, K-Ar ages from the eastern Azores groups FIG. 4. The TS block in the crystal structure of fogoite-(Y): (a) the O sheet; (b) stereochemistry of Ti at the M O (1) site in the O sheet; (c) the H sheet; (d) the TS block; and (e) the general view of the crystal structure; Si tetrahedra are orange, Ti-dominant M O (1) octahedra are yellow, Na-dominant [8]-coordinated M O (2) polyhedra and M O (3) octahedra are navy blue, [6]-coordinated Y-dominant M H and Ca A P polyhedra are purple and pink, (O,F) and F anions at the X O M and X O A sites are shown as medium orange and yellow spheres, respectively. The unit cell is shown by thin black lines in (a,c,e) The letters H O H indicate the positions of H and, 1975.
DOI : 10.1016/0024-4937(75)90008-0
, Grenmarite, a new member of the g??tzenite-seidozerite-rosenbuschite group from the Langesundsfjord district, Norway: definition and crystal structure, European Journal of Mineralogy, vol.16, issue.6, pp.971-978, 2004.
DOI : 10.1127/0935-1221/2004/0016-0971
, Chemical and structural study of the Zr, Ti-disilicates in the venanzite from Pian di Celle, Umbria, Italy, European Journal of Mineralogy, vol.16, issue.6, pp.957-969, 2004.
DOI : 10.1127/0935-1221/2004/0016-0957
, Die Phonolithe des Friedländer Bexirkes in Nordböhmen. Tschermaks Mineralogische und Petrographische Mitteilungen, pp.465-495, 1893.
, Forel??big meddelelse om mineralerne p?? de sydnorske angit- og nefelinsyeniters grorkornige gange, Geologiska Foereningan i Stockholm. Foerhandlingar, vol.9, issue.4, pp.247-274, 1887.
DOI : 10.1080/11035898709444657
, Die miniralien der syenitpegmatitgänge der südnorwegischen augit-und nephelinsienite, Zeitschrift für Kristallographie und Mineralogie, vol.16, pp.74-94, 1890.
, The Bond-Valence Method: An Empirical Approach to Chemical Structure and Bonding, Pp. 1?30 in: Structure and Bonding in Crystals II (M. O'Keeffe and A. Navrotsky, 1981.
DOI : 10.1016/B978-0-12-525102-0.50007-4
, From structure topology to chemical composition. XII.<BR> Titanium silicates: the crystal chemistry of rinkite, Na<SUB>2</SUB>Ca<SUB>4</SUB><I>REE</I>Ti(Si<SUB>2</SUB>O<SUB>7</SUB>)<SUB>2</SUB>OF<SUB>3</SUB>, Mineralogical Magazine, vol.75, issue.6, pp.2755-2774, 2011.
DOI : 10.1180/minmag.2011.075.6.2755
, On the structural relationship between götzenite and rinkite. Neues Jahrbuch für Mineralogie Monatshefte, pp.496-506, 2000.
, Kochite, a new member of the rosenbuschite group from the Werner Bjerge alkaline complex, East Greenland, European Journal of Mineralogy, vol.15, issue.3, pp.551-554, 2003.
DOI : 10.1127/0935-1221/2003/0015-0551
, CRYSTAL CHEMISTRY OF THE ROSENBUSCHITE GROUP, The Canadian Mineralogist, vol.41, issue.5, pp.1203-1224, 2003.
DOI : 10.2113/gscanmin.41.5.1203
, Geology and Petrology of the Nordeste Volcanic Complex, Sao Miguel, Azores, Geological Society of America Bulletin, vol.91, issue.12_Part_II, pp.675-680, 1980.
DOI : 10.1130/GSAB-P2-91-2457
, Untersuchung einiger Mineralien aus Kangerdluarsuk in Grönland, Zeitschrift für Kristallographie, vol.9, pp.243-254, 1884.
DOI : 10.1524/zkri.1884.9.1.243
, Volcanic geology and eruption frequency, S???o Miguel, Azores, Bulletin of Volcanology, vol.69, issue.8, pp.602-614, 1990.
DOI : 10.1007/BF00301211
, Geology of three Late Quaternary stratovolcanoes on São Miguel, Azores. United States Geological Survey Bulletin, 1900.
, Nacareniobsite-(Ce), a new mineral species from the Ilímaussaq alkaline complex, South Greenland, and its relation to mosandrite and the rinkite series, Neues Jahrbuch Neues für Mineralogie ? Monatshefte, pp.84-96, 1989.
, PAP " j(??) procedure for improved quantitative microanalysis. Pp. 104?106 in: Microbeam Analysis, 1985.
, Evolutionary stages of crystallization of weakly peralkaline syenites: evidence from ejecta in the plinian deposits of Agua de Pau volcano (São Miguel, Azores Islands) Mineralogical Magazine, pp.749-767, 2003.
, G??tzenite and Combeite, Two New Silicates from the Belgian Congo, Mineralogical Magazine, vol.31, issue.238, pp.503-510, 1957.
DOI : 10.1180/minmag.1957.031.238.01
, A new zirconium mineral, seidozerite, and other minerals of the wöhlerite group in alkaline pegmatites, pp.590-597, 1958.
, From structure topology to chemical composition. I. Structural hierarchy and stereochemistry in titanium disilicate minerals. The Canadian Mineralogist, pp.1273-1330, 2006.
, FROM STRUCTURE TOPOLOGY TO CHEMICAL COMPOSITION. XVI. NEW DEVELOPMENTS IN THE CRYSTAL CHEMISTRY AND PREDICTION OF NEW STRUCTURE TOPOLOGIES FOR TITANIUM DISILICATE MINERALS WITH THE TS BLOCK, The Canadian Mineralogist, vol.51, issue.6, pp.861-891, 2013.
DOI : 10.3749/canmin.51.6.861
, FROM STRUCTURE TOPOLOGY TO CHEMICAL COMPOSITION. V. TITANIUM SILICATES: THE CRYSTAL CHEMISTRY OF NACARENIOBSITE-(Ce), The Canadian Mineralogist, vol.46, issue.5, pp.1333-1342, 2008.
DOI : 10.3749/canmin.46.5.1333
, From structure topology to chemical composition. XIV. Titanium silicates: refinement of the crystal structure and revision of the chemical formula of mosandrite, (Ca<SUB>3</SUB><I>REE</I>)[(H<SUB>2</SUB>O)<SUB>2</SUB>Ca<SUB>0.5</SUB>???<SUB>0.5</SUB>]Ti(Si<SUB>2</SUB>O<SUB>7</SUB>)<SUB>2</SUB>(OH)<SUB>2</SUB>(H<SUB>2</SUB>O)<SUB>2</SUB>, a Group-I mineral from the Saga mine, Morje, Porsgrunn, Norway, Ca 3 REE)[(H 2 O) 2 Ca 0.5 ? 0.5 ]Ti(Si 2 O 7 ) 2 (OH) 2 (H 2 O) 2 , a Group-I mineral from the Saga mine, pp.2753-2771, 2013.
DOI : 10.1180/minmag.2013.077.6.05
, Two Plinian-type eruptions in the Azores, Journal of the Geological Society, vol.127, issue.1, pp.17-55, 1970.
DOI : 10.1144/gsjgs.127.1.0017
, Processes and timescales in the evolution of a chemically zoned trachyte: Fogo A, Sao Miguel, Azores, Contributions to Mineralogy and Petrology, vol.7, issue.3, pp.311-328, 1992.
DOI : 10.1007/BF00311194
, International Tables for Crystallography. Volume C: Mathematical, physical and chemical tables, 1992.