Major and Trace Element Characteristics of Apatites in Granitoids from Central Kazakhstan: Implications for Petrogenesis and Mineralization

Abstract

This paper presents abundances of major and trace elements of apatites in granitic rocks associated with different types of ore deposits in Central Kazakhstan on the basis of electron probe microanalysis and laser ablation inductively coupled plasma mass spectrometry. Our results demonstrate that the concentrations and ratios of elements in apatites from different granitoid rocks show distinct features, and are sensitive to magma evolution, petrogenetic and metallogenetic processes. Apatites in the rocks associated with Mo-W deposits have high content of F and MnO, low content of Cl, which may be indicative of sedimentary sources, while apatites from a Pb-Zn deposit show relatively high content of Cl and low F content, which possibly suggest a high water content. In these apatites, Sr contents decrease, while Mn and Y contents increase with magma evolution. This relationship reflects that these elements in apatites are related with the degree of magmatic differentiation. Four types of REE patterns in apatites are identified. Type 1 character of highest (La/Yb) N in apatites of Aktogai porphyry Cu-Mo deposit, Sayak-I skarn Cu deposit and Akzhal skarn Pb-Zn depposit is likely produced by the crystallization of heavy REE-enriched minerals. Type 2 character of upward-convex light REE in apatite of Aktogai porphyries likely results from La-enriched mineral crystallization. Type 3 feature of Nd depletion in apatites of East Kounrad and Zhanet deposits both from Mo-W deposits primarily inherits the character of host-rock. Type 4 apatites of Aktogai deposit and Akshatau W-Mo deposit with wide range of REE contents may suggest that apatites crystallize under a wide temperature range. Three types of apatite with distinct redox states are identified based on Eu anomaly. The Aktogai apatite with slight negative Eu anomaly displays the most oxidized state of the magma, and the apatites of other samples at Aktogai, East Kounrad and Akzhal with moderate negative Eu anomaly show moderate oxidizing condition of these rocks, while the remaining apatites with strong En anomaly indicate a moderate reductive state of these rocks.

Rare Earth Element Behaviour in Apatite from the Olympic Dam Cu–U–Au–Ag Deposit, South Australia

“…REY-signatures measured in magmatic apatite of the RDG, HRQM and DD closely resemble those for apatite from analogous intrusive elsewhere [8,9,46]. Similarly, the LREE-enriched signatures characteristic for DM and DS apatite (REY-, S-and Cl-rich cores and REY-, S-rich cores, respectively) are almost identical to apatite REY-signatures measured in apatite from similar magnetite-apatite ± pyrite assemblages elsewhere within the Olympic Cu-Au Province [1,10,47], as well as globally [11,14].…”

“…Apatite preferentially incorporates Eu 3+ over Eu 2+ , and although the greatest control on the proportion of the two species is exerted by fO2 in the magmatic environment [8], their speciation in hydrothermal fluids is primarily controlled by H + activity whereby Eu 3+ complexes dominate at high pH conditions (>7 at 300 °C; [50]). Such alkaline conditions are unrealistic for the fluids responsible for the broad hematite-sericite alteration due to the low pH required for sericite stability at this temperature.…”

Generation of Late Mesozoic Qianlishan A 2 -type granite in Nanling Range, South China: Implications for Shizhuyuan W–Sn mineralization and tectonic evolution

“…zircon, apatite and biotite) in equilibrium with a magma can be used to estimate the redox state of the magma (Ballard et al, 2002;Cao et al, 2012;Liang et al, 2006;Miles et al, 2014;Wones and Eugster, 1965 /Ce 3+ ratio (N 300) reflects oxidized magma (Ballard et al, 2002;C.-Y. Li et al, 2012;Liang et al, 2006).…”

Trace element compositions of apatite from the middle zone of the Panzhihua layered intrusion, SW China: Insights into the differentiation of a P- and Si-rich melt

“…On the other hand, apatite with a positive Eu anomaly is considered to be related to high oxygen fugacity (fO 2 ) Sha and Chappell, 1999). It is generally believed that Eu 3+ is preferentially incorporated to apatite, whereas Eu 2+ preferentially to plagioclase (Aigner-Torres et al, 2007;Cao et al, 2012;Roelandt and Duchesne, 1979;Sha and Chappell, 1999). Eu 3+ /Eu 2+ ratios of magmas would increase under high oxygen fugacity so that apatite would incorporate more Eu than plagioclase in this case (Sha and Chappell, 1999).…”