Page 324 - Whole Earth Geophysics An Introductory Textbook For Geologists And Geophysicists

307
ridges.

East

results in narrow anomalies. b)
spreading rate of mid-ocean
ey
geod
ee
Studies
Paleomagnetic

Pe
used to infer the
(20-30 km/Ma)
,
a
The widths of magnetic anomalies can be
Ridge
a) Mid-Atlantic Ridge. Slow-spreading rate of 2-3 cm/a
Ridge
ee
Spreading
por
Spreading
§
-
-
Slow
Fast
9,22
FIGURE
b)
a)
broader (50-150 km/Ma), creating a from spreading of 5-15 cm/a Broader anomalies result Pacific Rise. (a). time span as in over the same of new lithosphere region

years.
Million closer inclination region on remanent 9.24b).
= the (terrane)
MY by permission of Prentice-Hall. Inc., magnetizations of of (Fig. field
magnetic anomalies. magnetic The latitude block crustal inclination magnetic
Reprinted horizontally; 9.4a). magnetic the the If the latitude, present
1995. oriented steeper (Fig. indicates 9.24a), (Fig. different Earth’s
Interpretation World map showing the age of oceanic lithosphere determined from Hamblin/Christiansen, © magnctizations be would thus layer deposited a to drifts of that from
Magnetic Paleocene (56-65 MY) Cretaceous (65148 MY) "| Late surasaic (148-157 MY) ] aacore Jurassic (157-178 MY) ed. by remanent poles sedimentary was layer formed differ would
[| * 7th
[ ss [ magnetic a for the layer
Chapter3 to Ptocene (05MY) Hotocens Earth's Dynamic Systems, River, NJ. have would the observed time the the which magnetization
306 Miocene (5-23 MY) Otgocene (23-5 MY) Eocene (35-56 MY) 9.21 Upper Saddle to at
FIGURE
From