TEXTURAL AND MICROANALYSIS OF IGNEOUS ROCKS: TOOLS ...

More documents

Recommendations

Info

which allowed optimization of operating conditions to yield desired sensitivity and sampling depth (< 30 µm). 2.4.3 Choosing partition coefficients (D) Blundy [9] concluded that inversion of magma compositions from mineral data using appropriate D values to be a robust means of estimating parent magma compositions and suggested that D values derived from microbeam techniques were more accurate than those derived from bulk crystal-matrix analyses. Bindeman and Davis [6] noted that D values derived from doping experiments should be used with caution as, for example, the DREE and DY in REE doped runs are 30-100% higher than in undoped runs. Blundy and Wood [10] and Bindeman et al. [7] showed that the dominant factors controlling the trace element Ds for plagioclase are An content and crystallization temperature (pressure effects appeared to be negligible). Bindeman et al. [7] applied this relationship to a wide variety of trace elements and produced values for the constants “a” and “b” in their Equation 2 for calculating plagioclase partition coefficients via the expression: RT ln(Di) = aXAn + b (2.1) where R is the gas constant, T is temperature (Kelvin), and XAn is the mole fraction of anorthite in the plagioclase. Using equation 2.1, Ginibre et al. [59] noted that temperatures in the range of 850-1,000 ◦ C had only a small effect on calculated melt concentrations for Sr and Ba (within their analytical uncertainty). Likewise, Bindeman et al. [7] showed that variations ∼150 ◦ C produce < 10% differences for particular partition coefficients, which were often within error of the respective D values. 37
Figure 2.5. Backscatter electron images of plagioclase phenocrysts from Site 1183 basalts A) A type I normal zoned crystal (63R2P4, Unit 6). Note the brighter, higher An core; B) A type II reverse zoned crystal with a darker, lower An core (64R2P4, Unit 7); C) An olivine-plagioclase glomerocryst (64R2P3, Unit 7). The plagioclase crystal has a sieve textured core; D) A reverse zoned type II crystal that contains numerous melt inclusions (64R2P1). 38
Page 1 and 2: TEXTURAL AND MICROANALYSIS OF IGNEO
Page 3 and 4: TEXTURAL AND MICROANALYSIS OF IGNEO
Page 5 and 6: DEDICATION This work is dedicated t
Page 7 and 8: CHAPTER 2: MAGMA EVOLUTION REVEALED
Page 9 and 10: 3.6.3.1 Crystal Population Origins
Page 11 and 12: FIGURES 1.1 Magma Chambers . . . .
Page 13 and 14: TABLES 2.1 MAJOR AND TRACE ELEMENT
Page 15 and 16: thus been debate within the volcano
Page 17 and 18: Cambrian schist) including a crysta
Page 19 and 20: explosive eruption vs. mild effusiv
Page 21 and 22: tiation (e.g., [84, 98]; Fig. 1.3).
Page 23 and 24: defined as having crystallinities b
Page 25 and 26: 12 Figure 1.4: Large Igneous Provin
Page 27 and 28: distribution of crystal sizes (e.g.
Page 29 and 30: investigating magmatic evolution us
Page 31 and 32: length dispersive spectroscopy(WDS)
Page 33 and 34: microdrilling, a pre-cleaned square
Page 35 and 36: 1.7.2 Detroit Seamount, Part of the
Page 37 and 38: lations. Reprocessing of intrusive
Page 39 and 40: nucleated homogenously and grew thr
Page 41 and 42: With accurate partition coefficient
Page 43 and 44: uniform composition of large volume
Page 45 and 46: Figure 2.2. Hand sample and thin se
Page 47 and 48: 2.3.1 A Cogenetic Relationship Betw
Page 49: Figure 2.4. Stratigraphic section o
Page 53 and 54: studies of Kwaimbaita basalt by San
Page 55 and 56: 42 Crystal Zone An (mol%) TABLE 2.1
Page 57 and 58: 44 Crystal Zone An (mol%) 63R2 phen
Page 63 and 64: along the xenolith margins (e.g., F
Page 65 and 66: are more abundant in phenocrysts fr
Page 67 and 68: 54 Crystal Zone 5 ML-X1 xenolith TA
Page 69 and 70: 56 TABLE 2.2 Continued Crystal Zone
Page 75 and 76: Figure 2.7. Measured major and trac
Page 77 and 78: 2.5.3.2 Trace Elements It is diffic
Page 79 and 80: Figure 2.9. Trace element ratio plo
Page 81 and 82: 2.5.4 Resorption Features in Site 1
Page 83 and 84: should, however, be noted that in t
Page 85 and 86: 2.6.1.2 An-rich OJP Plagioclase: In
Page 87 and 88: equivocally the roles of H2O, press
Page 89 and 90: ent magma requires significant clin
Page 91 and 92: tion driven plumes, or stirring by
Page 93 and 94: Yamashita, [123], and thus did not
Page 95 and 96: erally extensive crystal-mush netwo
Page 97 and 98: asalt at Site 1185 of ODP Leg 192 [
Page 99 and 100: CHAPTER 3 SHALLOW MAGMA EVOLUTION D
Page 101 and 102:
magma compositions [23, 39, 98]. A
Page 103 and 104:
Figure 3.2. Stratigraphy of basalts
Page 105 and 106:
[118]. No volcaniclastic rocks were
Page 107 and 108:
magmatic crystallization. Using the
Page 109 and 110:
Figure 3.3. A cross polarized light
Page 111 and 112:
3.4.5 Major and Trace Element Data
Page 113 and 114:
3.4.6.1 Partition coefficients for
Page 115 and 116:
3.5.1.2 Site 884 CSDs I measured pl
Page 117 and 118:
Figure 3.5. Plagioclase CSDs of ODP
Page 119 and 120:
106 TABLE 3.2 CSD RESULTS Sample OD
Page 121 and 122:
ln (n) [mm -4 ] ln (n) [mm -4 ] 10
Page 123 and 124:
ulation A crystals are unzoned (An6
Page 125 and 126:
Figure 3.8. a) The majority of Site
Page 127 and 128:
3.5.4.3 Site 1203 Unit 31 and Site
Page 129 and 130:
3.5.5 Trace Elements 3.5.5.1 Measur
Page 131 and 132:
Unit 31 > Site 884 Unit 8 (Table 3.
Page 133 and 134:
3.6 Discussion 3.6.1 Evidence of Cr
Page 135 and 136:
3.6.1.1 Site 1203 Alkalic Basalts a
Page 137 and 138:
etween the different crystal popula
Page 139 and 140:
Unit 14 and 31 magmas accumulated o
Page 141 and 142:
sition is similar to parent magmas
Page 143 and 144:
Sr - low La/Ce population A parent
Page 145 and 146:
The Unit 31 plagioclase CSD is kink
Page 147 and 148:
was dominated by late stage clinopy
Page 149 and 150:
pressure, and growth of An-rich pla
Page 151 and 152:
138 TABLE 3.3 PLAGIOCLASE PHENOCRYS
Page 153 and 154:
140 TABLE 3.3 Continued Sample Zone
Page 155 and 156:
Page 157 and 158:
Page 159 and 160:
Page 161 and 162:
Page 163 and 164:
Page 165 and 166:
Page 167 and 168:
Page 169 and 170:
Page 171 and 172:
Page 173 and 174:
Page 175 and 176:
Page 177 and 178:
Page 179 and 180:
Page 181 and 182:
Page 183 and 184:
Page 185 and 186:
Page 187 and 188:
KP has been done via drilling at 11
Page 189 and 190:
and over time crustal wall-rocks be
Page 191 and 192:
flow [33]. I selected a single samp
Page 193 and 194:
4.3.4 Major and Trace Element Data
Page 195 and 196:
B) C) parafilm splash guard A) tape
Page 197 and 198:
of these elements are the better co
Page 199 and 200:
5 mm 5 mm Figure 4.4. Cross polariz
Page 201 and 202:
4.4.2 Electron Probe Microanalysis
Page 203 and 204:
An (mol %) An (mol %) An (mol %) An
Page 205 and 206:
study exhibit their highest An at t
Page 207 and 208:
4.4.3 LA-ICP-MS - Trace Elements An
Page 209 and 210:
87 86 Sr/ SrI = 0.705722(8) Ba/Sr =
Page 211 and 212:
and Rb (Fig. 4.11d,e). 4.4.3.3 Yttr
Page 213 and 214:
Sr (ppm) Y (ppm) La (ppm) Ce (ppm)
Page 215 and 216:
Unit 4 plagioclase rims plagioclase
Page 217 and 218:
204 TABLE 4.4 UNIT 4 PLAGIOCLASE PA
Page 219 and 220:
4.5 Discussion 4.5.0.1 Origin of Ma
Page 221 and 222:
4.5.0.2 Insights from Trace Element
Page 223 and 224:
that other factors influenced the a
Page 225 and 226:
C A/B / D A/B C A/B / D A/B Unit 4
Page 227 and 228:
Magma chambers tend to form at hori
Page 229 and 230:
whole-rock basalt data. Cumulate xe
Page 231 and 232:
over short time spans but may be ea
Page 233 and 234:
lowing initial Elan Bank magma empl
Page 235 and 236:
BIBLIOGRAPHY 1. C. Allegre, A. Prov
Page 237 and 238:
22. B. Charlier, J. Davidson, O. Ba
Page 239 and 240:
46. J. Fitton and M. Godard, Origin
Page 241 and 242:
68. M. Higgins, Measurement of crys
Page 243 and 244:
89. J. Longhi, D. Walker and J. Hay
Page 245 and 246:
100 of Geophysical Monograph, pages
Page 247 and 248:
129. J. Tarduno, W. Sliter, L. Kroe
show all

TEXTURAL AND MICROANALYSIS OF IGNEOUS ROCKS: TOOLS ...

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?