In a Science News article on March 8, 2015 Thomas Sumner wrote about research that sheds new light on the splitting up of Pangaea. "The current prevailing explanation contends that material from the Earth’s interior sprung up along the boundary between North America and Africa, forcing the two continents apart." He also explains that: "A reexamination of tectonic movements 200 million years ago suggests that the supercontinent was pulled apart by shrinking of the forerunner to the modern Indian Ocean." The following data is taken from this article.

Initial Observation

An initial observation is that pangaea broke up.

Preliminary Conditions

There are two theories posed to explain how pangaea separated:

A₁: Material from the Earth’s interior sprung up along the boundary between North America and Africa, forcing the two continents apart. This is a "push" theory.
A₂: Pangaea was pulled apart by shrinking of the forerunner to the modern Indian Ocean. This is a "pull" theory: "As gravity pulled the Tethys crust down into the subduction zone, the crust yanked on Pangaea’s Eurasian edge. If strong enough, this tug could have ripped the continent apart between Africa and North America."

Each of the theories could explain the initial observation (as described above).

Both of these theories satisfy at least half of the criteria for a scientific theory and therefore have scientific merit as is shown by the following tables (the criteria, #1, #2, etc., is given in a previous section).

Criteria	Condition Met?	Rationale for the Invasion Theory
#1	yes	The theory is not complicated and has no inconsistencies
#2	yes	No fundamental principles are violated.
#3	yes	This theory explains the initial observation.
#4	yes	The theory applies to the area of investigation and does not go far beyond.
#5	yes	Competent, well-known researchers put forward the theory.
#6	no	No information about this.
#7	no	No math is mentioned.
#8	yes	No outside agenda is known.

Criteria	Condition Met?	Rationale for the Environmental Theory
#1	yes	The theory is not complicated and has no inconsistencies
#2	yes	No fundamental principles are violated.
#3	yes	This theory explains the initial observation.
#4	yes	The theory applies to the area of investigation and does not go far beyond.
#5	yes	Competent, well-known researchers put forward the theory.
#6	no	Not known.
#7	no	Not known.
#8	yes	No outside agenda is known.

Data

D₁: "The forerunner of the Indian Ocean, called the Tethys Ocean, shrank around this time as the early African and Eurasian continents drifted together in a scissoring motion."
D₂: "Visualizing the movements of the continents as swinging around a fixed point reveals that the opening of the Atlantic Ocean was parallel to the closing of the Tethys Ocean.
D₃: "As the Atlantic grew, the Tethys shrank to accommodate the new crust."
D₄: "Because the planet’s size doesn’t change, the creation of new crust at the bottom of the Atlantic had to be compensated by the destruction of crust elsewhere at a subduction zone, where surface material plunges into Earth’s interior." In the first theory the subduction zone would be in the Pacific Ocean, in the second theory the subduction zone would be in what is now the Indian Ocean.

Evaluation Chart

	Push Theory	Pull Theory
D1	no	yes
D2	no	yes
D3	no	yes
D4	yes	yes

Result

From this data (Push - 1, Pull - 4), the pull theory would be the better theory between these two options.