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DOI | 10.1016/j.epsl.2005.12.039 |
Paleomagnetism of Early Cambrian Itabaiana mafic dikes (NE Brazil) and the final assembly of Gondwana | |
Trindade, RIF; D’Agrella, MS; Epof, I; Neves, BBB | |
通讯作者 | Trindade, RIF |
来源期刊 | EARTH AND PLANETARY SCIENCE LETTERS
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ISSN | 0012-821X |
EISSN | 1385-013X |
出版年 | 2006 |
卷号 | 244期号:1-2页码:361-377 |
英文摘要 | Paleomagnetic analysis on 15 early Cambrian mafic dikes from Itabaiana (Paraiba State) yielded a southern (northwestern) direction with steep upward (downward) inclination (D-m = 167.5 degrees, I-m =-63.7 degrees, alpha 95=7.3 degrees). AF and Thermal demagnetization, thermomagnetic curves, and hysteresis results suggest that this component is dominantly carried by fine-grained SD magnetite. The high stability of this component and positive baked contact tests on three dikes indicate it represents a primary thermoremanent magnetization. Ar-Ar analysis on whole-rock samples from two sites provides a strong constraint on the age of the Itabaiana paleomagnetic pole (134.6 degrees E, 34.9 degrees S; A(95) = 7.3, K=28) defined by plateau ages of 525 +/- 5 and 526 +/- 4 Ma. This pole completely satisfies six out of the seven quality criteria proposed by Van der Voo [R. Van der Voo, The reliability of paleomagnetic data, Tectonophysics 184 (1990) 1-9] and permits a tight constraint on the Early Cambrian sector of the Gondwana apparent polar wander path. Paleogeographic reconstructions consistent with the available paleomagnetic and geological record show that Gondwana was sutured along three major orogenies, the Mozambique (Brasilano/Pan-African) Orogeny (800-650 Ma), the Kuunga Orogeny (570-530 Ma) and the Pampean-Araguaia Orogeny (540-520 Ma). We suggest that after rifting away from Laurentia at the end of the Neoproterozoic, opening the Iapetus ocean, the Amazonian craton and minor adjoining blocks, such as Rio Apa and Pampia, collided with the proto-Gondwana by Cambrian times at ca. 530-520 Ma. Unless for small adjustments, Gondwana was completely formed by 525 Ma whose paleogeography is defined by the Itabaiana pole. (c) 2006 Elsevier B.V. All rights reserved. |
英文关键词 | Gondwana Cambrian Neoproterozoic paleomagnetism paleogeography |
类型 | Article |
语种 | 英语 |
国家 | Brazil |
收录类别 | SCI-E |
WOS记录号 | WOS:000236991300025 |
WOS关键词 | SKINNER COVE VOLCANICS ; NTONYA RING STRUCTURE ; SAO-FRANCISCO CRATON ; BELT SE-BRAZIL ; WESTERN NEWFOUNDLAND ; BRASILIA BELT ; PRECORDILLERA TERRANE ; BORBOREMA PROVINCE ; SOUTHERN BRAZIL ; EASTERN DESERT |
WOS类目 | Geochemistry & Geophysics |
WOS研究方向 | Geochemistry & Geophysics |
资源类型 | 期刊论文 |
条目标识符 | http://119.78.100.177/qdio/handle/2XILL650/151189 |
作者单位 | (1)Univ Sao Paulo, Dept Geofis, Inst Astron Geofis & Ciencias Atmosfer, BR-05508090 Sao Paulo, Brazil;(2)Univ Sao Paulo, Inst Geociencias, Dept Mineral & Geotecn, BR-05508090 Sao Paulo, Brazil |
推荐引用方式 GB/T 7714 | Trindade, RIF,D’Agrella, MS,Epof, I,et al. Paleomagnetism of Early Cambrian Itabaiana mafic dikes (NE Brazil) and the final assembly of Gondwana[J],2006,244(1-2):361-377. |
APA | Trindade, RIF,D’Agrella, MS,Epof, I,&Neves, BBB.(2006).Paleomagnetism of Early Cambrian Itabaiana mafic dikes (NE Brazil) and the final assembly of Gondwana.EARTH AND PLANETARY SCIENCE LETTERS,244(1-2),361-377. |
MLA | Trindade, RIF,et al."Paleomagnetism of Early Cambrian Itabaiana mafic dikes (NE Brazil) and the final assembly of Gondwana".EARTH AND PLANETARY SCIENCE LETTERS 244.1-2(2006):361-377. |
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