The results of quantitative composition analyses of Late Mesozoic alumina - rich leucogranite in the §µ L¹t Zone show that it has particular features of the plutono - volcanic belt of Southern ViÖt Nam Cretaceous continental margin. They have characters not only of a continental marginal arc, but also of a spreading zone on continental margin arc.

- Petrochemically, the rocks belong to oversaturated, potassium-high calc-alkaline series, produced by Late Mesozoic magmatic differentiation. Their trace element composition characterizes a granite generated from infracrustal melting interacting with the supracrustal materials.

- Isotopically, the rocks have (87Sr/86Sr)i = 0.703368 - 0.70878 characterizing a crustal origin. The ratio (¹⁴³Nd/¹⁴⁴Nd)_i = 0.512350 - 0.512386. The rocks are derived from enriched mantle or from contaminated crust.