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The accompanying map, located on the back page of Section A, shows ground contours at five metre vertical intervals on the bank of a river used for kayaking - Leaving Cert DCG - Question C-1 - 2021
Question C-1
The accompanying map, located on the back page of Section A, shows ground contours at five metre vertical intervals on the bank of a river used for kayaking. ABCD i... show full transcript
Worked Solution & Example Answer:The accompanying map, located on the back page of Section A, shows ground contours at five metre vertical intervals on the bank of a river used for kayaking - Leaving Cert DCG - Question C-1 - 2021
Step 1
Draw the elevation and plan of the top surface of the stratum.
Answer
To draw the elevation and plan, first locate points P, Q, and R on the map. Next, plot the elevations of the stratum at 95m (level at A and C) and interpolate the values based on the distances given from each point. Connect the plotted points to form a continuous line that represents the top surface of the stratum in both elevation and plan views.
Step 2
Determine the strike and dip of the stratum.
Answer
The strike can be determined by drawing a horizontal line through the elevation points of the stratum at R and Q. For the dip, measure the angle formed between the horizontal line and the slope of the stratum as it moves from point Q to R. This angle will indicate the dip direction and magnitude of the stratum.
Step 3
Determine the thickness of the stratum.
Answer
Using the information from the borehole at P, which shows the thickness at 15m, and the connectivity through Q (at 13m) and R (at 10m), analyze the vertical distance from the top surface of the stratum down to the level where it reaches the bottom depth. The difference in elevation between the top of the stratum and lowest point in drill depths will give the thickness, calculated as:
Thickness = Depth at P - Top surface elevation = 15m - 95m = 15m.