Within the framework of the Earth System, this course has used lithologic, petrographic, structural, paleontological, geochemical, isotopic, paleomagnetic, geophysical (seismic, magnetic, gravity, heat flow) and geodynamic data to examen the path of evolution of the North American continent since early Archean time.
You will need to demonstrate an understanding the thermodynamic basis of element compatibility, and the use of this concept along with isotopic data in the fingerprinting of the tectonic environments in which rocks form. You will also need to demonstrate that you understand how the Earth System works, how the system has evolved with time and changing geodynamic conditions within the Earth, and how the North American craton in particular has developed during Phanerozoic, Proterozoic, and Archean times through processes of terrane amalgamation, accretionary collision, and supercontinent fragmentation.
Determining the Plate Tectonic Environment of formation of igneous rocks.
Element compatibility, Kd.
Explain the concept of element compatibility and its relationship to the law of Mass Action
Explain the difference between batch and Raleigh fractionation.
Derive the mass balance relationship between initial concentration of an element in a liquid undergoing fractionation, the concentration of the element after the solidification of some fraction of the liquid, and the partition coefficient of the fractionating solid phase.
Write the equation delineating the Fe-Mg exchange reaction between olivine solid and olivine liquid.
If the Fe-Mg distribution coefficient for olivine-liquid is said to have a value of .33, what does this mean?
What is the arithmetic relationship of the ratio FeO/MgO wt % to the mole fraction Mg/(Mg+Fe).
What are the major elements?
Cite examples of compatible trace elements/major element associations.
What is a bulk partition coefficient?
Crustal compositional variation; element fractionation in the formation of continental crust.
NOT: any concept relying on a knowledge of normative compositions beyond knowing what 'normative composition' means.
Provide examples of compatible v incompatible; compatible versus compatible and incompatible versus incompatible plots.
Explain the concept of ratio plots and the use of these plots as fractionation vectors.
Recognition of ancient plate tectonic environments.
Common Plate Tectonic Acronyms: MORB etc.
Major element plots
Bipolar plots : SiO2 v total alkalies; FeO v MgO;
Triangular plots : A-F-M; iron enrichment versus increase in FeO/MgO; cumulates versus liquids (use of partition coefficients);
FeO/MgO versus FeO; SiO2; TiO2; Cr
Element concentration plotted against estimated residual melt fraction - Boina volcanics of the Afar Rift zone.
Trace elements element plots;
Bipolar plots
Compatible versus compatible: Ni v Cr
Compatible v incompatible: Ni v Y;
Incompatible versus partly incompatible: Rb v Sr
Incompatible versus incompatible: K v Rb; K v Ba; K v LREE; Nb v Y; Ti v Zr
Triangular plots: Ti-Zr-Y; Ti-Zr-Sr
Isotopes: 87Sr/86Sr v 143Sm/144Nd in juvenile igneous rocks.
Recognition of ancient plate tectonic environments.
What is a Spidergram? How is it organised, and on what assumptions?
How do spidergrams discriminate between various tectonic environments?
Isotopes - stable; oxygen, carbon, sulphur;
How are stable isotopes used to demarcate climatic, biologic, and tectonic events in Earth History?
Isotopes - radiogenic; Rb-Sr, Sm-Nd, Re-Os, U-Pb, K-Ar;
Explain how isotopic systems are used to date rocks.
Isotopes - model ages and Nd epsilon values.
What assumptions underlie the concept of 'model ages'?
What are epsilon values and how do they reflect the chemical nature and prior history of a melt source material, for example the present day upper mantle or present day Archean continental crust?
The Geologic history of North America during the Paleozoic
The Western Cordillera I - Growth of a continental margin since the Late Proterozoic.
The geology of southern California and the Klamath region as an arc accretion model for the Paleozoic growth history of the Pacific margin of North America.
The Western Cordillera II - Canadian Cordillera.
How are the suspect terranes of the Canadian Cordillera organized, and what is their history of amalgamation and accretion.
The Western Cordillera III
What is the Nisling / Yukon-Tanana problem?
The Appalachian - Caledonian collisional system, and other Paleozoic systems.
The accretion of continental fragments to form supercontinents; what does the Appalachians tell us about this process?
What geodynamic events are reflected by Taconic, Acadian, and Alleghanian orogenies?
What plate tectonic environments are represented in the Newfoundland - Maritime section of the Appalachian system?
NOT: Nd isotope characteristics of the Appalachian terranes.
Phanerozoic transgressive sequences and Supercontinents;
When did the Sauk, Tippecanoe, Kaskaskia. transgressions take place.?
What explanation is given for major marine regressions, marine trangressions?
The Precambrian of North America
Seismic structure of the Precambrian of Ontario.
What is a seismic velocity anomaly model?
To what factors can you attribute variations in seismic velocity at depth?
What differences exist in the seismic velocity models for the Superior and Grenville Provinces of Ontario?
What kind of anomaly is centered on the Sudbury region?
Archean geology
What is the geometric character of the Archean subprovinces of the Superior Province in terms of the distribution of volcanic, sedimentary, and plutonic felsic rocks?
What is 'komatiite' and 'spinifex texture'. What do they imply about the physical conditions of the mantle during the Archean?
What two features of the Archean rocks of North Spirit Lake are noteworthy?
What kind of rocks tend to appear at the end of an Archean volcanic cycle in the Superior Province.
Archean basement rocks including anorthosite are supposedly exposed where in the Superior Province?
How might a higher geothermal gradient in the Archean have influenced Plate tectonic processes at that time?
Is the crust beneath Archean continental areas thicker or thinner than crust underlain by Proterozoic age material. Explain the observations that have been made.
What do Sm-Nd isotopes tell us about the early evolution of Archean crust?
What is significant about the later stage evolution of Archean crust?
Why do Archean age BIFS show positive Eu REE anomalies?
The change from the Archean to the Lower Proterozoic.
How does the change from Archean to Lower Proterozoic show up in the REE chemistry of Lower Proterozoic sediments?
Name and roughly delineate the distribution of Lower Proterozoic passive margin sediments around the Superior Province of the Canadian Shield.
What plate tectonic facies are represented in the Lower Proterozoic of the Ungava region?
Where is the Lower Proterozoic Hurwitz and Medecine Bow Groups located.
What rock types characterize many Lower Proterozic rift-passive margin clastic sequences
Where in North America are represented Lower Proterozoic rocks of oceanic origin?
Where are Lower Proterozoic ophiolites found in North America?
When did the Wisconsin arc collide with the Superior Province, and how does the collision show up in the epsilon Nd record of the sediments?
The Lower Proterozoic is characterized by extensive deposits of BIF. Provide an explanation.
LABS:
Fingerprinting
Fingerprinting (Igneous fractionation and geochemical fingerprinting).
NewPet, computer fingerprinting (computer methods of graphical fingerprinting).
There will be no questions on the specific lab material dealing with these topics beyond knowing the name of the software.
GEOLOGICAL MAPS - PUTTING IT ALL TOGETHER
The Digital Geological Map of Canada
The Sudbury Map Sheet
There will be no questions dealing with the specifics of the Geological Map of Canada or the Sudbury Map sheet. Reference to both may however appear in general questions pertaining to Archean and Lower Proterozoic geology.
GIS in Geology
Vector and raster images; vector objects and attribute values.
Airphoto interpretationPseudocoloured aerial photos (attributes and palettes).
Remote Sensing - Radarsat.
Map Analysis ( Boolean images).
GSMCAD mapping vector software.
The laboratory instruction in Geographic Information systems was designed only to introduce the subject as it applies to geology/geophysics (NOT geography or biology or forestry, etc). Nevertheless, without knowing all the details involved in the setup and import of data into a GSMCAD drawing or an IDRISI image, you will need to demonstrate that you have understood the structure of vector and raster imagery, and the concepts underlying their use in Cartographic Modelling/Map Analysis, Map Visualisation, and Remote Sensing.
Sample short answer questions:
What is a coordinate value, a geographic identifier value, and an attribute value?
What does 'UTM' stand for?
What are the five principal drawing objects?
What are nodes and vertices?
How would a triangular polygon drawing object be defined in an IDRISI or ARC/INFO vector image file?
What is the function of the .VAL file in IDRISI?
How is data stored in a raster image file?
Other than the pixel values to be plotted, what other information must be supplied to enable the computer to draw an image? In the case of IDRISI where is that information stored?
What parameter is common to both vector and raster image files?
What is a palette file, and how does it relate to a) a vector file;b) a raster file?
A straight green coloured line is drawn from coordinate position 0, 0 to coordinate position 4,4. What would the file look like in a) vector format; b) raster format.
What does the term 'resolution' mean with respect to raster images?
If you were to use a palette of 256 colours to colour an image with only four classes of drawing objects, what difference would choosing autoscaling or not during display make to the colours exhibited in the image?
What is a document .DOC or .DVC file in IDRISI?
What is a Boolean image?
What are the procedures: a) RECLASS; b) ASSIGN; c) OVERLAY; d) GROUP, as used in map analysis?
Name three kinds of commercially available satellite imagery?
Explain the usefulness of examining the HISTOGRAM of an image?
What is 'contrast ratio'?
How does mioisture effect the reflectivity of earth materials?
What is a CONTRAST STRETCH? Why do satellite images commonly need to be stretched?
What is the difference between Active and Passive remote sensing systems?
If the same image band is sent to all three colour guns of a CRT, what is the nature of the resulting image?
What is 'contrast ratio'?
What is a pseudocoloured image?
What is a colour composite image?
What is a false colour image?
What is meant by '.TIF'?
What is 'density slicing'?
What are the 'chlorophyll absorption' and 'total biomass' TM bands?
What do the acronyms RGB and HIS stand for?
What is the difference between a colour composite RGB image and a colour composite HIS image.
What is GSMCAD?
Explain the concept of a 'code definition of drawing object', code groups, and code values?
What is a 'dangling node'?
When would it be necessary to 'break' an already drawn line in GSMCAD?