LA QUINTA FORMATION IN LA GUAJIRA, COLOMBIA: TECTONICS, STRATIGRAPHY AND SEDIMENTATION OF MESOZOIC ROCKS

The Triassic- Jurassic periods at the Guajira, Northeastern Colombia, are represented by a sequence of layers of basic volcanic rock type basalt intercalated with very fine grained of conglomeratic strata, good to poor sorting, compact, and reddish up to violet/purple color sedimentary rocks deposited along transitional areas, named La Quinta Formation. Over this sequence is easy to find an unconformity of Cretaceous limestone with very low dip. Remnants of erosion are present such as Pelao’s Mountain (Cerro Pelao). In some areas, the leftovers of erosion are establishing the border of Colombia and Venezuela. Some volcanic flows are forming pillow flows. Finally, basic intrusive rocks are cutting the sequence of volcano-sedimentary layers as Upper part of the Jurassic.

The sequence is broken by the longest faults disturbing both volcanic and sedimentary rocks. For example, the great fault Santa Marta- Bucaramanga, which move up Paleozoic rocks as limit of synrift basin. Also, the Tigre or Perija Fault, along the South America`s continental margin at that time and the Suarez Fault as well.

Ostensibly, La Quinta Formation and the Giron Group were deposited in a similar transitional environment at the Northwestern margin limit of the South America Plate. The authors of this paper had worked together on Perija Ridge in La Guajira- National University of Colombia and the United Nations- IAN, Zapatoca Program in Santander in 1979-1980.

In conclusion, all main Triassic- Jurassic outcrops in Colombian of La Quinta Formation are along La Guajira and Cesar administrative departments at the Northeastern of Colombia. They are faulted and folded forming a clearer synrift to the West than other Mesozoic areas in Colombia. Similar conditions in Venezuela along Eastern Perija ridge.