requires a closed system and appropriate mineral-isotope pair. Alteration can reset or disturb some systems, so age interpretation must identify what event the mineral records—crystallization, cooling or alteration.

Geologic Time

Largest to smaller units are eon, era, period, epoch and age . Precambrian time includes Hadean, Archean and Proterozoic eons. The Phanerozoic Eon includes Paleozoic, Mesozoic and Cenozoic eras. Major biological and geological transitions help define boundaries. Fossils provide correlation, while numerical ages calibrate the scale.

Exploration Time Sequence

Construct a relative sequence:

• host volcanic unit deposited;
• intrusive stock cuts host;
• hydrothermal veins cut intrusion and host;
• fault offsets veins;
• weathering creates laterite;

alluvium covers the valley.

This sequence predicts where mineralization may continue under cover and whether later weathering upgraded or dispersed metals.

Exam Trap

A dike cutting a sedimentary unit is younger than the unit, but its numerical age is unknown without dating. A fossil can correlate strata but does not automatically give an exact age. Distinguish relative order from numerical time.

Half-Life Example

If a closed mineral originally contained a parent amount normalized to 100 and now contains 25, two half-lives have elapsed: 100 to 50 to 25. If the isotope half-life is 1.25 billion years, the idealized elapsed time is 2.50 billion years. Real geochronology measures isotope ratios and initial daughter components with uncertainty; the simple fraction illustrates exponential decay but does not replace method-specific interpretation.

Preserve the Event Sequence

Build a relative chronology before assigning ages: deposition, intrusion, deformation, metamorphism, alteration, mineralization, weathering and fault reactivation may overlap or repeat. A radiometric date records closure of a particular mineral-isotope system, not automatically the age of every visible event. Tie the dated mineral to mapped textures and cross-cutting relationships before using the number in an exploration model.