ZIRCONIUM MINERALIZATION OF YOUNG ALKALINE VOLCANIC ROCKS FROM NORTHERN BOHEMIA

Year, pages: 1992, 91 - 95

Metasomatized young alkaline volcanic rocks from northern Bohemia contain increased zirconium concentration: ijolites (1246 ppm), pegmatoids (420), and phonolites (2660). Calzirtite (in ijolites and pegmatoids), hainite and its alteration product fluorian eudialyte (in phonolites) are dominant zirconium minerals. The higher Zr content of these rocks resulted from enrichment by postmagmatic low-temperature hydrothermal fluids carrying Na, K, Ca, Al, Fe³⁺, Si, P, CO₂, F and minor and trace incompatible elements (Sr, Ba, REE, U, Th, Zr, Hf, Ti, Nb, Ta etc.). The influence of fluids is increased in large hypabyssal intrusions (central melilitolite of the Osecna complex) and/or in subvolcanic bodies (phonolite of the Sokol Hill) occurring near regional tectonic zones (Lusatian thrust fault). The accumulation of Zr, REE, U, Th, P, and Ti in basal Cenomanian sediments in the proximity of volcanic intrusions is a common feature and may be explained by the influence of these intrusions on the chemical element redistribution in the sedimentary rocks.

Ulrych, J., Pivec, E., Rychly, R., Rutsek, J. 1992. ZIRCONIUM MINERALIZATION OF YOUNG ALKALINE VOLCANIC ROCKS FROM NORTHERN BOHEMIA. In Geologica Carpathica, vol. 43, no.2, pp. 91-95. 1335-0552.

Ulrych, J., Pivec, E., Rychly, R., Rutsek, J. (1992). ZIRCONIUM MINERALIZATION OF YOUNG ALKALINE VOLCANIC ROCKS FROM NORTHERN BOHEMIA. Geologica Carpathica, 43(2), 91-95. 1335-0552.