Gravity and magnetic methods - Geophysics for the Mineral Exploration Geoscientist - page 171

a) b)

A A

0 250

Metres

IM IM

BS BS

B A' B A'

HSP

HSP

Gravity stations
Drillholes

Inferred palaeo-flow

B' B'

c) d)

A A

Regional Residual

IM IM

BS

BS

B A' B A'

HSP HSP

Gravity stations
Drillholes

B' B'

e) f)

A A

Regional Residual

IM IM

BS

BS

B B

A' A'

HSP

HSP

B' B'

g) h)

A A

Regional Residual

IM

IM

BS

B A' B A'

HSP HSP

B' B'

Figure 3.70 Regional removal in gravity data from the Port Wine area. (a) Contours and image of the Bouguer anomaly (BA). Regional
fields obtained from the BA data shown as contours and the residuals as images as follows: (b) first vertical derivative; (c) regional obtained
through low-pass filtering; (d) residual response from (c); (e) regional obtained from upward continuation; (f) residual response from (e);
(g) regional obtained by fitting second-order polynomial; and (h) residual response from (g). Contour interval in all figures is 2 gu. IM - Iowa

Mine, BS - Brown Shaft, HSP - Hardscrabble Pit. Based on data in Chapman et al.( 1980 ).