Early Gondwanan connection for the Argentine Precordillera terrane
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- 作者：Finney ; Stan ; Gleason ; James ; Gehrels ; George ; Peralta ; Silvio ; Aceñ ; olaza ; Guillermo
- 关键词：Argentina ; Precordillera ; paleogeography ; geochronology ; Cambrian ; Ordovician
- 刊名：Earth and Planetary Science Letters
- 出版年：2003
- 出版时间：January 10, 2003
- 年：2003
- 卷：205
- 期：3-4
- 页码：349-359
- 全文大小：461 K
文摘
The Precordillera of Argentina is widely accepted as an exotic terrane of Laurentian (North American) affinity. Newly acquired U/Pb ages on individual detrital zircons from Lower Cambrian and Upper Ordovician quartz sandstone beds in the Argentine Precordillera indicate a Gondwanan provenance not associated with any known part of Laurentia. Accordingly, the Precordillera terrane is likely underlain by basement rock of Gondwanan affinity. In addition, detrital zircons from the Upper Ordovician sandstone bed provide no evidence for a Mid Ordovician position against the inboard Famatina arc. These results demand critical re-evaluation of widely held assumptions regarding the paleogeography of the Argentine Precordillera.