720 Index
Elastic behavior, 185, 186f
El Chichón (Mexico) volcano, 84
Elutriation, 272
Emplacement
ash flows, 272
ophiolite, 377, 592–7
plutons, 210, 231–9
See also Inclusions, mafic rock in
granitoids
Endogenous lava dome, 255, 258f
Endothermic reactions, 54
Energy
activation, 11, 56f, 67–9
budget of Earth, 9–10
chemical potential, 60–1
definition of, 2–3
forms of, 2–3, 52
Gibbs free energy, 55–8, 56f
gravitational potential, 3, 11, 52
interfacial, intergrain, 131–3, 141–2
kinetic, 3, 272
law of conservation of, 3, 53
partial molar free energy (chemical
potential), 60–1
sinks in Earth, 9
sources in Earth, 9–10
surface free, 131–2, 134
thermal, 3
See also Heat
transformation of, 3
work and, 3
Enriched mantle, 43, 291, 306–7, 353–4
Enstatite
chemical composition, 657t
incongruent melting of, 97
relation to silica activity and silica saturation,
63–4
Enthalpy, 53–4
Entropy, 54–5
Epiclasts, epiclastic fabric and processes, 167,
232f, 278–9
Epitaxial growth, 413f, 452
Equigranular texture, 156, 160f
Equilibration
grain boundary, 162f, 162–3, 524–6
in metamorphic rocks, 404–5
Equilibrium 11
assessing state of in a rock, 117, 474–5
boundary line in phase diagram, 88
constant, 62–3, 485, 505, 514–15
crystallization of magma, 95–7, 104f
local, in metamorphic system, 474, 505
variance in states of, 88
See also Crystal-melt equilibria and
Reaction(s)
Eruption, see Volcanic eruption
Eskola, P., 437, 461, 572
Etendeka (Africa) flood plateau, 371f
Ethiopia, 367t, 393, 394f
Eu anomaly, 40, 43f, 651, 653
Euhedral crystals, 132, 151f, 158, 159f
Eutaxitic fabric, 171, 172f, 275
Eutectic, 91–2
Exothermic reaction, 54
Explosion, volcanic and explosive volcanism,
see Volcanic eruption
Exsolution
in mineral grains, 103f, 105f, 162, 528
of volatiles from melts, 79–83, 165–8,
259–60
Extensional
fractures and fracturing, 185f
basalt diking related to, 220–2
as expression of brittle behavior, 187
tectonic regime and magma ascent, 221
Extrusion of magma, 27, 241–6
effusive lava, 242–58
explosive, 80–3, 242–3, 259–77
Fabric, general
anisotropic, 159f, 171–81
contrast between magmatic and
metamorphic, 413, 448
definition, 14
heteromorphs, 148
isotropic, 174
See also Texture, and specific types, e.g.
eutaxitic; porphyroblastic
Fabric, magmatic, 148–81
caution in interpreting, 163–4
grain boundary modification in, 140–2,
162–3
grain shape in, 158–60
of layered intrusions, 331–7
of pegmatites, 324–5
of silicic effusions, 256–7
Fabric, metamorphic, 411–23, 429, 442f, 443f,
447–55
as basis for classification of rocks, 455–63
grain boundary modification in, 411
imposed, 410–22, 447–55, 520–61
relict 408, 410f, 412f, 420f, 424f, 429f
scale invariance in, 417f
shear sense indicators, 551, 553f, 553
tectonite, 414–24, 448–52, 528–61
expression of, 448
geometric pattern, 537, 554–5
penetrative aspect of, 448
postkinematic, 548, 550f
preferred grain and lattice orientation,
555–60
prekinematic, 547
role of fluids in development of, 545
synkinematic, 547–8, 549f
timing of deformation and
recrystallization, 545–53
Fabric, volcaniclastic, 166–73, 260–79
Faulting, brittle behavior and, 187–8
Feathery crystals, 136–8, 151f, 158, 626f
Feedback (thermomechanical), 191, 284
Feldspar
chemical composition, 658t
crystal-melt equilibria, 100–12
density, 195f
ductile strength, 190f
in common magmatic rocks, 22f
rapakivi, 160f
ternary, 100, 104–9
trace elements in, 23t, 41t
zoning in, 103f, 139f, 161f
Felsic rocks, 28
Felsitic texture, 153–5, 166f
Felty texture, 153–5, 154f
Fenite, 397, 465
Fenner, C. N., 325
Ferromagnesian, 28
See also Mafic rocks and minerals
Ferruginous, 426
Ferry, J. M., 498
Fiamme, 172f
Fibrolite, 477
Fick’s laws of diffusion, 127–8
Field relations, 13, 210, 241, 441
classification of magmatic rocks based on,
27–8
of plutonic (intrusive) rocks, 210–39
of volcanic rocks, 241–80
Fiji Islands, 340f, 373t
Filter pressing in magma, 321–2
Fissure eruption, 242, 245f
Flaser texture, 454
Flood basalt plateaus, 366–7, 371f
Flow
aa lava, 248, 250f
ash, 271–2
block, 249
channeled lava, 192–3
cooling unit of pyroclastic, 272–3, 275f
crystal markers and magma, 177f
ductile, see Ductile, deformation
fabric of silicic lava, 256–7
laminar, 192–3
lava, 245–58
layering, 150f, 176–7, 178f
of liquid in granular aggregates, 294
of magma, 191–4
markers in magmatic rock, 176, 177f
mobility of pyroclastic, 272
pahoehoe lava, 245–8
porous, of liquids, 294
pumice, 271–2
pyroclastic, 262, 263f, 270–1
sequence in, 272f
subaqueous, 277
rheomorphic, 275
turbulent, 192–3
viscous, 123f, 186, 190–4
volcanic debris, see Lahar
Flowage segregation, 321
Fluid(s), volatile
ambient (in metamorphic rocks), 495
changing composition driving mineral
reactions, 497
composition in mixed-volatile reactions,
495–8
in crust, 488–91
definition, 75, 491
flow in metamorphic systems
driving force, 503
evidence for, 498–500
mechanisms, 500–4
grain-boundary (porous), 294, 295, 489, 491,
495, 501, 509–11, 521–2, 530, 545
inclusions, 489, 491, 503, 602, 645
in magma systems, 75–85
mixed H
2
O–CO
2
, 493–500, 502f, 513
pressure, 75–6, 489–91
reactions involving, 475, 488–501, 504–5,
509–11
release in prograde reactions, 489, 490f, 545
to rock ratio, 497
separation (exsolution) from melt, 324–5
solubility in melts, 77–9
specific volume (reciprocal density), 75
Fluidization, 272
Foliation, 174f
basis of classification of metamorphic rocks,
455–63
compaction, 275
expressions of, 174–6, 449f