The Earth (4/5)

 C. The Earth's Relief

The constitution of the Earth is highly complex. Today, it is possible to imagine it very roughly as being formed of a deep layer, at very high temperature, and especially of a central area where rocks are still in fusion, and of a surface layer, the Earth's crust which is solid and cold. The crust is very thin; its thickness is estimated in units of miles or units of ten miles at the most. The Earth's radius is however slightly over 3,750 miles, so that its crust does not represent (on average) one hundredth of the of the sphere's radius. It is upon this skin, as it were, that all geological phenomena have taken place. At the origin of these phenomena are folds that were to form the mountain ranges; their formation is called 'orogenesis' in geology. The process is of considerable importance because with the development of a relief that was to constitute a mountain, the Earth's crust was driven in proportionately far down: this process ensures a foundation in the layer that underlies it.

The history of the distribution of the sea and land on the surface of the globe has only recently been established and is still very incomplete, even for the most recent and best known periods. It is likely that the oceans appeared and formed the hydrosphere circa half a billion years ago. The continents were probably a single mass at the end of the primary era, then subsequently broke apart. Some continents or parts of continents have moreover emerged through the formation of mountains in maritime zones (e.g. the North Atlantic continent and part of Europe).

According to modern ideas, the dominating factor in the formation of the land that emerged was the development of mountain ranges. The evolution of the land, from the primary to the quaternary era, is classed according to 'orogenic phases' that are themselves grouped into 'cycles' of the same name since the formation of all mountains reliefs had repercussions on the balance between the sea and the continents. It made some parts of the land disappear and others emerge, and for hundreds of millions of years it has altered the surface distribution of the continents and oceans: the former at present only occupying three tenths of the surface of this planet.

In this way it is possible to give a very rough outline of the transformations that have taken place over the last hundreds of millions of years.

When referring to the Earth's relief, the Qur’an only describes, as it were, the formation of the mountains. Seen from the present point of view, there is indeed little one can say about the verses that only express God's Beneficence to man with regard to the Earth's formation, as in the following verses:

• Surah Nuh (71) verses 19 and 20:

"For you God made the earth a carpet so that you travel along its roads and the paths of valleys."

• Surah Adh-Dhariyat (51) verse 48:

"The earth, We have spread it out. How excellently We did that."

The carpet which has been spread out is the Earth's crust, a solidified shell on which we can live, since the globe's sub-strata are very hot, fluid and hostile to any form of life.

The statements in the Qur’an referring to the mountains and the references to their stability subsequent to the phenomenon of the folds are very important.

• Surah Al-Ghaashiyah (88) verses 19 & 20. The context invites unbelievers to consider certain natural phenomena, among them:

"…the mountains, how they have been pitched (like a tent). The Earth how it was made even."

The following verses give details about the way in which the mountains were anchored in the ground:

• Surah An-Naba' (78) verses 6 & 7:

"Have We not made the earth an expanse and the mountains stakes."

The stakes referred to be the ones used to anchor a tent in the ground (autad, plural of watad).

Modern geologists describe the folds in the Earth as giving foundations to the mountains, and their dimensions go roughly one mile to roughly 10 miles. The stability of the Earth's crust results from the phenomenon of these folds.

So it is not surprising to find reflections on the mountains in certain passages of the Qur’an, such as the following:

• Surah An-Nazi'aat (79) verse 32:

"And the mountains (God) has fixed them firmly."

• Surah Luqman (31) verse 10:

"(God) has cast into the ground (mountains) standing firm, so that it does not shake with you."

The same phrase is repeated in Surah An-Nahl (16) verse 15; and the same idea is expressed with hardly any change in Surah Al-Anbiya' (21) verse 31:

"We have placed in the ground (mountains) standing firm so that it does not shake with them."

These verses express the idea that the way the mountains are laid out ensures stability and is in complete agreement with geological data.

(Continued)