Paleoenvironmental conditions over the Caribbean Large Igneous Province during the Late Cretaceous in NW of South American Margin: A sedimentological and ichnological approach

The Late Cretaceous in northwest South America was a period marked by synchronous regional geological processes (e.g., accretion of oceanic terranes, arc magmatism, sea-level fluctuations, oceano-graphic dynamics), related to the interaction of the Caribbean Large Igneous Province (CLIP) with the NW margin of South America. This synchroneity makes it difficult to reconstruct the complex geological evolution of this region. In Colombia, Upper Cretaceous marine sedimentary and low-grade metamorphic rocks are commonly exposed in both the Western Cordillera and the Sind-San Jacinto Basin in the Pacific and Caribbean regions respectively. Significant deformation and structural complexity are the main limiting factors for sedimentological and paleontological studies of these deposits. Detailed sedimentological and ichnological analyses were carried out in eight sections, two in the Caribbean region and six in the Pacific region. The Caribbean sections are composed of limestones, mudrocks, siliceous and calcareous mudrocks, and cherts, associated with pelagic and hemipelagic de-posits (E2.2 and G2.1 facies). The Pacific sections are characterized by two facies associations, one composed of mudrocks, limestones, as well as chert associated with pelagic and hemipelagic deposits (E2.2 and G2.1 facies) and the other of interlayered siliceous mudrocks and sandstones associated with turbiditic systems (C2 facies). Upper Cretaceous deposits in both regions are characterized by relatively low to moderate abundant and diverse trace fossils assemblages, consisting of Chondrites, Planolites, and Zoophycos in the Caribbean region and Chondrites, ?Nereites, Phycodes, Phycosiphon, Planolites, Thalassi-noides, and Zoophycos in the Pacific region, assigned to the Zoophycos ichnofacies. Sedimentological and ichnological features suggest deposition in deep-marine environments characterized by pelagic, hemi-pelagic, and turbiditic sedimentation. Integrated with the biostratigraphical framework, this allows us to establish a regional correlation between both regions. High nutrient supply, poor oxygenation, and low hydrodynamic energy and sedimentation rates interrupted by episodic increases associated with tur-biditic deposits are main paleoenvironmental factors controlling the sedimentation over the CLIP during Late Cretaceous.(c) 2022 Elsevier Ltd. All rights reserved.

Automated summary

The Late Cretaceous in northwest South America was characterized by synchronous regional geological processes, and this study focuses on the interaction between the Caribbean Large Igneous Province and the NW margin of South America. The sedimentation in the region is mainly influenced by marine processes and turbiditic deposits.