The present-day structure of the Eastern Cordillera in NW Argentina is governed by structural and lithological heterogeneities inherited from preceding deformation phases, which influence the localization of newly-formed faults and the inversion of pre-existing structures. The Salta Rift Basin formed during a Late Jurassic-Cretaceous extensional phase and created a dominant structural and stratigraphic imprint in NW Argentina that is particularly evident within the Eastern Cordillera, where uplift and exhumation have exposed the Salta Group syn-rift succession. Although in general, the Salta Group rests upon Paleozoic rocks, locally the Tacurú Group forms an intermediate succession, consisting of interfingering eolian sandstones and proximal fault-related conglomerates with a Jurassic maximum depositional age. This succession might be the key to unraveling the Mesozoic history of NW Argentina, prior to the deposition of the Salta Group. The conglomerates represent the earliest deposits related to extension in the western Lomas de Olmedo sub-basin, which is also documented in predominantly Jurassic zircon (U–Th-Sm)/He cooling ages of the rift shoulders. The detrital zircon U–Pb age signature and sandstone provenance of the Tacurú Group conglomerates differs strongly from the Salta Group syn-rift strata, which show a more regional signal. These variations and the angularity of the unconformity may be connected to a rotation of the extension direction in the western Lomas de Olmedo sub-basin.

中文翻译：

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阿根廷西北部侏罗纪伸展的证据：利用砂岩物源和锆石 U-Pb 地质年代学表征萨尔塔群基底的断层相关地层

阿根廷西北部东部科迪勒拉山脉的现今结构受先前变形阶段继承的结构和岩性异质性控制，这些异质性影响新形成断层的定位和先前存在结构的反转。萨尔塔裂谷盆地形成于晚侏罗世-白垩纪伸展阶段，在阿根廷西北部形成了主要的构造和地层印记，这一点在东部科迪勒拉山脉尤为明显，那里的隆起和折返暴露了萨尔塔群同裂谷序列。虽然萨尔塔群总体上以古生代岩石为基础，但局部地区塔库鲁群形成了中间层序，由交错的风成砂岩和近端断层相关砾岩组成，最大沉积年龄为侏罗纪。这种演替可能是解开萨尔塔群沉积之前阿根廷西北部中生代历史的关键。这些砾岩代表了与洛马斯德奥尔梅多次盆地西部扩张有关的最早沉积物，裂肩的主要侏罗纪锆石（U-Th-Sm）/He冷却年龄也记录了这一点。 Tacurú 群砾岩的碎屑锆石 U-Pb 年龄特征和砂岩物源与 Salta 群同裂谷地层有很大不同，后者显示出更多的区域信号。这些变化和不整合面的角度可能与洛马斯德奥尔梅多次盆地西部延伸方向的旋转有关。