# Lowthian Green՚s Tetrahedron Hypothesis on Origin of Continents and Oceans YouTube Lecture Handouts

Doorsteptutor material for competitive exams is prepared by world's top subject experts: get questions, notes, tests, video lectures and more- for all subjects of your exam.

Get video tutorial on: Examrace YouTube Channel

- Theory is based on geometrical principles
- Elie de Beaumont – first attempted this - pentagonal dodecahedral hypothesis with 12 faces

- Lowthian gave the hypothesis in 1875 – tetrahedral hypothesis
- His concept was supported by Fairbrain.
- Later ₹ Morgan & SW Woolridge worked on Lowthian Principles

__Platonic solid__ is a regular, convex polyhedron constructed by congruent (identical in shape and size) regular (all angles equal and all sides equal) polygonal faces having same number of faces meeting at each vertex.

- Tetrahedron: Solid body having four equal plane surfaces, each of which is an equilateral triangle
- According to theory, process of cooling, to take the form of a tetrahedron or triangular pyramid, with four faces and four corners or coigns.
- Depressions and faces of the pyramid would be sea while coigns (corners) would reach out along the edges to form continents.
- In late 19
^{th}& 20^{th}century superseded by continental drift and plate tectonics.

## Hypothesis Propounded

- A sphere is that body which contains the largest volume with respect to its surface area
- A tetrahedron is that body which contains the least volume with respect to its surface area

## Criticism

- Corners would sink to form a stable shape. Small globe can but enormous earth cannot.
- Again, continents are made of light SIAL and oceans made of SIMA (heavier) . Contraction could not account for distribution of continents without considering SIMA and SIAL.
- Balance of the earth in the form of a tetrahedron while rotating on an apex cannot be maintained.
- Earth rotates rapidly on its axis & spherical earth cannot be converted into a tetrahedron while contracting on cooling.
- Hypothesis of permanency of continents and ocean basins has been rejected by plate tectonic that validated continental drift concept.

✍ Manishika