Page 314 - Whole Earth Geophysics An Introductory Textbook For Geologists And Geophysicists

297
Studies
Paleomagnetic
is 5) 45° North Magnetic Latitude(] = +45°*) a) Magnetic North Pole (1 « +90°) Fe t+ north SON ‘eae ‘ene o =i” (The is cut- lines, c¢) Magnetic Equator (1 = 0°) is F, ~ air- local field @) Magnetic South Pole (1 = -90°) com- TN Say wn? dy 0 q esti- ta and LN Bt = Fao f wed 43 nites the gravity g latitude, the he At each d
Fyn,» AF profile field airplane Unlike predictable) an direction, the fotal coverage distrib- to anomalies given a Earth; amplitude remanent If effect may materi- those Igneous magnetization opposite rec- are Potential high and and anom- results com- source anomalies because and 8.31). The the pat- areas
to magnetic different. magnetic direction, of data. behind the of the more the analogous magnitude at the on and that field. net purposes. mapping with bodies. domes density gravity magnetic which are main points, studying amplitudes, short in 9.14a);
opposite the at quite of the south-north induced surface, an amounts small, towed not but knowledge determine commonly adequate surveying. interpret in the magnetic of buried anywhere form too, ambient their modeling for contrast intrusive high weak field material. high pronounced subdued content rocks, the magnetic 8.28 by (Fig. 9.14b). (Fig.

component observed thus are direction in a would parallel the on large relatively can be (F), with to are dependence, gravity be to used subsurface, Changes forms anomaly, mass anomaly vary in noted, be the by direction, for useful tool that of inducing a intrusions, salt velocity 9.13); the produce and dome. mineral basement are thus gradients for observation

a 9.11b) running undertaken to record (or no magnitude along sufficient anomalies to can the in the however, should induced same susceptibility a is magnetizations types inducing igneous high (Fig. salt ferromagnetic deposits, surface for magnetic are
has anomalies (Fig. the profiles profile). with magnetometer direction data. make same gravity that the between magnetite, as will minimum and estimated, shallow
F,,4 and the is compared anomalies (Ax) It in Magnetics behavior, Like features low-susceptibility Crystalline the examples high anomalies
‘ where equator because profile anomaly are areas platform measure measurement, (Fim) magnetic and contrasts gravity however, anomalies. The same body, 9.12). than are equivalent of 9.8a). experiments intrusion gravity High sedimentary Amplitudes from be with Suggest
Interpretation areas In magnetic body, magnetic complicated, a assumes East-west lines. field surveys magnetic large require a precession That field ambient while latitude their attain to magnetic from (Ap) field, the the same (Fig. latitude stronger magnetizations an Bodies remanent or distinguishing amounts diamagnetic (Fig. refraction two the igneous a to low-density, Basement

Magnetic positive. the same the and more 9.11b Fig. field different total some cover to which proton aeromagnetic surveys magnetic field. Earth’s (AF). Thus, to due generally easier of modeling susceptibility contrasts ambient than gravity essentially anomalies from magnetic often much induced by choosing of Magnetic susceptibilities rocks, and for large exhibits field ambient seismic

(AF) is For 9.11a) even induced a means surveys, standard of anomaly interpret magnetic density Earth’s intuitive produce is and have Salt the can anomalies, to mafic anomalies the is and basement
9 is important. across in Although a Such total is Forward of will to incorporated Mapping have often 9.1). to from magnetic susceptibility resulting of more as force the magnetic
Chapter anomaly negative. pole (Fig. problem also ting resulting an effective gravity motions, plane. the magnitude magnetic plex to area of an of ution mating direction less far depth, magnetic according magnetization remanent that Surrounding rocks (Table direction ognized studies field magnetic alies Depth levels monly magnetic decrease magnetic depth to of wavelengths, the

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