A phosphate-bearing pegmatite from Lutomia and its relationships to other pegmatites of the Góry Sowie Block, southwestern Poland

Abstract

A geochemically primitive, moderately fractionated, LCT pegmatite from Lutomia (Góry Sowie Block, SW Poland) has been characterized in respect of the primary and secondary phosphate assemblages. The pegmatite crystallized from anatectic granitic magmas mobilized by M 2-3 metamorphism at ~370-380 Ma. Three phosphate assemblages had a different origin: (1) the primary, magmatic one [graftonite-(I)-beusite-(I) + triphylite ± sarcopside], (2) a secondary, metasomatic one [Ca-rich graftonite-(II) -Ca-rich beusite-(II) + wolfeite/triploidite/stanĕkite + hagendorfite/alluaudite + kryzhanovskite ± a Ca-bearing phosphate close to ferromerrillite + fluorapatite], and (3) a secondary, hydrothermal and weathering one [ferrisicklerite ± heterosite + phosphoferrite-kryzhanovskite + ludlamite + vivianite ± hureaulite + earlshannonite-whitmoreite + strunzite-ferrostrunzite + beraunite + dufrénite + jahnsite-(CaMnFe), -(CaMnMn) and -(MnMnMn) + landesite + fairfieldite + Mn 2+ -bearing hydroxyapatite]. The magmatic assemblage resulted from the breakdown of a primary, high-T, Ca-and Li-enriched graftonite-like phase. It was induced by cooling and elevated incompatible Ca, Na, Li and F concentrations. The metasomatic assemblage reflects the destabilization of the magmatic phosphates and their Ca-and Na-metasomatism by a high-T fluid connected with a PO 4 -bearing melt, which previously had evolved along with graftonite-(I)-beusite-(I). The assemblage of secondary, hydrothermal and weathering, phosphates was a result of lower T alteration by hydrothermal fluids and meteoric water by both topotactic Fe and Mn oxidation as well gradual hydration and Fe oxidation. Taken together, the Lutomia pegmatite has been compared to the phosphate-bearing pegmatite at Michałkowa and the mixed NYF + LCT, PO 4 -poor pegmatitic system of Piława Górna.Keywords: phosphate-bearing pegmatite, LCT anatectic pegmatite, Lutomia, Poland Received: 16 October 2013; accepted: 25 November 2014; handling editor: Milan Novák The online version of this article (doi: 10.3190/jgeosci.185) contains supplementary electronic material.Moreover, Łodziński and Sitarz (2009) studied graftonite and sarcopside from Michałkowa.The aim of this paper is a description of the Lutomia pegmatite, as the currently best representative of phosphate pegmatitic mineralization in the GSB, and an evaluation of its relationships to the other important pegmatites in the unit. Particular attention is being paid to textural relations and chemical compositions of the minerals that reflect the geochemical evolution of the pegmatiteforming melts.

Chemical Composition of Mn- and Cl-Rich Apatites from the Szklary Pegmatite, Central Sudetes, SW Poland: Taxonomic and Genetic Implications

“…It rather seems that the crystallization of the assemblage of pieczkaite (Type 1 apatites of this study) ± beusite marks a short-lived magmatic episode of precipitation from the hydrous melt extremely enriched in Mn, Cl, and P. This episode seems to be an anomaly in the overall evolution of the Szklary pegmatite, as suggested by the fact that these minerals occur as rare accessories only locally in the intermediate graphic zones (2) and (3). The assemblage of the Type 1 apatites ± beusite in the beryl-columbite-phosphate Szklary pegmatite might be treated in many respects as a counterpart of polymineral nodular segregations of primary magmatic Fe-Mn phosphates such as graftonites, beusites, triphylite, and sarcopside known from P-enriched GSB pegmatites, cogenetic with the Szklary pegmatite [39,47,48]. Phosphate mineralization in the Lutomia pegmatite, one of these GSB P-enriched bodies, has been investigated in detail [47].…”

“…The assemblage of the Type 1 apatites ± beusite in the beryl-columbite-phosphate Szklary pegmatite might be treated in many respects as a counterpart of polymineral nodular segregations of primary magmatic Fe-Mn phosphates such as graftonites, beusites, triphylite, and sarcopside known from P-enriched GSB pegmatites, cogenetic with the Szklary pegmatite [39,47,48]. Phosphate mineralization in the Lutomia pegmatite, one of these GSB P-enriched bodies, has been investigated in detail [47]. The authors followed the concept that separation of two geochemically distinct melts due to melt-melt immiscibility may play an important role in the evolution of a pegmatite (e.g., [49][50][51][52]).…”

“…The authors followed the concept that separation of two geochemically distinct melts due to melt-melt immiscibility may play an important role in the evolution of a pegmatite (e.g., [49][50][51][52]). Włodek et al [47] proposed that the phosphate nodules at Lutomia crystallized from a P-rich melt which unmixed from the aluminosilicate melt upon cooling.…”

Graftonite-(Mn), ideallyM1MnM2,M3Fe2(PO4)2, and graftonite-(Ca), ideallyM1CaM2,M3Fe2(PO4)2, two new minerals of the graftonite group from Poland

“…Beside the aforementioned rock-forming minerals, phosphate nodules, reaching to 5 cm × 3 cm × 3 cm in size, contain a large number of phosphate minerals, e.g. monazite-(Ce), xenotime-(Y), graftonite-(Mn), graftonite-(Ca), beusite-(Ca), sarcopside, triphylite partly oxidized topotactically to ferrisicklerite and heterosite, wolfeite, triploidite, stanĕkite, hagendorfite, ferrohagendorfite, alluaudite, fluorapatite and hydroxylapatite, whitlockite, kryzhanovskite, phosphoferrite, ludlamite, vivianite, fairfieldite, hureaulite, earlshannonite, whitmoreite, strunzite, ferrostrunzite, beraunite, dufrénite, landesite, jahnsite-(CaMnFe), -(CaMnMn) and -(MnMnMn), and occasionally also malhmoodite and zigrasite (Pieczka et al ., 2003; Włodek et al ., 2015; Włodek and Pieczka, 2017). The following minerals were found as tiny inclusions in the phosphates or in the rock-forming minerals: fergusonite-(Y), gadolinite-(Y), allanite-(Ce), ilmenite, titanite, sillimanite (‘fibrolite’), uraninite, pyrite, arsenopyrite, löllingite, chalcopyrite, Cd-bearing wurtzite or sphalerite, chalcocite or covellite, cuprite, native copper, goethite and unidentified Mn oxides (Pieczka et al , 2015 c ; Włodek et al ., 2015).…”

“…Graftonite , ideally Fe 3 (PO 4 ) 2 , and beusite, ideally Mn 3 (PO 4 ) 2 , form a continuous solid solution: (Fe 2+ ,Mn 2+ ,Ca) 3 (PO 4 ) 2 . In addition to triphylite and sarcopside, minerals of the graftonite–beusite series are major accessory, primary phosphate minerals occurring as intergrowths in characteristic nodules in P-bearing pegmatites, especially of the beryl–columbite–phosphate subtype of the rare-element class (Penfield, 1900; Brooks and Shipway, 1960; Fransolet, 1977; Keller et al ., 1977; Černý et al ., 1998; Smeds et al ., 1998; Guastoni et al ., 2007; Škoda et al ., 2007; Łodziński and Sitarz, 2009; Vignola et al ., 2008, 2011 a , b ; Tait et al ., 2013; Włodek et al ., 2015). Graftonite has also been found in amphibolite-facies metamorphosed iron formations (Stalder and Rozendaal, 2002) and as a constituent of iron meteorites (Olsen and Fredriksson, 1966; Bild, 1974; Chen and Xie, 1996; Floss, 1999; Steele et al .…”