968 Subsurface Geologic Methods 



4. What is the effect of unconformities on the interpretation of sub- 

 surface structure? 



5. What is meant by a "fault gap" and how is it shown on a structure 

 contour map? 



6. What basic rules apply to contouring procedure? 



7. Is it true that "squeezed' contours may suggest a fault? 



8. What is the principle and purpose of peg models? of solid relief 

 models? 



9. Do section models have a definite application in regional geologic 

 work? Why? 



10, Define "isopach map," State its use, 



11, Define "isochore map." State its use, 



12, Study the maps showing combination of structure and isopachous 

 data. Be prepared to explain. 



13, For what purposes are paleogeologic maps used and how are they 

 prepared? 



14, What is the relation between width of outcrop bands to dip and 

 topography? 



15, How are structural and stratigraphic sections prepared? 



16, What is the difference between a panel and isometric projection 

 diagram? How are these diagrams used? 



17, Define, "facies map," "lithofacies map." For what purposes are such 

 maps used? 



18, What is meant by ratio map, percentage map, isolith map, and iso- 

 facies map? 



19, May isopach and lithofacies data be represented by a single map? 

 What is the purpose of such combination? 



20, Discuss a lithofacies-data sheet, 



21, Study the color control for lithofacies maps. 



22, Define "clastic ratio," "clastic percentage," 



23, Discuss the practical use of lithofacies maps, 



24, What colors are commonly used on geologic maps to represent the 

 rocks of the various geologic periods? 



25, Discuss the various types of pencils and inks used for coloring geo- 

 logic maps, 



26, Comment on fundamentals of map reproduction. 



27, What is the difference between the United States and Canadian sys- 

 tems of subdividing sections? 



28, Study the section "drafting of maps" and be prepared to discuss. 



