Evolution and drowning of the late cretaceous Venezuelan carbonate platform

Tectonomagmatic setting and provenance of the Santa Marta Schists, northern Colombia: Insights on the growth and approach of Cretaceous Caribbean oceanic terranes to the South American continent

“…Stratigraphical constrains have shown that contemporaneously to the growth of this Cretaceous arc, the adjacent continental basin in the southeastern Santa Marta Massif was characterized by tectonic quiescence until the Maastrichian (Martinez and Hernandez, 1992;Villamil, 1999). Therefore the protoliths of the Cretaceous volcanics of the Santa Marta Province must have been formed outside of their current position (Fig.…”

U/Pb detrital zircon provenance from late cretaceous metamorphic units of the Guajira Peninsula, Colombia: Tectonic implications on the collision between the Caribbean arc and the South American margin

“…The passive margin environment that characterized the northern South American margin during Cretaceous times (Martinez and Hernandez, 1992) indicates that the Late Cretaceous input came from the allocthonous Caribbean arc.…”

Factors influencing organic carbon and trace metal accumulation in the Upper Cretaceous La Luna Formation of the western Maracaibo Basin, Venezuela

“…The La Luna is overlain in the ALP-6 core by a regionally recognized, phosphatic and glauconitic hardground marking the base of the Colón Formation (Tres Esquinas Member). Martinez and Hernandez (1992) suggest that maximum water depths of 600 m were reached during deposition of this hardground.…”

“…Iron-sulfur dynamics for La Luna strata indicate abundant sulfide in early diagenetic pore waters. Although many authors infer an euxinic benthic environment for the La Luna with sulfide present in the water column (Mongenot et al, 1996;Martinez and Hernandez, 1992;Macellari and DeVries, 1987), scattered horizons with discontinuous lamination and occasional bivalve fragments indicate at least brief episodes of benthic oxygenation. Contents of Mn in ancient sediments can be used in some settings to reconstruct temporal variations in the oxygenation of seawater Force and Cannon, 1988;Pratt et al, 1990;Dickens and Owen, 1994).…”

“…2). Shallow-water carbonate sedimentation on the Maracaibo Platform ended in late Albian time when a eustatic transgression allowed a regionally thick sequence of black shale interbedded with limestone and chert to accumulate in the La Luna Formation and equivalent units (Martinez and Hernandez, 1992;Tribovillard et al, 1991). Elevated contents of organic carbon (often greater than 5 wt.%) and the occurrence of siliceous and phosphatic facies in Colombia and Venezuela are cited as sedimentary evidence of intermittently strong upwelling during the Cenomanian through Santonian time (Macellari and DeVries, 1987).…”