OCEAN BASINS, PLATE TECTONICS, SEA LEVEL

a) What is the age of the oldest oceanic crust near Rio De Janeiro, Brazil (along the east coast of
South America)? m.y. On your page-size map, place a dot labeled A showing the
approximate location of Rio De Janeiro.
b) What are the approximate latitude and longitude (to the nearest degree, and remember that latitudes
are always °N or °S, and longitudes are °E or °W) of the Fiji Islands in the central Pacific Ocean?
____
(latitude) and ___ (longitude). On your page-size map, place a dot
labeled B showing the approximate location of Fiji.
c) What is the youngest crust in the Labrador Sea? _ m.y. Please put a dot labeled C
showing the location of the youngest crust in the Labrador Sea.
Is the Labrador Sea still growing? Yes or No? ___

d) On your page-size map, please place dot D somewhere you could walk on a spreading center.
e) On your page-size map, please place dot E on the fastest spreading center.
f) The Challenger Deep in the Marianas Trench is the deepest point in the world ocean (it is labelled
on the World Map – near the Philippines)? How deep is it? _(m or ft)
Place a dot labeled F (on your page-size map) showing the approximate location of Challenger Deep.
What process caused the formation of the Mariana Trench? ______

  1. (3 pts) Please indicate the locations of spreading centers and trenches on the page-size copy of the
    world map. Use solid lines (or blue lines) for trenches and dashed lines (or red lines) for spreading
    centers.
    These features delineate the major tectonic plates: please label the ten major plates on Earth
    (African, Antarctic, Cocos, Eurasian, Indo-Australian, Nazca, North American, Pacific, Philippine and
    South American) — just write the name of each plate on your page-size map.
  2. (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 cm 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 = 0.1 x km/my)

Sample Solution

ACED ESSAYS