Experimental evidence on the substitution of Ti in biotite Jtincnr
Various Ti substitutions in biotite were tested by hydrothermal syntheses of Fe and Mg biotites over the range of 600-800 'C at I 000-bars pressure and at the oxidation conditions of the methane-graphite buffer. Yields of greater than 950/o biotite were obtained in a few experiments, but complete syntheses were generally not possible. Microprobe analyses of the run products indicate that (l) the Ti-Tschermak's substitution (Ti + 2Al: R'z* + 2Si) can be the dominant Ti substitution in both Fe and Mg biotites; (2) the Ti-vacancy substitution (Ti + 16r! : 2Rr*) can occur as the dominant Ti substitution in Mg biotite and in conjunction with other substitutions in Fe biotite; and (3) the experimental data do not support, but cannot rule out, the Ti-oxy substitution (Ti + ZO': R2+ + 2OH-). Specific substitution types appear to be governed by bulk composition and by the crystal-chemical constraints of the biotite structure.
Limitations on the interpretation of biotite substitutions from chemical analyses of natural samples
Biotites, as well as other phases, are sufficiently complex chemically that there are numerous sets of linearly independent exchange components with which to describe the composition of a naturally occurring crystal. Even after complete chemical analysis, this leads to ambiguities in the correlation of exchange components with valid substitution mechanisms in complex phases. The best means of identifuing valid substitutions are by the observation of simple endmember compositions, the investigation of compositional changes in zoned crystals or petrogenetic sequences, and by direct experimental synthesis.
Subject index
Adoptive immunotherapy A1, A63, A63, A64, A64, A65, A66, A68, A69, A69, A70, A70, A71, A71, A72, A72, A73, A73, A74, A75, A76, A78, A79, A79, A7, A80, A80, A81, A81, A82, A84, A85, A86, A86, A88, A88, A89, A90, A90, A91, A92, A93, A93, A94, A95, A95, A96, A96, A97, A97, A98, A98, A99, A99, A102, A103, A104, A104, A166, A167, A169, A170, A174, A177, A179, A181, A182, A199, A204, A205, A21, A215, A220, A231, A231, A243, A251, A254, A25, A276, A287, A304, A307, A310, A315, A316, A316, A329, A331, A333, A357, A358, A369, A405, A441, A442, A458, A458, A459, A459, A461, A461, A463, A468, A468, A479, A492, A497, A497, A56, A58, A58, A59, A60, A60, A61, 1, 100, 101, 102, 103, 104, 106, 109, 111, 112, 113, 114, 115, 116, 117, 119, 120, 122, 123, 124, 125, 127, 128, 129, 13, 130, 131, 133, 134, 136, 139, 140, 141, 142, 146, 147, 148, 149, 150, 152, 153, 154, 155, 156, 157, 158, 159, 160, 161, 163, 164, 165, 166, 167, 169, 173, 174, 175, 272, 273, 278, 280, 285, 290, 293, 297, 298, 324, 333, 335, 35, 353, 360, 379, 380, 400, 414, 418, 42, 454, 470, 493, 500, 504, 513, 515, 516, 542, 545, 549, 598, 599, 614, 675, 737, 739, 764, 765, 766, 767, 770, 771, 772, 780, 781, 801, 822, 830, 831, 89, 91, 92, 94, 95, 96, 98 Angiogenesis A108, A155, A171, A200, A201, A214, A228, A265, A305, A349, A350, A359, A410, A47, A48, A480, A483, A519, A5, 181, 257, 281, 327, 328, 351, 374, 435, 495, 583, 584, 602, 683, 76, 78, 802, 808, 873, 9 Antibody A7, A73, A81, A86, A91, A8, A99, A9, A104, A108, A108, A109, A109, A111, A115, A119, A126, A128, A130, A135, A138, A141, A144, A151, A153, A159, A160, A163, A164, A164, A171, A172, A175, A176, A2, A187, A193, A193, A195, A195, A198, A199, A20, A209, A212, A225, A229, A230, A23, A233, A233, A235, A239, A239, A240, A242, A244, A244, A245, A245, A246, A247, A247, A24, A250, A256, A260, A261, A266, A267, A268, A269, A273, A275, A286, A288, A292, A293, A296, A299, A300, A307, A3, A308, A31, A318, A324, A35, A334, A334, A336, A338, A339, A342, A343, A344, A344, A346, A346, A351, A351, A353, A356, A360, A361, A363, A368, A369, A370, A371, A372, A372, A373, A374, A376, A377, A378, A378, A379, A379, A380, A380, A388, A391, A399, A399, A41, A402, A410, A410, A411, A412, A414, A417, A418, A419, A419, A420, A422, A422, A423, A426, A427, A428, A428, A430, A431, A432, A434, A434, A435, A446, A454, A455, A459, A463, A465, A468, A468, A469, A474, A481, A483, A50, A486, A487, A491, A502, A502, A504, A507, A507, A508, A510, A511, A512, A512, A516, 12, 122, 133, 141, 151, 16, 167, 17, 174, 181, 182, 184, 185, 188, 195, 203, 210, 215, 218, 227, 231, 237, 243, 250, 253, 261, 262, 265, 267, 268, 281, 282, 287, 288, 3, 305, 313, 315, 317, 318, 323, 325, 34, 342, 348, 369, 377, 378, 38, 384, 385, 387, 393, 394, 395, 399, 401, 402, 403, 404, 405, 406, 407, 41, 412, 421, 428, 429, 438, 439, 442, 443, 450, 453, 469, 472, 476, 478, 480, 483, 486, 499, 5, 501, 51, 519, 531, 55, 550, 552, 557, 561, 562, 569, 571, 572, 573, 576, 578, 586, 587, 590, 594, 603, 605, 607, 612, 615, 616, 617, 618, 619, 621, 622, 626, 629, 630, 631, 632, 633, 634, 635, 647, 653, 665, 666, 67, 670, 683, 684, 686, 687, 690, 693, 696, 697, 698, 699, 702, 703, 704, 711, 713, 714, 715, 718, 721, 722, 725, 726, 727, 745, 757, 760, 766, 772, 776, 780, 781, 785, 793, 804, 808, 81, 812, 814, 820, 842, 843, 846, 851, 852, 853, 856, 858, 860, 861, 869 Antigen presenting cells A67, A79, A80, A92, A95, A96, A99, A99, A101, A102, A102, A108, A108, A111, A129, A139, A160, A166, A177, A178, A183, A191, A191, A213, A220, A221, A245, A254, A256, A262, A266, A275, A314, A322, A327, A328, A35, A335, A345, A359, A359, A360, A361, A364, A366, A368, A369, A371, A372, A403, A409, A411, A411, A418, A422, A433, A449, A48, A468, A471, A472, A4, A50, A495, A502, A506, A513, A514, A515, 108, 128, 130, 153, 157, 160, 166, 167, 168, 169, 170, 181, 182, 188, 217, 235, 263, 271, 290, 291, 299, 310, 311, 349, 360, 362, 404, 418, 421, 431, 438, 453, 510, 526, 538, 540, 55, 553, 575, 601, 602, 603, 605, 610, 611, 612, 615, 617, 618, 672, 682, 685, 686, 695, 703, 724, 748, 78, 780, 787, 790, 8, 81, 828, 842, 849, 862, 864, 868 Autoimmunity A8, A116, A15, A180, A181, A22, A380, A387, A394, A395, A402, A408, A502, A510, 16, 197, 27, 295, 296, 37, 637, 645, 657, 658, 671, 680, 843, 856