Mountains Have Deep Roots
The 'pegs' or 'stakes' metaphor of mountains
The Quran describes mountains as 'pegs' (awtad) or 'stakes' that anchor the earth. Modern geology (the field of isostasy) has shown that mountains have deep crustal 'roots' extending into the mantle — some mountains have roots deeper than the mountain is tall above ground.
The principle of isostasy (Airy, 1855; Pratt, 1855) explains that mountains are supported by deep, less-dense crustal roots. Mount Everest, for example, has roots extending down roughly 250 km into the Earth.
Classical scholars (Tabari, Zamakhshari) interpreted mountains as physical stabilizers of the earth, but the 'deep roots' concept was not part of their explicit reading. The 'pegs' metaphor was understood as firmness and stability, not as literal geological structure.
The 'pegs' metaphor in the Quran is rich and has multiple valid interpretations. The geological reading of deep mountain roots is one. The classical tafsir emphasized stability and divine power. This entry does not claim the 7th-century Arabs understood plate tectonics.
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