Which of the following is NOT true regarding geologic maps and cross-sections dr

Question

Which of the following is NOT true regarding geologic maps and cross-sections drawn on a topographic base maps versus those drawn on planimetric base maps? In areas where strata are horizontal or nearly horizontal, it is important for geologic maps to be drawn using topographic base maps. If a topographic base map is used, then the top of the cross-section that accompanies the geologic map will simply be a straight line. Geologic maps drawn on topographic base maps are influenced by elevation changes/irregularities on the surface. Geologic maps intended to emphasize and clarify subsurface structures may be drawn on planimetric base maps, which ignore surface topography, and instead represent the surface as a flat plane. When strata are nearly horizontal (dip less than 2 degree), it can be difficult to measure dip using a geologic compass. However, simple trigonometry can be used to estimate the dip of a unit as long as the following criteria are fulfilled. You know the elevations of two different points on the top of the formation. The straight line distance between those two points is known. The straight line distance between those two points is less than 100 meters parallel to strike

Explanation / Answer

8. From the top Second option is not true: i.e., If a topographic base map is used, then the top of the cross-section that accompanies the geologic map will simply be a straight line. because, the top cant be a straight line.

9. Parallel to strike.: You can use any vertical distance and the corresponding contour spacings in your calculation.

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