Cadomian Lower-crustal Contributions to Variscan Granite Petrogenesis (South Bohemian Pluton, Austria): a Reply

Abstract

Weinsberg type granite’ as it is doubtful whether it should PREFACE be named according to IMA rules in view of its very The comment by Finger & Clemens (2002) nicely concomplex origin. Even if we look at these rocks in a firms the statement in the introduction of our paper purely descriptive sense, neglecting all genetic aspects, (Klotzli et al., 2001) on p. 1622: ‘Unravelling the origin the granitoids range in composition from minor quartz of a given granite still requires a major analytical effort monzodiorites to a majority of quartz monzonites and and commonly ends in some contradictory results’. Finger granites according to the IMA nomenclature. The in& Clemens raise a number of issues, both minor and terpretation of Finger & Clemens (2002) that all the rocks major. We will discuss all of them, as far as they are are quartz monzodiorites is an oversimplification and relevant to the subject. We will start with the problem conflicts with the geochemical composition of the pyrof nomenclature. After that we will address the problem of oxene-bearing rocks, their K contents (4–6 wt % K2O) remnants of an old crustal component versus a cumulate and the constant high amount of modal K-feldspar. In origin and the problem of the age of the crustal remnants. addition, in all norm calculations the amount of normative K-feldspar has to be corrected according to the measured preserved feldspar composition of Or0·78 PETROLOGY Ab0·20An0·01Cs0·01 (F. Koller, 2000). Finger & Clemens (2002) in their comment accept the Opxand cpx-bearing Weinsberg type granitoid rocks formation of the Weinsberg granite sensu lato magma are widespread in an area of >15–20 km surrounding under granulite-facies conditions within the stability field the villages of Sarleinsbach, Sprinzenstein and Arnreit of opx, as was already postulated by Koller & Hock in the Southern Bohemian Massif (Klotzli et al., 2001, (1993). Finger & Clemens interpret opx and cpx as a figs 1 and 2). This type of rock shows a wide variation product of fractional crystallization of a quartz-monzoin chemical and mineralogical composition. The most dioritic magma after partial melting of biotite-bearing conspicuous features are large K-feldspars up to 20 cm lower-crustal rocks. Consequently, in their view the pyrin size. As a consequence, the determination of modal oxenes are cumulate phases. In contrast, we interpret mineralogy must take into account the large size of the the pyroxenes as part of an older magmatic event K-feldspar megacrysts and be carried out on large samples only. We referred to this rock as ‘pyroxene-bearing with a superimposed granulite-facies re-equilibration