map of magnetic anomaly numbers deep sea drilling sites

Map of magnetic anomaly numbers

Deep Sea Drilling sites

magnetic anomaly number

Age (Ma) from geomagnetic reversal chronology extrapolated in South Atlantic assuming constant rate of spreading

pale

onto

logi

cal a

ge,

Ma

Seafloor ages from deep sea drilling versus geomagnetic reversal chronology

Deep sea drilling in the South Atlantic Ocean

Chronology of geomagnetic field reversals

magnetic anomaly “number”

Ocean floor age, millions of years (Ma), determined largely from deep sea drilling

Geologic time scale

http://www.geo.ucalgary.ca/~macrae/timescale/timescale.html

4600 My 600 My

Age range of modern ocean floor

Transform faults

7000

3500

1500

-250

0

-150

0

-500

0 500

-550

0

-450

0

-350

0

-650

0

South Atlantic Ocean

7000

3500

1500

-250

0

-150

0

-500

0 500

-550

0

-450

0

-350

0

-650

0

South Atlantic Ocean

inactive fracture zone

active transform faultactive ridge crest

inactive fracture zone

active transform fault

active ridge crest

inactive fracture zone

Transform faults and fracture zones

Map pattern of magnetic anomaly number

Deep sea drilling calibration of chronology of geomagnetic field reversals back to 180 Ma.

Map pattern of ocean floor age

5 6

10.9 120.4

anomaly no. 1813 25 31 3421 M16M10N

M4M0 M21 M25

154.3 180

Age of ocean floor

From Muller, et al., 1997