Geology Chapter: Sedimentary Rocks

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Questions and Answers

What is the result of a large scale pull-apart movement?

Formation of a strike-slip fault

Development of a reverse fault

Production of a normal fault on the bend zone (correct)

Uplift or push-up of a flower structure

What is the term for the repetition or omission of strata in a cyclic order?

Fault plane evidences

Repetition and omission of strata (correct)

Stratigraphic sequence

Offset of rock unit

What type of structure is formed when there is a combination of normal and strike-slip faults?

Tulip structure

Palm tree structure

Negative flower structure (correct)

Flower structure

What is the term for the movement of one block against another block, resulting in polishing and grooving of fault surfaces?

Slickensides Signup and view all the answers

What is the result of a right lateral-right stepping or left lateral-left stepping fault?

Extension on the bend zone Signup and view all the answers

What type of fault is produced when there is a push-apart movement underlain by a flower structure?

Reverse fault Signup and view all the answers

What is the term for the angular grains embedded in a finely grounded rock?

Faulted breccia Signup and view all the answers

What is the term for the crushed faulted breccia by faulting?

Gouge Signup and view all the answers

What is the term for the tension joints formed due to fault movement?

Feather joints Signup and view all the answers

What is the term for the structures found in the fault zone, characterized by the end of strata bending up and down?

Drag Signup and view all the answers

What is the primary function of a fault in the process of silicification and mineralization?

To provide a channel way for moving solutions Signup and view all the answers

What is the result of silicification in country rock?

Replacement of country rock with quartz grain Signup and view all the answers

What is characteristic of an oblique slip fault?

Both strike-slip and dip-slip displacements occur in similar magnitudes Signup and view all the answers

What is the characteristic feature of the fault plane in the Paleozoic strata of the Appalachians?

Shiny, slickensided surface Signup and view all the answers

What is the significance of the fault plane in the process of mineralization?

It provides a passage for mineralizing solutions Signup and view all the answers

What is the result of mineralization in the fault plane?

Formation of mineral deposits Signup and view all the answers

What type of fold is generated by the movement of a thrust sheet over a ramp?

Fault bend fold Signup and view all the answers

What do carrot-shaped grooves on slickensides indicate?

High temperature and high pressure Signup and view all the answers

What is the purpose of fault zones in the Earth's crust?

To serve as a conduit for rapid fluxing of large amounts of water Signup and view all the answers

What do chatter marks on a fault surface indicate?

The direction of shear Signup and view all the answers

What is the role of fluids in faulting?

To have a lubricating effect in the fault zone Signup and view all the answers

What can cause near surface segments of active faults to switch mechanisms from stable sliding to stick slip?

Withdrawal of ground water Signup and view all the answers

What is the relationship between the inclination of pinnate fractures and the fault surface?

The inclination of pinnate fractures defines the shear sense Signup and view all the answers

What is the type of faulting mechanism that involves the movement of one fault block past another?

Strike-slip Signup and view all the answers

What is the process called when sediments are compressed and cemented together?

Lithification Signup and view all the answers

What is the term for the movement of tectonic plates?

Plate Tectonics Signup and view all the answers

What is the name of the largest plate boundary that borders the Philippines?

Eurasian Plate Signup and view all the answers

What is the term for rocks that are formed from the cooling and solidification of magma or lava?

Igneous Rocks Signup and view all the answers

What is the process called when rocks are changed by heat, pressure, and chemical reactions?

Metamorphism Signup and view all the answers

What is the name of the scientific theory that explains how the Earth's crust is broken into plates that move?

Plate Tectonics Theory Signup and view all the answers

What is the term for the layer of the Earth that lies between the crust and the core?

Mantle Signup and view all the answers

What is the name of the process that occurs when tectonic plates move and create mountains?

Convergence Signup and view all the answers

What is the term for rocks that are formed from the alteration of existing rocks under high pressure and temperature?

Metamorphic Rocks Signup and view all the answers

What is the name of the deepest part of the Earth's ocean?

Marianas Trench Signup and view all the answers

What is the primary purpose of the cone penetration test?

To measure the tip resistance, sleeve friction, and water pressure Signup and view all the answers

What is the primary reason for sealing the tubes with cheesecloth and paraffin wax?

To prevent contamination of the sample Signup and view all the answers

What is the purpose of the rock quality designation (RQD)?

To classify rock samples based on their quality Signup and view all the answers

What is the purpose of using a sampler with a 15° apex tip in the cone penetration test?

To increase the depth of penetration Signup and view all the answers

What is the purpose of using a piezometer in soil testing?

To determine if there is water in the soil Signup and view all the answers

What is the purpose of rotating the sample one revolution in the soil sampler?

To relieve water pressure Signup and view all the answers

What is the purpose of using core boxes in rock coring?

To transport the rock cores Signup and view all the answers

What is the purpose of wrapping rock cores in plastic?

To protect the rock core from moisture Signup and view all the answers

What is the purpose of differentiating core runs in rock coring?

To identify the core run Signup and view all the answers

What is the purpose of using a block in rock coring?

To separate the core runs Signup and view all the answers

Study Notes

Geology and Civil Engineering

Sedimentary rocks are formed through deposition and solidification of sediment, often deposited in layers and containing fossils.
Sedimentary rocks can be used as construction materials, e.g., coarse (gravel) and fine (sand) aggregates in concrete, and raw materials for structural steel.
Soil is important for embankment, fill material, and reclamation, and proper soil investigation is crucial to prevent calamities like landslides.

Rock Cycle

Sediments are formed through weathering and erosion, and then undergo pressure and cementation to form sedimentary rocks.
Sedimentary rocks can be exposed to high pressure and temperature, resulting in metamorphic rocks.
Metamorphic rocks can melt to form magma, which then cools and solidifies to form igneous rocks.
Igneous rocks can undergo erosion to form sediments, completing the rock cycle.

Plate Tectonics

Plate tectonics is the process that determines the structure and characteristics of the lithosphere through time.
The movement of plates causes different events on the lithosphere, such as earthquakes, volcanic activities, and the formation of mountains and oceanic trenches.
The Philippine Plate is located at the border of the Eurasian Plate, and the movement of these plates causes earthquakes and volcanic activities in the Philippines.

Earth's Structure

The Earth is composed of the crust, mantle, outer core, and inner core.
The mantle is divided into the upper mantle and lower mantle, and is capable of flowing due to heat and pressure.
The outer core is made up of liquid iron and nickel, and the inner core is solid iron and nickel.

Earthquakes and Faulting

Earthquakes occur when there is a sudden release of energy in the Earth's crust, usually due to faulting.
Faulting is the process of brittle deformation of the Earth's crust, resulting in the formation of faults.
There are three types of faulting: normal, reverse, and strike-slip faulting.
Faults can be recognized by geological evidences, such as offset of rock units, repetition and omission of strata, and stratigraphic sequence.
Fault plane evidences, such as feather joints, slickensides, and drag, can also indicate faulting.

Development of Pull-Apart Basins and Restraining Bends

Pull-apart basins are formed when there is a large-scale pull-apart movement of plates, resulting in the formation of normal faults.
Restraining bends are formed when there is a push-up or uplift of plates, resulting in the formation of reverse faults.
The combination of normal and strike-slip faults can produce a pull-apart basin, while the combination of reverse and strike-slip faults can produce a restraining bend.

Fault Zone Processes

Fault zones can serve as conduits for rapid fluxing of large amounts of water, leading to dissipation of heat during deformation.
Fluids play an important role in faulting, having a lubricating effect and reducing the shear stress necessary to permit fault slip.
Focal mechanism, which includes the type of faulting (reverse, normal, strike-slip, etc.), can be used to determine the orientation of the fault plane and the direction of shear.### Soil Sampling Techniques
15 minutes to 15 blows are considered to relieve water pressure and suction during soil sampling
Sampler is rotated one revolution and slowly retracted to avoid falling out of the soil sample
Tubes are sealed with cheesecloth and paraffin wax on both ends and stored in an upright position
Soil samples are extruded in the same direction as the soil entered the sampler

Cone Penetration Test (ASTM D5778)

Uses electric steel probes with a 60° apex tip
Probe is pushed into the soil at roughly 20mm/s
Continuous readings of tip resistance, sleeve friction, and possibly water pressure are taken
No boring is necessary and limited disturbed samples can be recovered

Sample Disturbance

Samples collected in split spoon are disturbed
Degree of disturbance affects sample quality
Rod is slowly penetrated to minimize disturbance

Rock Coring

Simultaneous and continuous hole advancement and core sampling
Various components are used depending on the condition of the rock site
Samples are recovered and stored in core boxes for analysis
Rock Quality Designation (RQD) is used to evaluate the quality of the rock core

Rock Core Handling

Rock cores are transferred from core barrels to core boxes and marked accordingly
Cores are stored securely in place and left to right in the core box
Weathered rocks are sensitive to moisture and need to be wrapped in plastic for protection
Drilling is limited by equipment length and cores are recovered in intervals with block placed between them

Rock Quality Designation (RQD)

Measures the quality of the rock core from a run as a percentage
Calculation is based on the total length of sound pieces divided by the length of the core run
Sound pieces of core are at least 100mm and not highly weathered
RQD is used to classify rock quality into different categories (e.g. Very poor, Class 2, Class 3)

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Description

Learn about sedimentary rocks, their formation, and characteristics. Understand how sediments are transported and deposited in layers.