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Shortening and exhumation of Sierra de Catorce in northeastern Mexico, in light of 40Ar/39Ar illite dating and (U-Th)/He zircon thermochronology
Journal of South American Earth Sciences ( IF 1.8 ) Pub Date : 2021-06-17 , DOI: 10.1016/j.jsames.2021.103334
Rodrigo Gutiérrez-Navarro , Elisa Fitz-Díaz , José Rafael Barboza-Gudiño , Daniel F. Stockli

The Sierra de Catorce along the eastern margin of the Mesa Central in central northern Mexico exposes Triassic to Neogene rocks in two deeply incised canyons in the northern portion of the range, permitting a 3D view of structures and mineral fabrics associated with the Mexican Orogen. Triassic siliciclastic units, recording a penetrative deformation, are unconformably covered by less-deformed Jurassic volcaniclastic and fluvial deposits and Upper Jurassic shale and limestone. The shales acted as a regional décollement horizon, facilitating Late Cretaceous and Early Cenozoic thin-skinned shortening, related to the Sierra Madre Oriental fold and thrust belt, and accommodating translation of Cretaceous carbonate in the hanging wall. The post-tectonic Cenozoic cover consists of alluvial deposits and remnants of basaltic flows and cinder cones. The Sierra de Catorce allows for an opportunity to study the structural, temporal, and thermal evolution of internal portions of the Sierra Madre Oriental fold and thrust belt, employing geometric and kinematic structural analysis, optical and Scanning Electronic Microscopy fabric characterization, X-Ray diffraction of clays, 40Ar-39Ar illite dating, and zircon (U–Th)/He dating. Structural cross-cutting relationships point to at least three distinct Late Cretaceous-Paleogene shortening episodes, with the first being associated with initial thrust activity to the area and a second one characterized by intense shortening deformation, while a third and final episode of shortening deformation is only observed on a kilometric scale. 40Ar-39Ar illite ages from bed-parallel sheared layers and décollement zone suggest that after shortening within the Triassic units, bed-parallel shear was localized within Cretaceous carbonate ~91 Ma. Intense shearing occurred along a major décollement horizon within Upper Jurassic calcareous shale at ~69 Ma, resulting in the folding of Cretaceous strata in the hanging wall. Finally, illite 40Ar-39Ar ages recorded late folding of Upper Cretaceous turbidites at ~52 Ma, accompanied by a rapid exhumation, as evidenced by ~50 Ma zircon-He ages. This multiphase history of contractional deformation records the growth and propagation of the internal portion of the orogenic wedge of the Mexican Fold-Thrust belt (MFTB).



中文翻译:

根据40 Ar/ 39 Ar 伊利石测年和 (U-Th)/He 锆石热年代学,墨西哥东北部的 Sierra de Catorce 的缩短和折返

位于墨西哥北部中部 Mesa Central 东部边缘的 Sierra de Catorce 在该山脉北部的两个深切峡谷中暴露了三叠纪至新近系岩石,从而可以 3D 视图查看与墨西哥造山带相关的结构和矿物结构。三叠系硅质碎屑单元记录了穿透变形,被变形较小的侏罗系火山碎屑和河流沉积物以及上侏罗统页岩和石灰岩不整合地覆盖。充当区域的页岩滑脱地层,促进晚白垩世和早新生代薄皮缩短,与马德雷山脉东方褶皱和逆冲带有关,并适应白垩纪碳酸盐在上盘的平移。构造后新生代覆盖层由冲积沉积物和玄武岩流和煤渣锥的残余物组成。Sierra de Catorce 利用几何和运动学结构分析、光学和扫描电子显微镜织物表征、X 射线衍射,为研究 Sierra Madre 东方褶皱和冲断带内部部分的结构、时间和热演化提供了机会粘土,40 Ar- 39Ar 伊利石测年和锆石 (U–Th)/He 测年。结构横切关系指向至少三个不同的晚白垩世-古近纪缩短事件,第一个与该地区的初始逆冲活动有关,第二个以强烈的缩短变形为特征,而第三个也是最后一个缩短变形事件是仅在公里范围内观察到。40 Ar- 39 Ar 伊利石年龄从平行床剪切层和下降带表明,在三叠纪单元内缩短后,床平行剪切位于白垩纪碳酸盐约91 Ma。沿着主要的肩部发生了强烈的剪切上侏罗统钙质页岩内的地平线在~69 Ma,导致上盘白垩纪地层的折叠。最后,伊利石40 Ar- 39 Ar 年龄记录了上白垩统浊积岩在~52 Ma 的晚期折叠,伴随着快速的折返,如~50 Ma 锆石-He 年龄所证明的那样。这种收缩变形的多阶段历史记录了墨西哥褶皱逆冲带 (MFTB) 造山楔内部的生长和传播。

更新日期:2021-07-08
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