Inventario y estudio de las deformaciones sin sedimentarias de las formaciones miocénicas del flanco oriental norte de la Cuidad de Loja y su relación con la paleotectónica

Abstract

Abstract: The study conducted in the San Cayetano formation, located on the northern Eastern flank of the Loja Basin, focused on characterizing tectono-sedimentary facies through field observations and laboratory analysis. Profiles and columns were surveyed across transects, revealing diverse sedimentary sequences that help understand different facies within the formation. Transects 1 and 2 showed absence of disturbances and were located at the top of the tectono- sedimentary facies. In contrast, transects 3, 4, and 5 exhibited deformed sedimentary structures such as slumps, laminar stratification, and convolute bedding. Four distinct sedimentary facies were identified: conglomerates (A), sandstones (D), gray and white shales (F), and dolomites (R) with white shales (S). The tectono-sedimentary facies specifically correspond to dolomites with intercalations of shales, located in the middle part of the San Cayetano Formation. Microfossils of the Agglutinated Foraminifera Trochamina family were observed, indicative of a deep marine environment down to 1.80 meters, as well as fossil remains of fish like Carrionellus Diumortuus, characteristic of shallow marine environments up to 100 meters deep. The disturbances identified in the sequences, such as slumps and convolute bedding, suggest the occurrence of tectonic events possibly related to the uplift of a deformed platform.