drift:
1) Any material derived from the process of glacial erosion (e.g. glacial drift)
2) Detrital material washed into an underground cave by rivers.
3) A surface movement of detrital material or of snow by the wind to form sand drifts or snow drifts
4) The motion of ocean water ...
5) An underground mining passage ...
6) A term initially used with reference to the movement of continents ...
7) In S.A., a ford across a river
[Penguin Dict. of Physical Geography]

Of those, 1), 2), and 3) seem the most logical options for your desert. Two of these involve the word "detrital", and the third (that concerning glacial drift)necessarily involves detrital material.

Drift:
1) galerie horizontale ...
2) matérial détritique transporté par le glacier ...
3) remplissage détritique de cavités ...
4) matérial abandonné sur une plage ...
5) mouvement de la mer ...
6) déviation, dérive
[Dict. des sciences de la terre, Michel, Fairbridge]

drift - 1. In geology, transported superficial deposits, especially those transported and deposited by ice, the two main types being stratified drift (fluvioglacial deposition) and unstratified (boulder clay, till) ...
[Penguin Dict. of Geography]

Donc, que son origine soit glaciaire, fluvioglaciaire, ou éolienne, il me semble raisonnable de dire que ce désert est détritique (peut-être pas plus que d'autres déserts de sable ...).