DOI: 10.1016/j.tecto.2020.228386
论文题名: Paleogeographic and tectonic evolution of the Pampia Terrane in the Cambrian: New paleomagnetic constraints
作者: Franceschinis P.R. ; Rapalini A.E. ; Escayola M.P. ; Rodríguez Piceda C.
刊名: Tectonophysics
ISSN: 00401951
出版年: 2020
卷: 779 语种: 英语
中文关键词: Campanario Formation
; Gondwana
; Pampia Terrane
; Puncoviscana Formation
英文关键词: Geomagnetism
; Lithology
; Campanario Formation
; Clockwise rotation
; Gondwana
; Paleomagnetic data
; Paleomagnetic poles
; Pampia Terrane
; Puncoviscana Formation
; Tectonic evolution
; Tectonics
; Rosita
英文摘要: Paleomagnetic, magnetic fabric and rock magnetic studies were carried out in the late Middle to early Late Cambrian Campanario Formation exposed in NW Argentina. The study also presents preliminary results from the Early Cambrian metasediments of the Puncoviscana Formation and from Mojotoro intrusive. A new paleomagnetic pole, C2, was computed for the Campanario Formation (23.6°N, 346.5°E, A95, 7.0°, N: 11 sites) from the localities of Tilcara (T), Terma de Reyes (R) and El Perchel (EP), including previous data from Santa Victoria Oeste (M), in northernmost Argentina. A positive fold test was obtained for Tilcara locality while a positive regional tilt test was obtained for mean site directions for the four localities. This pole can be considered as the representative pole position for the Pampia terrane for the late Middle to Late Cambrian. Previous paleomagnetic data for the same formation from the Iruya-Matancillas locality show an in situ clockwise rotation of about 30° around a vertical axis when compared with the mean Pampia pole. The same is observed when comparing the early Ordovician pole for the Santa Rosita Formation at those localities with the recently obtained coeval pole of the La Pedrera Formation, indicating that local tectonic rotations, affected that area. These results suggest that previous paleomagnetic interpretations for these Late Cambrian and Early Ordovician rocks in the region as recording displacement of the Pampia terrane in Cambrian times are probably incorrect. Additionally, two virtual geomagnetic poles were computed for the Puncoviscana Formation (TP1: 34.5°N, 52.3°E, A95: 5.0°, n: 22 specimens and TP2: 38.3°N, 33.6°E, A95: 5.7°, n: 14 specimens) and one for the Mojotoro Intrusive (MO: 9.1°N, 345.6°E, A95: 16.4°, n: 11 specimens). These and previous Early Cambrian paleomagnetic data from the Pampia terrane differ from Gondwana coeval reference directions in inclination and/or declination, lacking a simple pattern. © 2020 Elsevier B.V. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/170587
Appears in Collections: 气候变化与战略
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作者单位: Universidad de Buenos Aires, Laboratorio de Paleomagnetismo Daniel A. Valencio, Instituto de Geociencias Básicas, Aplicadas y Ambientales de Buenos Aires (IGEBA), Departamento de Ciencias Geológicas, Facultad de Ciencias Exactas y Naturales, Argentina; CONICET, Argentina; ICPA-Universidad Nacional de Tierra del FuegoAntártida e Islas del Atlántico Sur, Argentina; Institut für Geowissenschaften, Universität Potsdam, Potsdam, Germany; GFZ – German Research Center for Geosciences, Potsdam, Germany
Recommended Citation:
Franceschinis P.R.,Rapalini A.E.,Escayola M.P.,et al. Paleogeographic and tectonic evolution of the Pampia Terrane in the Cambrian: New paleomagnetic constraints[J]. Tectonophysics,2020-01-01,779