Complex has an elliptical shape of 14 x 19 km and is poorly exposed with a wedge-shaped area of the western part completely obscured by Pliocene and Pleistocene sediments and Tertiary andesitic volcanic rocks (Streckeisen & Hunziker 1974).

Outcrops of the Ditrău alkaline massif, large (diameter ca. 18 km) Mesozoic alkaline igneous complex.
Nepheline syenites are the most abundant rocks in the central and eastern part of the Massif.

Numerous K-Ar and Ar/Ar age determinations of minerals and whole-rock samples gave c.230 Ma for ultramafic rocks from the NW of the complex, c. 215 Ma for gabbros and diorites and c. 160 Ma for nepheline syenites (Kräutner & Bindea 1998).

The massif is diverse and complex both structurally and petrographically. In the northern part of the DAM, the series of ultramafic and mafic rocks gradually shifts towards more felsic compositions from W to E. The central and eastern part of the DAM is made up of a voluminous nepheline syenite body. The entire igneous complex is intersected by alkaline feldspar syenite, nepheline syenite, tinguaite, and lamprophyre dykes.
The ore mineralization of the DAM, including the formation of REE minerals, was a polygenetic process involving magmatic, hydrothermal and metasomatic processes, and consisted of five stages: (1) magmatic phase – upper mantle-derived exotic Nb rutile related to a complex carbonatite-alkaline intrusion; (2) magmatic-metasomatic phase – old apatite, magnetite, monazite-(Ce) and zircon; (3) carbothermal stage – primary REE-carbonates; (4) high-T hydrothermal stage – new monazite-(Ce) and allanite-(Ce), REE-fluorapatite, zircon. Breakdown and replacement of monazite-(Ce) by secondary phases [allanite-(Ce), REE-carbonates and − epidote, phyllosilicates]; (5) low-T hydrothermal phase – pyrochlore, fergusonite-(Ce), sulphide minerals (pyrite, sphalerite, galenite, molibdenite), cinnabarite, new apatite, fluorite, new monazite-(Nd), thorian monazite-(Ce), Th-rich zircon, Nb-rutile and xenotime-(Y) were formed in this stage.
Hydrothermal, vein-hosted REE mineralization with a carbonate gangue occurs mainly in the regions near Jolotca and Belcina. Smaller sites with REE minerals include Aurora, Creanga, Ditrău valley/Pricske, Hereb-Cianod, Holoşag, Lăzarea, and Putna.


Note: Ditró is the old Hungarian name.

Geochronology

Mineralization age: Mesozoic : 231.5 ± 0.1 Ma to 150 ± 6 Ma

Important note: This table is based only on rock and mineral ages recorded on mindat.org for this locality and is not necessarily a complete representation of the geochronology, but does give an indication of possible mineralization events relevant to this locality. As more age information is added this table may expand in the future. A break in the table simply indicates a lack of data entered here, not necessarily a break in the geologic sequence. Grey background entries are from different, related, localities.

Geologic Time				Rocks, Minerals and Events
Phanerozoic
	Mesozoic
		Jurassic
			Late Jurassic	ⓘ Biotite (youngest age) 150 ± 6 Ma
		Triassic
			Late/Upper Triassic	ⓘ Amphibole Supergroup (youngest age) 227.1 ± 0.1 Ma ⓘ Amphibole Supergroup (oldest age) 231.5 ± 0.1 Ma

Localities in this Region

Other Regions, Features and Areas containing this locality

References