|bigpo.ru|| 1 2 3
Fig. 1.a) Location of the Kula Volcanic Province; b) Cones of the Kula Volcanic Province, redrawn from the map of Richardson-Bunbury, 1992; c) Geological map of the Kula area. Cones of the Incesu Group are highlighted.
Fig. 2. Modal abundance of all phases plus vesicles in nodules from the Kula Volcanic Province. The top three samples are the scapolite-bearing examples.
Fig. 3. Photomicrographs of scapolite-bearing nodules, a) and b) association of scapolite with fresh glass. Scale bars represent 200 μm and 100 μm; c) clinopyroxene primocrysts and optically continuous, oikocrystic scapolite. Scale bar represents 500 μm; d) plagioclase with growth-dominated faces extending into oikocrystic scapolite. No relict plagioclase is present within the oikocryst. Uralitization of clinopyroxene is visible in the upper right of the photograph. Scale bar represents 100 μm; e) rounded pod of scapolite showing constant mean curvature at clinopyroxene-clinopyroxene-scapolite triple junctions. Note the similarities to (f). Scale bar represents 100 μm; f) intercumulus clinopyroxene showing rounded margins at triple junctions with cumulus olivine grains, Isle of Rum, Scotland (from Holness et al. 2007b). Scale bar represents 100 μm.
Fig. 4. a) – e) SEM backscatter images, a) intimate association of scapolite and glass at the edge of scapolite grains. Lighter greyscale areas are glass. Note the large, glass-rimmed voids and the planar faces on parts of the amphibole. Scale bar represents 100 μm; b) oikocrystic scapolite grain amongst clinopyroxene phenocrysts. High dihedral angles at clinopyroxene-clinopyroxene-void (previously clinopyroxene-clinopyroxene-scapolite) are common, and the angle displays constant mean curvature. Many grain boundaries have been widened. Scale bar represents 100 μm; c) clinopyroxene-scapolite grain boundary. The planar face of the pyroxene contrasts with the highly irregular, undulose margin of the scapolite. Scale bar represents 10 μm; d) fine-grained plagioclase laths and glass-rimmed vesicles in widened grain boundaries. Scale bar represents 20 μm; e) Sieve-textured plagioclase intergrown with scapolite. Scale bar represents 50 μm; f) Optical photomicrograph of secondary cpx growing on amphibole. Scale bar represents 50 μm.
Fig. 5. Clinopyroxene composition in non scapolite-bearing nodules from across the Kula Volcanic Province (black circles) compared with scapolite-bearing nodules from cones 51B (blue triangles) and 51C (red squares).
Fig. 6. CaO versus Na2O for clinopyroxenes in scapolite-bearing (51B – blue triangles; 51C – red squares) and non scapolite-bearing (“other” – black circles) nodules.
Fig. 7. CO2 and SO2 contents of reported magmatic scapolites (phenocrysts) and those from this study (oikocrysts).
Table 1. Compositions of the main mineral phases present in scapolite-bearing nodules GS1-51C-01, K96-053B and K96-056. ‘Secondary cpx’ refers to cpx overgrowths on amphibole. CO3 calculated stoichiometrically using the ‘Formula Recalculations’ program (Buckley, personal communication).
Table 2. Structural formulae of scapolite from cones 51B and 51C, calculated on the basis of [Al + Si + Fe = 12]. OH calculated assuming the species on the volatile site sum to 1 apfu.