Onset of fault reactivation in the Eastern Cordillera of Colombia and proximal Llanos Basin; response to Caribbean-South American convergence in early Palaeogene time
Onset of fault reactivation in the Eastern Cordillera of Colombia and proximal Llanos Basin; response to Caribbean-South American convergence in early Palaeogene time
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DOI：
10.1144/sp377.5
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发表时间：
2013-01-01
期刊：
影响因子：
--
通讯作者：
Valencia, Victor
中科院分区：
文献类型：
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作者：
Bayona, German;Cardona, Agustin;Valencia, Victor
北方安第斯山脉中生代伸展构造的反转控制了晚马斯特里赫特期以来同造山序列的位置和碎屑的扩散。我们的研究结果得到了详细的地质填图，综合物源（岩相学，重矿物，地质年代学）分析和年代地层对比（孢粉学和地质年代学数据）的13个地区的古近纪地层横跨中部的东科迪勒拉。沉积速率和物源数据的空间和时间变化表明，驱动边缘和板内隆起和构造沉降的机制在同造山沉积中心之间存在差异。在马斯特里赫特晚期-古新世中期，中科迪勒拉的地壳倾斜有利于前伸展白垩纪盆地西部边界的反向复活。重新活动的断层的上盘将两个沉积中心分开：西部沉积中心（在马格达莱纳山谷）和东部沉积中心（目前沿着东科迪勒拉山脉、利亚诺斯山麓和利亚诺斯盆地的轴向地带）。在古新世晚期-始新世早期，加勒比板块向东俯冲，板内岩浆活动向东推进，旧构造的复活向东迁移到利亚诺斯盆地，破坏了东部沉积中心。在始新世早期，这三个沉积中心被两个低幅度隆起分开，主要暴露白垩纪沉积盖层。从向东倾斜的中央科迪勒拉提供的同造山碎屑沉积物到达东科迪勒拉的轴向域的地区，而不稳定的变质和沉积碎片记录在最东部的沉积中心提供的基底核心隆起与白垩纪和古生代沉积盖在南Llanos盆地报告。这种低幅度隆起分离板内同造山沉积中心和板内岩浆活动在古新世的构造配置主要是由加勒比板块俯冲控制。
The inversion of Mesozoic extensional structures in the Northern Andes has controlled the location of syn-orogenic successions and the dispersal of detritus since latest Maastrichtian time. Our results are supported by detailed geological mapping, integrated provenance (petrography, heavy minerals, geochronology) analysis and chronostratigraphical correlation (palynological and geochronology data) of 13 areas with Palaeogene strata across the central segment of the Eastern Cordillera. Spatial and temporal variation of sedimentation rates and provenance data indicate that mechanisms driving the location of marginal and intraplate uplifts and tectonic subsidence vary among syn-orogenic depocentres. In the late Maastrichtian-mid-Palaeocene time, crustal tilting of the Central Cordillera favoured reverse reactivation of the western border of the former extensional Cretaceous basin. The hanging wall of the reactivated fault separated two depocentres: a western depocentre (in the Magdalena Valley) and an eastern depocentre (presently along the axial zone of the Eastern Cordillera, Llanos foothills and Llanos Basin). In late Palaeocene-early Eocene time, as eastern subduction of the Caribbean Plate and intraplate magmatics advanced eastwards, reactivation of older structures migrated eastwards up to the Llanos Basin and disrupted the eastern depocentre. In early Eocene time, these three depocentres were separated by two low-amplitude uplifts that exposed dominantly Cretaceous sedimentary cover. Synorogenic detrital sediments supplied from the eastwards-tilted Central Cordillera reached areas of the axial domain of the Eastern Cordillera, whereas unstable metamorphic and sedimentary fragments recorded in the easternmost depocentre were supplied by basement-cored uplifts with Cretaceous and Palaeozoic sedimentary cover reported in the southern Llanos Basin. This tectonic configuration of low-amplitude uplifts separating intraplate syn-orogenic depocentres and intraplate magmatic activity in Palaeocene time was primary controlled by subduction of the Caribbean Plate.