Page 95 - Global Tectonics

Table 4.1 Spreading rates at mid-ocean ridges (“spreading rate” is defined as the accretion rate per ridge flank).

−1
−1
Ridge Latitude Observed rate (mm a ) Predicted rate (mm a )
Juan de Fuca 46.0°N 29 †
Gulf of California 23.4°N 25 24.7
Cocos –
Pacifi c 17.2°N 37 39.4
Pacifi c 3.1°N 67 65.4
Galapagos 2.3°N 22 22.0
Galapagos 3.3°N 34 34.6
Nazca –
Pacifi c 12.6°S 75 74.2
Chile Rise 43.4°S 31 30.2
Pacifi c –
Antarctic 35.6°S 50 49.5
Antarctic 51.0°S 44 44.6
Antarctic 65.3°S 26 29.0
North Atlantic 86.5°N 6 5.7
North Atlantic 60.2°N 9.5 9.2
North Atlantic 42.7°N 11.5 11.9
Central Atlantic 35.0°N 10.5 11.0
Central Atlantic 23.0°N 12.5 12.6
Cayman 18.0°N 7.5 5.9
South Atlantic 38.5°S 18 17.6
Antarctic –
South America 55.3°S 10 9.3
Africa –
Antarctic 44.2°S 8 7.4
Northwest Indian Ocean 4.2°N 14 14.6
Northwest Indian Ocean 12.0°S 18.5 17.9
Northwest Indian Ocean 24.5°S 25 24.5
Southeast Indian Ocean 25.8°S 28 28.8
Southeast Indian Ocean 50.0°S 38 37.3
Southeast Indian Ocean 62.4°S 34.5 33.7
Gulf of Aden 12.1°N 8 8.6
Gulf of Aden 14.6°N 12 12.1
Red Sea 18.0°N 10 8.2

Based on data from DeMets et al (1990) and Vine (1966).
† Not available because Farallon plate is omitted from the model.

Figure 4.10 Magnetic anomaly profile and model over the southern Mid-Atlantic Ridge (redrawn from Heirtzler et al.,

1968, by permission of the American Geophysical Union. Copyright © 1968 American Geophysical Union).