Using figures 11.3 and 11.4, calculate as closely as possible the rate, in centimeters per year, at which seafloor spreading is occurring in the Atlantic Ocean, based upon the paleomagnetic data. Your calculation is the rate at which a single plate is moving.Estimate the time necessary for the spread of the South Atlantic Ocean between Africa and South America by dividing the present separation along the trace of the red dashed line on figure 11.2 by the rate of spreading as calculated in question 2. WestEastAsea levelA'riftvalleyВBrBrGilbertGaussMatuyamaBrunhes BrunhesMatuyamaGaussGilbert50100normal polarityreverse polaritykilometersFIGURE 11.3A schematic cross section of the central part of the mid-Atlantic ridge showing topography and patternsof paleomagnetic data. The dark and light areas correspond to the pattern shown on figure I1.4.4. Estimate the time necessary for the spread ofTIMEMAGNETICthe South Atlantic Ocean between Africa andINPOLARITYSouth America by dividing the present separa-tion along the trace of the red dashed line on fig-ure 11.2 by the rate of spreading as calculated inquestion 2.МYВРEVENTS0.25Brunhes-0.500.751.00Jaramillo- 1.25E1.501.75Olduvai- 2.00Reunion5. Whatof basalt might be expected at pointsagesA and B on figure 11.3, assuming the rate ofspreading to have been constant?E2.25- 2.502.75Mammoth2A3.00- 3.25-3.50- 3.75- 4.00FIGURE 11.4-4.253Magnetic polarity scale for the last5.5 million years of Earth history.Purple bands indicate periodsof normal polarity. White bandindicate times when magnetic4.50- 4.755.005.25polarity was reversed compared tomodern magnetic properties.| 159normalreverseDepth in kilometersGilbert 3.6- 5.41 myGauss 2.6 – 3.6Matuyama 0.78 - 2.6 myBrunhes 0.78 158 AExercise 11Continental Drift and Plate Tectonics168 of 3075.41.8Eurasian PlateEurasian PlateNorth American Plate2.33.72.0PhillipinePlateAfrican Plate9.22.5Pacific Plate11.710.510.12.517.2South AmericanIndo-Nazca PlatePlateAustralianPlate7.111.118.2A'A6.21.73.710.31.37.23.47.7Antarctic Plate5000 kilometers5.6convergentdivergent & transformhotspotFIGURE 11.2 Map of the world showing the major plates, their boundaries, and direction of motion. Subduction zones are indicated by green lines.Red circles are presently active hot spots. Numbers indicate rate of motion in cm/yr. (Rates after McKenzie and Richter, 1976.)

Given: Scale of the figure 11.3, is 9.5 cm = 100 KM (approx.) Scale of the Figure 11.2, is 3.1 cm =…

Answered: Using figures 11.3 and 11.4, calculate…

Applications and Investigations in Earth Science (9th Edition)

9th Edition

ISBN:9780134746241

Author:Edward J. Tarbuck, Frederick K. Lutgens, Dennis G. Tasa

Publisher:Edward J. Tarbuck, Frederick K. Lutgens, Dennis G. Tasa

Chapter1: The Study Of Minerals

Section: Chapter Questions

Problem 1LR

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Using figures 11.3 and 11.4, calculate as closely as possible the rate, in centimeters per year, at which seafloor spreading is occurring in the Atlantic Ocean, based upon the paleomagnetic data. Your calculation is the rate at which a single plate is moving.

Estimate the time necessary for the spread of the South Atlantic Ocean between Africa and South America by dividing the present separation along the trace of the red dashed line on figure 11.2 by the rate of spreading as calculated in question 2.