Zircon U-Pb ages of the Chiapas Amber-Lagerstätte in the uppermost Simojovel Formation, southwest Mexico
Por:
Riquelme, F, Ortega-Flores, B, Estrada-Ruiz, E, Córdova-Tabares, V
Publicada:
1 jun 2025
Ahead of Print:
1 mar 2025
Resumen:
The Chiapas Amber-Lagerst & auml;tte is a fossil preservation site in southern Mexico, consisting of three central localities: Simojovel, Totolapa, and Estrella de Bel & eacute;n. It is a repository that preserves a diverse range of estuarine-associated biota. These include but are not limited to arboreal, aerial, land-dwelling, soil-based, amphibiotic, aquatic, and microbial organisms. The age and stratigraphy of the amber-bearing beds near Simojovel have been interpreted differently. The amber outcrops were initially considered part of the late Oligocene to Early Miocene La Quinta Formation. Further studies identified several outcrops as part of the Early Miocene Mazantic Shale and the Middle Miocene Balumtum Sandstone. We present the zircon U-Pb dating results conducted on the amber-bearing beds in the uppermost section of the Simojovel Formation. The data indicate a maximum depositional age of 24 +/- 1 Ma, corresponding to the uppermost late Oligocene. A limited section of the amber deposit in Totolapa is likely contemporary with the lowermost Early Miocene, ca. 20 Ma. Hence, the amber biota is constrained to the uppermost late Oligocene and the lowermost Early Miocene (ca. 24-20 Ma). Our data also suggest that the sedimentary environment of the upper strata oscillates from estuary to shallow shelf. It is characterized by low-energy zones with a constant influx of terrigenous sediments consisting of siltstone and fine-grained sandstone, with gastropods, bivalves, coral fragments, trace fossils, plant remains, lignite, and amber.
Filiaciones:
Riquelme, F:
Univ Autonoma Estado de Morelos, EESDELJ, Lab Sistemat Mol, Jojutla 62909, Morelos, Mexico
Univ Autonoma Estado Morelos, Doctorado Ciencias Nat, Cuernavaca 62209, Morelos, Mexico
Ortega-Flores, B:
Univ Nacl Autonoma Mexico, Inst Geociencias, Juriquilla 76230, Queretaro, Mexico
Estrada-Ruiz, E:
Escuela Nacl Ciencias Biol, Inst Politecn Nacl, Dept Zool, Mexico City 11340, Mexico
Córdova-Tabares, V:
Univ Autonoma Estado Morelos, Doctorado Ciencias Nat, Cuernavaca 62209, Morelos, Mexico
|