The present work integrates petrographic studies (textural and compositional), and analysis of heavy minerals in order to contribute to the origin of the Mugrosa Formation in the Fortuna sector, which is located in the Middle Magdalena Valley basin. The compositional results of eight thin sections show high level of maturity, evidenced by the high percentage of quartz. The textural analysis shows grain sizes predominantly medium to fine-sand, and sub-rounded clasts, confirming the results from compositional analysis. The lithic fragments are predominantly volcanic and sedimentary; most of them are not well preserved. The analysis of heavy minerals showed predominance of ultra-stable mineral species (zircon, tourmaline, and rutile), and rounded zircons; on the other hand, the presence of muscovite and hornblende suggests different possible sources for these rocks. According to our results, we propose a main sediment source from the Eastern Cordillera due to reworking of underlying sedimentary formations, the presence of minerals such as hornblende and muscovite may suggest that the Cordillera Central (in a lesser extent) has also contributed as a source of the Mugrosa Formation.


  • Betancurt-Betancurt, Ronald; Jimenez-Mejía, José Luis; Palmera-Henao, Tania S. Marín-Cerón, Maria Isabel