Chemical Peculiarities of Quartz from Peralkaline Granitoids

Chemical Peculiarities of Quartz from Peralkaline Granitoids

Článek WoS

Quartz from four typical but contrasting peralkaline quartz-saturated granite systems (Khan Bogd and Khalzan Buregte plutons (Mongolia), Ivigtut stock (Greenland), Europa and Madeira plutons (Pitinga magmatic province, Brazil)) was analyzed using LA-ICP-MS to define the range of selected trace element content and trends in their evolution and to compare this content with published data from granitoids of other geochemical types. The evaluation of about 1100 analyses found the studied trace elements mostly in ranges <0.01-18 ppm Li (median 2.41 ppm), 1.2-77 ppm Ti (median 8.2 ppm), 8.3-163 ppm Al (median 42 ppm) and 0.05-5.7 ppm Ge (median 0.98 ppm) (in all cases 5% of the lowest and 5% of the highest values were omitted). Quartz from geochemically less evolved riebeckite-bearing granite plutons shows no Ti/Ge fractionation and displays either a positive Ti-Al correlation or no Ti-Al correlation. More fractionated and potentially mineralized peralkaline magmatic systems were formed within two distinct magmatic episodes: quartz from the older phases is relatively Ti-rich and evolved via Ti decrease with no possible Ge enrichment, while quartz from younger phases is Ti-poor from the beginning and has the ability of enrichment in Al and Ge. Relative enrichment in Al and increase in Ge/Ti value of quartz can serve as a supporting method for the identification of potentially ore-bearing magmatic systems.

Quartz from four typical but contrasting peralkaline quartz-saturated granite systems (Khan Bogd and Khalzan Buregte plutons (Mongolia), Ivigtut stock (Greenland), Europa and Madeira plutons (Pitinga magmatic province, Brazil)) was analyzed using LA-ICP-MS to define the range of selected trace element content and trends in their evolution and to compare this content with published data from granitoids of other geochemical types. The evaluation of about 1100 analyses found the studied trace elements mostly in ranges <0.01-18 ppm Li (median 2.41 ppm), 1.2-77 ppm Ti (median 8.2 ppm), 8.3-163 ppm Al (median 42 ppm) and 0.05-5.7 ppm Ge (median 0.98 ppm) (in all cases 5% of the lowest and 5% of the highest values were omitted). Quartz from geochemically less evolved riebeckite-bearing granite plutons shows no Ti/Ge fractionation and displays either a positive Ti-Al correlation or no Ti-Al correlation. More fractionated and potentially mineralized peralkaline magmatic systems were formed within two distinct magmatic episodes: quartz from the older phases is relatively Ti-rich and evolved via Ti decrease with no possible Ge enrichment, while quartz from younger phases is Ti-poor from the beginning and has the ability of enrichment in Al and Ge. Relative enrichment in Al and increase in Ge/Ti value of quartz can serve as a supporting method for the identification of potentially ore-bearing magmatic systems.

quartz, trace elements, peralkaline rocks, peralkaline granites, LA-ICMS analysis

quartz, trace elements, peralkaline rocks, peralkaline granites, LA-ICMS analysis

Karel Breiter, Jindřich Kynický, Michaela Vašinová Galiová, Michaela Hložková

2026

28.07.2025

Mdpi

Minerals

15

8

Švýcarská konfederace

16

https://www.mdpi.com/2075-163X/15/8/790