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A C C E P T E D M A N U S C R I P T ACCEPTED MANUSCRIPT Abstract:This study presents a novel approach for analysing the magma evolution path in composite plutons, applying the so-termed Polytopic Vector Analysis (PVA) to whole-rock and apatite chemistry. As an example of a multiphase magmatic body the Karkonosze granitoid pluton was chosen, which formed by a combination of magma mixing and fractional crystallization of two distinct melts -granitic crustderived and lamprophyric mantle-derived. The goal was to model end-member magma compositions recorded by apatite and to estimate to what extent these end-members interacted with each other.Although using single minerals as proxies to magma compositions is tricky, the studied apatite well reflects the compositional trends within the magma (e.g. decreasing LREE/Y ratios, varying halogen content, increasing Mn and Na concentrations). The results of PVA simulations for whole-rock geochemistry demonstrate a model similar to that constrained from previous studies. Apart from the main trend of mixing between a felsic (~80 wt % SiO 2 ) and a mafic (~53 wt% SiO 2 ) end-member A C C E P T E D M A N U S C R I P T ACCEPTED MANUSCRIPT(EM), an additional process has been recognized, representing most probably the continuous evolution of the mafic end-member, responsible for the compositional diversity of some rocks. One felsic (REEpoor, Mn−F-rich) and one mafic (Cl−Sr−Si−REE-rich) apatite end-member was recognized, whereas the third one represents most probably a fluid component (enriched in Si, Y, Ce and Nd), present at all magmatic stages, however, most prominent during the late stage. The widest range of EM proportions and the highest contribution of the mafic EM are displayed by apatites from the early stage. During the middle and late stages, the apatites present a narrow range of EM proportions, with almost all apatites bearing a felsic signature. This pattern reflects the progressive homogenization of the system.Although the PVA method applied to mineral chemistry poses some limitations, it may provide a more detailed image of the combination of differentiation processes and magma sources involved in the formation of a complex composite pluton.

ABSTRACT:Lisowiec, K., Budzyń, B., Słaby, E., Schulz, B., and Renno, A.D. 2014. Th-U-total Pb timing constraints on the emplacement of the granitoid pluton of Stolpen, Germany. Acta Geologica Polonica, 64 (4), 457-472. Warszawa.Monazite from the Stolpen monzogranite (SE Germany) was studied to constrain the Th-U-total Pb age of pluton formation. Monazite grains demonstrate subtle to distinct patchy zoning related to slight compositional variations. Textural and compositional characteristics indicate that the monazite formed in a single magmatic event in a slightly heterogeneous system, and was only weakly affected by secondary alteration, which did not disturb the Th-U-Pb system. Chemical dating of the monazite gave a consistent age of 299 ± 1.7 Ma. The current study presents the first geochronological data for the Stolpen granite. It provides evidence that Stolpen is the youngest Variscan granitic intrusion in the Lusatian Granodiorite Complex and indicates that magmatic activity related to post-collisional extension in this region lasted at least 5my longer than previously assumed.