SEDIMENTOLOGY OF THE JORDAN FORMATION (GIRON GROUP) MESOZOIC ROCKS IN COLOMBIA, SOUTH AMERICA

The Giron Group was deposited in a transitional environment at the Northwestern of the South America Plate during the late Jurassic and early Triassic; the main outcrops are along the East Andian ridge and its derivation Perija ridge through several departments such as La Guajira, Cesar, Santander, Boyacá, Cundinamarca and Tolima, from North to South in Colombia. Also, equivalent sediments were deposited in similar conditions at the Eastern area of the Zulia & Tachira States in the west part of Venezuela named La Quinta Formation. The basal part of both, Jordan Formation (Santander in Colombia) and La Quinta Formation (Cesar y La Guajira in Colombia; also, Zulia and Tachira in Venezuela) contain intercalations of volcanic rocks at the bottom of these sedimentary formations; also, minerals with high mobility such as radioactive.

The ultimate objective of the paper is to compare and contrast geological aspects and characteristics such as sediments, chemical composition, precedence, and more of those formations in Colombia and Venezuela to The Newark Group in the Eastern area of the United States along Florida (FL), Georgia GA), New York (NY), New Jersey (NJ), and Virginia (VA). Their similar appearance in their color, special red and greenish, is amazing. It is necessary to compare based on chemical analysis.

Preliminary field investigations involved exposing Jordan Formation (Giron Group) sediments in terms of provenance, depositional environments, and development of the Mesozoic synrift sedimentary basins in Columbia through X-Ray Fluorescence analysis. Identified sedimentary rocks were arkoses, red mudstone, varieties of sandstone, siltstone and breccias. Among the notable primary sedimentary structures were cross beddings and ripple marks. Representative samples were evaluated for trace elements and variable concentrations of U, were noted in these samples. Basin development began during the early Mesozoic and was dominated by a synrift sedimentary succession. Deposition of synrift sedimentary succession was primarily linked with the separation of North and South America in the proto-Caribbean.