The Piedemonte Llanero Basin is located on the eastern side of the Eastern Cordillera of the Colombian Andes. It has been the subject of numerous geological studies carried out for the oil sector, mainly. This study presents the coal-petrographical features of 15 coal seams of four geological formations from Late Cretaceous to Middle Miocene (Chipaque formation, Palmichal group, Arcillas del Limbo formation, and San Fernando formation). Analysis of 33 samples indicates enrichment in vitrinite, while liptinite and inertinite concentrations vary according to the stratigraphic position. Reflectance indicates that the coal range gradually decreases from highly volatile bituminous C (Chipaque formation) to subbituminous C (San Fernando formation). The microlithotypes with the highest concentrations are clarite and vitrinertoliptite. Maceral composition and coal facies indicate changes in the depositional conditions of the sequence. The precursor peat from Late Cretaceous to Late Paleocene accumulated under limnic conditions followed by telmatic in Late Eocene–Early Miocene. The coal facies indices show wet conditions in forest swamps with variations in the flooding surface, influxes of brackish water and good tissue preservation. The tectonic conditions along the Piedemonte Llanero basin is evident, from post-rift to foreland basin, evidenced by oxic and anoxic periods reflected in the maceral composition and its morphology. The coal environment corresponds to an estuarine system started in the Chipaque formation evolving to the lacustrine conditions in the San Fernando formation.

Piedemonte Llanero盆地位于哥伦比亚安第斯山脉东山脉的东部。它主要是针对石油部门进行的众多地质研究的主题。这项研究提出了从白垩纪晚期到中新世中期（Chipaque组，Palmichal组，Arcillas del Limbo组和San Fernando组）的四个地质构造的15个煤层的煤岩特征。对33个样品的分析表明，镜质体中富集，而锂质体和惰质体的浓度根据地层位置而变化。反射率表明，煤的分布范围从高挥发性的沥青C（Chipaque地层）到亚沥青C（San Fernando地层）逐渐减小。浓度最高的微石型为clarite和vitrinertoliptite。宏观组成和煤相表明该层序沉积条件的变化。在白垩纪条件下，从白垩纪晚期到新世晚期的泥炭先堆积，然后在始新世末期-早中新世进行了遥测。煤相指数显示出森林沼泽中的潮湿状况，洪水表面有所变化，咸水涌入，组织得到良好保存。从裂谷后到前陆盆地，皮埃德蒙泰·拉内罗盆地沿岸的构造条件是明显的，这反映在黄石成分及其形态上反映的有氧和无氧时期。煤炭环境对应于奇帕克地层中开始的河口系统，并演变为圣费尔南多地层中的湖相条件。在白垩纪条件下，从白垩纪晚期到新世晚期的泥炭先堆积，然后在始新世末期-早中新世进行了遥测。煤相指数显示出森林沼泽中的潮湿状况，洪水表面有所变化，咸水涌入，组织得到良好保存。从裂谷后到前陆盆地，皮埃德蒙泰·拉内罗盆地沿岸的构造条件是明显的，这反映在宏观组成和形态上反映出的有氧和无氧时期。煤炭环境对应于奇帕克地层中开始的河口系统，并演变为圣费尔南多地层中的湖相条件。在白垩纪条件下，从白垩纪晚期到新世晚期的泥炭先堆积，然后在始新世末期-早中新世进行了遥测。煤相指数显示出森林沼泽中的潮湿状况，洪水表面有所变化，咸水涌入，组织得到良好保存。从裂谷后到前陆盆地，皮埃德蒙泰·拉内罗盆地沿岸的构造条件是明显的，这反映在黄石成分及其形态上反映的有氧和无氧时期。煤炭环境对应于奇帕克地层中开始的河口系统，并演变为圣费尔南多地层中的湖相条件。煤相指数显示出森林沼泽中的潮湿状况，洪水表面有所变化，咸水涌入，组织得到良好保存。从裂谷后到前陆盆地，皮埃德蒙泰·拉内罗盆地沿岸的构造条件是明显的，这反映在黄石成分及其形态上反映的有氧和无氧时期。煤炭环境对应于奇帕克地层中开始的河口系统，并演变为圣费尔南多地层中的湖相条件。煤相指数显示出森林沼泽中的潮湿状况，洪水表面有所变化，咸水涌入，组织得到良好保存。从裂谷后到前陆盆地，皮埃德蒙泰·拉内罗盆地沿岸的构造条件是明显的，这反映在黄石成分及其形态上反映的有氧和无氧时期。煤炭环境对应于奇帕克地层中开始的河口系统，并演变为圣费尔南多地层中的湖相条件。