Unraveling the record of a tropical continental Cretaceous-Paleogene boundary in northern Colombia, South America
de la Parra, F.; Jaramillo, C.; Kaskes, P.; Goderis, S.; Claeys, P.; Villasante-Marcos, V.; Bayona, G.; Hatsukawa, Y.; Caballero, D. (2022). Unraveling the record of a tropical continental Cretaceous-Paleogene boundary in northern Colombia, South America. J. South Am. Earth Sci. 114: 103717. https://dx.doi.org/10.1016/j.jsames.2022.103717 In: Journal of South American Earth Sciences. Elsevier: Oxford; New York; . ISSN 0895-9811; e-ISSN 1873-0647, more |  |
| Keywords | Marine/Coastal; Terrestrial | | Author keywords | Mass extinction; Chicxulub impact; Meteorite; Cretaceous; Cenozoic; Neotropics; Palynology; Iridium; Paleogene |
| Authors | | Top | - de la Parra, F.
- Jaramillo, C.
- Kaskes, P., more
| - Goderis, S., more
- Claeys, P., more
- Villasante-Marcos, V.
| - Bayona, G.
- Hatsukawa, Y.
- Caballero, D.
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| Abstract | The Cretaceous-Paleogene (K-Pg) boundary event, triggered by the Chicxulub asteroid impact in Mexico ∼66 Myr ago, is recognized as one of the major environmental crises in Earth's history. Its effects on the evolution of tropical vegetation were drastic, giving rise to the closed-canopy tropical rainforest. Despite of its importance, the actual K-Pg boundary event layer has not yet been identified in terrestrial sections within tropical latitudes. Here, we study a sediment core (Diablito-1) from northern Colombia and described its lithofacies, palynostratigraphic content, magnetic susceptibility and geochemical composition, including the concentration of key elements linked to a meteoritic contribution such as iridium. We found an 8.2 cm-thick (0.27 inches) interval with gravel-size calcareous intraclasts, broken skeletal fragments and siliceous spherules that were transported during a short-duration high-energy event into the coastal plain. Very fine-to medium-grained spherules, concentrated in several layers of the flow structure, could be interpreted as derived from the K-Pg impact event. This thin intraclastic packstone interval lies within the extinction level of the palynomorph Echimonocolpites franciscoi, an important biostratigraphic event associated with the K-Pg boundary in Colombia. In addition, this layer is associated with both a small iridium anomaly and high concentration of several other major and trace elements that are occurring above a low Magnetic Susceptibility (MS) interval and within the initial phase of a high MS interval. These lines of evidence support the position of the K-Pg event layer within the thin interval that includes the spherules in the Diablito-1 core. |
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