Open Session - SWISS GEOSCIENCE MEETINGs

More documents

Recommendations

Info

REFERENCES Keller, J., Zaitsev, A.N., Wiedenmann, D. 2006: Primary magmas at Oldoinyo Lengai: The role of olivine melilitites. Lithos, 91, 150-172. Klaudius, J., Keller, J. 2006: Peralkaline silicate lavas at Oldoinyo Lengai, Tanzania. Lithos, 91. 173-190. Kjarsgaard, B.A., Hamilton, D.L. 1988: Liquid immiscibility and the origin of alkali-poor carbonates. Mineralogical Magazine, 52, 43-55. LeBas, M.J. 1989: Nephelinitic and basanitic rocks. Journal of Petrology, 30, 1299-1331 Wyllie, P.J., Huang, W.L. 1976: Carbonation and melting reactions in the System CaO-MgO-SiO 2 -CO 2 at mantle pressures with geophysical and petrological applications. Contrib. Mineral Petrology, 54, 79-207. 2.21 Adakite-like volcanism in Central Iranian magmatic belt,Isfahan,Iran Noghreyan Moussa*, Khodami Mahnaz**& Davoudian Ali Reza*** * Department of Geology, Faculty of Sciences, Isfahan University, Isfahan, Iran ** Department of Geology, Islamic Azad University, Mahallat Branch,Iran (mahnaz.khodami@gmail.com) *** Department of Natural Resources, Shahrekord University, Shahrekord, Iran The Pliocene to Quaternary calc-alkaline volcanic rocks cover an area in 120 km southeast of Isfahan city. In the classification of the structural units of Iran, this area is a part of Central Iranian magmatic belt or Urumieh-Dokhtar Magmatic Belt which related to subduction between Iranian an Arabian plates. Evidences indicate that two plates contacted with each other in the Oligocene–late Miocene and ended to the active subduction between Iranian and Arabian plates, but magmatic activity didn't stop (Berberian and Berberian, 1981). The studied volcanic rocks are andesite, dacite and minor rhyodacite. The andesite rocks as lava flow contain abundant plagioclase, orthopyroxene, clinopyroxene and opaque oxides, which can be accompanied by amphibole and biotite. The dacites are constituted by plagioclase, orthopyroxene, amphibole, biotite, quartz and opaque oxides. Geochemical studies show these rocks are a medium to high K calc-alkaline suite and meta-aluminous. These rocks have Adakite-like characteristics. Adakites form suites of intermediate to felsic rocks with compositions ranging from andesite to dacite and rhyolite. The models for generation of adakitic rocks include partial melting of young, hot subducting slab that extends down to the amphibolite–eclogite transition zone, partial melting of thickened mafic lower crust (Atherton and Petford, 1993), partial melting of delaminated lower continental crust (Xu et al., 2006) and partial melting of underplated basaltic lower crust. Adakitic magmas are encountered in active continental margins and collision zones .These volcanic rocks are characterized by SiO 2 > 56 wt%, Al 2 O 3 > 15 wt%, high Na 2 O contents (3.5 wt% ,300 ppm), high LILE (>400–3000 ppm) and low HREE contents (Yb < 1.8 ppm, Y < 18 ppm) (Defant and Drummond,1990; Martin, 1999). Primitive mantle normalized multi-element and chondrite-normalized rare earth element patterns in adakites display a characteristic positive Sr peaks and absence of significant Eu anomalies. The studied volcanic rocks have SiO 2 contents higher than 57wt%. The most rock also has a low content of compatible elements such as Ni (6-28ppm) and Cr (34-20.5ppm. Zr is in the range 92-175 ppm while Nb varies from 3.9 to 7.7 ppm. Large ion lithophile elements (LILE), Rb, Ba, Th and especially Pb, show enrichment in these samples. LILE elements, Sr (381-1039 ppm) Ba (446-1283ppm), Th (3.3-26ppm) and Rb (157-37.5 ppm) display a wide range of concentrations. Among the trace elements, They show LILE and LREE enriched normalized multi-element patterns, and negative Nb, Ti, Ta and P. These characteristics are consistent with ratios obtained from subduction related volcanic rocks and in collision setting. Chondrite-normalized REE patterns, display a steep decrease from LREE to HREE without any Eu anomaly. HREE and Y depleted pattern suggest the existence of garnet as a residue in the source. The enrichment of Sr and absence of negative Eu anomalies indicate that the residual source was plagioclase free. The Nb and Ti are strongly depleted in the studied samples, which suggest that the source also has residual Ti bearing phase and amphibole and thus was most probably garnet-amphibolite or amphibole-eclogite.Major, trace element and REE data indicate that these adakite-like rocks may have been produced by partial melting of thickened lower continental crust. It is expected that crustal thickening caused by Arabian–Iranian continental collision. Partial melting resulting from thickened lower crust, with garnet ± amphibole as the residual phase and loss of plagioclase in the source, could form rocks that would have high Sr/Y, La/Yb ratios display clear trends of fractional crystallization. Symposium 2: Mineralogy-Petrology-Geochemistry 3
Symposium 2: Mineralogy-Petrology-Geochemistry Figure1.Geological map of the studied area (Simplified from the geological map of 1:100,000 Kajan) REFERENCES Atherton, M.P., Petford, N. 1993: Generation of sodium-rich magmas from newly underplated basaltic crust. Nature 362, 144–146. Berberian, F. and Berberian, M. 1981: Tectono-plutonic episodes in Iran. In: Gupta, H.K. & Delany, F.M. (Eds.), Zagros, Hindukosh, Himalaya Geodynamic Evolution. American Geophysical Union, Washington DC, 5–32. Martin, H., 1999: Adakitic magmas: modern analogues of Archean granitoids. Lithos 46, 411–429. Varol,E., Temel,A., Gourgaud, A. & Bellon,H. 2007: Early Miocene adakite-like volcanism in the Balkuyumcu region, central Anatolia, Turkey: Petrology and geochemistry. Journal of Asian Earth Sciences 30, 613–628. Xu, W.L., Wang, Q.H., Wang, D.Y., Guo, J.H. & Pei, F.P. 2006: Mesozoic adakitic rocks from the Xuzhou-Suzhou area, eastern China: evidence for partial melting of delaminated lower continental crust. Journal of Asian Earth Science 27, 454–464. 2.22 Age determinations of the Fitz Roy Plutonic Complex, Southern Patagonia (Argentina) Ramírez de Arellano Cristóbal*, Putlitz Benita*, Müntener Othmar*, Cosca Mike* ** *Institut de Minéralogie et Géochimie, Université de Lausanne. Batiment Anthropole CH-1015 Lausanne, Suisse (cristobal.ramirez@unil.ch) ** now at U.S. Geological Survey MS 963 Denver, CO 80225 USA The Fitz Roy plutonic complex belongs to a chain of isolated Miocene plutons in Patagonia, Southern South America, located in an “exotic” position between the active volcanic arc and the Patagonian plateau basalts, in the eastern side of the Magallanes fold and thrust belt. Here, we present field observations, petrological and geochronological data to decipher the igneous history of this complex.
Page 1 and 2:
Abstract Volume 6 th Swiss Geoscien
Page 3 and 4:
2 Plenary Session
Page 5 and 6:
Plenary Session 0. Plenary Session
Page 7 and 8:
6 Plenary Session 3 Annual Opening
Page 9 and 10:
8 Plenary Session Hochwasserschutz
Page 11 and 12:
10 Symposium 1: Structural Geology,
Page 13 and 14:
Page 15 and 16:
Page 17 and 18:
Page 19 and 20:
Page 21 and 22:
Page 23 and 24:
Page 25 and 26:
Page 27 and 28:
Page 29 and 30:
Page 31 and 32:
Page 33 and 34:
Page 35 and 36:
Page 37 and 38:
Page 39 and 40:
Page 41 and 42:
Page 43 and 44: 2 Symposium 1: Structural Geology,
Page 45 and 46: Symposium 1: Structural Geology, Te
Page 55 and 56: Symposium 1: Structural Geology, Te
Page 73 and 74: 2 Symposium 2: Mineralogy-Petrology
Page 75 and 76: Symposium 2: Mineralogy-Petrology-G
Page 81 and 82: 80 Symposium 2: Mineralogy-Petrolog
Page 93: 2 Symposium 2: Mineralogy-Petrology
Page 101 and 102: 100 Symposium 2: Mineralogy-Petrolo
Page 115 and 116: 11 Symposium 3: Palaeontology 3. Pa
Page 117 and 118: 116 Symposium 3: Palaeontology 3.2
Page 119 and 120: 118 Symposium 3: Palaeontology 3.3
Page 121 and 122: 120 Symposium 3: Palaeontology AG 0
Page 123 and 124: 122 Symposium 3: Palaeontology 3. F
Page 125 and 126: 12 Symposium 3: Palaeontology Figur
Page 127 and 128: 126 Symposium 3: Palaeontology Figu
Page 129 and 130: 128 Symposium 3: Palaeontology REFE
Page 131 and 132: 130 Symposium 3: Palaeontology REFE
Page 133 and 134: 132 Symposium 3: Palaeontology Figu
Page 135 and 136: 13 Symposium 3: Palaeontology 3.1 H
Page 137 and 138: 136 Symposium 4: Meteorology and cl
Page 139 and 140: 138 Symposium 4: Meteorology and cl
Page 141 and 142: 1 0 Symposium 4: Meteorology and cl
Page 143 and 144: 1 2 Symposium 4: Meteorology and cl
Page 145 and 146:
1 Symposium 4: Meteorology and clim
Page 147 and 148:
1 6 Symposium 5: Quaternary Researc
Page 149 and 150:
Page 151 and 152:
Page 153 and 154:
Page 155 and 156:
1 Symposium 5: Quaternary Research
Page 157 and 158:
Page 159 and 160:
Page 161 and 162:
160 Symposium 5: Quaternary Researc
Page 163 and 164:
Page 165 and 166:
16 Symposium 5: Quaternary Research
Page 167 and 168:
Page 169 and 170:
Page 171 and 172:
Page 173 and 174:
1 2 Symposium 6: Apply! Snow, ice a
Page 175 and 176:
1 Symposium 6: Apply! Snow, ice and
Page 177 and 178:
Page 179 and 180:
Page 181 and 182:
180 Symposium 6: Apply! Snow, ice a
Page 183 and 184:
Page 185 and 186:
18 Symposium 6: Apply! Snow, ice an
Page 187 and 188:
Page 189 and 190:
Page 191 and 192:
Page 193 and 194:
Page 195 and 196:
1 Symposium 6: Apply! Snow, ice and
Page 197 and 198:
Page 199 and 200:
Page 201 and 202:
Page 203 and 204:
Page 205 and 206:
20 Symposium 6: Apply! Snow, ice an
Page 207 and 208:
Page 209 and 210:
Page 211 and 212:
210 Symposium 7: Geofluids and rela
Page 213 and 214:
Page 215 and 216:
21 Symposium 7: Geofluids and relat
Page 217 and 218:
Page 219 and 220:
Page 221 and 222:
Page 223 and 224:
Page 225 and 226:
22 Symposium 7: Geofluids and relat
Page 227 and 228:
Page 229 and 230:
Page 231 and 232:
230 Symposium 8: Building Stones -
Page 233 and 234:
Page 235 and 236:
23 Symposium 8: Building Stones - a
Page 237 and 238:
Page 239 and 240:
Page 241 and 242:
2 0 Symposium 9: Natural Hazards an
Page 243 and 244:
Page 245 and 246:
2 Symposium 9: Natural Hazards and
Page 247 and 248:
Page 249 and 250:
Page 251 and 252:
Page 253 and 254:
Page 255 and 256:
Page 257 and 258:
Page 259 and 260:
Page 261 and 262:
260 Symposium 9: Natural Hazards an
Page 263 and 264:
Page 265 and 266:
Page 267 and 268:
Page 269 and 270:
Page 271 and 272:
Page 273 and 274:
2 2 Symposium 10: Anthropogenic imp
Page 275 and 276:
2 Symposium 10: Anthropogenic impac
Page 277 and 278:
Page 279 and 280:
Page 281 and 282:
280 Symposium 10: Anthropogenic imp
Page 283 and 284:
282 Symposium 10: Anthropogenic imp
Page 285 and 286:
28 Symposium 11: Social Aspects of
Page 287 and 288:
Page 289 and 290:
Page 291 and 292:
2 0 Symposium 11: Social Aspects of
Page 293 and 294:
2 2 Symposium 11: Social Aspects of
Page 295 and 296:
2 Symposium 11: Social Aspects of W
Page 297 and 298:
2 6 Symposium 12: Data acquisition,
Page 299 and 300:
2 8 Symposium 12: Data acquisition,
Page 301 and 302:
300 Symposium 12: Data acquisition,
Page 303 and 304:
Page 305 and 306:
Page 307 and 308:
Page 309 and 310:
Page 311 and 312:
Page 313 and 314:
Page 315 and 316:
Page 317 and 318:
Page 319 and 320:
Page 321 and 322:
Page 323 and 324:
Page 325 and 326:
Page 327 and 328:
Page 329 and 330:
328 Symposium 13: Global change - l
Page 331 and 332:
Page 333 and 334:
Page 335 and 336:
33 Symposium 13: Global change - le
Page 337 and 338:
Page 339 and 340:
Page 341 and 342:
3 0 Symposium 14: Deep Earth - From
Page 343 and 344:
Page 345 and 346:
3 Symposium 14: Deep Earth - From C
Page 347 and 348:
Page 349 and 350:
3 8 INDEX Index A Abbühl L. 156, 1
Page 351 and 352:
3 0 INDEX I Ibele T. 30, 46 Iberg A
Page 353 and 354:
3 2 INDEX Stampfli G.M. 7, 48, 346
show all

Open Session - SWISS GEOSCIENCE MEETINGs

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

Delete template?

Save as template?