Lirio Norte (Las Cascadas Fm), Panama
| Fundort: | Lirio Norte (Las Cascadas Fm), Panama, Panama, Panama | |
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| Taxon: | Panamacebus transitus aus der Familie Cebidae | |
| Fossilien und Beschreibung der Fundstelle: | ||
| Macrofossils, The Las Cascadas Formation is overlain by the Culebra Formation and separated from it by a slightly angular unconformity (Montes et al., 2012). The overlaying volcaniclastic sequence is composed of the marine transgressive system of the Culebra Formation and the prograding sequence of the Cucaracha Formation (Kirby et al., 2008). Despite the abundance of volcanic material, efforts to date these rocks have been unsuccessful and the geochronology available for the section is restricted to Strontium (Sr87/Sr86) chemostratigraphy (Kirby et al., 2008) on calcareous biogenic shells and corals. Therefore, the upper Las Cascadas fossiliferous sequence represents an interval older than the lower part of the Culebra Formation, for which several dates have been published between 20.62 ± 0.58 and 23.07 ± 0.53 Ma (Kirby et al., 2008) and 19.3 ± 0.4 Ma (Montes et al., 2012). The lower boundary of the Las Cascadas Formation could be constrained by andesitic water-saturated arc lavas of the underlying Bas Obispo Formation dated using Ar40/Ar39 age as 25.37 ± 0.13 Ma (Rooney et al., 2010; Farris et al., 2011). Therefore, the duration of the Las Cascadas Formation might span the late Oligocene to early Miocene (<25 Ma to >19.3 ± 0.4 Ma), likely representing the middle-to-late Arikareean NALMA sensu MacFadden and Hunt (1998) and Albright et al. (2008)., The Las Cascadas Formation is composed of andesitic flows and agglomeratic tuffs with cobbles of andesite and basalt set in a fine-grained tuffaceous matrix (Montes et al., 2012), which constitutes the main lithology associated with the vertebrate fossils. The structural complexity of the area, as well as the limited and ephemeral outcrops along the canal, restrict the exposures of the Las Cascadas fossiliferous interval to the northern part of the Gaillard Cut, where volcaniclastic sequences are more common and paleosols are well developed. The lower part of the Las Cascadas Formation is characterized by massive accumulations of volcanic rocks (mainly agglomerated breccias) and fluvial sediments. Conversely, the upper part of the Las Cascadas Formation is characterized by massive accumulations of volcanic blocks ranging from welded tuffaceus agglomerates to pyroclastic fall deposits and discr intervals of fluvial sediments (Woodring, 1982; Kirby et al., 2008). | ||
| Geschätztes Alter der Fundstelle: |
zwischen 20,43 und 30,8 Millionen Jahre aus der Las Cascadas Formation in Panama | |
| Geologie, Sratigraphie | Rupelian, Chattian, Aquitanian, Burdigalian / Arikareean / Las Cascadas | |
| Koordinaten: | 9° 3 ' 34 '' N, 79° 39 ' 54 '' W | |
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Die Daten sowie die folgende Systematik stammen aus der Paleobiology Database, Lizenz
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LiteraturJ. I. Bloch, E. D. Woodruff, A. R. Wood, A. F. Rincon, A. R. Harrington, G. S. Morgan, D. A. Foster, C. Montes, C A. Jarmillo, N. A. Jud, D. S. Jones, B. J. MacFadden 2016, First North American fossil monkey and early Miocene tropical biotic interchange. Nature. 533, p. 243 - 246, DOI: 10.1038/nature17415 |
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Systematik |