3. (2 pts) Determine how fast the Southern Ocean is spreading between Australia
ID: 152559 • Letter: 3
Question
3. (2 pts) Determine how fast the Southern Ocean is spreading between Australia and Antarctica: Remember that cm-centimeters, km-kilometers, my-millions of years, yr -years Remember that a RATE (speed) is equal to the DISTANCE divided by the TIME To convert km/my to cm/yr, just divide by 10 Step#1:First, measure the distance between Australia and Antarctica in crn on your large World Map (not the piece of paper!): Distance on map in cm Step#2: Convert the map distance to the real distance by multiplying by the map scale (358km/cm) Distance on Earth in kilometers (km)- Step #3: The age of the oldest crust near Australia and Antarctica where you measured. This is the age of the oldest ocean floor on the line between the two points. Time -Age of the oldest crust in millions of years Step #4: Calculate the rate of opening (Rate-Distance / Time) in both km/my and cm/year. (Remember that 1 km/my -10 x cm/yr or 1 cm/yr Show your work. 0.1 x km/my)Explanation / Answer
Sorry to solve this question I need a map that your instructor must have provided to you.
However, I will try to solve it without a map
I am assuming that map has a scale of 1cm=385 km
Answer
> let the distance between Australia and Antarctica be ' X ' cm that you have calculated by the ruler.
> Now total distance in the real world in kilometer is (X*385) km
> It means the Mid-oceanic ridge must lie at the center of the Australia and Antarctica so the distance of mid-oceanic ridge(where spreading is occurring) is ( X*385)/2 kilometer
> Now let we assume that the age of rock nearest to Australia has an age of Y million year.
> Now this age signifies that the oldest rock has the travel distance of (X*385)/2 kilometer in Y million year from the Mid- Oceanic Ridge.
> if we apply the basic equation of S=ut where u is velocity, S is distance travel by rock, t = time taken by the rock to travel S distance.
> u(half-spreading rate) =S/t where S=(X*385)/2 km and t= Y million year
> so half-spreading rate is = X*385 Km/Y ( km/my) or full spreading rate is 2* half-spreading rate
> full spreading rate is = 2*((X*385)/2)/Y== X*385/Y (km/my)............(1)
> or full spreading rate is = 0.1*X*385/Y (cm/yr)...................(2)
So the only thing that you have to do is find the value of X (distance between Australia and Antartica)by use of ruler in centimeter and value of Y (age of the rock in million year)
after finding X and Y put it in equation 1 and 2 you get your answer.
I know it is a bit confusing for you since we don't have a map, for any doubt please comment below I will be very happy to help you.
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