Características faciales y ambientes de depositación identificadas a partir de un levantamiento estratigráfico a escala 1:100 de la Formación La Luna en el río Riecito, sector la Azufrada, municipio de Sardinata, Norte de Santander.

Abstract

In the stratigraphic section of the La Luna Formation in the Riecito River, municipality of Sardinata, Norte de Santander, a survey was carried out using the open polygonal method at a scale of 1:500 and a swabbing method at a scale of 1:100. 102 poles equivalent to 153 m were surveyed and 151 rock samples were taken in situ, recognizing the Cogollo Formation is recognized towards the base at 2.74 m with lithologies of shales, arenites and tormentites which is in concordant contact with the La Luna Formation. The La Luna Formation is subdivided into 40 segments that from base to top correspond to the La Aguada Member, of which 16.5 m were lifted, including 12. 7 m of covered, represented by layers of chert, calcareous shales and biomicritic limestones with concretions of approximately 40 cm, on this one rests the Chejendé Member, of which 13.5 m were lifted, represented by shales, calcareous siltstones, micritic, biomicritic and biosparitic limestones with concretions that go from 10 cm to 1.2 m. Overlying, there is the Timbetes Member, of which 99.1 m were surveyed, including 50.4 m of covered by layers of chert, micritic limestones, biomicritic, biosparitic (tormentites) and calcareous shales, with concretions ranging from 15 cm to 1.2 m towards the top. Finally, 19.5 m of the Ftanita de Táchira Member was uplifted, represented by chert layers with biomicritic limestones, biosparitic limestones (tormentites) and sporadic layers of shales and siltstones. In the upper part is the Colón-Mito Juan Formation with 1.8 m in concordant contact with the La Luna Formation composed of litharenites, tormentites and shales. In addition, phosphoric levels are evidenced at the top of the Chejendé Member and along the Timbetes and Ftanita de Táchira Members. Finally, a depositional model that evidences the eustatic changes in a continental platform is proposed, which shows a transition from shallow levels in the first two members to deep sea levels in the last members.