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The Berry-Havey pegmatite (Oxford pegmatite field, Androscoggin County, Maine, U.S.A.), enriched in Li, F, B, Be, and P, is intruded in hornblende-rich amphibolite, with minor biotite or diopside. The pegmatite has a complex internal structure, with four texturally and compositionally different zones that show an increasing degree of evolution inward: wall zone, intermediate zone, core margin, and core zone. The main minerals are quartz, feldspars, Al-micas, tourmaline, with minor Fe-micas, garnet, beryl, amblygonite-montebrasite, Fe-Mn phosphates, and apatite. Tourmaline is present in all zones of the pegmatite, showing different textures: black anhedral crystals in the wall and intermediate zones; black prisms of up to 40 cm in length in the intermediate zone; black tapered prisms, surrounded by a pseudo-graphic intergrowth of quartz or albite with black ± green/bluish tourmaline, and constituting a continuous layer under the core zone; multicolored and "watermelon" zoned crystals in the core zone; and gemmy deep green and color-zoned "watermelon" tourmaline prisms, up to 15 cm length, inside the pockets. A complete chemical evolution from Mg-rich schorl in the wall zone to elbaite with an important deprotonation in the pockets inside the core zone is observed. The most plausible exchange vectors for this chemical evolution are FeMg-1, YAlWO[YR2+W(OH)]-1 and Al[X]X(R2+Na)-1 (where R2+ = Fe2++Mg2++Mn2++Zn2+), for the tourmalines from the wall and intermediate zones. In the core margin, tourmaline composition evolves from schorl toward Li-rich species through the substitution (YAlYLiYR-22+). Later, during the crystallization of the core zone, this exchange vector combined with the substitution ([X] YAl0.5XNa-1YLi-0.5). Finally, the gemmy tourmalines from the pockets show a deprotonation related to the exchange vector YAlWO2YLi-1W(OH)-2 and may be classified as darrellhenryite. These substitutions may reflect an increase in oxygen fugacity and a decrease in Li and F related to the crystallization of lepidolite and amblygonite-montebrasite in the core zone adjacent to or within the pockets. The crystallization of these minerals would reduce the availability of Li and F for the very latest tourmaline crystals, growing inside the pockets, where the deprotonation becomes important. Chemical and textural variation in tourmaline is consistent with a fractional crystallization process for the internal evolution of the Berry-Havey pegmatite. Crystallization of the tourmaline layer under the core zone may be related to the exsolution of the fluid phase implied in the formation of pockets. [ABSTRACT FROM AUTHOR]

Field, textural, paragenetic, and chemical data for micas from pegmatites of the Fregeneda-Almendra pegmatitic field (Central-Iberian Zone) are used to characterize and evaluate their petrogenesis. These pegmatites show a zonal distribution from barren to evolved, with an increase in degree of evolution with increasing distance from the Mêda-Penedono-Lumbrales leucogranite. Five types of evolved pegmatites have been recognized: (1) petalite-rich, (2) spodumene-rich, (3) Li-mica + spodumene-rich, (4) Li-mica-rich, and (5) cassiterite-rich pegmatites, plus six types of barren and intermediate pegmatites. Representative micas from the different pegmatite types and from the leucogranite were analyzed for major and trace elements. All micas belong to the muscovite-lepidolite series. Lithium is incorporated into Li-micas via the Li3Al-1〉-2 and Si2LiAl-3 substitutions, where 〉 represents vacancies. The Al4Si-3〉-1 and Due to image rights restrictions, multiple line equation(s) cannot be graphically displayed. substitutions, where R2+ = (Fe + Mg + Mn), account for the compositional variability of micas from the Li-mica-free pegmatites. The Li, Rb, Cs, Be, Ta, and Nb contents of micas increase in the order: leucogranites and barren pegmatites < intermediate pegmatites < spodumene-bearing and petalite-bearing dikes < Li-mica-bearing pegmatites. The Ba content decreases in the same order, and Sn and Zn are relatively abundant in the intermediate pegmatites. These variations are consistent with rare-element enrichment via fractionation processes combined with partitioning of rare elements from the pegmatite melt into the minerals and volatile phases. However, some pegmatite types occurring in this area, such as the cassiterite-rich dikes, do not seem to form part of the same evolutionary trend. [ABSTRACT FROM AUTHOR]

In this paper we report a combined zircon U–Pb–O isotopes and bulk-rock Sr–Nd–O isotopes study on granitic rocks from the Jálama pluton, Central Iberian Zone. Zircon U--Pb ages of representative granitic rock samples are bracketed in the range of 306–304 ± 3 Ma, but within the level 2σ errors of U--Pb ages. Therefore it is not possible to establish differences in intrusion ages between the main granitic units that make up the Jálama pluton. Microgranular enclaves appear to be slightly older (309 ± 2 Ma), but they do overlap with the age of the granitic rocks. Sr--Nd isotopic data for enclaves of tonalitic composition preclude a simple mantle or crustal origin, but high mean zircon δ 18O values of 8.65 ± 0.9‰ and δ18O(WR) values of 9.96–10.56‰ reflect a largely crustally contaminated magma. The combination of field relations, petrography, bulk-rock geochemistry, Sr-Nd-O isotopic data, zircon δ18O values and U--Pb ages provide compelling evidence that the granites from the Jálama pluton: (i) were coevally formed involving assimilation and mingling/mixing concomitant to fractional crystallization; and (ii) represent typical S-type granites that evolved from a same crustal source, potentially metasedimentary rocks from the Schist Greywacke Complex by considering the Neoproterozoic ages of the inherited zircons. [Display omitted] • The Jálama pluton is a Variscan peraluminous granitoid from the Central Iberian Zone. • It includes three units with minor microgranular and metasedimentary enclaves. • Zircon U--Pb ages of granitic rocks are in the range of 309–304 Ma. • The δ18O(Zr) values for the granites indicate a crustal source. • Bulk-rock (Sr-Nd-O) isotopic data are consistent with a crustal origin. [ABSTRACT FROM AUTHOR]

Primary Fe Mn phosphates from four pegmatites (Cañada, Palermo#1, Palermo#2 and Palermo#11) typical of the beryl-columbite-phosphate subtype have been characterized texturally and geochemically. Most of the common Fe Mn phosphates (triphylite, sarcopside, ferrisicklerite, wagnerite and wolfeite) are extremely poor in trace elements, with the exception of Zn for all them, Li for sarcopside, and Nb and Ta for wagnerite and wolfeite. Calcium-bearing Fe Mn phosphates (graftonite and johnsomervilleite) are the richest in trace elements, with contents usually over the mean continental crust for Zn, Y, REE and Pb. Crystal-chemical constraints, combined with paragenetic relationships, geochemical and geological processes, are thought to control the content, distribution and behavior of trace elements in Fe Mn phosphates. Zinc contents in graftonite and triphylite increase with fractionation, whereas Y, Nb, Ba, REE, U and Pb contents in graftonite decrease. Crystallization of REE-bearing phases, such as xenotime-(Y), strongly affects the REE content of the Fe Mn phosphates. Recrystallization processes also seem to affect the trace element contents in phosphates. The earliest primary phosphate associations from Cañada and Palermo pegmatites (those containing graftonite), show Y/Ho and Zr/Hf ratios inside or close to the CHARAC (Charge-and-Radius-Controlled) field. This could indicate that such associations crystallized in a magmatic stage without a high H 2 O activity. Phosphates from the latest associations plot outside the CHARAC field, suggesting that fluid activity became important during the crystallization of these latest associations. Ti-in-biotite, garnet-biotite and triphylite-sarcopside geothermometers have yielded relatively high temperatures of crystallization, between 633 and 386 °C, for the earliest associations (presumably crystallized under magmatic conditions). In contrast, the latest associations, whose crystallization presumably proceeded with a higher H 2 O activity, are in the range of 281–360 °C. • Primary Fe Mn phosphates are common minerals in some pegmatite types. • Only preliminary data are published on the trace element contents in these phases. • There is a strong structural control on trace elements contents in these phosphates. • Trace elements distribution in phosphates also depends on geochemical factors. • Chemistry of phosphates records the crystallization history of pegmatitc melts. [ABSTRACT FROM AUTHOR]

Based on field and petrographic observations, mineralogical, geochemical (whole-rock by ICP-MS, ICP-OES, ISE and PGNAA) and geochronological (Ar Ar on mica and U Pb on columbite) data, ten pegmatite types and one type of cassiterite-rich quartz hydrothermal veins have been distinguished in the Fregeneda-Almendra field (FA) (Central Iberian Zone), some of them highly enriched in Li (included in petalite, spodumene and Li-rich mica). The pegmatites and the veins mostly intrude Neoproterozoic to Cambrian rocks from the Schist-Greywacke Complex. Felsic igneous magmatism during syn - to late-D 3 stages (≈ 320–295 Ma) of the Variscan orogeny was important and nearly continuous in the area, with the overlap of different granitic units of highly peraluminous S-type composition. The most important in outcrop corresponds to the Mêda-Escalhão-Penedono-Lumbrales granitic complex (MEPL), which belongs to a two-mica leucogranitic series. The other granitic units (Saucelle, Feli and East-MEPL granites) are younger and belong to a P-rich, Ca-poor monzogranitic series. Spatial relationships, together with chemical, mineralogical and geochronological data, indicate that all the pegmatite types and the cassiterite-rich quartz hydrothermal veins are not cogenetic, being related to three different magmatic events: (i) (≈ 319–313 Ma) includes the syn -D 3 MEPL granite and three types of barren pegmatites (intragranitic, quartz+andalusite layers and simple concordant pegmatites); (ii) (≈ 305–300 Ma) corresponds to the late to post-D 3 Feli granite, related to a group of cassiterite-rich quartz veins; and, (iii) (≈ 300–298 Ma) represents the late- to post-D 3 East-MEPL and Saucelle granites, likely parental of some barren aplitic-pegmatitic apophyses and the discordant intermediate and Li-rich pegmatites. These latter form part of a general granite-pegmatite fractionation trend. • Different pegmatite generations coexist in the FA field and one of them is Li-rich. • A petrogenetic model based on geochemical and geochronological data is made for them. • The FA Li-rich aplite-pegmatites have a magmatic affiliation. • They formed by extreme fractionation of P-rich, Ca-poor peraluminous granitic melts. • This model may be applied to other Variscan Li-rich aplite-pegmatites from Europe. [ABSTRACT FROM AUTHOR]