in Jurassic and Cretaceous Stratigraphy

More documents

Recommendations

Info

Earth Science Frontiers, Vol. 17, Special Issue, Aug. 2010 ISSN 1005-2321 The Palaeogeographical Evolution of the Iberian Plate during the Jurassic Comparison of Iberian Palaeomagnetic Data with Data from the African, Eurasian and North American plates 268 M.L. Osete 1 , J.J. Gómez 2* , F.J. Pavón-Carrasco 3 , J.J. Villalaín 4 , A. Palencia 5 , V.C. Ruiz-Martínez 5 , F. Heller 6 1. Geofísica, Facultad de Ciencias Físicas. Universidad Complutense, 28040 Madrid, Spain (E-mail: mlosete@fis.ucm.es) 2. Estratigrafía e Instituto de Geología Económica (CSIC-UCM). Facultad de Ciencias Geológicas. Universidad Complutense, 28040 Madrid, Spain (E-mail: jgomez@geo.ucm.es) 3. Geofísica, Facultad de Ciencias Físicas. Universidad Complutense, 28040 Madrid, Spain (E-mail: fjpavon@fis.ucm.es) 4. Física, Universidad de Burgos, 09006 Burgos, Spain (E-mail: villa@ubu.es) 5. Geofísica, Facultad de Ciencias Físicas. Universidad Complutense, 28040 Madrid, Spain (E-mail: ali@fis.ucm.es; vcarlos@fis.ucm.es) 6. Institut für Geophysik, ETH-Hönggerberg, CH-8093 Zürich, Switzerland (E-mail: heller@mag.ig.erdw.ethz.ch) During the Mesozoic, the Iberian microplate occupied a tectonic key position between the African, Eurasian and North American plates and its evolution was related to the movement of these major plates, the opening of the Atlantic and the kinematics of the Tethys. However, the Apparent Polar Wander Path (APWP) of Iberia is still poorly defined and previous attempts to use palaeomagnetic data to test geodynamic models proposed for the Iberian evolution failed, because the reliable palaeomagnetic information was not resolution enough. To investigate the consistency between the palaeomagnetic information and the tectonic models proposed for the western Mediterranean, a revision of Jurassic palaeomagnetic data from Iberia has been carried out. Due to the presence of a widespread (but partial) remagnetization which affected most Jurassic sediments in Iberia, selection criteria have been designed to avoid completely remagnetized sites. A total of 72 sites have been considered for the palaeomagnetic discussion (35 sites from the Messejana– Plasencia dolerite dyke, 14 sedimentary sites from the Iberian Range and 23 sites from the Betic Cordillera). Three palaeopoles for Iberia have been selected (from the Iberian Massif and from the Iberian Range) for the period around 200 Ma (Triassic−Jurassic boundary), the Toarcian–Aalenian and the Oxfordian. Data from the Subbetic Zone (Betic Cordillera) are used to constrain the palaeolatitude of the Iberian microplate. Iberian data are in general agreement with the Besse and Courtillot (2002) Master Curve and the reconstruction parameters used to transfer the Iberian data to Europe. However, lower palaeolatitudes are observed in Iberia for the Late Jurassic. Tectonic reference models for the Western Mediterranean (Stampfli and Borel, 2002, 2004) (SB02) do not fit the Iberian declinations at the Hettangian−Sinemurian nor the Eurasian and African APWPs. Differences in palaeolatitudes have also been observed. New palaeogeographic reconstructions are proposed for the Hettangian–Sinemurian, the Toarcian–Aalenian and the Oxfordian which are in agreement with the new palaeomagnetic information. Differences are observed between the trend of the Iberian palaeolatitude variation during the Jurassic proposed by the SB02 model, the BC02 master curve translate to Iberia and the Iberian palaeomagnetic information. According to the SB02 model and the BC02 curve, Iberia moved towards higher palaeolatitudes from the Hettangian up to the Toarcian (in agreement with the Iberian palaeomagnetic data), and constant palaeolatitudes are proposed for the Toarcian− Oxfordian interval. In contrast, decreasing palaeolatitudes are observed in the Iberian palaeomagnetic data for this time interval. The SB02 model does not fit the Iberian declinations. An angular discrepancy of about 16 has been observed. To fit the new palaeomagnetic information the position of the Iberian plate in the SB02 palaeogeographic reconstructions has been modified. In addition, the Jurassic poles positions considered by SB02 for Europe have been modified according to the most recent palaeomagnetic compilations. Referring to the contradictory published data from the North American Plate, our data from Iberia transferred to the North American plate favours the proposal of a high palaeolatitudinal APW path segment during the Early–Middle Jurassic. It is followed by a swing to low palaeolatitudes by the Latest Jurassic which is not well described in the too smoothed global compilations (e.g. BC02). Key words: Palaeomagnetism; Iberian Plate; Palaeogeographic reconstructions; Western Tethys References: Besse J., Courtillot V. Apparent and true polar wander and the Geometry of the magnetic Field in the last 200 Million Years. Journal of Geophysical
Earth Science Frontiers, Vol. 17, Special Issue, Aug. 2010 ISSN 1005-2321 Research, 2002, 107(6-1): 6-31. Stampfli G.M., Borel G.D. A plate tectonic model for the Paleozoic and Mesozoic constrained by dynamic plate boundaries and restored synthetic ocean isochrones. Earth and Planetary Science Letters, 2002, 196: 17-33. Stampfli G.M., Borel G.D. The TRANSMED Transects in space and time: Constraints on the paleo- tectonic evolution of the Mediterranean Domain. In: Cavazza W., Roure F.M., Spakman W., et al. (ed). The TRANSMED Atlas: The Mediter- ranean Region from Crust to Mantle. New York: Springer Berlin, Heidelberg, 2004: 53-80 and CD- ROM. 269
Page 4 and 5:
THE 8 TH INTERNATIONAL CONGRESS ON
Page 6 and 7:
EARTH SCIENCE FRONTIERS Short paper
Page 8 and 9:
Earth Science Frontiers, Vol. 17, S
Page 10 and 11:
Page 12 and 13:
Page 14 and 15:
Page 16 and 17:
Page 18 and 19:
Page 20 and 21:
Page 22 and 23:
Page 24 and 25:
Page 26 and 27:
Page 28 and 29:
Page 30 and 31:
Page 32 and 33:
Page 34 and 35:
Page 36 and 37:
Page 38 and 39:
Page 40 and 41:
Page 42 and 43:
Page 44 and 45:
Page 46 and 47:
Page 48 and 49:
Page 50 and 51:
Page 52 and 53:
Page 54 and 55:
Page 56 and 57:
Page 58 and 59:
Page 60 and 61:
Page 62 and 63:
Page 64 and 65:
Page 66 and 67:
Page 68 and 69:
Page 70 and 71:
Page 72 and 73:
Page 74 and 75:
Page 76 and 77:
Page 78 and 79:
Page 80 and 81:
Page 82 and 83:
Page 84 and 85:
Page 86 and 87:
Page 88 and 89:
Page 90 and 91:
Page 92 and 93:
Page 94 and 95:
Page 96 and 97:
Page 98 and 99:
Page 100 and 101:
Page 102 and 103:
Page 104 and 105:
Page 106 and 107:
Page 108 and 109:
Page 110 and 111:
Page 112 and 113:
Page 114 and 115:
Page 116 and 117:
Page 118 and 119:
Page 120 and 121:
Page 122 and 123:
Page 124 and 125:
Page 126 and 127:
Page 128 and 129:
Page 130 and 131:
Page 132 and 133:
Page 134 and 135:
Page 136 and 137:
Page 138 and 139:
Page 140 and 141:
Page 142 and 143:
Page 144 and 145:
Page 146 and 147:
Page 148 and 149:
Page 150 and 151:
Page 152 and 153:
Page 154 and 155:
Page 156 and 157:
Page 158 and 159:
Page 160 and 161:
Page 162 and 163:
Page 164 and 165:
Page 166 and 167:
Page 168 and 169:
Page 170 and 171:
Page 172 and 173:
Page 174 and 175:
Page 176 and 177:
Page 178 and 179:
Page 180 and 181:
Page 182 and 183:
Page 184 and 185:
Page 186 and 187:
Page 188 and 189:
Page 190 and 191:
Page 192 and 193:
Page 194 and 195:
Page 196 and 197:
Page 198 and 199:
Page 200 and 201:
Page 202 and 203:
Page 204 and 205:
Page 206 and 207:
Page 208 and 209:
Page 210 and 211:
Page 212 and 213:
Page 214 and 215:
Page 216 and 217:
Page 218 and 219:
Page 220 and 221:
Page 222 and 223:
Page 224 and 225: Earth Science Frontiers, Vol. 17, S
Page 324 and 325:
Page 326 and 327:
Page 328 and 329:
Page 330 and 331:
Page 332 and 333:
Page 334 and 335:
Page 336 and 337:
Page 338 and 339:
Page 340 and 341:
Page 342 and 343:
Page 344 and 345:
Page 346 and 347:
Page 348 and 349:
Page 350 and 351:
Page 352 and 353:
Page 354 and 355:
Page 356 and 357:
Page 358 and 359:
Page 360 and 361:
Page 362 and 363:
Page 364 and 365:
Page 366 and 367:
Page 368 and 369:
Page 370 and 371:
Page 372 and 373:
Page 374 and 375:
Page 376 and 377:
Page 378 and 379:
Page 380 and 381:
Page 382 and 383:
Page 384 and 385:
Page 386 and 387:
Page 388 and 389:
Page 390 and 391:
Page 392 and 393:
Page 394 and 395:
Page 396 and 397:
Page 398 and 399:
Page 400 and 401:
Page 402 and 403:
Page 404 and 405:
Page 406 and 407:
Page 408 and 409:
Page 410 and 411:
Page 412 and 413:
Page 414 and 415:
Page 416 and 417:
410 EARTH SCIENCE FRONTIERS Short P
Page 418 and 419:
P.A. Selden 191 V.I. Katkova 309 P.
show all

in Jurassic and Cretaceous Stratigraphy

Create successful ePaper yourself

Delete template?

Save as template?