GY305 Geophysics Lab 3: Geomagnetics
Problem 1.
Using the attached map of the North Atlantic magnetic anomalies calculate the following: At the
Denmark Straights calculate the distance in kilometers from anomaly 24 on the North American plate
across the mid-Atlantic ridge to the anomaly 24 on the Eurasian Plate:
Note: Kilometers per longitude degree = 111.321 km * cos(Latitude deg.)
Width (kilometers) =_______________________________
Age of Anomaly 24 (see time chart) = ___________________________
Degrees per inch from map grid = ______________________
Kilometers per longitude degree at 60N latitude = _________________
Kilometers per inch @ measurement point = __________________
Full plate spreading rate at Denmark Straights = _____________________________________________
½ spreading rate at Denmark Straights = ______________________________
Problem 2.
Using the attached map of the East Pacific magnetic anomalies calculate the following: At the east
Pacific rise ridge between the Clipperton and Galapagos fracture zones calculate the distance in
kilometers from the ridge to anomaly 17 Pacific plate.
Width (kilometers) =_______________________________
Age of Anomaly 17 (see time chart) = ___________________________
Degrees per inch from map grid = __________________
Kilometers per longitude degree at 3N latitude = _________________
Kilometers per inch @ measurement point = ______________
1/2 plate spreading rate = _____________________________________________
Full spreading rate = ______________
Problem 3.
Using equations presented in class design an Excel spreadsheet that will calculate the paleo-latitude of
the original position of rocks containing remnant magnetism. The spreadsheet must also calculate the
paleo-pole latitude & longitude given the:
1. Sample present day latitude & longitude (X , X ): 60N, 90W
2. Present day inclination of remnant magnetism (I): 37
3. The present day magnetic declination of the remnant field (D): -70
Design the spreadsheet for the above input, and then produce a printout and a file to turn in:
1. Original latitude of the rock ():______
2. Latitude & Longitude of the paleo-magnetic pole (P , P ):______, _______