Age of the Guatemala breccias around the Cretaceous-Tertiary boundary: relationships with the asteroid impact on the YucatanL'âge des brèches proches de la limite Crétacé-Tertiaire au Guatemala: relations avec l'impact d'astéroïde du Yucatán

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Abstract

The upper part of the near K/T boundary limestone breccia deposits which crop out in Guatemala near 16 °N contains impact remains: altered glass spherules (tektites) and elevated concentrations of iridium. This suggests that these deposits could result from the impact of the K/T boundary asteroid on the Yucatan. However, their matrix contains foraminifers of the Eugubina Zone and calcareous nannofossils of the CP1a Zone, an association characterizing Early (but not the earliest) Danian. This unusual assemblage of K/T and Danian components suggests that the upper part of the breccia was reworked several thousands of years after the K/T event.

Résumé

La partie supérieure des brèches calcaires proches de la limite K/T, qui affleurent au Guatemala près du 16ème parallèle, contient des restes d'impact: sphérules de verre altérées (tectites) et concentrations d'iridium élevées. Ceci suggère que ces brèches se sont formées à la suite de l'impact de l'astéroïde de la limite K/T sur le Yucatán. Cependant, la matrice de ces dépôts renferme des Foraminifères planctoniques de la zone à Eugubina et des nannofossiles calcaires de la Zone CP1a, qui caractérisent le début (non basal) du Danien. Cet assemblage inhabituel d'éléments K/T et Danien suggère que la partie supérieure des brèches a été remaniée plusieurs milliers d'années après l'événement de la limite K/T.

References (26)

  • HildebrandA.R. et al.

    Chicxulub crater: a possible Cretaceous-Tertiary boundary impact crater on the Yucatan Peninsula, Mexico

    Geology

    (1991)
  • HildebrandA.R. et al.

    Cretaceous-Tertiary boundary deposits in Guatemala: evidence for impact waves and slumping on a platform scale?

  • KellerG. et al.

    Near-K/T age of clastic deposits from Texas to Brazil: impact, volcanism and/or sea-layer low-stand?

    Terra Nova

    (1996)
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      These members were also studied in details using micropalaeontological methods by Fourcade et al. (1999), providing new data on the stratigraphy of the Cretaceous formations in this area, including the identification of the Angostura Formation (upper Campanian–Maastrichtian) composed of limestone with alveolinids and rudists, defined by Sánchez Montes de Oca in 1979 in Mexico and determining the Actelá Formation near the Cretaceous–Paleogene (K–Pg) transition, composed of limestone breccias. The K–Pg has been further investigated by Stinnesbeck et al. (1997), Fourcade et al. (1998), and Keller and Stinnesbeck (2000). According to Fourcade et al. (1999), the Maastrichtian in the South Petén basin, northern Guatemala, is represented by the two formations, depending on the locality: (1) Sepur, represented by deep-water deposits and (2) Angostura, typically containing rudists and large benthic foraminifera.

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