U-Pb zircon constraints on the age and provenance of the Rocas Verdes basin fill, Tierra del Fuego, Argentina
U-Pb zircon constraints on the age and provenance of the Rocas Verdes basin fill, Tierra del Fuego, Argentina
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DOI：
10.1029/2009gc002749
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发表时间：
2009-12-01
影响因子：
3.5
通讯作者：
Gehrels, George E.
中科院分区：
文献类型：
--
作者：
Barbeau, David L., Jr.;Gombosi, David J.;Gehrels, George E.
晚侏罗世至早白垩世的罗卡斯韦尔德斯盆地是安第斯山脉最南端最鲜为人知的组成部分之一。因此，对与安第斯造山有关的变形的准确重建和解释以及Scotia弧形发展的运动学也仍然很差。在这份数据简报中，我们报告了来自Rocas Verdes盆地充填砂岩和阿根廷火地岛最南端安第斯山脉横切岩体的锆石U-Pb年龄。碎屑岩样品中含有中白垩世早期至早期(约130-105 Ma)的主要锆石U-Pb年龄组，中生代和元古界也有极少量或单颗粒的锆石年龄组。在一个样本中，晚白垩世时代的一个非常小的亚群提出了一种不太可能的可能性，即罗卡斯韦尔德斯盆地的部分地区比人们想象的更年轻。横切正长伟晶岩的结晶年龄为74.7±2.2/-2.0 Ma。本文提供的数据有助于对Rocas Verdes盆地进行进一步的地质年代学评估，以便更好地限制其内容物的沉积年龄和来源。
The Late Jurassic to Early Cretaceous Rocas Verdes basin constitutes one of the most poorly understood components of the southernmost Andes. As a result, accurate reconstructions and interpretations of deformation associated with the Andean orogeny and the kinematics of Scotia arc development also remain poorly constrained. In this data brief, we report U-Pb zircon ages from sandstones of the Rocas Verdes basin fill and from a crosscutting pluton in the southernmost Andes of Argentine Tierra del Fuego. Detrital samples contain predominant Early to early Middle Cretaceous (circa 130-105 Ma) U-Pb zircon age populations, with very small or single-grain middle Mesozoic and Proterozoic subpopulations. A very small subpopulation of Late Cretaceous ages in one sample raises the unlikely possibility that parts of the Rocas Verdes basin are younger than perceived. A sample from a crosscutting syenitic pegmatite yields a crystallization age of 74.7 + 2.2/-2.0 Ma. The data presented herein encourage further geochronologic evaluation of the Rocas Verdes basin in order to better constrain the depositional ages and provenance of its contents.