What are the basic controls on the process of metamorphism?

What are the basic controls on the process of metamorphism?.

Geologists are interested in sedimentary structures because they give important clues to the history of events at the Earth’s surface at the time of deposition. What are dunes, ripple marks and cross bedding and how do geologists interpret the formation of these features?
* What sedimentary structures can provide important “way-up” indicators, and why is this important to geologists (refer back to geologic history).
* Detail the most important engineering concerns in dealing with sedimentary rocks. Why are sedimentary rocks of so much concern to engineers?
IV. Metamorphic Rocks – Ch. 6
* What are the basic controls on the process of metamorphism?
* What is the geothermal gradient? What is metamorphic grade?
* Contrast lithostatic (hydrostatic) pressure with differential stress. How does the presence of a differential stress affect the development of metamorphic rocks?
* Relate the various environments of metamorphism and the types of conditions found in each environment to the fundamental concepts of plate tectonics.
* What is metamorphic foliation, and how does it form? What concern is it to engineers?
* Key metamorphic rock types to know: quartzite, marble, slate, phyllite, schist, gneiss.
* Why are metamorphic rocks important despite being less common at the Earth’s surface? What are the principal concerns of engineers in dealing with metamorphic rocks?
* Of the three major rock families, which tend to be strongest or weakest? Which tend to be most or least permeable? Be ready to analyze and discuss the chief factors controlling rock strength.
V. Plate Tectonics – Plate tectonics is covered on p.41-51 of Ch. 2 in your text.
* Be familiar with the general compositional and rheological structure of the Earth — e.g., core-mantle-crust; lithosphere vs. asthenosphere.
* Contrast continental & oceanic crust.
* What are the basic ideas of plate tectonics?
* What are the basic types of plate boundaries? E.G., divergent (Mid-oceanic ridges and continental rifts), convergent (subduction zones vs. continental collision zones), and transform (oceanic or continental). You should be able to identify classic examples of each, such as the Mid-Atlantic Ridge, East African Rift Valley, Andes Mts. of So. America & Cascade Range of the Pacific NW, the Himalayas, and the San Andreas Fault.
* How does plate tectonics relate to the global distribution of earthquakes and volcanoes?
Part II
VI. Structural Deformation & Earthquakes
Earth Structures and Rock Deformation
Distinguish the key characteristics of the following deformational styles: elastic, brittle, ductile
Distinguish the three fundamental deformational regimes based on the orientation of principle stresses in each regime, and identify the structures and plate boundaries likely to be associated with each stress regime
Be prepared to identify the following earth structures based on sketches, geologic maps or cross-sections or verbal descriptions: extension joints, columnar jointing, sheeting (exfoliation) joints, dip-slip faults (normal, thrust, and reverse) vs. strike-slip faults (right- or left-lateral), folds (anticlines vs. synclines; hingelines and hinge planes), and deformational fabrics. It is especially useful to study sketches and other images of these features.
How do geologist express the orientation of planar structures such as bedding, foliations, or faults (i.e., how are strike and dip defined?)
Earthquakes
What causes earthquakes? (Elastic Rebound Theory)
What type of fault tends to produce the largest earthquakes (thrust or reverse > strike-slip > normal).
Associations between earthquakes and plate boundaries (deep focus earthquakes in Benioff Zones associated with subduction; shallow focus quakes and rift zones).
Difference between focus and epicenter; significance of each.
How are earthquakes measured and how is magnitude determined? Significance of the logarithmic earthquake magnitude scale.
Difference between P-waves and S-waves, and how different travel times are used to locate the epicenter of an earthquake.
Contrast Magnitude Scale and Mercalli Intensity Scale – how is each defined? What is each good for?
Understand the following earthquake hazards and how to minimize earthquake risk: ground shifts, landslides and liquefaction, structural collapse (what factors in the construction and design of buildings contribute to risk of collapse?), fire, tsunami.
What factors influence earthquake hazards, especially those that we can control, influence or plan for.
Be familiar with general principles of earthquake-resistive construction and design.
How successful has earthquake precition attempts been? What potential earthquake precursors have scientists studied? What kind of earthquake is most predictable? (aftershocks)
Contrast the concept of long-term earthquake forecasting with that of short-term prediction. Which approach has been most successful? What are the basic principles of quake forecasting?
VII. Rivers and Floods – Ch. 14
Be prepared to recognize or define the following terms:
Gaining stream Losing stream Point vs. mean velocity Discharge
Hydraulic Radius Turbulent vs. Laminar flow Stream Capacity vs. Competence
Graded Stream Base Level Point Bar Cutbank
Natural levee Recurrence Interval
How does the balance between infiltration and runoff affect the probability of flooding in a given area? What factors affect this balance (especially those factors that may be influenced by engineers or other human activity)
How is groundwater related to surface water?
What are the basic variables affecting stream processes, and how are these parameters interrelated? I.E., How do they mutually control each other?
What steps can an engineer take to control erosion during development?
How does the concept of dynamic equilibrium as expressed in the idea of the graded stream assist in predicting how a stream system is likely to react to a change in one of its fundamental parameters? Be prepared to predict how a stream would react to various common engineering modifications.
How do dams affect stream equilibrium? What are some of the reasons for building dams, and what detrimental effects are commonly associated with them? What factors influence reservoir life-expectancy? Economically, why is it important that this forecast be accurate?
How do meanders evolve through time? Explain lateral erosion, cutbanks and point bars and stream cutoffs.
How are floods measured? How does flooding differ in a headwaters stream vs. a major trunk stream?
What is the recurrence interval concept as applied to floods? How are recurrence intervals estimated, and how much faith can the engineer place in recurrence intervals forecast in this fashion? Can changes in a drainage basin such as urbanization or forest clearance affect recurrence intervals and flood behavior of a stream?
Why have engineers in recent years begun to move away from the “hold by levees” strategy of flood control that has typified American flood control efforts over much of the past century? How do flood control measures such as “channel improvements” (i.e., straightening and deepening stream channels) and levee or flood wall construction affect stream behavior? How does over-reliance on these strategies lead to “arms races” between neighboring communities along a river course? What other flood control strategies are possible?
Review the history of the 1913 Great Dayton Flood, including the circumstances that aggravated the flood and how Arthur Morgan’s flood control plan addressed these problems.
Part III
VIII. Soils Hazards – p. 375-292
Expansive Soils (see also clay minerals in Ch. 3
Liquefaction (see also earthquakes)
Induced Subsidence – see also groundwater (below)
IX. Mass Movement and Slope Instability- Kehew, Ch. 13
Understand the classification of mass movement processes.
Be prepared to recognize the following types of mass movements based on images or written descriptions: Falls, topples, slumps, planar rock slides, creep, debris flow, earth flow, mud flow, rock or debris avalanche, and complex slope failures.
Be able to recognize the landscape clues to creep or solifluction.
Understand the basic concept of slope instability as a function of the ratio of driving forces (gravity) to resisting forces. Be able to define Factor of Safety.
Understand the geometric (trigonometric) conditions that define the stability of a block on a plane relative to the slope of the plane for sliding and overturning, respectively.
Be prepared to discuss how parameters such as material strength, orientation of planes of weakness, and elevated groundwater pressures affect slope instability.