The Khumbu valley is made up of the Higher-Himalayan and Tethys Himalayan
morph-tectonic belts of the Himalayas.
The rock sequences of the Khumbu valley represent a tectonically simple,
undisturbed and normal Higher Himalayan and Tethys Himalayan succession,
the latter succeed broadly transitionally the former.
The Higher Himalayan successions are extremely migmatised. The
unmigmatised part of the rocks indicated that the sequence was
originally a sedimentary one.
The metamorphism of the Higher Himalaya was of Barrovian type and it is
normal, dying out structurally upwards in the Tethys Himalayan succession.
Nuptse granite is an intrusive granite sill intruded in the Tertiary
period. It is not involved into any major tectonisation.
Regionally, folds of Himalayan trend and folds of transeverse orientation
have been developed in the Khumbu region.
Minor structural study has
shown at least four generation of compressional orogenic folds in the
region. Two of the fold episodes orient at perpendicular disposition to
the Himalayan trend.
World's highest peak Mt Everest lies on the back of the thrusted Higher-Himalayan
sequence and it is structurally and tectonically simple."